OF SCIEN CE
Transcript of OF SCIEN CE
rillAT TRANSFER AND PRESSURE PROFILES IN THE VICINITY OF ANNULAR OR IFICES
by
PETER STANTON WILLIAMS
A THES I S
submitted to
OREGON STATE COLLEGE
in partial fulfillment of the requirements for the
degree of
MASTER OF SCIEN CE
June 1961
APPROYED I
Redacted for Privacy
Chergc of Xefor
Dorn of frrtdnrtc sohool
Redacted for Privacy
Redacted for Privacy
Redacted for Privacy
Drte thcals 1o pncocntod June 25 1960
ypcd W Jencttc Crane
ACKNOWLEDGMENTS
The author wishes to express his gratitude to
Dr James G Knudsen for his guidance during the course
of this research to the National Science Foundation for
financing the project and to Mr Azimuddin Faruqui and
Mr K Nar ayanan for their help in constructing the
equipment and taking the i n itial data
TABLE OF CONTENTS
Chapter Page
I Introduction bull bull bull bull bull 1
II Theory and Previous Work bull bull 4
III Experimental Apparatus bull 8
Test Section bull bull bull bull bull bull 8 Sen sing Probe Assembly bull bull bull bull 11 Power Source bull bull bull bull bull bull 12 Temperature Measuring bull bull 12 Air Source bull bull bull bull bull bull bull bull bull 15 Pressure Probe bull bull bull bull bull bull bull bull bull 16
IV Experimental Program bull bull bull 17
v Experimental Procedure bull 20
VI Calculation of Experimental Data bull 22
VII Analysis of Data bull bull 27
Variat ion of Heat Transfer Rate with Distance from the Baffle bull bull 27
Rate of Heat Transfer at the Point
Effect of Upstream Baffles on Heat
Heat Transfer in the Test Sect ion
Heat Transfer at the Baff le and Maximum Point as a Function of
Correlation of Data at the Baff le bull 36
of Maximum Heat Trans f er bull bull bull bull 39
Transfer at the Orifice Center bull bull bull 42
with No Orifice bull bull bull bull bull bull bull bull 42 Pressure Drop Data bull bull bull bull bull bull 44
Pressure Drop bull bull bull bull bull bull bull 47
VIII Summary of Re sults 51
IX Re commendations 53
Nomenclature 54
Bibliography bull 56
Append ix 57
LIST OF FIGURES
Figure Page
1 Cross Section of Test Section and Probe bull bull bull bull bull bull bull bull bull bull bull bull 9
2 Experimental Apparatus 10
3 Sensing Probe bull bull bull 13
4 Drawing of Assembled Probe 14
5 Variation of Heat Transfer Rate with Distance from Baffle - 1 364 11 and 1 216 Sizes bull bull bull bull bull bull bull bull bull bull 29
6 Variation of Heat Transfer Rate with Distance from Baffle - 1 316 11 Size bull 30
7 Variation of Heat Transfer Rate with Distance from Baffle - 1 516 Size bullbull 31
8 Effect of Orifice Size on Position and Value of Maximum Heat Transfer bull bull 34
9 Correlation of the Point of Maximum Heat Transfer with Orifice Size bullbull 35
10 Rate of Heat Transfer at Baffle Center 37
11 Correlation of Heat Transfer Data at Baffle Center bull bull bull bull bull bullbull 38
12 Rate of Heat Transfer at the Point of Maximum Heat Transf er bull bull bull bull bull bull bull bull 40
13 Correlation of Heat Transfer Data at the Point of Maximum Heat Transfer 41
14 Effect of Upstream Baffles on Heat Transfer at Baff le Center bull bull bull bull bull 43
15 Heat Transfer with No Baffle 4 5
16 Orifice Pressure Drop Function versus Reynolds number bull bull bull bull bull bull bull bull bull bull bull bull bull bull 46
17 Heat Transfer at the Baffle and Maximum Point as a Function of Ori fice Pressure DIO p bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 48
18
Fi gure Pa ge
Var iation of Heat Transfer Rate and Pressure Drop with Orific e Size at a Con stant Flow Rate bull bull bull bull bull bull 50
bull bull bull bull bull bull bull bull
bull bull
I
II
III
IV
v
VI
VII
VIII
I X
z
LIST OF TABLES
Pa ge
Summary of Experimental Program bull bull 19
Position of Maximum Heat Transfer 32
Calculated Heat Transfer Data 57
Pressure Profile Data bull bull bull 67
Rate of Heat Tr ansfer at the Baffle Center middot bull bull bull bull bull 70
Rate of Heat Transfer at the Point of Maximum Heat Transfer bull bull bull bull bull bull bull bull bull bull bull bull 72
Effect of Upstream Baffles on Heat Trar1sfer bull bull bull bull bull bull bull bull bull bull bull 74
Heat Transfer in the Test Section without Orifice bullbullbullbullbullbullbullbull 75
Pressure Drop Function 76
71bull r ntal bull bull bull bull bull bull bull bull bull bull bull bull
HEAT TRANSFER AND PRESSURE PROFILRS IN THE VICINITY OF ANNULAR ORIFICES
- CHAPTER I
INTRODUCTION
The most common type of industrial heat transfer
equipment is the shell and tube heat exchanger which
consists of a bundle of tubes contained in a cylindrical
shell Heat is transferred from the hot fluid to the cold
fluid through the tube walls as one fluid flows through
the tubes and the other flows through the shell surroundshy
ing the tubes
Most commercial multitube heat exchangers contain
bafflesmiddot to guide the fluid through the equipment and to
prevent stagnant regions from forming in the shell As a
result the flow pattern in the shell is very complicated
and considerable variation of the local rate of heat transshy
fer occurs because of the various types of flow which exist
in the baffled passage The research described in this
thesis concerns a study of one small portion of the shell
side of a heat exchanger
There are three main types of baffles used in commershy
cial heat exchangers
1middot Orifice baffles extend through the cross section
of the shell and all of the shellbullside flow is
through the annular orifice formed at each point
where the tube passes through the baffle
2
2 Disk and doughnut baffles consist of disks and
doughnuts or annular rings placed alternately
along the length of the tube bundle~ There is
some flow through the annular orifices formed
where the tubes pass through the baffles but a
large portion of the flow is around the baffles
3 Segmental baffles are segments of a circle and
Bre arranged so that the fluid flows back and
forth across the tube bank There is still some
f~ow through the small area where each tube goes
through the baffle
In the case of disk and doughnut and segmental baffles
small annular clearances must be allowed at the point where
the tube goes through the baffle so that the bundle may be
assembled easily Thus in all of the types of exchangers
some shell-side fluid flows through the annular orifice
where the tubes pass through the baffles It has been
shown that this is an area of high rate of heat transfer
but its effect on the overall performance of the heat exshy
changer is not well known Also the prediction of rates
of heat transfer 1n these orifices is not yet possible
The purpose of this research was to make an extensive
study of the heat transfer rates in the vicinity of these
annular orifices and to determine the effect of orifice
size flow rate and upstream conditions The work was
5
performed in a onebulltube single orifice type baffle heat
exchanger and provision was made to measure local rates
of heat transfer in the vicinity of the baffle
4
CHAPTER II
THEORY AND PREVI OUS WORK
In 1701 Newton defined the heat transfer rate qc
from a surface of a solid to a fluid by the equat ion
= ~A(tw - t) (1)q0
where hm is the coefficient of heat transfer from the surshy
face to the fluid excluding any radiation A is the area
of the surface tw is the surface temperature of the wall
and t is the bulk temperature of the fluid The equation
for the point of local surface coefficient h is given by
dqdA = h(tw- t) (2)
The mechan ism and the laws covering heat transfer by
true conduction in solids and by radiation through transshy
parent media are well known However with heat transfer
from a solid to a fluid the situation is far more complex
The mechanism of flow of the fluid to a large extent deshy
termines the rate of heat transfer for a given temperature
difference
In addition the coefficient hm depends on certain
physical properties of the flowing fluid the dimensions
of the apparatus the velocity of the fluid past the surshy
face and frequently the temperature potential AT
It was the purpose of t his research to measure the
local shell -side heat transfer coefficient and correlate
it with the several variables mentioned a bove
5
The heat transfer coefficient for fluids flowing inshy
side tubes is more e a sily measured and correlated due to
the simple geometry of t he tube i nterior Much work has
been done on the tube-side coefficients with one of the
more useful e quations being the Dittus - Boelter equation
( 4 p 450) ~
0 023 (---ctwGJbulla (~np M ( 3 ) M k
with the following cond itions satisfied
(1) Fluid properties evaluated at the arithmetic
mean bulk temperature
(2 Reynolds number gt10000
(3) 0 7 lt Pr lt 100
(4) n = 04 for heating and 0 3 for cooling
(5) Ldw gt60
Colburn (3 p 197) obtained an equation for tubeshy
side heat transfer coefficients in which the Stanton
number is used instead of the Nusselt number
hm ) (~~ 23 _ (dwG) 0 2 ( GC k - 0 bull 023 U (4)
p
Much of the research done on average shell-side heat
transfer coefficients has resulted in empirical correlashy
tions of the form of equations (3) and (4) above Several
investigations have been made for a certain set of phys~al
6
variables but the r esults have ne ver satisf a ctorily been
correlated to appl y for all types of heat exchangers
Some basic 1ork has been done recently however on
the local shell-side coefficients Ambrose (1) studied
the local heat transfer coefficients i n a model heat exshy
changer with segmental baffles This study was fairly
extensive at the baffle center but the data were quite
limited for the space between the baffles Gurushankar1ah
(5) further extended Ambroses work by studying a single
baffle space in detail
The results of these two studies indicated a need for
detailed information 1n the vicinity of the baffle Hence
Lee () investigated a single baffle s pace between two
orifice baffles and obtained considerable information on
the rates of heat transfer in the annular orifices Since
his work was carried out in a multitube mode l heat ex~
changer the determination of the rate of flow through the
individual orifice was difficult because of t he outer
clearances existing in the exchanger For this reason the
present research was undertaken to study the rate of heat
transfer in a single annular orifice through which the flow
could be accurately determined
Bell and Bergelin (2) have studied i n detail the pres shy
sure drop coeff icients for the annular orifices formed beshy
tween a circular disk and a circular tube These results
also appl y to the annular orifioe formed when a rod extends
7
through a circular hole in a plata This study was extenshy
sive in the fact that it considered the baffle thickness as
well as the orifice size but no heat transfer data were
presented
Sullivan and Bergelin (9) studied flow through a
single annular orifice through multiple annular orifices
i n parallel and flow around a single baffle both with and
without leakage through the baffle A generalized expres shy
sion is presented for the pressure drop across one baffle
section of a tubular exchanger with leakage through the
tube holes in the baffle but the effect of leakage area
upon heat transfer is only discussed qualitatively The
pressure drop data is correlated by plotting cent as a funcshy
tion of the Reynolds number where cent equals
d1 )22( ~ P) s c e (d2 -
M-2
8
CHAPTER III
~PERI1ffiNTAL APr ARATUS
The heat transfer test section was essentially a
single tube heat exchanger The inner tube was a l-in
OD aluminum tube with an electrically heated probe midshy
way between the two ends of the tube
Test Section
The shell as constructed from lucite plastic tubing
2 5-in I D and 3-in O D The te t section d a total
lengt h of 54 58 inches I t consisted of two sections
The upstream section was 40 i n ches in length in order to
assure freedom from entrance effects and the downstream
section was 13 12 inches in length To further assure
uniform flow a bundle of short copper tubes was placed a
few inches downstream from the entrance Both of these
sections had 12 i nch flanges on one end so t hat a 18
i nch thick orifice plate could be clamped between them
Heat transfer coefficients were measured in the vicinity of
t h is orifice A cross section of the center of the test
section is shown in Figure 1 and the experimental appara~
tus is shown in Figure 2
Cooled air supplied by a Roots -type blower was used
as the shell-side fluid throughout this study It entered
the test section through a l-in ID 1 12-in OD plasshy
tic pipe at the upstream end of the calming section Tbs
j Jl l 6- 11 BOLTS II I nbull middot~11 I HEATING ELEMENTS
J T ( T
-f-shy - - - f-_- __L
7 777 _y A
IT 1] I
I
FIGURE I CROSS SECTION OF TEST SECTION AND PROBE
10
FIGURE 2 EXPERIMENTAL APP1Ub~fUS
11
air left the test section through nine equally spaced 12
ineh holes placed around the side of the tube at the exit
end
Sensing Probe Assembly
The sensing probe was designed to measure the local
heat transfer coefficients at any point along the tube and
around the tube in the test section The tube was designed
so that it could be easily moved up- and downstream to
measure the heat transfer coefficients at various positions
in relation to the orifice
The sensing tube assembly consisted of the sensing
probe the thermoctmple lead s and selector switch the
power lines and the two aluminum tubes between which the
probe was centered
Imbedded in the sensing probe were seven iron-constanshy
tan thermocouples for measuring the temperatures around the
tube The lead wires from these thermocouples were conshy
nected to a seleotor switch at the downstream end or the
aluminum tube A layer of Saran wrap was placed around the
tube over the t hermocouple and three lengths of Trophet C
resistance ribbon were wrapped around the tube nd conshy
nected in series to the power leads
The heating surface of the probe was formed by these
three one inch wide strips of Trophet C resistance ribbons
The ribbons were 0002 inches thick and had a resistance of
12
0 271 ohms per foot and a thermal conductivity of 763
Btuhr ft 2 degFft They were held in position by four
copper bars placed in four parallel longitudinal slots
These copper bars served as connectors for the electrical
leads A photograph of the sensing probe is shown in
Figura 3 and a drawing of the assembled probe is given in
Figure 4
Power Source
Direct current was used to heat the resistance ribbon
on the sensing probe The current was regulated by a slide
wire resistor The po er source consisted of a Raytheon
Voltage Stabilizer to stabilize the city power source at
115 volts and an automatic selenium rectifier with an alshy
ternating current input of 115 volts at 60 cycles per
second and an output of 12 volts and 35 amperes direct
current
Temperature Measuring
The temperatures around the sensing probe were calcushy
lated from the emf readings of the ironbulloonstantan thermoshy
couples The emf measuring system consisted of the seven
probe thermocouples a separate thermocouple for measuring
the inlet air temperature a thermocouple selector switch
a cold junction and a Leeds and Northrup Type K Potentishy
ometer The potentiometer was placed on a Fischer
13
THERMOCOUPLE JUNCTIONS~ ~------- HOLES FOR THERMOCOUPLE LEADS
~----- SCREWS
~ff+--- CONNECTING BARS
END VIEW
POWER LEADS SOLDERED TO LOWER CONNECTING BAR
iER PLASTIC PIECE
RESISTANCE RIBBONS LOCATION OF THERMOCOUPLES
FIGURE 4 DRAWING OF ASSEMBLED SENSING PROBE
15
Vibradamp support to absorb the vibrations produced by the
air blower
Air Source
Air was used as the shell-side cooling fluid during
the study The air was pumped through the test section by
a Roots type air blower with a rating of 280 ofm at 3 12
psig outlet pressure The hot air leaving the blower was
passed tbxfugh two finned-tube box-type coolers and one
tubular edoler to oool it to approximately room temperature
The air flow rate was measured by passing it through a
flow measuring orifice in the line Two sharpbull edged orishy
ficas were used f or flow measurements The calibration
curves for these orifices were presented by Ambrose (1
p 166)
The pressure taps on each side of the orifice were
connected to two differential manometers containing 0 83
and 2 95 specific gravity fluids respectively The presshy
sure drop through the test section and test orifice was
measured by a pressure tap placed 13 inches upstream and
one placed 6 12 inches downstream from the orifice Two
pressure ga ges were used to measure the pressure at the
inlet to the flow orifice and to indicate the statio pres~
sure at the test section inlet
16
Pressure Probe
A probe was designed to measure the pressure drop
between the pressure tap 13 i nches upstream from the ori shy
fice baff le and any point downstream from the tap The
probe eonsisted of a l~in OD copper tube with six 132
i n ch holes even l y s paced around the tube The upstream
pressure tap and the pressure probe were connected to a
differential manometer so the pressure drop to various
points up- and downstream of the orifice could be measshy
ured
17
CHAPTER IV
EXPERIMENTAL PROGRAM
The experimental program was designed to measure the
heat transfer coefficients and pressure drops in the vicinshy
ity of annular orifices The four orifice sizes studied
were 1 364 1 216 l 316 and 1 516 inches~ The inner
tube used in each case was a 1-in OD alumintim tube
Hence tube to baffle clearances were respectively 3128
232 332 and 532 of an inch
Heat transfer coefficients were measured at poait~ons
1 i nch upstream at the orifice center and at 12 1
1 12 and 2 inches downstream for all orifices In addishy
middottion the heat transfer coefficient at a point 2 12
inches downstream from the 1 516 inch orifice was measured
and at the points 12 l 12 and 2 inches upstream from
the 1 364 inch orifice
The heat transfer coefficients at each point were
measured at five different flow rates for the 1 364 inch
orifice and at six different flow rates for the other orishy
fice sizes The high pressure drop through the small orishy
fice size limited the number of flow rates which could be
studied
The flow rate was calculated from the pressure drop
across the flow orifice This flow was corrected to cubic
feet per minute at 68degF and one atmosphere pressure by
18
using the orifice pressure and the test section pressure
which were measured by pressure gages
It was desired to determine a relationship between the
heat transfer coefficient and the total pressure drop for
each orifice size The pressure drop across each orifice
at various flow rates was measured by means of the presshy
sure probe described in Chapter III It was also desired
to obtain pressure profiles for each orifice size since
these might be similar to the heat transfer profiles The
pressure drop was measured from a point 13 inches upstream
of the orifice to points at 1 and 12 ineh upstream the
orifice center 12 1 1 12 and 2 inches downstream
The experimental program is summarized in Table I
TABLE I
SUla~RY OF EXPER IMENTAL PROGRAM
Position Investigated-Distance from Orifice-Inches
Orifice Range of Flow Rate Size Heat Transfer Pressure Drop CFM at 68degF amp 1 atm
1 364 2U 1 12U 1U 12U c 12U C 12D lD 10 - 18 l2D lD 1 12D 2D 1 12D 2D
1 216 1U c 12D lD 1 l2D 2D 12U c 12D lD 10 - 35
1 316 1U c 12D lD 1 l2D 2D l2U C 12D lD 12 - 50
1 516 1U c x2D lD 1 l2D 1U 12U C 12D 12 - 90 2D 2 1 2D l D 1 l2D 2D 2 12D
20
CHAPTER v
EXPERI MENTAL PROCEDURE
The experimental procedure for measuring the heat
transfer coefficients ~d corresponding flow rates reshy
quired the following procedure
(1) Install the orifice size to be studied in the
test section
(2) Place the heat transfer probe in the position up
or downstream from the orifice where the middot heat
transfer rate is to be studied
(3) Fill the cold junction thermos with cracked ice
(4) Measure the atmospheric pressure
(5 Open bypass line from blower and close line to
test section
(6) Turn on the cooling water for the exchangers used
to cool the air leaving the blower
(7) Start the automatic selen ium rectifier by turning
on the t 1mer bull
(8 ) Connect the voltage stabilizer to the wall outlet
(9) middot Set the slide wire resistor to the maximum re shy
s1atanee I
(10) Start the blower
(11 Open the line to the test section until the de shy
sired flow rate is obtained
(12) Switch on the probe direct current power source
21
(13) Adjust the slide wire resistor to obtain the
desired current
(14) After the thermocouples have reached equilibrium
values record the e m bullf across each of the
seven probe thermocouples and also the entering
air thermocouple
(15) Record the direct current amperage
(16) Record the gage pressure at the flow orifice and
the entrance to the test section
(17) Record the manometer measurement of the pressure
drop across the flow orifice and also the presshy
sure drop through the test section
22
CHAPTER VI
CALCULAT ION OF EXPERIMENTAL DATA
The local heat transfer coefficients were calculated
from the temperatures measured on the probe surface the
air temperature and the current input The results were
calculated by using the Alwae III-E computer
The general expression for calculation of the heat
transfer coefficients was derived by Ambrose (1 p 79)
The equation is derived by making an energy balance around
a small increment of the center resistance heating ribbon
The two ribbons tnstalled adjacent to the center ribbon
reduced the amount of logitudinal conduction and assured
little longitudinal temperature variation in the center
ribbon
A heat balan ce on this small increment of resistance
ribbon yields the following
(the heat conducted in) + (heat generated) = (heat
conducted out) +(Heat convected to the fluid) + (heat
radiated to the surroundings) + (Heat conducted into
the plastic center of the probe)
This gives the equation
kzw dtdS + 12RdS kzws [ t + (~) ds] + hwdS (t-ta )
+ ~Aad wd o middot+ qcAond 1 -~- wdS 5 )
23
Hence solving for h gi~ea
i2R kz d2t Qrad qcond w + -d$2 - ~- A
h = ( 6)t - ta
Since S = re where 9 equals the enclosed angle ~n radians
dS rd9 ( 7)
and
dt - dt (8)dS - rd9
Differentiating with respect to S
d2t (9)rd9dS
from which
(10)
Substitut1ng into the equation for heat transfer coeffishy
cient gives
h = i2R Qcond A (11)
w
The rate of radial heat conduction into the plastic
tube making up the probe was assumed to have negligible
effect on the heat transfer coefficient It was also
assumed that the heat loss by radiation from the ribbon
was negligible since all data were obtained with the ribbon
at a temperature less than 125degF
24
When t he rad iation and conduction terms are neglected
Eq (11) becomes
(12)
The following con stants are known
R = 0 271 ohmsft
w = 100 i n ches
k = 763 Btuhr rt2 degFft
z = 0 002 inches
r = 12 inch
Eq (12) putting 9 in degrees then reduces to
1110 12 + 2404 d 2t d92
( 15)h = ------~--~-------t - ta
Thi s equation was programed for the Alwac III- E comshy
puter and used to calculate the local heat transfer coefshy
ficients from the observed data
The average heat transfer coefficient around the tube
at a given position in the t est section was calculated by
averaging the local coefficients calculated from Eq (13 )
It was found 1n the course of the experimental work
that thermocouple numbers 1 and 7 were indicating higher
temperatures than would be expected This resulted in h1
and ~ being lower than the other local coefficients around
the tube Since the fluid was flowing parallel to the axis
of the probe the circumferential variation i n rate of heat
25
transfer should be small Hence in obtaining the average
coefficient around the tube the values of h1 and h7 were
not used even though they were calculated and are tabulated
1n Table I II in the Appendix
Then
(14
A Nusselt number as calculated from this aver age heat
transfer coefficient using the tube diameter as the characshy
teristic dimension
(15)
The air flow rates through the test section were calshy
culated by measuring the pressure drop across the flow orishy
fice the air temperature the pressure at the flow orifice
and the pressure at the entrance to the test section The
orifice calibration curves (1 p 166 ) were used to obtain
a value of the orifice coefficient f8e where Q equals
the flow in cubic feet per minute at 68deg F and one atmosmiddot
phere pressure and te is the density of air at the exchanger
and e the density of the air at the flow orifice The
den sity of the air can be expressed by
e = 2 703 p (16)T
where T equals the temperature in OR and P equals the absoshy
lUte pressure i n lb1n2 Using the value of e Qfo from
26
the calibration charts as A and Eq (16) solving for Q
gives
( 17
This equation was used to calculate the flow rate for
each flow studied
The Reynolds number used i n the correlation of the
data was the equivalent Reynolds number defined as
Re)eb ~ d2 - dl)Uf ( 18 ) lL
where d1 is the outside diameter of the inner tube and d2
is the orifice diameter U is the flow velocity through the
annular orifice e is the density of the air and U- is t he
viscosity of the air This equation can be transformed t o
(Re) b = 1611 Q (19) e dl + d2
where d1 and d2 are in inches
The pressure drop data were calculated i nto a dimenshy
sionless pressure drop function cent where
d1 )22( ~ P)gc f av(d2 shycent 2 bull (20
M-
For air this equation reduces to
where d2 and d1 are in i nches D P is expressed i n inches of
2 95 specific gravity fluid and P av is expressed as lbft3
27
CHAPTER VII
ANALYSIS OF DATA
In analyzing the heat transfer data an attempt was
made to correlate it 1n terms of the dimensionless groups
(Nusselt number Prandtl number and Reynolds number) which
appear in Eqs (3) and (4) Consequently all of the av~
erage heat transfer coefficients hav were brought into
the form ( Nu)( Pr)~3 bull The Nusselt number was based on the
tube diameter and the thermal conductivity of the air at
the flowing temperature The tube diameter was used in the
Nusselt number because comparison could then be made with
previous experimental work on heat exchangers which have
commonly used the Nusselt number defined as in Eq (15)
From the standpoint of dimensional analysis this is
equivalent to considering the tube diameter as the characshy
teristic length so far as the heat transfer is concerned
The Prandtl number of the air was taken as 0 7 in all
cases
Variation of Heat Transfer Rate with Distance from the Baffle
Considerable variation was observed in the rate of
heat transfer in the vicinity of the baffle In order to
obtain the variation with respect to position the term
(Nu)(Pr)-13 was plotted versus the flow rate Q for each
position and orifice studied Cros s plots were then made
28
at constant flow rates in order to obtain the variation of
(Nu)(Pr) -13 with position The resulting cross plots are
shown 1n Fi gures 5 6 and 7 for the four orifices studshy
ied
About one inch upstream from the orifice the heat
transfer coefficient begins to rise rapidly and continues
to do so until it reaches a maximum some distance downshy
stream After the maximum point the heat transfer coef fi shy
cient decreased slowly The heat transfer rate was found
to reach a maximum at a different position downstream for
each orifice size These figures also show that for a
given orifice size the maximum heat transfer rate occurs
a pproximately at the same point for all flow rates The
position of the maximum point f or each or ifice size is
shown in Table II
The region immediately downstream from the orifice is
one of h i gh turbulence due to the jetting action of the air
flowing through the orifice As the air flows t hrough the
orifice the streamlines continue to converge for some dis shy
tance downstream The point of maximum heat transfer is
probably at the point where the streamlines be gin to diverge
and a boundary layer begins to build up on the tube Tle
decreasing heat transfer coefficient beyond the maximum
point indicated the formation of a boundary layer
Since the position of the maximum point is independent
of flow rate middot it is possible to correlate it with respect
_ ct 11shyz-
100
0 136 ORIFICE
(
I 0
I )
~ 00
~p 0
I 0
--r--- ~
ISCFIII
-_ OCFM
rbull abull
~ middot~ a-1 z-
12fORIFICE
100
200
100
0 0 UPITRAM ORIFICE DISTANCE CENTER
CFM
h I DOWNSTREAM
DISTANCE
FIGURE 5 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLpound
30
too
700
800
100 ~ f gtf
400
z ~
100
100
100
0
13fORIFICE
~ -~ -- ---
)
~
~
-
I ~ ~OCFM
I vI~-~ OCFM
J ---
Iamp CFM
I 0 I I UPSTREAM ORIFICE DOWNSTREAM DIITANOE GENTER DIITANCI
FIGURE 6 VARIATION OF HEAT TRANSFER RATE WITH DISllNCE FROM BAFFLE
--
--- --
31
100
100
700
100
_ 100
f 9- 400 z-
100
tOO
100
0 - I 0 I I I UHTRIAM OAtfiCI DOWIIITMAM
+ I tyl6 ORIFICE
v I
~~ ~CFM
I v ~CFMI
v v 7
~~ v ~ iOCFM
- ~~ I-shy1-shy ~ICFM
DIITMCI OINTIR DIITANCI
FIGURE 7 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLE
32
TABLE II
POSITION OF MAXIMUM HEAT TRANSFER
Position of Maximum Orifice Size Heat Transfer
(inches) (inches downstream)
1 364 050
1 216 100
1 316 125
1 516 200
33
to orifice size Figure 8 shows the effect of the orifice
size on the position and value of the maximum heat transfer
at a constant flow rate of 15 cubic feet per minute It
can be seen that the larger the orifice size the further
downstream the point of maximum heat transfer occurs
Also as the orifice size increased the rate of heat
transfer decreased for a given flow rate The broken line
indicates the variation of the point of maximum heat transshy
fer with position and size The position of the point of
maximum heat transfer rate downstream from the orifice was
correlated with orifice size by means of the dimensionless
groups (Lde) and (d1de) where L is the distance downshy
stream from the orifice where the maximum rate of heat
transfer occurs d1 is the outside diameter of the inner
tube and de is the equivalent diameter of the orifice
ie de = d2-dlbull
Figure 9 shows a plot of Ld 6 versus d1d6 for the
four orifice sizes studied The four points on this logshy
log plot are approximately in a straight line and the
equation of this line is
Lde = 0 44 d1de)028 (22)
Although the above relationship represents a correlashy
tion of dimensionless groups it is based upon only one
tube diameter and needs to be substantiated further by
studying other tube diameters and other orifice sizes
34
aoo
400
aoo ~
-~ middot-CLshyJ z
200 -
100
0
ORIFICE CENTER
l~
l
t
I J~
1pound~
I
0 I I~
AT 15 CFM
-
bull ~ 1~6~
~ v~
~
~--~~6
~~~ ___ v v V -_
~ o q
~ I 16
v
~
ogWNSTREANI STANCE
FIGURE 8 EFFECT OF ORIFICE SIZE ON POSITION AND VALUE OF MAXIMUM HEAT TRANSFER
35
50
loshy____ -~
~ ~ -shylltl-shy~ r0
2 10 30
FIGURE 9 CORRELATION OF THE POINT OF MAXIMUM HEAT TRANSFER WITH
ORIFICE SIZE
36
Correlation of Data at the Baffle
The heat transfer data were correlated by obtaining a
relationship between the group (Nu)(Pr)-13 and a
Reynolds number based on twice the clearance (d2 - d1
between the tube and the baffle It was found that the
most satisfactory correlation could be obtained when the
term - d1 was used as the length term in the Reynoldsd2
number
Figure 10 shows the variation of the heat transfer
rate at the center of the orifice e xpressed as a function
of Reynolds number and the orifice size This shows that
for a given Reynolds number the heat transfer at the center
of the orifice is greatest for the smallest orifice size
In order to obtain a general correlation of the data
shown i n F1gure 10 the effect of the dimensionless ratio
d1de was considered This ratio considers all of the
geometric factor s needed to describe the annular orifice
The thiclaless of the orifice plate is also a factor but
was constant i n this i nvestigation
The data for the heat transfer at the baffle center
are shown in Figure 11 in which (Nu)( Pr)-13 is plotted
versus (Re)ebd1 de) 0 55 This data on a log-log plot
lies on a straight line for (Re)eb( dld8 )0 55 greater
than 3 x 104 The equation for cor relating the heat
37
4XI~middot~-r~------~--~~------~
Icf t--to_+--_c-c-________ SYMBOL SIZE
0 1~4
6 ~~
9 ~~ -o ~
(Re)eb
FIGURE 10 RATE OF HEAT TRANSFER AT BAFFLE CENTER
38
500
0
4 0 lcf
~ ~
~ ~iC-
~ ~
~IL 0~ 0 SYMBOL SIZE-
p 0 1364-
r 6 1~16 -~ -
9 1~16 --o 1~16
I I
FIGURE II CORRELATION OF HEAT TRANSFER DATA AT BAFFLE CENTER
39
transfer at the center bullOf the a nnular orifice was found by
the method of least s quares to be
(Nu)( Pr)-1 3 = 0018 ( Re)ebO Bl( dlde)04~ (23)
3 x 104 ltRe)eb(a1de)055 lt 105)
Rate of Heat Transfer at the Point of Maximum Heat Transfer-The heat transfer rate at the point of maximum heat
transfer is plotted in Figure 12 to show the variation with
Reynolds number and the size of the orifice It is shown
gives the h1gh st heat transfer ~ate at its point of maxibull
that for a given Reynolds number the smallest orifice size yen il
mum heat transfer
The data ~or the maximum poi~t could be correlated by
plotting (Nu) Pr)-13 versus (Re)eb(d1de)06 This plot
is shown 1n Figure 13 and the resulting eurve shows that
(Nu(Pr)-13 is not a simple p0wer function of the Reynolds
number as was the case for heat transfer at the baffle
center The reason for this is probably because other
factors such as intensity and scala of turbulence should
be considered At the orifice center the streamlines of
the flowing stream are converging_ and thus the flow is
quite stable Downstream from the orifice is a region of
large eddy currents and probably large scale turbulence
These factors could con ceivably cause the results which
were obtained for the point of maximum heat transfer
40
If)
~middotshy Q_-I z_
10~~~--------r----~~--~--
SYMBOL SIZE
0 13$4
6 1~8
Q 13-18
-o 1~8
7)(104
(Re)eb
FIGURE 12 RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
41
Ia ~
0 I
c ~ ~ c v
~ ~lt w ~
17
~ b
v ~ ( SYMBOL SIZE
-~ 0 f-64 -v ~ 6 t211e
~ Q I~~~
-o - l~rs I I
FIGURE 13 CORRELATION OF HEAT TRANSFER DATA AT THE POINT OF MAXIMUM HEAT TRANSFER
4 2
Effect of Upstream Baffles on Heat Transfer at the Orifice Center
The heat transfer rate at the orifice center using the
single orifice in a test section is a pproximately 13 of the
value that was obtained by Lee (7) using a model heat exshy
changer with orifice baffles Lee investigated the cent r al
baffles of the heat exchanger and thus the coeff icients he
obtained would be affected by the presence of a number of
upstream baffles To determine the effect of upstream
baffles an additional l 516 inch baffle was placed four
inches upstream 1n the test section The resulting data are
shown in Figure 14 where (Nu)(Prmiddot)-13 is plotted versus
(Re) eb for the case of a single baffle 1n the test section
and also the case of an additional baffle placed four inches
upstream Comparison is made with the results obtained by
Lee middot(7) using a four-baffle and a ten-baffle model heat exshy
changer Good a greement is obtained with Lees work and the
results show the marked effect that upstream baffles have on
the downstream heat transfer rate The additional up tream
ba ffle caused sufficient turbulence 1n the test section to
i n crease the heat transfer rate nearly three-fold at the
center of the next baffle
Heat Transfer i n the Test Section with No Orifice
In order to check the accuracy 6f the equipment the
orifice baffle was removed and the heat transfer mea sured
with the probe in the empty test section The data were
43
~~BAFFLES
0 l BAFFLE -shy
ll_9 2 BAFFLES
V 4 BAFFLES-LEE
4 10 BAFFLES- LEE lJf ~
~rv ~~ ~ v flvv ~~
I ~ J ~ L v
0
v
( V
40 3XIo 7XIa
(Re)eb
FIGURE 14 EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER AT BAFFLE CENTER
44
compared with heat transfe r coefficients predicted by the
equations for annuli which are recommended in the litera shy9
ture The two equa~ ions u sed tor comparison were
(hfe)=0 023 (rltGr e (~~ur4 (~r45 (24)
which was presente~ by Wiegant (10)
and ( h ) (cnM~5(M~l o14 o 023 CPG k j Mij - (de GJMb )0 2 ( 2 5)
which was presented by McAdams (8 p 242) The comparshy
i son is s hown in Figure 15 lq (25) gives a value which
is low by about ten percent while Eq (24) g ives values
which are high by as much as twenty -five percent when comshy
pared with the experimental data The se equations are gembull
erally considered to give coefficients with an accuracy of
about twenty percent Therefore the present experimental
data are within the accuracy of these equations Also the
plot indicate s that for a Reynold s number greater than 2 x
104 the slope of the line is the same for the experimental
data as for the equations
Pressure Drop Data
The total pressure drop across the orifice was measured
as a function of the flow rate and the orifice size The
pressure drop was expressed as a d1mens1onleas quantity r)
which ie plCltted ver sus the Reynolds number in Figure 18
The pressure drop function cent correlates for all or1f1oe
45
200
100
s z
10 5XI10 10
0 EXPERIMENTAL
--McADAMS
-WIEGAND L
V
~ ~ ~
P ~ ~
LL~ L
v~
~
v v
v 1 ~ ~ v
v -gt
~
~ ~
~
6Xid
FIGURE 15 HEAT TRANSFER WITH NO BAFFLE
46
0 1~4 -~ a 6 t216
Q t316 lJ J
-0 as a )t
A LEE I -shy SULLIVAN 8
p
10bull
BERGELIN
I _ll I
I ~
i I
~middot
lo II
f fl
J j
~middot
A)101
1q
I Ill
1 I3 X 10ao1
FIGURE 16 ORIFICE PRESSURE DROP FUNCTION VS REYNOLDS NUMBER
47
sizes- The present data extends the range covered by preshy
vious workers and agrees well with their work The preshy
vious work of Lee () for a heat exchanger containing 10
orifice baffles and also the data of Su livan and Bergelin
(9) for pressure drop in a model heat exchanger with a
single baffle is shown 1n Figure 16 long with the present
results~ This figure may be used to predict the preseure
drop from the equivalent Reynolds number of the annular
orifice
The pressure drop between individual points 1n the
vicinity of the orifice and an upstream pressure tap wa s
measured to obtain a pressure drop profile As might be
expected 1n all cases the profiles showed a rapid decrea e
in static pressure immediately upstream from the orifice
There was however little or no recovery of the pressure
loss downstream The 1 364 inch orifice did show a maxishy
mum point in the pressure drop but this maximum occurred at
the orifice center and total recovery was reached about 12
inch downstream
Heat Transfer at the Baffle and Maximum Point as a Function of Pressure Drop
In order to compare the effect of the total pressure
drop on the heat transfer at the baffle and the point of
maximum heat transfer Figure 17 was plotted showing
(Nu)(Pr)-13 as a function of the total pressure drop This
shows that for a given pressure drop the largest orifice
48
1200
1000
~ a -sshyz-
100
60 100 700
AT MAXIMUM POINT I 15116 2 13116 3 1~6 4 1364
AT ORIFICE CENTER
60
1
v
r ~ ~ ~
5
~
8 7
13116
8
~
1364
v
~
e6
1~6
v
~~ v ~ ~ -~ ~
~
~ v
l
~
vamp
I ~ ~
~
v L ~
v
I-
5
k= ~~
~ ~ ~
--I
v ~
FIGURE 17 HEAT TRANSFER AT THE BAFFLE AND MAXIMUM POINT AS A FUNCTION OF
ORIFICE PRESSURE DROP
49
size has the greatest heat transfer coefficient This is
true at both the orifice center and at the point of maxishy
mum heat transfer
Another comparison can be made by plotting the heat
transfer coefficient and the pressure drop versus the orishy
fice size at a constant flow rate Figure 18 shows this
plot This graph shows that at a constant flow rate the
pressure drop as well as the heat transfer coefficient
increases as the size of the orifice is decreased In
choosing an orifice size for maximum efficiency 1t would
be necessary to know the pumping power available as well
as the heat transfer desired
70 I I 700
AT 15 CFM 60 ---
~ aug
50 ---
NV
40 ~
~ ~ ~
~ _
MAXIMUM POINT ---- --- ~
1-----t---~ _
~00Qj ~
~t--- ORIFICE CENTER 10 1100
1---~ n
u0 01 02 03 Q35
a ltl
de inches
FIGURE 18 VARIATION OF HEAT TRANSFER RATE AND PRESSURE DROP WITH ORIFICE SIZE AT A CONSTANT FLOW RATE
cn 0
51
CHAPTER VI II
SUMMARY OF RESULTS
This study revealed several significant facts about
the heat transfer in the vicinity of annular orifices
Probably the most important contribution was the presshy
entation of the heat transfer profiles in the vicinity ot
the annular orifice ~ r s shown that t~ local heat
transfer coeffieient re~ches a maximum at a point downshy
stream from the orifice The distance downstream at which
this maximum oocurs is t1ven by the equation
22
The heat transfer coefficients at the center of the
orifice were correlated and found to follow the equation
(Nu)(Pr)-13 = 00176 (Re)eb08l(d 1de) 0 middot4~ (23)
3 x 104 lt( Re) 9 b( d1d6 )055 ltlo5 )
The heat transfer at the point of maximum heat trans
fer for each orifice size was correlated and presented in
Figure 13 as a plot of (Nu)(Pr)-l3 versus (Re)eb(d1de) 06
No simple po-orer relationship exists between the terms
Intensity and scale of turbulence downstream from the orishy
fice are probably important factors which affect the heat
transfer
The large effect of an upstream orifice on the heat
transfer rate at the second orifice was demonstrated by the
52
study of two 1 516 inch orifices in the test section The
added turbulence at the center of the second orifice was
found to raise the heat transfer rate almost three times
over that obtained for a single baffle
The pressure profiles in the vicinity of the orifice
indicate that nearly all the pressure drop occurs at the
orifice center~ Total pressure drop data were correlated
by a pressure drop function cent as a function of the Reynolds
number and good agreement obtained with the results of other
workers
The pressure drop and heat transfer data were correbull
lated by plotting the heat transfer as a function of the
pressure drop for each orifice size It was shown that for
a given pressure drop the largest orifice size gives the
greatest heat transfer coefficient
As a final presentation it was shown that the pressure
drop and the heat transfer coefficient both i ncrease i n
value at a constant flow rate as the orifice size is de shy
creased This is important in choosing the optimum clearshy
ance for orifice baffles
53
CHAPTER IX
RECOMMENDATIONS
A great deal of work remains to be done in the field of
evaluating shellmiddotside heat transfer coefficients This
study included only one tube size and air was the only f luid
used It is recommended that further studies be conducted
using other fluids and tube sizes It will also be necessary
to study several baffle types
The adde d turbulence due to a s e cond baffle placed upbull
s t ream would suggest that the heat transfer coef ficients at
a certain position i n relation to a baffle would increase as
the flow progressed through the exchanger It is recomshy
mended that an extensive s t udy should be made between baffles
the full length of a model heat exchanger
It is further recommended that the pressure drop study
be continued to include other fluids tube sizes and baffle
arrangements
Effects of turbulence downstream from the baff le should
be studied by i n vestigations with hot-wire anemometer equipshy
ment to determi ne t urbulence scale and i ntensity
54
NOMENCLATURE
Area of heat transfer
Heat capacity of the fluid
Outside diameter of the tube
Orifice diameter
Equivalent diameter of the orifice (d2 - dl)
Inside diameter of the test section
Inside diameter of the tube
Gravitational constant
G Mass velocity
h Local heat transfer coefficient
Coefficient of heat transfer from surface to fluid
i Direct current amperes
k Thermal conductivity of the fluid
L Distance downstream of the point of maximum heat transfer
p Absolute pressure
L P Total pressure drop across the orifice
Q Flow in cubio feet per minute at 1 atmosphere and 680 F
q Heat transferred
Thermal energy conducted into the sensing probe
Thermal energy radiated from the resistance ribbon
Resistivity of the resistance ribbon
s Length of the resistance ribbon
T Temperature oR
55
t Temperature of the resistance ribbon deg F
ta Temperature of the bulk stream oF
tw Wall temperature of the tube OF
U Veloc ity of the fluid
w Width of the resistance ribbon
z Thickness of the resistance ribbon
eeuro Density of the fluid in the test section
Density of the fluid at the flow orificef 0
AL Viscosity of the fluid
E9 Angle measured around the tube
Dimensionl ess groups
(Nu) Nusselt number hd1k
(Pr Prandtl number C~k
(Re)eb Equivalent Reynolds number at the baffle (d2 - d1 )uejt-Lshy
(Re)e Equivalent Reynolds number in the test section ( d 8 - d 1 )U fu
cent Orifice pressure drop function 2(~P ) gc~av(d2 - d1) 2
Al
56
BI BLIOGRAPHY
1 Ambrose Tommy W Local shell-side heat transfer coefshyficients in baffled tubular heat exchanger PhD thesis Corvallis Oregon State College 1957 183 numb leaves
2 Bell K J and o P Bergelin Flow through annular orif ices Transactions of the American Society of Mechanical Engineers 70593-601 1957
3 Colburn Allan P A method of correlating forced con shyvection heat transfer data and a comparison with fluid friction Transactions of the American Institute of Chemical Engineers 24 174-210 1933
4 Dittus F w and L M K Boelter Heat transfer 1n automobile radiators of the tubular type University of California Publications in Engineering 2443-461 1930
5 Gurushankariah M s Local shell-side heat transfer coefficients in the vicinity of baffles in tubular heat exchangers Masters thesis Corvallis Ore gon State Colle ge 1958 97 numb leaves
6 Knudsen James G and Donald L Katz Fluid dynamics and heat transfer New York McGraw-Hill 1958 576 p
7 Lee Kyu Sung Local shell-side heat transfer coeffishycients and pressure drop in a tubular heat exchanger with orifice baffles Masters thesis Corvallis Oregon State College 1959 118 numb leaves
8 McAdams William H Heat transmission 3d ed New York McGra ~-Hill 1954 532 p
9 Sullivan F W and 0 P Bergelin Heat transfer and fluid friction in a shell-andbulltube exchanger with a single baffle Chemica l Engineer ing Progress Symposium Series 52 ( 18) 85-94 1956
10 Wiegand J H Discussion on annular heat transfer coshyef f icients for turbulent flow Transactions of American Institut e of Chemical Eng i n eers 41147-153 1945
AP PENDIX
57
TABLE III
CALCULATED HEAT TRANSFER DATA
Baffle Hole Diameter Run No (inches)
1 - 59 1 364
60 - 102 1 216
103 - 138 1 316
139 - 206 1 516
207 - 212 No orifice
213 - 218 2nd - 1 516
TABLE III
CALCULATED HEAT TRANSFER DATA
Local Heat Transfer Coefficients Run
T0 bull Po s ition CFM hr h2 h3 h4 hs he ~ hav Nuav
1 c 1026 10 59 1476 16 09 1559 1510 1435 1203 1518 8511 2 1290 1369 1738 1878 18 05 1755 1689 1515 1773 9964 3 1416 1636 198 1 2068 1977 1924 1845 1715 1959 11030 4 1627 1991 2301 2382 2268 2194 20 ~98 1929 2249 12664 5 1776 2252 2669 2863 2713 2517 2338 2126 2620 14759 6 l2ttD 1109 2311 3317 3386 3373 3387 3394 3071 3371 18888 7 1258 3089 4583 4866 4683 4701 4643 4194 4695 26301 8 1433 38 8 5 55 83 5791 5495 5430 5436 5008 5547 31192 9 1681 4992 7378 7649 6980 6864 6870 64 28 7148 40180
10 1 D 1102 2371 3332 3511 3356 3342 3427 3102 3394 19012 11 1308 3218 4379 45 24 42 53 4255 4373 3965 43 57 24446 12 14 64 38 58 5146 5142 4839 4787 4903 4597 4963 278 79 13 1706 5218 6664 6269 58 81 5884 6237 5973 61 87 34718 14 15
1 l2D 1115 1275
2131 2661
2955 3638
2972 3720
2941 3675
2913 3576
28 22 34 74
2613 3278
2921 36 17
163 09 20246
16 1498 34 87 4644 4503 4441 4371 4343 4194 4460 25010 17 1695 4449 5743 5324 5222 5154 5157 5015 5320 298 97 18 2D 1049 1715 23 90 2550 2610 2656 2624 2208 2566 14363 19 1241 2117 2964 3145 3218 3221 3203 2759 3150 17757 20 1532 28 67 3936 4100 4188 4201 4167 3676 4118 23224 21 1674 3459 4508 4598 4746 4795 4792 4299 4688 26337 22 lU 1074 253 340 380 3 86 388 377 354 374 2097 23 1287 292 392 433 440 441 429 406 427 2394 24 1508 322 439 492 498 499 487 461 48 3 2713 25 18 07 3 38 464 519 5 24 520 499 463 5 05 28 40
~~ (]I agt
TABLE III Continued
Run No Position CFM h 1 h2 ~3 h4 h5 h6 ~ h
av Nu
av 26 c 1029 1171 1491 1589 15 28 1 4 62 1377 1293 1489 83 44 27 1266 1395 1746 1853 18 02 1685 1556 1453 1728 9704 28 1430 1637 2037 2175 2060 1909 1735 1591 1983 11159 29 1729 1982 24 96 2751 2507 2268 2030 1886 2410 13579 30 12D 1054 2934 4041 4321 4326 4423 4359 3706 4298 24160 31 1294 3385 4 8 26 52 42 5326 5450 5277 4566 52 24 293 50 32 1431 3784 5347 5721 57 bull75 58 44 5700 5084 5677 31870 33 1770 52 75 7 7 33 87 35 9005 9007 8267 7059 85 49 48050 34 lD 1058 3235 4401 4444 3877 3496 3451 3294 3934 21973 35 1263 38 98 5484 5330 4347 3964 3981 3987 4621 25823 36 18 36 6701 89 17 7855 6369 5597 5769 6283 69 01 38718 37 1 12D 1029 2404 31 8 2 3333 3459 3624 3577 3045 3435 19264 38 1315 3182 4033 4162 4310 4496 4502 4015 4301 24142 39 1426 3628 4389 4510 4573 4760 4804 43 8 5 4607 25678 40 1757 4547 5559 5(35 5931 6282 63 70 6060 5975 33471 41 2 11D 1080 2034 28 38 3155 3144 3145 2966 2540 3050 17027 42 1305 2650 3 4 87 3aoz 3595 3751 3595 3153 36 46 20405 43 1434 3167 39 07 4156 4371 4320 4126 3709 4176 23395 44 1804 4096 4 9 66 5691 5714 5586 53 15 48 65 5454 30582 45 12U 1088 409 516 557 564 5 60 535 513 5 46 30 67 46 1318 470 579 6 22 631 6 17 5 97 579 6 09 3422 47 14 13 540 640 676 6 86 681 6 60 6 54 6 69 3754 48 1773 641 740 774 782 7 69 749 746 763 42 87 49 l 11 U 1054 270 356 391 397 393 3 71 346 38 2 2133 50 1240 303 399 446 449 447 4 21 398 432 2420 51 1419 361 476 522 530 528 507 467 493 2760 52 1 1(2U 1032 236 311 342 347 344 325 301 334 18 78 53 1314 270 366 403 407 408 386 351 394 2217
(Tt tO
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ h av Nu av
54 1448 301 408 447 454 452 431 403 438 24 61 55 1782 353 494 548 544 415 529 531 506 2843 56 2U 10 61 220 287 316 320 322 303 268 310 1735 57 1216 249 335 370 377 378 353 307 363 2044 58 1322 263 356 394 398 399 374 327 384 2159 59 1639 310 433 478 481 482 452 393 465 2617
60 1D 10 68 2011 2536 2657 2681 2694 2560 15 62 2625 14938 61 1399 2520 3239 3369 3371 33r82 32 39 1946 3320 18968 62 1669 2781 3655 3820 38 76 3883 3738 2355 3794 21712 63 1959 3524 42 37 4399 4438 4497 4417 3047 4397 25156 64 2295 4426 5288 5396 5372 5240 5410 3369 5341 30680 65 2636 5490 6531 6662 6565 6379 6820 4249 6591 37938 66 3390 7869 9538 9462 9387 8924 10508 62 91 9564 59601 67 1U 1190 352 368 401 413 407 395 293 397 2256 68 1559 397 422 462 475 471 456 331 4 57 2603 69 1904 434 465 5 13 529 528 504 358 508 2901 70 2211 493 526 573 5 92 588 564 4 15 569 3257 71 2289 569 587 6 30 649 6 61 6 49 460 635 36 44 72 2727 637 6 60 7 09 733 751 743 521 719 4140 73 3210 728 755 8 15 8 43 8 62 8 54 616 826 4765 74 2nD 1210 181 2256 2393 2399 2333 2206 1325 2317 13158 75 1420 2340 2752 2899 2913 2850 2728 1701 2828 16121 76 1692 2853 3306 3452 3471 3379 3217 2134 3365 19217 77 1894 3102 3588 3713 3736 3670 3557 2455 3653 20892 78 2301 3682 4259 4433 4467 43 83 4289 2892 4366 250 30 79 2621 4117 4828 5017 5012 5030 5109 3071 4999 28785
m 0
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ hav Nuav
80 3230 5158 6006 62 13 61 18 6134 6695 4094 6233 359 87 8 1 12nD 1155 15 27 1854 2028 2064 20 85 1987 1164 1968 118 31 82 1689 2046 24 8 2 2688 2739 2760 2658 1749 2665 152 73 83 1244 2088 2317 2339 2345 2373 2381 1487 2351 13432 84 2100 3211 3539 34 21 3462 3512 3696 2575 3526 20284 85 2292 3 5 05 3761 3648 36 25 36 79 3957 2933 3734 21517 86 2907 4420 48 22 4679 46 04 4705 5206 3792 48 03 27741 87 33 80 59 35 69 38 7404 77 10 7 8 36 7 0 86 5190 7394 427 44 88 1 12D 1 4 27 2 4 58 28 31 3037 3021 2987 2927 18 57 2 9 61 16913 89 18 75 34 75 3 9 87 4230 4255 4317 4337 2734 4225 24258 90 22 59 4221 4796 5046 5052 51 01 5389 3491 5077 29206 91 2682 4978 5664 5943 5966 6054 6573 408 1 60 40 34795 92 3417 63 16 71 02 7 3 93 7385 75 40 8 6 95 51 45 7623 44017 93 c 1 5 17 1240 1305 1399 1467 1479 1429 9 26 1423 8251 94 20 34 1554 1623 1720 18 21 18 53 18 72 1215 1778 10229 95 2 3 48 1795 1843 198 5 2097 2171 2274 1540 2074 11947 96 2716 2028 2048 22 01 2 3 44 2444 2661 18 90 2340 13505 97 3247 2410 2375 2663 2778 2949 3298 2378 2793 1615 98 11 35 967 1040 1124 1186 1200 1142 728 1138 6496 99 14 06 1135 1220 1318 1384 1403 1 3 61 8 77 1336 7656
100 2311 1 8 54 18 78 1980 20 90 2136 2227 1653 2062 118 31 10 1 2666 2085 2094 2227 2 3 62 2438 2626 1902 2349 13508 102 3392 2635 2582 28 01 3026 3141 3529 2567 3016 17390
103 1 U 1235 349 395 434 436 4 28 411 286 423 2416 104 20 10 434 5 02 559 577 569 5 37 345 552 3177 105 28 14 538 626 685 711 7 21 682 424 6 8 6 3966
Q) j-J
TABIE III Continued
Run No Position CFM h1 h2 h3 h4 h5 hu h7 hav Nuav
106 3492 614 7 1 6 7 84 8 13 8 33 7 85 4 88 7 87 4562 107 4395 7 86 894 964 996 1005 9 64 640 9 65 56 06 108 50 75 9 11 10 22 1081 1112 1125 1085 7 24 1085 63 16 109 G 1344 9 22 1042 1120 1 1 46 1173 1131 7 04 1120 63 87 110 1936 1162 1340 1442 1474 1509 14 7 3 9 09 1441 82 77 111 2846 1631 1797 1902 1966 2027 2079 1342 19 2 3 11108 112 3484 207e 2144 2236 2307 2385 2574 1694 2268 13138 113 4066 24 65 24 42 2535 2648 2757 31 71 2178 2 5 96 15078 114 50 12 3059 2916 30 1 5 3176 3312 4059 2849 3105 180 46 115 1D 1362 2268 26 13 2613 26 35 2605 2503 15 46 2617 14934 116 1958 2993 3580 3580 3586 3539 3 5 02 2144 3571 20492 117 2812 4430 50 32 4913 4 9 86 4991 5196 3088 4981 287 66 118 3432 58 16 62 13 6067 61 18 60 66 6698 4143 61 16 354 16 119 40 22 71 71 7 4 62 7369 7419 7329 82 74 51 8 1 7395 42909 120 5026 105 95 11456 115 81 11574 11548 14010 80 91 11540 671 15 121 2D 1244 18 57 2277 2363 2305 2210 2107 1466 2289 13038 122 1960 2622 3240 3388 33 23 3226 31 40 2)99 3294 18919 123 2817 3762 45 87 4739 46 56 45 14 4 6 47 30 15 4624 26689 124 3491 50 22 5723 58 53 57 44 5542 60 18 3871 57 16 330 73 125 4096 61 29 68 16 69 79 6805 65 90 74 79 4677 67 98 39400 126 5037 82 27 94 60 95 69 93 57 9023 11324 65 05 93 52 542 83 127 12D 1278 14 70 1 6 48 1652 1638 1 6 34 1641 9 73 1 6 43 9369 128 1947 19 63 2155 2149 2151 2131 2190 1347 2147 12342 129 2769 2615 2791 2773 28 52 2716 2954 18 96 2783 1 60 82 130 3439 3208 3265 3239 3593 3133 3624 2515 3308 19174 131 4103 3637 35 88 3577 4077 3459 42 66 3138 3676 21343 132 49 78 45 82 44 60 44 8 1 55 17 43 25 5749 4227 4700 27288
Q) tlgt
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
133 1 12D 1299 2094 2507 2622 2625 2567 2489 1465 2578 14736 134 1973 29 56 3505 3772 3790 3718 3718 2115 3700 21290 135 2788 3941 4727 5069 5099 5 0 07 5231 2984 4976 28781 136 3473 5155 59 81 6308 6339 62 39 68 96 4204 6217 36052 137 4118 6135 71 8 6 7662 7731 76 91 87 16 49 8 5 7568 43985 138 4973 7765 94 75 10396 10861 10694 13646 66 64 10357 602 25
139 1ttn 1253 1242 1493 1460 1442 1431 1424 8 84 1457 83 01 140 2366 1942 2150 1961 1910 1897 19 62 1206 1980 11400 141 3461 3007 2957 2562 2513 2606 3143 18 51 2660 15400 142 4325 3942 3571 3060 2999 3198 4248 2631 3207 18618 143 5677 508 6 4359 39 88 3800 42 29 57 78 36 26 4094 23824 144 67 59 64 55 5330 4988 47 25 5494 2517 48 09 5134 29906 145 84 08 9326 72 26 7726 85 56 9172 12319 7733 8170 47626 146 86 54 9831 7582 818 9 94 90 9869 13116 78 97 8783 512 96 147 7376 7335 58 7 6 5941 5796 68 29 81 65 5954 6111 35662 148 2 11 D 4254 4106 48 02 4994 5038 5042 56 78 3419 4969 28881 149 5708 5487 6253 6466 6524 6527 78 63 45 8 2 64 43 37566 150 69 7 8 7983 9440 9848 98 34 97 32 13249 6701 9714 566 59 151 1254 1434 18 53 1947 1915 1850 1760 1186 1891 10772 152 2713 2696 3175 32 94 3288 3237 3288 20 44 3249 18728 153 87 30 118 07 14733 15758 15504 15305 26297 9617 15325 892 71 154 5811 5278 6543 6861 69 30 69 82 7 8 74 4478 68 29 39531 155 4246 3780 4736 4975 49 66 4936 5162 3113 4903 28301 156 (v 1270 8 15 935 959 966 9 51 9 23 6 35 953 5430 157 2714 1164 1390 1427 1447 1454 1455 9 08 1430 8242 158 4310 1655 18 96 1942 1988 2002 2111 1305 1957 11349
(j) ~
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 fry hav Nuav
159 6012 2208 2400 2450 2513 2548 28 20 18 00 2478 14416 160 7279 2696 2881 2927 2989 3081 3599 2340 2970 17326 161 86 90 3257 3360 3 3 76 34 26 3558 4455 2943 3430 2000 162 12D 4368 2209 2600 2558 2518 2466 2774 1753 2536 14713 163 5833 2730 3092 3028 2974 2913 3501 2287 3002 174 78 164 7643 3320 3681 3630 3651 3530 4623 3181 3623 21116 165 87 39 3920 4303 4300 4708 4178 61 60 3937 4372 25456 166 1268 962 1203 1205 1186 1118 1084 725 1178 6693 167 2678 14 67 1785 1779 1752 1698 1726 10 70 1754 88 49 168 1 12D 12 83 936 1217 1414 1397 1239 1190 7 65 1317 7484 169 2729 2502 2930 2914 2934 2956 2979 17 52 2934 16866 170 4345 3884 4357 4283 4318 4421 4836 28 59 4345 25151 171 6036 5546 5858 5764 5791 6028 7129 4184 5860 34045 172 6578 7167 7769 7907 79 82 8263 10492 5915 7980 46437 173 87 84 10237 112 23 120 26 12727 12968 185 19 85 98 12236 71103 174 1278 1344 1803 18 72 1835 1790 1712 1063 1825 10355 175 2711 2328 2972 2932 2893 28 78 2863 1667 2919 167 51 176 4351 3934 4414 4353 4281 4321 4654 28 63 4342 25088 177 5994 5076 5824 5838 5818 59 29 6914 4205 5852 33885 178 1 11 U 1223 388 432 465 464 449 435 338 453 2585 179 2351 521 602 6 22 675 6 57 619 436 639 3687 180 34 48 6 05 1725 803 8 27 8 11 760 518 792 4593 181 4513 718 850 934 9 68 9 57 8 99 609 9 27 5386 18 2 5714 8 32 981 1060 1102 11 06 1034 6 59 1062 61 82 183 6997 1025 1182 1258 1295 1309 1234 8 18 1261 7 3 44 184 8709 1295 1487 1 5 42 1594 1626 1612 1156 1562 9080
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
185 2 12D 4249 3560 4400 4670 4791 4695 47 81 2931 4639 268 37 186 5737 4926 58 54 61 92 6248 62 38 67 78 4134 6131 35590 187 7432 6390 7726 83 46 85 44 86 34 10371 5658 8313 48310 188 8723 7718 107 88 11933 12099 13046 186 22 79 39 119 67 69505 189 1 4 35 1340 1735 18 57 18 52 17 81 1711 1144 18 06 10256 190 2718 2399 3023 3187 3207 3138 30 53 1931 3139 18025 191 7 5 07 6189 80 11 9200 9427 9703 11364 5720 9085 527 38 192 8544 78 42 10666 125 42 13312 13775 178 20 6976 125 74 729 86 193 1287 1417 16 97 18 7 18 69 18 08 1720 1046 1800 10223 194 27 17 2450 2940 3187 3214 3157 3054 1749 3125 17954 195 42 53 3560 4222 45 90 4679 46 63 4743 2741 4539 26247 196 6068 48 69 57 79 6335 65 8 6 66 04 7172 4338 63 26 366 78 197 7389 58 86 72 8 6 82 23 8584 8936 10658 50 60 8257 4798 6 198 86 88 78 91 100 27 120 56 130 29 14299 190 81 6492 12353 71850 199 5864 4694 5 6 67 61 94 6419 65 48 7192 3950 6207 360 14 200 2 D 4177 38 36 4547 48 09 4775 4628 5006 2715 46 90 261 30 201 5712 5170 62 39 66 38 6599 6604 7518 4167 65 20 378 00 202 73 63 7201 8986 98 43 9733 9914 13353 6219 9619 55810 203 8604 10043 13118 148 41 150 42 158 66 25206 82 5 3 14717 85290 204 12 68 1506 18 41 1971 1966 1868 1799 11 42 1913 10880 205 2659 2571 3127 3276 32 50 3130 3069 18 80 3196 18 350 206 39 80 36 76 4347 4573 45~67 4473 46 34 28 37 4490 25910
o 207 Orifice 11496 10 64 1360 15 39 1 5 80 1 6 15 1496 8 58 15 24 88 83 208 9433 8 95 11 78 13 26 1394 1386 1263 727 1346 78 48 209 7387 746 9 77 1123 1184 1159 1048 6 11 1111 64 74 210 52 36 566 7 66 900 934 909 8 21 499 8 27 48 02
0) CJ1
TABLE III Continued
Run No Position CFM h 1 h2 hs h4 h5 h6 h7 hav Nuav
211 212
3309 1293
414 257
563 3 19
6 68 3 57
6 91 3 37
6 72 351
7 37 337
38 4 2 46
4 40 341
3748 1942
213 214 215 216 217 218
c of 2nd 1 516 1235
1919 2712 3320 4153 4704
1532 2447 35 46 4312 5567 74 29
2 1 87 3312 4225 52 86 6902 8 6 50
2360 3555 4340 56 12 7 0 49 8 9 40
2409 3598 4 8 85 5718 7713 9593
2347 2101 35 33 3453 48 00 49 62 5562 59 86 72~6 7 8 79 93 76 11237
1243 20 64 3054 4 2 8 1 5114 6983
2326 35 00 4638 5545 7225 91 40
132 13 200 27 26672 31968 41711 52811
bull
67
TABLE IV
PRESSURE PROFILE DATA
Baffle Flow Qpening Rate ~p
(Inches) Position (CFM) (Inches 295 S G Fluid)
1 364 l2 11 U 1012 0 254 1248 0197 1493 0 141 1718 0112
c 1000 9 80 1210 1710 1436 28 75 1746 4320 1011 1080 1277 2050 1393 3020 1 6 28 4450
12D 1011 9 75 1236 1520 1450 2510 1603 3450
1 D 1011 975 1256 1700 1480 2690 158 1 4070
1 12D 1010 950 1259 1750 1462 2650 1631 3710
2 11 D 1124 1315 1360 2130 1505 2850 1689 4125
1 216 12U 1294 045 1949 0324 2374 0282 2704 0225 3367 0169
c 1326 265 18 81 5 90 2313 990 2731 1480 3439 2660
12D 1272 2 49 1957 661
68
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Pos ition (CPM) Inches 2 95 S G Fluid)
2559 1275 3033 1940 3639 3025
1 216 1nD 1257 242 16 96 476 2117 8 05 2561 1280 2990 1895 3431 26 bull00
1 316 12U 1309 0 479 2004 0422 28 28 0 352 3526 0281 42 28 0225 5199 0225
c 1308 1 43 1998 272 28 14 5 10 3478 795 4248 1235 5048 1885
l2D 1286 140 2005 3 45 2831 725 3495 1180 4194 1805 5046 2945
1 11D 1322 150 2039 352 2841 735 43 77 1980 5378 3440
1 516 12U 1278 0493 2732 0493 4315 0408 5744 0352 7494 0352 8932 0422
c 1300 0 506 2731 1985 4310 348 6080 6 45
69
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Position (CPM) (Inches 295 SG Fluid)
7607 1090 8830 1585
l2D 1343 0549 2738 225 4566 583 6112 1195 7536 2055 9043 3415
1 516 1uD 1249 0464 2713 224 4155 579 5620 1150 7428 2115 90 70 3405
1 12D 1301 0493 2735 220 4501 616 61 50 1235 7440 2065 8862 3445
2D 1265 0 478 2750 226 4366 594 6578 1270 7678 2240 8945 5280
2 12D 1295 0493 2725 222 4293 600 5807 1120 7568 2200 9070 3615
TABLE V
RATE OF HEAT TR AN SFER Ar THE BAFFL~~ CID-TT ER
Orifice Size
(Inches)
Flow Rate
( CFM)
Re d e G tU
R~) 055 Nuav NuPr-l3
1 364 10 26 12 90
8 075 10015
43400 54 600
85 11 99 64
95 83 112 19
1416 11 140 59 900 110 30 124 20 16 27 12 800 68 900 126 64 142 60 17 29 13 610 73 200 135 79 152 90 17 76 13980 75 200 147 59 166 19
1 216 11 35 14 06
8 600 10 660
27000 33500
6 4 96 76 56
73 14 8 6 12
1517 11500 36100 82 51 9291 20 34 15400 48400 10229 115 18 23 11 17500 55000 118 31 13322 2348 17 800 55900 11947 13452 2666 20 200 63400 13508 15210 27 16 20 600 64700 135 05 152 07 32 47 24600 77200 161 57 18 193 3392 25 700 80700 17390 195 8 1
1 316 1344 19 36
9898 14 260
24800 35 700
63 8 7 8 2 77
71 92 93 20
28 46 20 9 60 52 500 111 08 125 08 34 84 25 660 64200 131 38 147 93 40 66 50 12
29900 36900
74800 92400
150 78 18046
169 78 203 20
~ 0
TABLE V Continued
Orifice Flow Re Size Rate d e G R~rmiddot55 NuPr-13(Inches) (CFM) U Nuav
1 516 12 70 8 847 16800 54 ~0 61 14 2 14 18 900 35800 82 42 92 80 43 10 30 000 56900 11349 127 79 60 12 41900 79400 14416 16232 7279 50700 96100 17326 19509 86 90 60540 115000 20098 22529
TABLE VI
RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
Orifice Size
(Inches)
1 364
1 216
1 316
Flow Rate
(CFM)
1054 1294 1431 1681 1770
1068 1399 1669 1959 2295 2636 3390
1299 1973 2788 34 73 4118 4973
Re deG Mshy
8 300 9870
11260 13200 13 930
8100 10600 12650 14850 17400 19980 25700
9 570 14500 20500 25600 30300 36600
R~r-6 51900 61700 70500 82 500 87 100
28200 36900 44000 51700 60 600 69500 89400
26100 39600 56000 69900 82700 99 900
Nuav
2416 293 5 3187 4018 4805
14938 18968 21712 25156 30680 37938 59601
14736 21290 28781 36052 439 85 60225
Uu Pr-1 3
27204 33050 3589 4524 541 0
16820 21358 24448 28326 34546 427 18 67111
16593 23973 32407 40595 495 1 678 13
TABLE VI Continued
Orifice Flow Re Size Rate deG R~rmiddot6 NuPr-13(Inches) (CFM ) M- Nuav
1 516 1268 88 30 17700 108 8 1225 2689 18700 37400 1835 2066 3980 27700 55700 2591 2917 4177 29100 58 500 2713 3055 5712 39800 80000 378 0 425 6 7362 51300 103000 5581 6284 8 604 59 900 120000 8529 9604
74
TABLE VII
EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER
l 516 Inch Orifice
Center ot 2nd Baffle 4 Downstream
Plow Rate (CFM)
1235 1919 2712 3320 4153 4704
Flow Rate (CFM)
1270 2714 4310 6012 7279 8690
(Re)eb -8600 1321
13400 2003 18900 2687 23100 5197 28900 4171 32800 5281
Center ot Single Battle
-8847 543
18900 824 30000 1135 41900 1442 50700 1733 60540 2001
(Nu)(Pr)-l3
1487 2255 3003 3600 4697 5946
(Nu)(Pr)-13
611 928
1278 1623 1951 2253
75
ABLE VIII
HEAT TRANSFER IN THE TEST SECTION WITHOUT ORIFICE
CFM Ute) 0b h Nu
1293 5-951 3 41 1942
33 09 15251 649 3746
5236 24193 827 4802
7387 34001 1111 6474
9433 43419 1346 7848
11496 52-914 1524 8883
76
TABLE IX
PRESSURE DROP FUNCTION
Orltlee Size Flow Rate incbea ~CFM (Re)eb X 10bull8
1 364 1011 7957 0808 1256 9885 1468 1480 11648 2765 1581 12443 4160 1689 1_3293 4 020
1 216 1257 9530 1327 1696 12858 2663 2117 16049 4615 2561 19415 7581 2990 22668 11560 3431 26011 16440
l 316 1322 9736 1819 2039 15016 4332 2845 20952 9275 3495 25739 15300 4377 32014 26800 5378 39607 50100
1 516 1011 7 957 oaos 1256 9885 1469 1480 11646 2765 1581 12443 4160 1689 13293 4020
77
TABLE X
EXPERIMENTAL DATA
Baffle Hole Diameter Run No
1 - 59
60 - 102
103 - 138
139 - 206
207 - 212
213 - 218
(Inches)
1 364
1 216
1 316
1 516
No Baffle
2nd - 1 516
TABLE X
EXPERIMENTAL DATA
Run Thermocouple Reading s (mv) No Position CFM I tc1 tc2 tc3 tc4 t c 5 tc6 tc7 tcair
1 c 1026 530 2055 1825 1768 1782 1802 1837 1965 1198 2 1290 612 2059 18 65 1809 18 32 1851 1880 1965 1160 3 1416 714 2151 1970 1931 1965 1988 2026 209 5 1130 4 1627 8 21 2235 2084 2 049 2093 2126 2173 2266 1130 5 1776 865 2203 2033 1970 2015 2084 2159 2 264 1121 6 12D 1109 542 1636 1507 1499 1499 1498 1498 1528 1218 7 1258 651 1670 1522 1503 1513 1513 1516 1548 1221 8 1433 750 1625 1480 1467 148 3 1487 1487 1516 1153 9 168 1 8 73 1656 1494 148 1 1511 1517 1517 1543 1159
10 1rtD 1102 485 1545 1450 1437 1446 1447 1442 1466 1220 11 13 08 6 10 1571 1470 1460 1476 1476 1469 1498 1194 12 1464 730 1 623 1509 1508 1528 1 5 32 1524 1548 1173 13 11 06 8 71 1663 1559 158 1 1606 160 6 1 583 1601 1190 14 1 12D 1115 520 1698 1579 1575 1 577 1580 1590 1615 1280 15 1275 6 10 1692 1567 1558 1 561 1570 1580 1601 1234 16 1498 770 1760 1619 1630 1 635 1642 1645 1661 1204 17 1695 912 1775 1635 1670 1689 1686 168 6 1701 1165 18 2D 1049 510 1736 15~2 1567 1558 1 553 1558 1620 1236 19 12 41 610 1655 1517 149 1 148 1 148 1 148 4 1546 1108 20 1 5 32 7 35 1720 1550 1530 1520 1519 1523 158 0 1104 21 16 74 8 8 0 1900 1 727 1714 1696 1691 1692 1753 1169 22 1U 1074 38 5 3 324 2740 2534 2478 2 465 2503 258 0 1210 23 1287 4 35 3510 2 870 2682 2 610 2599 2638 27 1 9 1190 24 1 5 08 470 3 618 2920 2690 2 637 2627 2 664 2747 1177 25 18 07 525 4 088 3235 2962 2905 2910 2988 3130 1169
z ())
TABLE X Continued
Run No Position CFM I tc1 tc 2
Thermocouple Readings te3 tc4 tc5
(mv) tc6 tc7 tcair
26 c 10~29 6 32 2340 2~092 2032 2060 2~097 2152 2~213 1211 27 12 66 679 2270 2 047 1993 2013 2069 2142 2 210 1 182 28 1430 723 2336 2097 2033 2080 2153 2~255 2 356 1 138 29 1729 8 52 2318 2070 1980 2061 2158 2279 2367 1121 30 12D 1054 570 1520 1 4 20 1402 1400 1396 1400 1 443 1159 31 1294 6 69 1599 1469 1444 1439 1433 1 442 1485 1168 32 1430 7 88 1720 1562 1536 1532 1528 1537 158 0 118 5 33 1770 8 81 1641 1488 1450 1~441 1 441 1_466 1518 1 163 34 1D 1058 548 1579 1498 1495 1526 1553 1_557 1 571 1 276 35 1263 640 1609 1509 1515 1570 1599 1598 1 598 1 266 36 18 36 8 47 1538 1452 1483 1553 1602 1 590 1 558 1195 37 1 12D 1029 5 41 1 578 1499 148 4 1473 1461 1465 1-512 1200 38 1315 6 30 159 1 1504 1493 1482 1470 1470 1505 118 5 39 1 4 26 743 1765 168 1666 1660 1645 1642 1678 1270 40 1757 8 54 1744 1648 1634 1620 1598 1 593 - 1612 1223 41 2D 1080 5 30 1734 1604 1570 1 570 1570 1 588 1 640 128 1 42 1305 6 40 1744 1622 1589 1 608 1593 1 609 1 661 1240 43 1434 750 1798 1687 1658 1 636 -1641 1 661 1 711 1_220 44 18 04 8 41 1 764 1666 1607 1605 1614 1 635 1 675 1205 45 12nu 1088 415 2614 2295 2195 2 169 2174 2217 2256 1171 46 1318 477 2805 2477 2371 2342 2364 2 401 2 438 1 163 47 1413 5 28 2930 2 646 2 555 2 526 2532 2570 2 577 1 199 48 1773 550 2740 2518 2450 2431 2448 2 479 2 480 1 170 49 1 11 U 1054 380 3175 2670 2505 2 461 2467 2 534 2 621 1 258 50 1240 420 3268 2738 2 546 2 510 2 508 258 2 2 649 1214 51 1419 451 3364 2B07 2 632 2590 2 590 2 651 2773 1 215 52 1 12U 1032 360 3 165 2 629 2 450 2402 2403 2 473 2 bull568 1 163
--I lt0
TABLE X Continued
Run No Position CFM I tc1 tc2
lhermocoup1e Reading s tc3 tc4 t c 5
(mv) tc6 tc7 tc a ir
5 3 1314 38 9 3178 2592 2411 2367 2361 2432 2555 1140 54 1448 403 3095 2544 238 1 2336 2336 2390 2476 1158 55 178 2 427 3006 2434 2286 2253 255 3 2299 2397 1154 56 2 11U 1061 360 3369 2814 2619 2567 2560 2650 2833 1220 57 1216 360 3044 2512 2338 2290 2288 2374 2566 1150 58 1322 387 3196 2614 2425 2383 2382 2472 2670 1138 59 1639 403 3020 2438 2272 2238 2238 2318 2502 1127
60 1D 1068 612 1552 1424 1400 1395 1396 1426 1745 0945 61 1399 612 1355 1246 1230 1229 1230 1250 1509 0872 62 1669 710 1436 1293 1272 1265 1266 1286 1551 0847 63 1959 900 159 5 1468 1444 14 38 1432 1446 1720 0851 64 2295 730 1169 1105 1098 1099 1108 1100 1298 0781 65 2636 8 80 1202 1129 1121 1126 1 138 1115 1342 0748 66 3390 9 35 1060 o 9s7 0999 1001 1017 0971 1154 0703 67 1nu 1190 370 2225 2188 2104 2080 2120 2209 2 7 15 0990 68 1559 368 2005 1950 1871 18 48 1876 1951 2408 0916 69 1904 368 1870 18 1 4 17 34 1711 1730 18 07 2238 0875 70 22 bull11 471 228 6 2 204 2099 2063 2092 218 $ 2732 0840 71 2289 471 2030 2000 1925 1895 18 96 19 5 2498 0785 72 2727 4 71 1854 18 23 1753 17 23 1716 3758 2241 0743 73 3210 471 1680 1651 158 6 1559 1551 158 1 1950 omiddot7o9 74 2uD 1210 404 1261 1212 1198 1197 1205 1222 139 1 0978 75 14 20 540 1321 1260 1242 1 240 1249 1268 148 7 0918 76 1692 7 18 1467 138 6 1364 1361 1376 1405 1678 0883 77 18 94 903 1708 1 591 1565 1560 1575 1603 1948 0 857 78 2301 903 1530 1432 1407 1402 1415 1432 1738 0815
ro 0
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc117 tcair
79 2621 6 50 1069 1 020 1009 1009 1009 1007 1~189 o739 80 3230 901 1200 1128 1113 1119 1119 1086 1341 0694 81 82
l2D 1155 1689
360 575
1191 1345
1142 1252
1122 1218
1118 1210
1118 1209
1132 1228
1292 1446
0916 0822
83 1244 430 1163 1134 1131 1130 1129 1132 1292 0877 84 2100 645 1175 1135 1147 1 142 1138 1122 1286 0757 85 2292 8 25 1 354 1310 1327 1330 1323 1285 148 6 0728 86 2907 8 23 1180 1138 1151 1158 1149 1107 1268 0687 87 3380 902 1113 1049 1025 1011 1006 1042 1178 0673 88 89
1 12D 1427 1875
480 615
118 2 1140
1140 1095
1124 1077
1125 1075
1129 1072
1137 1072
1290 1243
0880 0790
90 2259 8 41 1296 1231 1207 1206 1203 1182 1419 0757 91 2682 8 80 1231 1170 1149 1147 1142 1112 1350 0731 92 3417 940 1142 1092 1076 1076 1069 1021 1252 0693 93 c 15 17 431 1321 1298 1268 1249 1250 1273 1522 0841 94 2034 505 1285 1263 1235 1209 1205 1206 1464 0759 95 2348 6 10 1395 1379 1334 1302 1286 1268 1536 0732 96 2716 706 1486 1480 1427 1383 1358 1311 1572 0 700 97 3247 7 56 1417 1430 1375 1320 1284 1223 1450 0660 98 1135 400 1425 1388 1352 1329 1330 1 364 1651 0893 99 14 06 440 1379 1341 1304 128 2 1281 1305 1583 0 831
100 2311 680 1602 1593 1553 1514 1502 1480 1 7 27 0 802 101 2666 680 1471 1469 1428 1390 1372 1335 1564 0761 102 3392 798 1491 1 509 1449 1395 1372 1305 1534 0 719
103 1U 1235 410 2469 2295 2173 2165 2226 2361 3120 0 897 104 2010 410 2017 1848 1 737 1706 1747 1865 2582 0753 105 28 14 410 1682 1535 1457 1427 1437 1520 2109 0 660
00 t-
TABLE X Continued
Ru n Thermocouple Rea ding s (mv No Positi on CFM I tc1 tc2 tc3 tc4 tc5 tc6 tc7 tcair
106 3492 440 1649 1499 1420 1391 1390 1470 2042 0620 107 4395 550 18 33 1679 1597 1564 1570 1640 2223 0583 108 5075 588 1779 1642 1580 1550 1552 1 615 2 191 0548 109 c 1344 398 1464 1 399 1364 1353 1350 1380 1689 0 907 110 1936 459 1369 1290 1253 1242 1 237 1259 1574 078 2 111 2846 580 1347 128 5 1251 1232 1220 1215 1 5 23 0 683 112 34 8 4 700 1392 1369 1339 1317 1299 1259 1599 0 636 113 4066 8 13 1449 1458 1427 1391 1363 1270 1595 0 591 114 5012 930 1484 1530 1500 1453 1420 1272 1580 0 580 115 1D 1362 513 1269 1218 1 217 1214 1220 1238 1460 0 893 116 19 58 600 1187 1122 1121 1120 1124 1133 1352 0798 117 2812 705 1052 1008 1015 1010 1011 1001 1218 0691 118 34 32 913 1105 1075 1085 1081 1086 1047 1301 0645 119 4022 980 1038 1021 1026 1023 1029 0983 1211 0 609 120 5026 982 0 8 61 0839 0836 0836 0837 0791 0955 0570 121 2D 1244 475 1320 1246 1233 1240 1255 1275 1434 0925 122 1 9 60 5 50 1160 1088 1074 1079 1089 1100 1260 078 7 123 2817 6 80 1096 1024 1 013 1018 1029 1022 1201 0 700 124 3491 960 1248 1175 1163 1172 1192 1153 1435 0 658 125 4096 989 1141 1089 1078 108 9 1105 1051 1310 0629 126 50 37 989 0983 0933 0929 0 936 0949 0880 1090 0 602 127 128
12D 1278 1947
402 545
1270 1261
1 230 1216
1228 1216
1230 1 215
1235 1223
1242 1219
1483 1514
0 913 0778shy
129 2769 695 1273 1234 1237 1221 1251 1212 1525 0678 130 131 132
34 39 4103 4978
8 40 9 80 9 80
1336 1448 1271
1322 1458 1 288
1328 1 462 1286
1 259 1 356 1157
1353 1492 1311
1261 1329 1138
1 555 160 7 1343
0 629 0 600 0599
(l) l)
TABLE X Continued
Run No Position CFM I tel tc 2
Thermocouple Readings tc3 tc4 tc5
( mv) tc6 tc7 tcair
133 1 l2D 1299 5 16 1 28 1 1212 1196 1195 1205 1221 1478 0869 134 1973 6 15 1163 1098 1073 1071 1079 1083 1343 0751 135 136
27 88 34 73
802 9 -_78
1187 1214
1099 1131
1069 1104
1066 1101
1075 1~110
1l061 1066
1370 1360
0662 0618
137 4118 9 81 1084 1010 0983 0979 0982 o937 1209 0581 138 4973 98 1 0969 0897 0 868 0855 0860 0799 1041 0572
139 1D 1253 409 1371 1293 1298 1301 1309 1321 1578 0928 140 2366 480 1130 1 090 1 121 1130 1137 1132 1390 0744 141 34 61 6 38 1081 1086 1152 1161 1147 1069 1382 0644 142 143 144
4325 5677 6759
7 90 939 998
1110 1115 1034
1161 1208 1139
1253 1268 1180
1265 1302 1215
1228 1230 1123
1080 1056 0970
13$913r12 8
0601 0561 0542
145 84 08 989 0863 0961 0934 0895 0871 0 785 09 9 0530 146 86 54 9 80 0808 0901 0 872 0821 0809 0733 0891 0498 147 7376 9 80 0 927 1032 1027 1 040 0961 0889 1032 0511 148 2D 4254 776 1 050 0 981 0965 0961 0962 0922 1155 0579 149 5708 991 1102 1031 1014 1009 1010 0931 1227 0528 150 69 78 990 0914 0853 0839 0 839 0843 0759 0996 0521 151 1254 490 1 479 1352 1329 1334 1351 1379 1607 0930 152 2713 7 00 1310 1220 1201 1201 1211 1209 1516 0723 153 8730 991 0809 0756 0742 0745 0 748 0663 0874 0543 154 5811 966 1219 1108 108 6 1081 1079 1033 1330 0650 155 42 46 8 02 1248 1136 1114 1114 1118 1103 1376 0 699 156 c 1270 429 1671 1571 1551 1545 1563 1600 1933 0929 157 2714 488 1398 1285 1 267 1258 1262 1275 1628 0729 158 4310 642 1424 1318 1299 1282 1283 1261 1683 0617
co ~
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc7 tc a 1r
159 60 12 780 1461 1388 1370 1349 1343 1279 1700 0 573 160 72 79 8 60 1402 1344 1330 1312 1292 1189 1 566 0 520 161 8690 982 1472 1442 1437 1 422 1392 1224 1602 0 521 162 163
12D 4368 5833
6 30 8 30
1195 1368
1105 1270
1111 1283
1117 1294
1131 1313
1081 1194
1369 1553
0613 0 553
164 76 43 959 1428 1338 1348 1341 1371 1180 1488 0535 165 8739 984 1345 1272 1272 1208 129 3 1059 1361 0550 166 1268 459 1701 1548 1541 1547 1589 1 625 1976 0 973 167 2678 570 1485 1351 1349 1356 138 1 1 385 1795 0760 168 169
1 12D 128 3 2729
448 650
1664 1314
1501 1232
1425 1233
1428 1229
1491 1229
1527 1232
1869 1571
0 962 0767
170 4345 847 1245 1179 1187 1182 1172 1132 1476 0 650 171 6036 9 76 1139 1109 1117 1114 1095 1020 1332 0588 172 6578 9 72 0982 0949 0942 0938 0926 0 8 50 1079 0560 173 87 84 9 72 0880 0854 0 8 36 0822 0818 0 749 0941 0585 174 1278 480 1564 1416 1397 1403 1417 1445 1733 0998 175 2711 590 128 3 1175 4 1178 1182 1187 1195 1493 0796 176 4351 8 90 1331 1259 1266 1275 1272 1235 1592 0 682 177 5994 9 60 1228 1152 1150 1151 1143 1075 1 360 0644 178 lU 1223 408 2282 2140 2052 2052 2106 2188 2626 0 878 179 2351 408 178 1 1623 158 5 1519 1556 1634 2068 0717 180 3448 482 1888 1675 1570 1541 1572 1665 2199 0629 181 4513 563 2026 1797 168 4 1644 1670 1770 2385 0583 182 5714 589 1913 1700 1610 1568 1580 1 682 2382 0551 middot 183 6997 653 1903 1718 1643 1611 1612 1700 2326 0 549 184 8709 6 80 1738 158 3 1543 1510 1498 1519 1 912 0577 185 186
2 12D 4249 5737
660 9 74
1055 1221
0 979 1122
0960 1093
0 952 1088
0959 1090
0 956 1054
1147 1350
0661 0602
187 7432 9 8 1 1065 0981 0951 0942 0 939 0881 1135 0582 CD ~
TABLE X Continued
Run No Position CFM I t o1 to 2
188 87 23 9 83 0944 0 879 189 1435 585 18 26 1630 190 2718 690 1433 1298 191 7507 950 1070 0961 192 85 44 964 0982 0 881 193 1287 600 1806 1668 194 2717 7 80 1579 1444 195 4253 8 81 1371 1260 196 60 68 9 78 1252 1152 197 73 89 975 1100 1000 198 86 88 973 0953 0 871 199 58 64 9 81 1269 1155 200 2D 4 1 77 915 1362 1251 201 5712 975 1213 1111 202 7363 9 78 1036 0 951 203 8 604 973 0932 0861 204 1268 6 95 2015 18 20 205 2659 6 96 1405 1295 206 39 80 7 98 1261 1174
No 207 Orifice 114 96 509 1325 1148 208 94 33 509 1477 1243 209 7487 5 09 1686 1409 210 5236 505 2094 1691 211 3309 428 2188 1 778 212 1293 392 2976 2560
Thermo ooup1e Readin g s (mv) to 3 to4 to
5 to
6 to7 toair
0 851 0847 0 8 29 0759 0987 0592 158 4 1583 1611 1647 1993 0986 1270 1266 1 279 1298 1604 0 789 0916 0908 0900 0 858 1115 0602 08 39 0 823 0 818 0 770 1035 0602 1609 1602 1629 1676 2153 0979 139 1 1385 1400 1 430 1938 0776 1212 1201 1205 1201 1601 0669 1 105 1086 1086 1 052 1371 0621 0952 0936 0923 0870 1195 0582 0 8 20 0 801 078 1 0 729 1044 0569 1108 1090 108 2 1043 1407 0610 1218 1221 1241 1202 1582 0659 1081 1083 1084 1031 1 368 0622 0921 0924 0919 0 841 1111 0 610 08 34 0831 0 821 0 751 1003 0 630 1761 1761 1 809 1861 2399 0966 1271 1271 1295 1311 1650 0797 1150 1150 1161 1149 1440 0703
1083 1057 1053 1109 1566 0~530 1158 1125 1138 1217 1763 0 526 1291 1250 1278 1383 2038 0542 1518 1478 1519 1657 2420 0 589 1596 1557 1601 1737 2441 0688 2370 2344 2409 2561 3 297 0921
()) (11
TABLE X Continued
Run Thermocouple Readings (mv) No Position CFM I tc 1 tc2 tc3 tc4 tc tc tc tc i5 6 7 a r
C of 2nd 213 516 1235 4 63 1 432 1291 1265 1258 1 268 1 308 1550 0 971 214 1919 6 17 1357 1223 1196 1191 1199 1211 1461 0 851 215 27 12 8 35 1401 1259 1278 1220 1230 1218 1511 0 762 216 3320 981 1439 1305 1270 1259 1275 1238 1450 0719 217 41 53 980 1251 1142 1132 1094 1121 1088 1305 0 695 218 404 987 1102 1042 1030 1 bull006 1014 0960 1133 0681
Supplementary Equations
Calculating temperatures from thermocouple readings
t = -026tc)2 + 3512(tc) + 3201 (26)
where t is the temp in deg F and tc is the thermocouple reading in millishyvolts
Calculation of the thermal conductivity of air
k = 00000245ta + 0 0132 (27)
where k is the thermal conductivity in Btuhr rt2 degFft and ta is the air temp 1n OF
I I
bull co m
APPROYED I
Redacted for Privacy
Chergc of Xefor
Dorn of frrtdnrtc sohool
Redacted for Privacy
Redacted for Privacy
Redacted for Privacy
Drte thcals 1o pncocntod June 25 1960
ypcd W Jencttc Crane
ACKNOWLEDGMENTS
The author wishes to express his gratitude to
Dr James G Knudsen for his guidance during the course
of this research to the National Science Foundation for
financing the project and to Mr Azimuddin Faruqui and
Mr K Nar ayanan for their help in constructing the
equipment and taking the i n itial data
TABLE OF CONTENTS
Chapter Page
I Introduction bull bull bull bull bull 1
II Theory and Previous Work bull bull 4
III Experimental Apparatus bull 8
Test Section bull bull bull bull bull bull 8 Sen sing Probe Assembly bull bull bull bull 11 Power Source bull bull bull bull bull bull 12 Temperature Measuring bull bull 12 Air Source bull bull bull bull bull bull bull bull bull 15 Pressure Probe bull bull bull bull bull bull bull bull bull 16
IV Experimental Program bull bull bull 17
v Experimental Procedure bull 20
VI Calculation of Experimental Data bull 22
VII Analysis of Data bull bull 27
Variat ion of Heat Transfer Rate with Distance from the Baffle bull bull 27
Rate of Heat Transfer at the Point
Effect of Upstream Baffles on Heat
Heat Transfer in the Test Sect ion
Heat Transfer at the Baff le and Maximum Point as a Function of
Correlation of Data at the Baff le bull 36
of Maximum Heat Trans f er bull bull bull bull 39
Transfer at the Orifice Center bull bull bull 42
with No Orifice bull bull bull bull bull bull bull bull 42 Pressure Drop Data bull bull bull bull bull bull 44
Pressure Drop bull bull bull bull bull bull bull 47
VIII Summary of Re sults 51
IX Re commendations 53
Nomenclature 54
Bibliography bull 56
Append ix 57
LIST OF FIGURES
Figure Page
1 Cross Section of Test Section and Probe bull bull bull bull bull bull bull bull bull bull bull bull 9
2 Experimental Apparatus 10
3 Sensing Probe bull bull bull 13
4 Drawing of Assembled Probe 14
5 Variation of Heat Transfer Rate with Distance from Baffle - 1 364 11 and 1 216 Sizes bull bull bull bull bull bull bull bull bull bull 29
6 Variation of Heat Transfer Rate with Distance from Baffle - 1 316 11 Size bull 30
7 Variation of Heat Transfer Rate with Distance from Baffle - 1 516 Size bullbull 31
8 Effect of Orifice Size on Position and Value of Maximum Heat Transfer bull bull 34
9 Correlation of the Point of Maximum Heat Transfer with Orifice Size bullbull 35
10 Rate of Heat Transfer at Baffle Center 37
11 Correlation of Heat Transfer Data at Baffle Center bull bull bull bull bull bullbull 38
12 Rate of Heat Transfer at the Point of Maximum Heat Transf er bull bull bull bull bull bull bull bull 40
13 Correlation of Heat Transfer Data at the Point of Maximum Heat Transfer 41
14 Effect of Upstream Baffles on Heat Transfer at Baff le Center bull bull bull bull bull 43
15 Heat Transfer with No Baffle 4 5
16 Orifice Pressure Drop Function versus Reynolds number bull bull bull bull bull bull bull bull bull bull bull bull bull bull 46
17 Heat Transfer at the Baffle and Maximum Point as a Function of Ori fice Pressure DIO p bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 48
18
Fi gure Pa ge
Var iation of Heat Transfer Rate and Pressure Drop with Orific e Size at a Con stant Flow Rate bull bull bull bull bull bull 50
bull bull bull bull bull bull bull bull
bull bull
I
II
III
IV
v
VI
VII
VIII
I X
z
LIST OF TABLES
Pa ge
Summary of Experimental Program bull bull 19
Position of Maximum Heat Transfer 32
Calculated Heat Transfer Data 57
Pressure Profile Data bull bull bull 67
Rate of Heat Tr ansfer at the Baffle Center middot bull bull bull bull bull 70
Rate of Heat Transfer at the Point of Maximum Heat Transfer bull bull bull bull bull bull bull bull bull bull bull bull 72
Effect of Upstream Baffles on Heat Trar1sfer bull bull bull bull bull bull bull bull bull bull bull 74
Heat Transfer in the Test Section without Orifice bullbullbullbullbullbullbullbull 75
Pressure Drop Function 76
71bull r ntal bull bull bull bull bull bull bull bull bull bull bull bull
HEAT TRANSFER AND PRESSURE PROFILRS IN THE VICINITY OF ANNULAR ORIFICES
- CHAPTER I
INTRODUCTION
The most common type of industrial heat transfer
equipment is the shell and tube heat exchanger which
consists of a bundle of tubes contained in a cylindrical
shell Heat is transferred from the hot fluid to the cold
fluid through the tube walls as one fluid flows through
the tubes and the other flows through the shell surroundshy
ing the tubes
Most commercial multitube heat exchangers contain
bafflesmiddot to guide the fluid through the equipment and to
prevent stagnant regions from forming in the shell As a
result the flow pattern in the shell is very complicated
and considerable variation of the local rate of heat transshy
fer occurs because of the various types of flow which exist
in the baffled passage The research described in this
thesis concerns a study of one small portion of the shell
side of a heat exchanger
There are three main types of baffles used in commershy
cial heat exchangers
1middot Orifice baffles extend through the cross section
of the shell and all of the shellbullside flow is
through the annular orifice formed at each point
where the tube passes through the baffle
2
2 Disk and doughnut baffles consist of disks and
doughnuts or annular rings placed alternately
along the length of the tube bundle~ There is
some flow through the annular orifices formed
where the tubes pass through the baffles but a
large portion of the flow is around the baffles
3 Segmental baffles are segments of a circle and
Bre arranged so that the fluid flows back and
forth across the tube bank There is still some
f~ow through the small area where each tube goes
through the baffle
In the case of disk and doughnut and segmental baffles
small annular clearances must be allowed at the point where
the tube goes through the baffle so that the bundle may be
assembled easily Thus in all of the types of exchangers
some shell-side fluid flows through the annular orifice
where the tubes pass through the baffles It has been
shown that this is an area of high rate of heat transfer
but its effect on the overall performance of the heat exshy
changer is not well known Also the prediction of rates
of heat transfer 1n these orifices is not yet possible
The purpose of this research was to make an extensive
study of the heat transfer rates in the vicinity of these
annular orifices and to determine the effect of orifice
size flow rate and upstream conditions The work was
5
performed in a onebulltube single orifice type baffle heat
exchanger and provision was made to measure local rates
of heat transfer in the vicinity of the baffle
4
CHAPTER II
THEORY AND PREVI OUS WORK
In 1701 Newton defined the heat transfer rate qc
from a surface of a solid to a fluid by the equat ion
= ~A(tw - t) (1)q0
where hm is the coefficient of heat transfer from the surshy
face to the fluid excluding any radiation A is the area
of the surface tw is the surface temperature of the wall
and t is the bulk temperature of the fluid The equation
for the point of local surface coefficient h is given by
dqdA = h(tw- t) (2)
The mechan ism and the laws covering heat transfer by
true conduction in solids and by radiation through transshy
parent media are well known However with heat transfer
from a solid to a fluid the situation is far more complex
The mechanism of flow of the fluid to a large extent deshy
termines the rate of heat transfer for a given temperature
difference
In addition the coefficient hm depends on certain
physical properties of the flowing fluid the dimensions
of the apparatus the velocity of the fluid past the surshy
face and frequently the temperature potential AT
It was the purpose of t his research to measure the
local shell -side heat transfer coefficient and correlate
it with the several variables mentioned a bove
5
The heat transfer coefficient for fluids flowing inshy
side tubes is more e a sily measured and correlated due to
the simple geometry of t he tube i nterior Much work has
been done on the tube-side coefficients with one of the
more useful e quations being the Dittus - Boelter equation
( 4 p 450) ~
0 023 (---ctwGJbulla (~np M ( 3 ) M k
with the following cond itions satisfied
(1) Fluid properties evaluated at the arithmetic
mean bulk temperature
(2 Reynolds number gt10000
(3) 0 7 lt Pr lt 100
(4) n = 04 for heating and 0 3 for cooling
(5) Ldw gt60
Colburn (3 p 197) obtained an equation for tubeshy
side heat transfer coefficients in which the Stanton
number is used instead of the Nusselt number
hm ) (~~ 23 _ (dwG) 0 2 ( GC k - 0 bull 023 U (4)
p
Much of the research done on average shell-side heat
transfer coefficients has resulted in empirical correlashy
tions of the form of equations (3) and (4) above Several
investigations have been made for a certain set of phys~al
6
variables but the r esults have ne ver satisf a ctorily been
correlated to appl y for all types of heat exchangers
Some basic 1ork has been done recently however on
the local shell-side coefficients Ambrose (1) studied
the local heat transfer coefficients i n a model heat exshy
changer with segmental baffles This study was fairly
extensive at the baffle center but the data were quite
limited for the space between the baffles Gurushankar1ah
(5) further extended Ambroses work by studying a single
baffle space in detail
The results of these two studies indicated a need for
detailed information 1n the vicinity of the baffle Hence
Lee () investigated a single baffle s pace between two
orifice baffles and obtained considerable information on
the rates of heat transfer in the annular orifices Since
his work was carried out in a multitube mode l heat ex~
changer the determination of the rate of flow through the
individual orifice was difficult because of t he outer
clearances existing in the exchanger For this reason the
present research was undertaken to study the rate of heat
transfer in a single annular orifice through which the flow
could be accurately determined
Bell and Bergelin (2) have studied i n detail the pres shy
sure drop coeff icients for the annular orifices formed beshy
tween a circular disk and a circular tube These results
also appl y to the annular orifioe formed when a rod extends
7
through a circular hole in a plata This study was extenshy
sive in the fact that it considered the baffle thickness as
well as the orifice size but no heat transfer data were
presented
Sullivan and Bergelin (9) studied flow through a
single annular orifice through multiple annular orifices
i n parallel and flow around a single baffle both with and
without leakage through the baffle A generalized expres shy
sion is presented for the pressure drop across one baffle
section of a tubular exchanger with leakage through the
tube holes in the baffle but the effect of leakage area
upon heat transfer is only discussed qualitatively The
pressure drop data is correlated by plotting cent as a funcshy
tion of the Reynolds number where cent equals
d1 )22( ~ P) s c e (d2 -
M-2
8
CHAPTER III
~PERI1ffiNTAL APr ARATUS
The heat transfer test section was essentially a
single tube heat exchanger The inner tube was a l-in
OD aluminum tube with an electrically heated probe midshy
way between the two ends of the tube
Test Section
The shell as constructed from lucite plastic tubing
2 5-in I D and 3-in O D The te t section d a total
lengt h of 54 58 inches I t consisted of two sections
The upstream section was 40 i n ches in length in order to
assure freedom from entrance effects and the downstream
section was 13 12 inches in length To further assure
uniform flow a bundle of short copper tubes was placed a
few inches downstream from the entrance Both of these
sections had 12 i nch flanges on one end so t hat a 18
i nch thick orifice plate could be clamped between them
Heat transfer coefficients were measured in the vicinity of
t h is orifice A cross section of the center of the test
section is shown in Figure 1 and the experimental appara~
tus is shown in Figure 2
Cooled air supplied by a Roots -type blower was used
as the shell-side fluid throughout this study It entered
the test section through a l-in ID 1 12-in OD plasshy
tic pipe at the upstream end of the calming section Tbs
j Jl l 6- 11 BOLTS II I nbull middot~11 I HEATING ELEMENTS
J T ( T
-f-shy - - - f-_- __L
7 777 _y A
IT 1] I
I
FIGURE I CROSS SECTION OF TEST SECTION AND PROBE
10
FIGURE 2 EXPERIMENTAL APP1Ub~fUS
11
air left the test section through nine equally spaced 12
ineh holes placed around the side of the tube at the exit
end
Sensing Probe Assembly
The sensing probe was designed to measure the local
heat transfer coefficients at any point along the tube and
around the tube in the test section The tube was designed
so that it could be easily moved up- and downstream to
measure the heat transfer coefficients at various positions
in relation to the orifice
The sensing tube assembly consisted of the sensing
probe the thermoctmple lead s and selector switch the
power lines and the two aluminum tubes between which the
probe was centered
Imbedded in the sensing probe were seven iron-constanshy
tan thermocouples for measuring the temperatures around the
tube The lead wires from these thermocouples were conshy
nected to a seleotor switch at the downstream end or the
aluminum tube A layer of Saran wrap was placed around the
tube over the t hermocouple and three lengths of Trophet C
resistance ribbon were wrapped around the tube nd conshy
nected in series to the power leads
The heating surface of the probe was formed by these
three one inch wide strips of Trophet C resistance ribbons
The ribbons were 0002 inches thick and had a resistance of
12
0 271 ohms per foot and a thermal conductivity of 763
Btuhr ft 2 degFft They were held in position by four
copper bars placed in four parallel longitudinal slots
These copper bars served as connectors for the electrical
leads A photograph of the sensing probe is shown in
Figura 3 and a drawing of the assembled probe is given in
Figure 4
Power Source
Direct current was used to heat the resistance ribbon
on the sensing probe The current was regulated by a slide
wire resistor The po er source consisted of a Raytheon
Voltage Stabilizer to stabilize the city power source at
115 volts and an automatic selenium rectifier with an alshy
ternating current input of 115 volts at 60 cycles per
second and an output of 12 volts and 35 amperes direct
current
Temperature Measuring
The temperatures around the sensing probe were calcushy
lated from the emf readings of the ironbulloonstantan thermoshy
couples The emf measuring system consisted of the seven
probe thermocouples a separate thermocouple for measuring
the inlet air temperature a thermocouple selector switch
a cold junction and a Leeds and Northrup Type K Potentishy
ometer The potentiometer was placed on a Fischer
13
THERMOCOUPLE JUNCTIONS~ ~------- HOLES FOR THERMOCOUPLE LEADS
~----- SCREWS
~ff+--- CONNECTING BARS
END VIEW
POWER LEADS SOLDERED TO LOWER CONNECTING BAR
iER PLASTIC PIECE
RESISTANCE RIBBONS LOCATION OF THERMOCOUPLES
FIGURE 4 DRAWING OF ASSEMBLED SENSING PROBE
15
Vibradamp support to absorb the vibrations produced by the
air blower
Air Source
Air was used as the shell-side cooling fluid during
the study The air was pumped through the test section by
a Roots type air blower with a rating of 280 ofm at 3 12
psig outlet pressure The hot air leaving the blower was
passed tbxfugh two finned-tube box-type coolers and one
tubular edoler to oool it to approximately room temperature
The air flow rate was measured by passing it through a
flow measuring orifice in the line Two sharpbull edged orishy
ficas were used f or flow measurements The calibration
curves for these orifices were presented by Ambrose (1
p 166)
The pressure taps on each side of the orifice were
connected to two differential manometers containing 0 83
and 2 95 specific gravity fluids respectively The presshy
sure drop through the test section and test orifice was
measured by a pressure tap placed 13 inches upstream and
one placed 6 12 inches downstream from the orifice Two
pressure ga ges were used to measure the pressure at the
inlet to the flow orifice and to indicate the statio pres~
sure at the test section inlet
16
Pressure Probe
A probe was designed to measure the pressure drop
between the pressure tap 13 i nches upstream from the ori shy
fice baff le and any point downstream from the tap The
probe eonsisted of a l~in OD copper tube with six 132
i n ch holes even l y s paced around the tube The upstream
pressure tap and the pressure probe were connected to a
differential manometer so the pressure drop to various
points up- and downstream of the orifice could be measshy
ured
17
CHAPTER IV
EXPERIMENTAL PROGRAM
The experimental program was designed to measure the
heat transfer coefficients and pressure drops in the vicinshy
ity of annular orifices The four orifice sizes studied
were 1 364 1 216 l 316 and 1 516 inches~ The inner
tube used in each case was a 1-in OD alumintim tube
Hence tube to baffle clearances were respectively 3128
232 332 and 532 of an inch
Heat transfer coefficients were measured at poait~ons
1 i nch upstream at the orifice center and at 12 1
1 12 and 2 inches downstream for all orifices In addishy
middottion the heat transfer coefficient at a point 2 12
inches downstream from the 1 516 inch orifice was measured
and at the points 12 l 12 and 2 inches upstream from
the 1 364 inch orifice
The heat transfer coefficients at each point were
measured at five different flow rates for the 1 364 inch
orifice and at six different flow rates for the other orishy
fice sizes The high pressure drop through the small orishy
fice size limited the number of flow rates which could be
studied
The flow rate was calculated from the pressure drop
across the flow orifice This flow was corrected to cubic
feet per minute at 68degF and one atmosphere pressure by
18
using the orifice pressure and the test section pressure
which were measured by pressure gages
It was desired to determine a relationship between the
heat transfer coefficient and the total pressure drop for
each orifice size The pressure drop across each orifice
at various flow rates was measured by means of the presshy
sure probe described in Chapter III It was also desired
to obtain pressure profiles for each orifice size since
these might be similar to the heat transfer profiles The
pressure drop was measured from a point 13 inches upstream
of the orifice to points at 1 and 12 ineh upstream the
orifice center 12 1 1 12 and 2 inches downstream
The experimental program is summarized in Table I
TABLE I
SUla~RY OF EXPER IMENTAL PROGRAM
Position Investigated-Distance from Orifice-Inches
Orifice Range of Flow Rate Size Heat Transfer Pressure Drop CFM at 68degF amp 1 atm
1 364 2U 1 12U 1U 12U c 12U C 12D lD 10 - 18 l2D lD 1 12D 2D 1 12D 2D
1 216 1U c 12D lD 1 l2D 2D 12U c 12D lD 10 - 35
1 316 1U c 12D lD 1 l2D 2D l2U C 12D lD 12 - 50
1 516 1U c x2D lD 1 l2D 1U 12U C 12D 12 - 90 2D 2 1 2D l D 1 l2D 2D 2 12D
20
CHAPTER v
EXPERI MENTAL PROCEDURE
The experimental procedure for measuring the heat
transfer coefficients ~d corresponding flow rates reshy
quired the following procedure
(1) Install the orifice size to be studied in the
test section
(2) Place the heat transfer probe in the position up
or downstream from the orifice where the middot heat
transfer rate is to be studied
(3) Fill the cold junction thermos with cracked ice
(4) Measure the atmospheric pressure
(5 Open bypass line from blower and close line to
test section
(6) Turn on the cooling water for the exchangers used
to cool the air leaving the blower
(7) Start the automatic selen ium rectifier by turning
on the t 1mer bull
(8 ) Connect the voltage stabilizer to the wall outlet
(9) middot Set the slide wire resistor to the maximum re shy
s1atanee I
(10) Start the blower
(11 Open the line to the test section until the de shy
sired flow rate is obtained
(12) Switch on the probe direct current power source
21
(13) Adjust the slide wire resistor to obtain the
desired current
(14) After the thermocouples have reached equilibrium
values record the e m bullf across each of the
seven probe thermocouples and also the entering
air thermocouple
(15) Record the direct current amperage
(16) Record the gage pressure at the flow orifice and
the entrance to the test section
(17) Record the manometer measurement of the pressure
drop across the flow orifice and also the presshy
sure drop through the test section
22
CHAPTER VI
CALCULAT ION OF EXPERIMENTAL DATA
The local heat transfer coefficients were calculated
from the temperatures measured on the probe surface the
air temperature and the current input The results were
calculated by using the Alwae III-E computer
The general expression for calculation of the heat
transfer coefficients was derived by Ambrose (1 p 79)
The equation is derived by making an energy balance around
a small increment of the center resistance heating ribbon
The two ribbons tnstalled adjacent to the center ribbon
reduced the amount of logitudinal conduction and assured
little longitudinal temperature variation in the center
ribbon
A heat balan ce on this small increment of resistance
ribbon yields the following
(the heat conducted in) + (heat generated) = (heat
conducted out) +(Heat convected to the fluid) + (heat
radiated to the surroundings) + (Heat conducted into
the plastic center of the probe)
This gives the equation
kzw dtdS + 12RdS kzws [ t + (~) ds] + hwdS (t-ta )
+ ~Aad wd o middot+ qcAond 1 -~- wdS 5 )
23
Hence solving for h gi~ea
i2R kz d2t Qrad qcond w + -d$2 - ~- A
h = ( 6)t - ta
Since S = re where 9 equals the enclosed angle ~n radians
dS rd9 ( 7)
and
dt - dt (8)dS - rd9
Differentiating with respect to S
d2t (9)rd9dS
from which
(10)
Substitut1ng into the equation for heat transfer coeffishy
cient gives
h = i2R Qcond A (11)
w
The rate of radial heat conduction into the plastic
tube making up the probe was assumed to have negligible
effect on the heat transfer coefficient It was also
assumed that the heat loss by radiation from the ribbon
was negligible since all data were obtained with the ribbon
at a temperature less than 125degF
24
When t he rad iation and conduction terms are neglected
Eq (11) becomes
(12)
The following con stants are known
R = 0 271 ohmsft
w = 100 i n ches
k = 763 Btuhr rt2 degFft
z = 0 002 inches
r = 12 inch
Eq (12) putting 9 in degrees then reduces to
1110 12 + 2404 d 2t d92
( 15)h = ------~--~-------t - ta
Thi s equation was programed for the Alwac III- E comshy
puter and used to calculate the local heat transfer coefshy
ficients from the observed data
The average heat transfer coefficient around the tube
at a given position in the t est section was calculated by
averaging the local coefficients calculated from Eq (13 )
It was found 1n the course of the experimental work
that thermocouple numbers 1 and 7 were indicating higher
temperatures than would be expected This resulted in h1
and ~ being lower than the other local coefficients around
the tube Since the fluid was flowing parallel to the axis
of the probe the circumferential variation i n rate of heat
25
transfer should be small Hence in obtaining the average
coefficient around the tube the values of h1 and h7 were
not used even though they were calculated and are tabulated
1n Table I II in the Appendix
Then
(14
A Nusselt number as calculated from this aver age heat
transfer coefficient using the tube diameter as the characshy
teristic dimension
(15)
The air flow rates through the test section were calshy
culated by measuring the pressure drop across the flow orishy
fice the air temperature the pressure at the flow orifice
and the pressure at the entrance to the test section The
orifice calibration curves (1 p 166 ) were used to obtain
a value of the orifice coefficient f8e where Q equals
the flow in cubic feet per minute at 68deg F and one atmosmiddot
phere pressure and te is the density of air at the exchanger
and e the density of the air at the flow orifice The
den sity of the air can be expressed by
e = 2 703 p (16)T
where T equals the temperature in OR and P equals the absoshy
lUte pressure i n lb1n2 Using the value of e Qfo from
26
the calibration charts as A and Eq (16) solving for Q
gives
( 17
This equation was used to calculate the flow rate for
each flow studied
The Reynolds number used i n the correlation of the
data was the equivalent Reynolds number defined as
Re)eb ~ d2 - dl)Uf ( 18 ) lL
where d1 is the outside diameter of the inner tube and d2
is the orifice diameter U is the flow velocity through the
annular orifice e is the density of the air and U- is t he
viscosity of the air This equation can be transformed t o
(Re) b = 1611 Q (19) e dl + d2
where d1 and d2 are in inches
The pressure drop data were calculated i nto a dimenshy
sionless pressure drop function cent where
d1 )22( ~ P)gc f av(d2 shycent 2 bull (20
M-
For air this equation reduces to
where d2 and d1 are in i nches D P is expressed i n inches of
2 95 specific gravity fluid and P av is expressed as lbft3
27
CHAPTER VII
ANALYSIS OF DATA
In analyzing the heat transfer data an attempt was
made to correlate it 1n terms of the dimensionless groups
(Nusselt number Prandtl number and Reynolds number) which
appear in Eqs (3) and (4) Consequently all of the av~
erage heat transfer coefficients hav were brought into
the form ( Nu)( Pr)~3 bull The Nusselt number was based on the
tube diameter and the thermal conductivity of the air at
the flowing temperature The tube diameter was used in the
Nusselt number because comparison could then be made with
previous experimental work on heat exchangers which have
commonly used the Nusselt number defined as in Eq (15)
From the standpoint of dimensional analysis this is
equivalent to considering the tube diameter as the characshy
teristic length so far as the heat transfer is concerned
The Prandtl number of the air was taken as 0 7 in all
cases
Variation of Heat Transfer Rate with Distance from the Baffle
Considerable variation was observed in the rate of
heat transfer in the vicinity of the baffle In order to
obtain the variation with respect to position the term
(Nu)(Pr)-13 was plotted versus the flow rate Q for each
position and orifice studied Cros s plots were then made
28
at constant flow rates in order to obtain the variation of
(Nu)(Pr) -13 with position The resulting cross plots are
shown 1n Fi gures 5 6 and 7 for the four orifices studshy
ied
About one inch upstream from the orifice the heat
transfer coefficient begins to rise rapidly and continues
to do so until it reaches a maximum some distance downshy
stream After the maximum point the heat transfer coef fi shy
cient decreased slowly The heat transfer rate was found
to reach a maximum at a different position downstream for
each orifice size These figures also show that for a
given orifice size the maximum heat transfer rate occurs
a pproximately at the same point for all flow rates The
position of the maximum point f or each or ifice size is
shown in Table II
The region immediately downstream from the orifice is
one of h i gh turbulence due to the jetting action of the air
flowing through the orifice As the air flows t hrough the
orifice the streamlines continue to converge for some dis shy
tance downstream The point of maximum heat transfer is
probably at the point where the streamlines be gin to diverge
and a boundary layer begins to build up on the tube Tle
decreasing heat transfer coefficient beyond the maximum
point indicated the formation of a boundary layer
Since the position of the maximum point is independent
of flow rate middot it is possible to correlate it with respect
_ ct 11shyz-
100
0 136 ORIFICE
(
I 0
I )
~ 00
~p 0
I 0
--r--- ~
ISCFIII
-_ OCFM
rbull abull
~ middot~ a-1 z-
12fORIFICE
100
200
100
0 0 UPITRAM ORIFICE DISTANCE CENTER
CFM
h I DOWNSTREAM
DISTANCE
FIGURE 5 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLpound
30
too
700
800
100 ~ f gtf
400
z ~
100
100
100
0
13fORIFICE
~ -~ -- ---
)
~
~
-
I ~ ~OCFM
I vI~-~ OCFM
J ---
Iamp CFM
I 0 I I UPSTREAM ORIFICE DOWNSTREAM DIITANOE GENTER DIITANCI
FIGURE 6 VARIATION OF HEAT TRANSFER RATE WITH DISllNCE FROM BAFFLE
--
--- --
31
100
100
700
100
_ 100
f 9- 400 z-
100
tOO
100
0 - I 0 I I I UHTRIAM OAtfiCI DOWIIITMAM
+ I tyl6 ORIFICE
v I
~~ ~CFM
I v ~CFMI
v v 7
~~ v ~ iOCFM
- ~~ I-shy1-shy ~ICFM
DIITMCI OINTIR DIITANCI
FIGURE 7 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLE
32
TABLE II
POSITION OF MAXIMUM HEAT TRANSFER
Position of Maximum Orifice Size Heat Transfer
(inches) (inches downstream)
1 364 050
1 216 100
1 316 125
1 516 200
33
to orifice size Figure 8 shows the effect of the orifice
size on the position and value of the maximum heat transfer
at a constant flow rate of 15 cubic feet per minute It
can be seen that the larger the orifice size the further
downstream the point of maximum heat transfer occurs
Also as the orifice size increased the rate of heat
transfer decreased for a given flow rate The broken line
indicates the variation of the point of maximum heat transshy
fer with position and size The position of the point of
maximum heat transfer rate downstream from the orifice was
correlated with orifice size by means of the dimensionless
groups (Lde) and (d1de) where L is the distance downshy
stream from the orifice where the maximum rate of heat
transfer occurs d1 is the outside diameter of the inner
tube and de is the equivalent diameter of the orifice
ie de = d2-dlbull
Figure 9 shows a plot of Ld 6 versus d1d6 for the
four orifice sizes studied The four points on this logshy
log plot are approximately in a straight line and the
equation of this line is
Lde = 0 44 d1de)028 (22)
Although the above relationship represents a correlashy
tion of dimensionless groups it is based upon only one
tube diameter and needs to be substantiated further by
studying other tube diameters and other orifice sizes
34
aoo
400
aoo ~
-~ middot-CLshyJ z
200 -
100
0
ORIFICE CENTER
l~
l
t
I J~
1pound~
I
0 I I~
AT 15 CFM
-
bull ~ 1~6~
~ v~
~
~--~~6
~~~ ___ v v V -_
~ o q
~ I 16
v
~
ogWNSTREANI STANCE
FIGURE 8 EFFECT OF ORIFICE SIZE ON POSITION AND VALUE OF MAXIMUM HEAT TRANSFER
35
50
loshy____ -~
~ ~ -shylltl-shy~ r0
2 10 30
FIGURE 9 CORRELATION OF THE POINT OF MAXIMUM HEAT TRANSFER WITH
ORIFICE SIZE
36
Correlation of Data at the Baffle
The heat transfer data were correlated by obtaining a
relationship between the group (Nu)(Pr)-13 and a
Reynolds number based on twice the clearance (d2 - d1
between the tube and the baffle It was found that the
most satisfactory correlation could be obtained when the
term - d1 was used as the length term in the Reynoldsd2
number
Figure 10 shows the variation of the heat transfer
rate at the center of the orifice e xpressed as a function
of Reynolds number and the orifice size This shows that
for a given Reynolds number the heat transfer at the center
of the orifice is greatest for the smallest orifice size
In order to obtain a general correlation of the data
shown i n F1gure 10 the effect of the dimensionless ratio
d1de was considered This ratio considers all of the
geometric factor s needed to describe the annular orifice
The thiclaless of the orifice plate is also a factor but
was constant i n this i nvestigation
The data for the heat transfer at the baffle center
are shown in Figure 11 in which (Nu)( Pr)-13 is plotted
versus (Re)ebd1 de) 0 55 This data on a log-log plot
lies on a straight line for (Re)eb( dld8 )0 55 greater
than 3 x 104 The equation for cor relating the heat
37
4XI~middot~-r~------~--~~------~
Icf t--to_+--_c-c-________ SYMBOL SIZE
0 1~4
6 ~~
9 ~~ -o ~
(Re)eb
FIGURE 10 RATE OF HEAT TRANSFER AT BAFFLE CENTER
38
500
0
4 0 lcf
~ ~
~ ~iC-
~ ~
~IL 0~ 0 SYMBOL SIZE-
p 0 1364-
r 6 1~16 -~ -
9 1~16 --o 1~16
I I
FIGURE II CORRELATION OF HEAT TRANSFER DATA AT BAFFLE CENTER
39
transfer at the center bullOf the a nnular orifice was found by
the method of least s quares to be
(Nu)( Pr)-1 3 = 0018 ( Re)ebO Bl( dlde)04~ (23)
3 x 104 ltRe)eb(a1de)055 lt 105)
Rate of Heat Transfer at the Point of Maximum Heat Transfer-The heat transfer rate at the point of maximum heat
transfer is plotted in Figure 12 to show the variation with
Reynolds number and the size of the orifice It is shown
gives the h1gh st heat transfer ~ate at its point of maxibull
that for a given Reynolds number the smallest orifice size yen il
mum heat transfer
The data ~or the maximum poi~t could be correlated by
plotting (Nu) Pr)-13 versus (Re)eb(d1de)06 This plot
is shown 1n Figure 13 and the resulting eurve shows that
(Nu(Pr)-13 is not a simple p0wer function of the Reynolds
number as was the case for heat transfer at the baffle
center The reason for this is probably because other
factors such as intensity and scala of turbulence should
be considered At the orifice center the streamlines of
the flowing stream are converging_ and thus the flow is
quite stable Downstream from the orifice is a region of
large eddy currents and probably large scale turbulence
These factors could con ceivably cause the results which
were obtained for the point of maximum heat transfer
40
If)
~middotshy Q_-I z_
10~~~--------r----~~--~--
SYMBOL SIZE
0 13$4
6 1~8
Q 13-18
-o 1~8
7)(104
(Re)eb
FIGURE 12 RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
41
Ia ~
0 I
c ~ ~ c v
~ ~lt w ~
17
~ b
v ~ ( SYMBOL SIZE
-~ 0 f-64 -v ~ 6 t211e
~ Q I~~~
-o - l~rs I I
FIGURE 13 CORRELATION OF HEAT TRANSFER DATA AT THE POINT OF MAXIMUM HEAT TRANSFER
4 2
Effect of Upstream Baffles on Heat Transfer at the Orifice Center
The heat transfer rate at the orifice center using the
single orifice in a test section is a pproximately 13 of the
value that was obtained by Lee (7) using a model heat exshy
changer with orifice baffles Lee investigated the cent r al
baffles of the heat exchanger and thus the coeff icients he
obtained would be affected by the presence of a number of
upstream baffles To determine the effect of upstream
baffles an additional l 516 inch baffle was placed four
inches upstream 1n the test section The resulting data are
shown in Figure 14 where (Nu)(Prmiddot)-13 is plotted versus
(Re) eb for the case of a single baffle 1n the test section
and also the case of an additional baffle placed four inches
upstream Comparison is made with the results obtained by
Lee middot(7) using a four-baffle and a ten-baffle model heat exshy
changer Good a greement is obtained with Lees work and the
results show the marked effect that upstream baffles have on
the downstream heat transfer rate The additional up tream
ba ffle caused sufficient turbulence 1n the test section to
i n crease the heat transfer rate nearly three-fold at the
center of the next baffle
Heat Transfer i n the Test Section with No Orifice
In order to check the accuracy 6f the equipment the
orifice baffle was removed and the heat transfer mea sured
with the probe in the empty test section The data were
43
~~BAFFLES
0 l BAFFLE -shy
ll_9 2 BAFFLES
V 4 BAFFLES-LEE
4 10 BAFFLES- LEE lJf ~
~rv ~~ ~ v flvv ~~
I ~ J ~ L v
0
v
( V
40 3XIo 7XIa
(Re)eb
FIGURE 14 EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER AT BAFFLE CENTER
44
compared with heat transfe r coefficients predicted by the
equations for annuli which are recommended in the litera shy9
ture The two equa~ ions u sed tor comparison were
(hfe)=0 023 (rltGr e (~~ur4 (~r45 (24)
which was presente~ by Wiegant (10)
and ( h ) (cnM~5(M~l o14 o 023 CPG k j Mij - (de GJMb )0 2 ( 2 5)
which was presented by McAdams (8 p 242) The comparshy
i son is s hown in Figure 15 lq (25) gives a value which
is low by about ten percent while Eq (24) g ives values
which are high by as much as twenty -five percent when comshy
pared with the experimental data The se equations are gembull
erally considered to give coefficients with an accuracy of
about twenty percent Therefore the present experimental
data are within the accuracy of these equations Also the
plot indicate s that for a Reynold s number greater than 2 x
104 the slope of the line is the same for the experimental
data as for the equations
Pressure Drop Data
The total pressure drop across the orifice was measured
as a function of the flow rate and the orifice size The
pressure drop was expressed as a d1mens1onleas quantity r)
which ie plCltted ver sus the Reynolds number in Figure 18
The pressure drop function cent correlates for all or1f1oe
45
200
100
s z
10 5XI10 10
0 EXPERIMENTAL
--McADAMS
-WIEGAND L
V
~ ~ ~
P ~ ~
LL~ L
v~
~
v v
v 1 ~ ~ v
v -gt
~
~ ~
~
6Xid
FIGURE 15 HEAT TRANSFER WITH NO BAFFLE
46
0 1~4 -~ a 6 t216
Q t316 lJ J
-0 as a )t
A LEE I -shy SULLIVAN 8
p
10bull
BERGELIN
I _ll I
I ~
i I
~middot
lo II
f fl
J j
~middot
A)101
1q
I Ill
1 I3 X 10ao1
FIGURE 16 ORIFICE PRESSURE DROP FUNCTION VS REYNOLDS NUMBER
47
sizes- The present data extends the range covered by preshy
vious workers and agrees well with their work The preshy
vious work of Lee () for a heat exchanger containing 10
orifice baffles and also the data of Su livan and Bergelin
(9) for pressure drop in a model heat exchanger with a
single baffle is shown 1n Figure 16 long with the present
results~ This figure may be used to predict the preseure
drop from the equivalent Reynolds number of the annular
orifice
The pressure drop between individual points 1n the
vicinity of the orifice and an upstream pressure tap wa s
measured to obtain a pressure drop profile As might be
expected 1n all cases the profiles showed a rapid decrea e
in static pressure immediately upstream from the orifice
There was however little or no recovery of the pressure
loss downstream The 1 364 inch orifice did show a maxishy
mum point in the pressure drop but this maximum occurred at
the orifice center and total recovery was reached about 12
inch downstream
Heat Transfer at the Baffle and Maximum Point as a Function of Pressure Drop
In order to compare the effect of the total pressure
drop on the heat transfer at the baffle and the point of
maximum heat transfer Figure 17 was plotted showing
(Nu)(Pr)-13 as a function of the total pressure drop This
shows that for a given pressure drop the largest orifice
48
1200
1000
~ a -sshyz-
100
60 100 700
AT MAXIMUM POINT I 15116 2 13116 3 1~6 4 1364
AT ORIFICE CENTER
60
1
v
r ~ ~ ~
5
~
8 7
13116
8
~
1364
v
~
e6
1~6
v
~~ v ~ ~ -~ ~
~
~ v
l
~
vamp
I ~ ~
~
v L ~
v
I-
5
k= ~~
~ ~ ~
--I
v ~
FIGURE 17 HEAT TRANSFER AT THE BAFFLE AND MAXIMUM POINT AS A FUNCTION OF
ORIFICE PRESSURE DROP
49
size has the greatest heat transfer coefficient This is
true at both the orifice center and at the point of maxishy
mum heat transfer
Another comparison can be made by plotting the heat
transfer coefficient and the pressure drop versus the orishy
fice size at a constant flow rate Figure 18 shows this
plot This graph shows that at a constant flow rate the
pressure drop as well as the heat transfer coefficient
increases as the size of the orifice is decreased In
choosing an orifice size for maximum efficiency 1t would
be necessary to know the pumping power available as well
as the heat transfer desired
70 I I 700
AT 15 CFM 60 ---
~ aug
50 ---
NV
40 ~
~ ~ ~
~ _
MAXIMUM POINT ---- --- ~
1-----t---~ _
~00Qj ~
~t--- ORIFICE CENTER 10 1100
1---~ n
u0 01 02 03 Q35
a ltl
de inches
FIGURE 18 VARIATION OF HEAT TRANSFER RATE AND PRESSURE DROP WITH ORIFICE SIZE AT A CONSTANT FLOW RATE
cn 0
51
CHAPTER VI II
SUMMARY OF RESULTS
This study revealed several significant facts about
the heat transfer in the vicinity of annular orifices
Probably the most important contribution was the presshy
entation of the heat transfer profiles in the vicinity ot
the annular orifice ~ r s shown that t~ local heat
transfer coeffieient re~ches a maximum at a point downshy
stream from the orifice The distance downstream at which
this maximum oocurs is t1ven by the equation
22
The heat transfer coefficients at the center of the
orifice were correlated and found to follow the equation
(Nu)(Pr)-13 = 00176 (Re)eb08l(d 1de) 0 middot4~ (23)
3 x 104 lt( Re) 9 b( d1d6 )055 ltlo5 )
The heat transfer at the point of maximum heat trans
fer for each orifice size was correlated and presented in
Figure 13 as a plot of (Nu)(Pr)-l3 versus (Re)eb(d1de) 06
No simple po-orer relationship exists between the terms
Intensity and scale of turbulence downstream from the orishy
fice are probably important factors which affect the heat
transfer
The large effect of an upstream orifice on the heat
transfer rate at the second orifice was demonstrated by the
52
study of two 1 516 inch orifices in the test section The
added turbulence at the center of the second orifice was
found to raise the heat transfer rate almost three times
over that obtained for a single baffle
The pressure profiles in the vicinity of the orifice
indicate that nearly all the pressure drop occurs at the
orifice center~ Total pressure drop data were correlated
by a pressure drop function cent as a function of the Reynolds
number and good agreement obtained with the results of other
workers
The pressure drop and heat transfer data were correbull
lated by plotting the heat transfer as a function of the
pressure drop for each orifice size It was shown that for
a given pressure drop the largest orifice size gives the
greatest heat transfer coefficient
As a final presentation it was shown that the pressure
drop and the heat transfer coefficient both i ncrease i n
value at a constant flow rate as the orifice size is de shy
creased This is important in choosing the optimum clearshy
ance for orifice baffles
53
CHAPTER IX
RECOMMENDATIONS
A great deal of work remains to be done in the field of
evaluating shellmiddotside heat transfer coefficients This
study included only one tube size and air was the only f luid
used It is recommended that further studies be conducted
using other fluids and tube sizes It will also be necessary
to study several baffle types
The adde d turbulence due to a s e cond baffle placed upbull
s t ream would suggest that the heat transfer coef ficients at
a certain position i n relation to a baffle would increase as
the flow progressed through the exchanger It is recomshy
mended that an extensive s t udy should be made between baffles
the full length of a model heat exchanger
It is further recommended that the pressure drop study
be continued to include other fluids tube sizes and baffle
arrangements
Effects of turbulence downstream from the baff le should
be studied by i n vestigations with hot-wire anemometer equipshy
ment to determi ne t urbulence scale and i ntensity
54
NOMENCLATURE
Area of heat transfer
Heat capacity of the fluid
Outside diameter of the tube
Orifice diameter
Equivalent diameter of the orifice (d2 - dl)
Inside diameter of the test section
Inside diameter of the tube
Gravitational constant
G Mass velocity
h Local heat transfer coefficient
Coefficient of heat transfer from surface to fluid
i Direct current amperes
k Thermal conductivity of the fluid
L Distance downstream of the point of maximum heat transfer
p Absolute pressure
L P Total pressure drop across the orifice
Q Flow in cubio feet per minute at 1 atmosphere and 680 F
q Heat transferred
Thermal energy conducted into the sensing probe
Thermal energy radiated from the resistance ribbon
Resistivity of the resistance ribbon
s Length of the resistance ribbon
T Temperature oR
55
t Temperature of the resistance ribbon deg F
ta Temperature of the bulk stream oF
tw Wall temperature of the tube OF
U Veloc ity of the fluid
w Width of the resistance ribbon
z Thickness of the resistance ribbon
eeuro Density of the fluid in the test section
Density of the fluid at the flow orificef 0
AL Viscosity of the fluid
E9 Angle measured around the tube
Dimensionl ess groups
(Nu) Nusselt number hd1k
(Pr Prandtl number C~k
(Re)eb Equivalent Reynolds number at the baffle (d2 - d1 )uejt-Lshy
(Re)e Equivalent Reynolds number in the test section ( d 8 - d 1 )U fu
cent Orifice pressure drop function 2(~P ) gc~av(d2 - d1) 2
Al
56
BI BLIOGRAPHY
1 Ambrose Tommy W Local shell-side heat transfer coefshyficients in baffled tubular heat exchanger PhD thesis Corvallis Oregon State College 1957 183 numb leaves
2 Bell K J and o P Bergelin Flow through annular orif ices Transactions of the American Society of Mechanical Engineers 70593-601 1957
3 Colburn Allan P A method of correlating forced con shyvection heat transfer data and a comparison with fluid friction Transactions of the American Institute of Chemical Engineers 24 174-210 1933
4 Dittus F w and L M K Boelter Heat transfer 1n automobile radiators of the tubular type University of California Publications in Engineering 2443-461 1930
5 Gurushankariah M s Local shell-side heat transfer coefficients in the vicinity of baffles in tubular heat exchangers Masters thesis Corvallis Ore gon State Colle ge 1958 97 numb leaves
6 Knudsen James G and Donald L Katz Fluid dynamics and heat transfer New York McGraw-Hill 1958 576 p
7 Lee Kyu Sung Local shell-side heat transfer coeffishycients and pressure drop in a tubular heat exchanger with orifice baffles Masters thesis Corvallis Oregon State College 1959 118 numb leaves
8 McAdams William H Heat transmission 3d ed New York McGra ~-Hill 1954 532 p
9 Sullivan F W and 0 P Bergelin Heat transfer and fluid friction in a shell-andbulltube exchanger with a single baffle Chemica l Engineer ing Progress Symposium Series 52 ( 18) 85-94 1956
10 Wiegand J H Discussion on annular heat transfer coshyef f icients for turbulent flow Transactions of American Institut e of Chemical Eng i n eers 41147-153 1945
AP PENDIX
57
TABLE III
CALCULATED HEAT TRANSFER DATA
Baffle Hole Diameter Run No (inches)
1 - 59 1 364
60 - 102 1 216
103 - 138 1 316
139 - 206 1 516
207 - 212 No orifice
213 - 218 2nd - 1 516
TABLE III
CALCULATED HEAT TRANSFER DATA
Local Heat Transfer Coefficients Run
T0 bull Po s ition CFM hr h2 h3 h4 hs he ~ hav Nuav
1 c 1026 10 59 1476 16 09 1559 1510 1435 1203 1518 8511 2 1290 1369 1738 1878 18 05 1755 1689 1515 1773 9964 3 1416 1636 198 1 2068 1977 1924 1845 1715 1959 11030 4 1627 1991 2301 2382 2268 2194 20 ~98 1929 2249 12664 5 1776 2252 2669 2863 2713 2517 2338 2126 2620 14759 6 l2ttD 1109 2311 3317 3386 3373 3387 3394 3071 3371 18888 7 1258 3089 4583 4866 4683 4701 4643 4194 4695 26301 8 1433 38 8 5 55 83 5791 5495 5430 5436 5008 5547 31192 9 1681 4992 7378 7649 6980 6864 6870 64 28 7148 40180
10 1 D 1102 2371 3332 3511 3356 3342 3427 3102 3394 19012 11 1308 3218 4379 45 24 42 53 4255 4373 3965 43 57 24446 12 14 64 38 58 5146 5142 4839 4787 4903 4597 4963 278 79 13 1706 5218 6664 6269 58 81 5884 6237 5973 61 87 34718 14 15
1 l2D 1115 1275
2131 2661
2955 3638
2972 3720
2941 3675
2913 3576
28 22 34 74
2613 3278
2921 36 17
163 09 20246
16 1498 34 87 4644 4503 4441 4371 4343 4194 4460 25010 17 1695 4449 5743 5324 5222 5154 5157 5015 5320 298 97 18 2D 1049 1715 23 90 2550 2610 2656 2624 2208 2566 14363 19 1241 2117 2964 3145 3218 3221 3203 2759 3150 17757 20 1532 28 67 3936 4100 4188 4201 4167 3676 4118 23224 21 1674 3459 4508 4598 4746 4795 4792 4299 4688 26337 22 lU 1074 253 340 380 3 86 388 377 354 374 2097 23 1287 292 392 433 440 441 429 406 427 2394 24 1508 322 439 492 498 499 487 461 48 3 2713 25 18 07 3 38 464 519 5 24 520 499 463 5 05 28 40
~~ (]I agt
TABLE III Continued
Run No Position CFM h 1 h2 ~3 h4 h5 h6 ~ h
av Nu
av 26 c 1029 1171 1491 1589 15 28 1 4 62 1377 1293 1489 83 44 27 1266 1395 1746 1853 18 02 1685 1556 1453 1728 9704 28 1430 1637 2037 2175 2060 1909 1735 1591 1983 11159 29 1729 1982 24 96 2751 2507 2268 2030 1886 2410 13579 30 12D 1054 2934 4041 4321 4326 4423 4359 3706 4298 24160 31 1294 3385 4 8 26 52 42 5326 5450 5277 4566 52 24 293 50 32 1431 3784 5347 5721 57 bull75 58 44 5700 5084 5677 31870 33 1770 52 75 7 7 33 87 35 9005 9007 8267 7059 85 49 48050 34 lD 1058 3235 4401 4444 3877 3496 3451 3294 3934 21973 35 1263 38 98 5484 5330 4347 3964 3981 3987 4621 25823 36 18 36 6701 89 17 7855 6369 5597 5769 6283 69 01 38718 37 1 12D 1029 2404 31 8 2 3333 3459 3624 3577 3045 3435 19264 38 1315 3182 4033 4162 4310 4496 4502 4015 4301 24142 39 1426 3628 4389 4510 4573 4760 4804 43 8 5 4607 25678 40 1757 4547 5559 5(35 5931 6282 63 70 6060 5975 33471 41 2 11D 1080 2034 28 38 3155 3144 3145 2966 2540 3050 17027 42 1305 2650 3 4 87 3aoz 3595 3751 3595 3153 36 46 20405 43 1434 3167 39 07 4156 4371 4320 4126 3709 4176 23395 44 1804 4096 4 9 66 5691 5714 5586 53 15 48 65 5454 30582 45 12U 1088 409 516 557 564 5 60 535 513 5 46 30 67 46 1318 470 579 6 22 631 6 17 5 97 579 6 09 3422 47 14 13 540 640 676 6 86 681 6 60 6 54 6 69 3754 48 1773 641 740 774 782 7 69 749 746 763 42 87 49 l 11 U 1054 270 356 391 397 393 3 71 346 38 2 2133 50 1240 303 399 446 449 447 4 21 398 432 2420 51 1419 361 476 522 530 528 507 467 493 2760 52 1 1(2U 1032 236 311 342 347 344 325 301 334 18 78 53 1314 270 366 403 407 408 386 351 394 2217
(Tt tO
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ h av Nu av
54 1448 301 408 447 454 452 431 403 438 24 61 55 1782 353 494 548 544 415 529 531 506 2843 56 2U 10 61 220 287 316 320 322 303 268 310 1735 57 1216 249 335 370 377 378 353 307 363 2044 58 1322 263 356 394 398 399 374 327 384 2159 59 1639 310 433 478 481 482 452 393 465 2617
60 1D 10 68 2011 2536 2657 2681 2694 2560 15 62 2625 14938 61 1399 2520 3239 3369 3371 33r82 32 39 1946 3320 18968 62 1669 2781 3655 3820 38 76 3883 3738 2355 3794 21712 63 1959 3524 42 37 4399 4438 4497 4417 3047 4397 25156 64 2295 4426 5288 5396 5372 5240 5410 3369 5341 30680 65 2636 5490 6531 6662 6565 6379 6820 4249 6591 37938 66 3390 7869 9538 9462 9387 8924 10508 62 91 9564 59601 67 1U 1190 352 368 401 413 407 395 293 397 2256 68 1559 397 422 462 475 471 456 331 4 57 2603 69 1904 434 465 5 13 529 528 504 358 508 2901 70 2211 493 526 573 5 92 588 564 4 15 569 3257 71 2289 569 587 6 30 649 6 61 6 49 460 635 36 44 72 2727 637 6 60 7 09 733 751 743 521 719 4140 73 3210 728 755 8 15 8 43 8 62 8 54 616 826 4765 74 2nD 1210 181 2256 2393 2399 2333 2206 1325 2317 13158 75 1420 2340 2752 2899 2913 2850 2728 1701 2828 16121 76 1692 2853 3306 3452 3471 3379 3217 2134 3365 19217 77 1894 3102 3588 3713 3736 3670 3557 2455 3653 20892 78 2301 3682 4259 4433 4467 43 83 4289 2892 4366 250 30 79 2621 4117 4828 5017 5012 5030 5109 3071 4999 28785
m 0
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ hav Nuav
80 3230 5158 6006 62 13 61 18 6134 6695 4094 6233 359 87 8 1 12nD 1155 15 27 1854 2028 2064 20 85 1987 1164 1968 118 31 82 1689 2046 24 8 2 2688 2739 2760 2658 1749 2665 152 73 83 1244 2088 2317 2339 2345 2373 2381 1487 2351 13432 84 2100 3211 3539 34 21 3462 3512 3696 2575 3526 20284 85 2292 3 5 05 3761 3648 36 25 36 79 3957 2933 3734 21517 86 2907 4420 48 22 4679 46 04 4705 5206 3792 48 03 27741 87 33 80 59 35 69 38 7404 77 10 7 8 36 7 0 86 5190 7394 427 44 88 1 12D 1 4 27 2 4 58 28 31 3037 3021 2987 2927 18 57 2 9 61 16913 89 18 75 34 75 3 9 87 4230 4255 4317 4337 2734 4225 24258 90 22 59 4221 4796 5046 5052 51 01 5389 3491 5077 29206 91 2682 4978 5664 5943 5966 6054 6573 408 1 60 40 34795 92 3417 63 16 71 02 7 3 93 7385 75 40 8 6 95 51 45 7623 44017 93 c 1 5 17 1240 1305 1399 1467 1479 1429 9 26 1423 8251 94 20 34 1554 1623 1720 18 21 18 53 18 72 1215 1778 10229 95 2 3 48 1795 1843 198 5 2097 2171 2274 1540 2074 11947 96 2716 2028 2048 22 01 2 3 44 2444 2661 18 90 2340 13505 97 3247 2410 2375 2663 2778 2949 3298 2378 2793 1615 98 11 35 967 1040 1124 1186 1200 1142 728 1138 6496 99 14 06 1135 1220 1318 1384 1403 1 3 61 8 77 1336 7656
100 2311 1 8 54 18 78 1980 20 90 2136 2227 1653 2062 118 31 10 1 2666 2085 2094 2227 2 3 62 2438 2626 1902 2349 13508 102 3392 2635 2582 28 01 3026 3141 3529 2567 3016 17390
103 1 U 1235 349 395 434 436 4 28 411 286 423 2416 104 20 10 434 5 02 559 577 569 5 37 345 552 3177 105 28 14 538 626 685 711 7 21 682 424 6 8 6 3966
Q) j-J
TABIE III Continued
Run No Position CFM h1 h2 h3 h4 h5 hu h7 hav Nuav
106 3492 614 7 1 6 7 84 8 13 8 33 7 85 4 88 7 87 4562 107 4395 7 86 894 964 996 1005 9 64 640 9 65 56 06 108 50 75 9 11 10 22 1081 1112 1125 1085 7 24 1085 63 16 109 G 1344 9 22 1042 1120 1 1 46 1173 1131 7 04 1120 63 87 110 1936 1162 1340 1442 1474 1509 14 7 3 9 09 1441 82 77 111 2846 1631 1797 1902 1966 2027 2079 1342 19 2 3 11108 112 3484 207e 2144 2236 2307 2385 2574 1694 2268 13138 113 4066 24 65 24 42 2535 2648 2757 31 71 2178 2 5 96 15078 114 50 12 3059 2916 30 1 5 3176 3312 4059 2849 3105 180 46 115 1D 1362 2268 26 13 2613 26 35 2605 2503 15 46 2617 14934 116 1958 2993 3580 3580 3586 3539 3 5 02 2144 3571 20492 117 2812 4430 50 32 4913 4 9 86 4991 5196 3088 4981 287 66 118 3432 58 16 62 13 6067 61 18 60 66 6698 4143 61 16 354 16 119 40 22 71 71 7 4 62 7369 7419 7329 82 74 51 8 1 7395 42909 120 5026 105 95 11456 115 81 11574 11548 14010 80 91 11540 671 15 121 2D 1244 18 57 2277 2363 2305 2210 2107 1466 2289 13038 122 1960 2622 3240 3388 33 23 3226 31 40 2)99 3294 18919 123 2817 3762 45 87 4739 46 56 45 14 4 6 47 30 15 4624 26689 124 3491 50 22 5723 58 53 57 44 5542 60 18 3871 57 16 330 73 125 4096 61 29 68 16 69 79 6805 65 90 74 79 4677 67 98 39400 126 5037 82 27 94 60 95 69 93 57 9023 11324 65 05 93 52 542 83 127 12D 1278 14 70 1 6 48 1652 1638 1 6 34 1641 9 73 1 6 43 9369 128 1947 19 63 2155 2149 2151 2131 2190 1347 2147 12342 129 2769 2615 2791 2773 28 52 2716 2954 18 96 2783 1 60 82 130 3439 3208 3265 3239 3593 3133 3624 2515 3308 19174 131 4103 3637 35 88 3577 4077 3459 42 66 3138 3676 21343 132 49 78 45 82 44 60 44 8 1 55 17 43 25 5749 4227 4700 27288
Q) tlgt
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
133 1 12D 1299 2094 2507 2622 2625 2567 2489 1465 2578 14736 134 1973 29 56 3505 3772 3790 3718 3718 2115 3700 21290 135 2788 3941 4727 5069 5099 5 0 07 5231 2984 4976 28781 136 3473 5155 59 81 6308 6339 62 39 68 96 4204 6217 36052 137 4118 6135 71 8 6 7662 7731 76 91 87 16 49 8 5 7568 43985 138 4973 7765 94 75 10396 10861 10694 13646 66 64 10357 602 25
139 1ttn 1253 1242 1493 1460 1442 1431 1424 8 84 1457 83 01 140 2366 1942 2150 1961 1910 1897 19 62 1206 1980 11400 141 3461 3007 2957 2562 2513 2606 3143 18 51 2660 15400 142 4325 3942 3571 3060 2999 3198 4248 2631 3207 18618 143 5677 508 6 4359 39 88 3800 42 29 57 78 36 26 4094 23824 144 67 59 64 55 5330 4988 47 25 5494 2517 48 09 5134 29906 145 84 08 9326 72 26 7726 85 56 9172 12319 7733 8170 47626 146 86 54 9831 7582 818 9 94 90 9869 13116 78 97 8783 512 96 147 7376 7335 58 7 6 5941 5796 68 29 81 65 5954 6111 35662 148 2 11 D 4254 4106 48 02 4994 5038 5042 56 78 3419 4969 28881 149 5708 5487 6253 6466 6524 6527 78 63 45 8 2 64 43 37566 150 69 7 8 7983 9440 9848 98 34 97 32 13249 6701 9714 566 59 151 1254 1434 18 53 1947 1915 1850 1760 1186 1891 10772 152 2713 2696 3175 32 94 3288 3237 3288 20 44 3249 18728 153 87 30 118 07 14733 15758 15504 15305 26297 9617 15325 892 71 154 5811 5278 6543 6861 69 30 69 82 7 8 74 4478 68 29 39531 155 4246 3780 4736 4975 49 66 4936 5162 3113 4903 28301 156 (v 1270 8 15 935 959 966 9 51 9 23 6 35 953 5430 157 2714 1164 1390 1427 1447 1454 1455 9 08 1430 8242 158 4310 1655 18 96 1942 1988 2002 2111 1305 1957 11349
(j) ~
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 fry hav Nuav
159 6012 2208 2400 2450 2513 2548 28 20 18 00 2478 14416 160 7279 2696 2881 2927 2989 3081 3599 2340 2970 17326 161 86 90 3257 3360 3 3 76 34 26 3558 4455 2943 3430 2000 162 12D 4368 2209 2600 2558 2518 2466 2774 1753 2536 14713 163 5833 2730 3092 3028 2974 2913 3501 2287 3002 174 78 164 7643 3320 3681 3630 3651 3530 4623 3181 3623 21116 165 87 39 3920 4303 4300 4708 4178 61 60 3937 4372 25456 166 1268 962 1203 1205 1186 1118 1084 725 1178 6693 167 2678 14 67 1785 1779 1752 1698 1726 10 70 1754 88 49 168 1 12D 12 83 936 1217 1414 1397 1239 1190 7 65 1317 7484 169 2729 2502 2930 2914 2934 2956 2979 17 52 2934 16866 170 4345 3884 4357 4283 4318 4421 4836 28 59 4345 25151 171 6036 5546 5858 5764 5791 6028 7129 4184 5860 34045 172 6578 7167 7769 7907 79 82 8263 10492 5915 7980 46437 173 87 84 10237 112 23 120 26 12727 12968 185 19 85 98 12236 71103 174 1278 1344 1803 18 72 1835 1790 1712 1063 1825 10355 175 2711 2328 2972 2932 2893 28 78 2863 1667 2919 167 51 176 4351 3934 4414 4353 4281 4321 4654 28 63 4342 25088 177 5994 5076 5824 5838 5818 59 29 6914 4205 5852 33885 178 1 11 U 1223 388 432 465 464 449 435 338 453 2585 179 2351 521 602 6 22 675 6 57 619 436 639 3687 180 34 48 6 05 1725 803 8 27 8 11 760 518 792 4593 181 4513 718 850 934 9 68 9 57 8 99 609 9 27 5386 18 2 5714 8 32 981 1060 1102 11 06 1034 6 59 1062 61 82 183 6997 1025 1182 1258 1295 1309 1234 8 18 1261 7 3 44 184 8709 1295 1487 1 5 42 1594 1626 1612 1156 1562 9080
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
185 2 12D 4249 3560 4400 4670 4791 4695 47 81 2931 4639 268 37 186 5737 4926 58 54 61 92 6248 62 38 67 78 4134 6131 35590 187 7432 6390 7726 83 46 85 44 86 34 10371 5658 8313 48310 188 8723 7718 107 88 11933 12099 13046 186 22 79 39 119 67 69505 189 1 4 35 1340 1735 18 57 18 52 17 81 1711 1144 18 06 10256 190 2718 2399 3023 3187 3207 3138 30 53 1931 3139 18025 191 7 5 07 6189 80 11 9200 9427 9703 11364 5720 9085 527 38 192 8544 78 42 10666 125 42 13312 13775 178 20 6976 125 74 729 86 193 1287 1417 16 97 18 7 18 69 18 08 1720 1046 1800 10223 194 27 17 2450 2940 3187 3214 3157 3054 1749 3125 17954 195 42 53 3560 4222 45 90 4679 46 63 4743 2741 4539 26247 196 6068 48 69 57 79 6335 65 8 6 66 04 7172 4338 63 26 366 78 197 7389 58 86 72 8 6 82 23 8584 8936 10658 50 60 8257 4798 6 198 86 88 78 91 100 27 120 56 130 29 14299 190 81 6492 12353 71850 199 5864 4694 5 6 67 61 94 6419 65 48 7192 3950 6207 360 14 200 2 D 4177 38 36 4547 48 09 4775 4628 5006 2715 46 90 261 30 201 5712 5170 62 39 66 38 6599 6604 7518 4167 65 20 378 00 202 73 63 7201 8986 98 43 9733 9914 13353 6219 9619 55810 203 8604 10043 13118 148 41 150 42 158 66 25206 82 5 3 14717 85290 204 12 68 1506 18 41 1971 1966 1868 1799 11 42 1913 10880 205 2659 2571 3127 3276 32 50 3130 3069 18 80 3196 18 350 206 39 80 36 76 4347 4573 45~67 4473 46 34 28 37 4490 25910
o 207 Orifice 11496 10 64 1360 15 39 1 5 80 1 6 15 1496 8 58 15 24 88 83 208 9433 8 95 11 78 13 26 1394 1386 1263 727 1346 78 48 209 7387 746 9 77 1123 1184 1159 1048 6 11 1111 64 74 210 52 36 566 7 66 900 934 909 8 21 499 8 27 48 02
0) CJ1
TABLE III Continued
Run No Position CFM h 1 h2 hs h4 h5 h6 h7 hav Nuav
211 212
3309 1293
414 257
563 3 19
6 68 3 57
6 91 3 37
6 72 351
7 37 337
38 4 2 46
4 40 341
3748 1942
213 214 215 216 217 218
c of 2nd 1 516 1235
1919 2712 3320 4153 4704
1532 2447 35 46 4312 5567 74 29
2 1 87 3312 4225 52 86 6902 8 6 50
2360 3555 4340 56 12 7 0 49 8 9 40
2409 3598 4 8 85 5718 7713 9593
2347 2101 35 33 3453 48 00 49 62 5562 59 86 72~6 7 8 79 93 76 11237
1243 20 64 3054 4 2 8 1 5114 6983
2326 35 00 4638 5545 7225 91 40
132 13 200 27 26672 31968 41711 52811
bull
67
TABLE IV
PRESSURE PROFILE DATA
Baffle Flow Qpening Rate ~p
(Inches) Position (CFM) (Inches 295 S G Fluid)
1 364 l2 11 U 1012 0 254 1248 0197 1493 0 141 1718 0112
c 1000 9 80 1210 1710 1436 28 75 1746 4320 1011 1080 1277 2050 1393 3020 1 6 28 4450
12D 1011 9 75 1236 1520 1450 2510 1603 3450
1 D 1011 975 1256 1700 1480 2690 158 1 4070
1 12D 1010 950 1259 1750 1462 2650 1631 3710
2 11 D 1124 1315 1360 2130 1505 2850 1689 4125
1 216 12U 1294 045 1949 0324 2374 0282 2704 0225 3367 0169
c 1326 265 18 81 5 90 2313 990 2731 1480 3439 2660
12D 1272 2 49 1957 661
68
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Pos ition (CPM) Inches 2 95 S G Fluid)
2559 1275 3033 1940 3639 3025
1 216 1nD 1257 242 16 96 476 2117 8 05 2561 1280 2990 1895 3431 26 bull00
1 316 12U 1309 0 479 2004 0422 28 28 0 352 3526 0281 42 28 0225 5199 0225
c 1308 1 43 1998 272 28 14 5 10 3478 795 4248 1235 5048 1885
l2D 1286 140 2005 3 45 2831 725 3495 1180 4194 1805 5046 2945
1 11D 1322 150 2039 352 2841 735 43 77 1980 5378 3440
1 516 12U 1278 0493 2732 0493 4315 0408 5744 0352 7494 0352 8932 0422
c 1300 0 506 2731 1985 4310 348 6080 6 45
69
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Position (CPM) (Inches 295 SG Fluid)
7607 1090 8830 1585
l2D 1343 0549 2738 225 4566 583 6112 1195 7536 2055 9043 3415
1 516 1uD 1249 0464 2713 224 4155 579 5620 1150 7428 2115 90 70 3405
1 12D 1301 0493 2735 220 4501 616 61 50 1235 7440 2065 8862 3445
2D 1265 0 478 2750 226 4366 594 6578 1270 7678 2240 8945 5280
2 12D 1295 0493 2725 222 4293 600 5807 1120 7568 2200 9070 3615
TABLE V
RATE OF HEAT TR AN SFER Ar THE BAFFL~~ CID-TT ER
Orifice Size
(Inches)
Flow Rate
( CFM)
Re d e G tU
R~) 055 Nuav NuPr-l3
1 364 10 26 12 90
8 075 10015
43400 54 600
85 11 99 64
95 83 112 19
1416 11 140 59 900 110 30 124 20 16 27 12 800 68 900 126 64 142 60 17 29 13 610 73 200 135 79 152 90 17 76 13980 75 200 147 59 166 19
1 216 11 35 14 06
8 600 10 660
27000 33500
6 4 96 76 56
73 14 8 6 12
1517 11500 36100 82 51 9291 20 34 15400 48400 10229 115 18 23 11 17500 55000 118 31 13322 2348 17 800 55900 11947 13452 2666 20 200 63400 13508 15210 27 16 20 600 64700 135 05 152 07 32 47 24600 77200 161 57 18 193 3392 25 700 80700 17390 195 8 1
1 316 1344 19 36
9898 14 260
24800 35 700
63 8 7 8 2 77
71 92 93 20
28 46 20 9 60 52 500 111 08 125 08 34 84 25 660 64200 131 38 147 93 40 66 50 12
29900 36900
74800 92400
150 78 18046
169 78 203 20
~ 0
TABLE V Continued
Orifice Flow Re Size Rate d e G R~rmiddot55 NuPr-13(Inches) (CFM) U Nuav
1 516 12 70 8 847 16800 54 ~0 61 14 2 14 18 900 35800 82 42 92 80 43 10 30 000 56900 11349 127 79 60 12 41900 79400 14416 16232 7279 50700 96100 17326 19509 86 90 60540 115000 20098 22529
TABLE VI
RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
Orifice Size
(Inches)
1 364
1 216
1 316
Flow Rate
(CFM)
1054 1294 1431 1681 1770
1068 1399 1669 1959 2295 2636 3390
1299 1973 2788 34 73 4118 4973
Re deG Mshy
8 300 9870
11260 13200 13 930
8100 10600 12650 14850 17400 19980 25700
9 570 14500 20500 25600 30300 36600
R~r-6 51900 61700 70500 82 500 87 100
28200 36900 44000 51700 60 600 69500 89400
26100 39600 56000 69900 82700 99 900
Nuav
2416 293 5 3187 4018 4805
14938 18968 21712 25156 30680 37938 59601
14736 21290 28781 36052 439 85 60225
Uu Pr-1 3
27204 33050 3589 4524 541 0
16820 21358 24448 28326 34546 427 18 67111
16593 23973 32407 40595 495 1 678 13
TABLE VI Continued
Orifice Flow Re Size Rate deG R~rmiddot6 NuPr-13(Inches) (CFM ) M- Nuav
1 516 1268 88 30 17700 108 8 1225 2689 18700 37400 1835 2066 3980 27700 55700 2591 2917 4177 29100 58 500 2713 3055 5712 39800 80000 378 0 425 6 7362 51300 103000 5581 6284 8 604 59 900 120000 8529 9604
74
TABLE VII
EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER
l 516 Inch Orifice
Center ot 2nd Baffle 4 Downstream
Plow Rate (CFM)
1235 1919 2712 3320 4153 4704
Flow Rate (CFM)
1270 2714 4310 6012 7279 8690
(Re)eb -8600 1321
13400 2003 18900 2687 23100 5197 28900 4171 32800 5281
Center ot Single Battle
-8847 543
18900 824 30000 1135 41900 1442 50700 1733 60540 2001
(Nu)(Pr)-l3
1487 2255 3003 3600 4697 5946
(Nu)(Pr)-13
611 928
1278 1623 1951 2253
75
ABLE VIII
HEAT TRANSFER IN THE TEST SECTION WITHOUT ORIFICE
CFM Ute) 0b h Nu
1293 5-951 3 41 1942
33 09 15251 649 3746
5236 24193 827 4802
7387 34001 1111 6474
9433 43419 1346 7848
11496 52-914 1524 8883
76
TABLE IX
PRESSURE DROP FUNCTION
Orltlee Size Flow Rate incbea ~CFM (Re)eb X 10bull8
1 364 1011 7957 0808 1256 9885 1468 1480 11648 2765 1581 12443 4160 1689 1_3293 4 020
1 216 1257 9530 1327 1696 12858 2663 2117 16049 4615 2561 19415 7581 2990 22668 11560 3431 26011 16440
l 316 1322 9736 1819 2039 15016 4332 2845 20952 9275 3495 25739 15300 4377 32014 26800 5378 39607 50100
1 516 1011 7 957 oaos 1256 9885 1469 1480 11646 2765 1581 12443 4160 1689 13293 4020
77
TABLE X
EXPERIMENTAL DATA
Baffle Hole Diameter Run No
1 - 59
60 - 102
103 - 138
139 - 206
207 - 212
213 - 218
(Inches)
1 364
1 216
1 316
1 516
No Baffle
2nd - 1 516
TABLE X
EXPERIMENTAL DATA
Run Thermocouple Reading s (mv) No Position CFM I tc1 tc2 tc3 tc4 t c 5 tc6 tc7 tcair
1 c 1026 530 2055 1825 1768 1782 1802 1837 1965 1198 2 1290 612 2059 18 65 1809 18 32 1851 1880 1965 1160 3 1416 714 2151 1970 1931 1965 1988 2026 209 5 1130 4 1627 8 21 2235 2084 2 049 2093 2126 2173 2266 1130 5 1776 865 2203 2033 1970 2015 2084 2159 2 264 1121 6 12D 1109 542 1636 1507 1499 1499 1498 1498 1528 1218 7 1258 651 1670 1522 1503 1513 1513 1516 1548 1221 8 1433 750 1625 1480 1467 148 3 1487 1487 1516 1153 9 168 1 8 73 1656 1494 148 1 1511 1517 1517 1543 1159
10 1rtD 1102 485 1545 1450 1437 1446 1447 1442 1466 1220 11 13 08 6 10 1571 1470 1460 1476 1476 1469 1498 1194 12 1464 730 1 623 1509 1508 1528 1 5 32 1524 1548 1173 13 11 06 8 71 1663 1559 158 1 1606 160 6 1 583 1601 1190 14 1 12D 1115 520 1698 1579 1575 1 577 1580 1590 1615 1280 15 1275 6 10 1692 1567 1558 1 561 1570 1580 1601 1234 16 1498 770 1760 1619 1630 1 635 1642 1645 1661 1204 17 1695 912 1775 1635 1670 1689 1686 168 6 1701 1165 18 2D 1049 510 1736 15~2 1567 1558 1 553 1558 1620 1236 19 12 41 610 1655 1517 149 1 148 1 148 1 148 4 1546 1108 20 1 5 32 7 35 1720 1550 1530 1520 1519 1523 158 0 1104 21 16 74 8 8 0 1900 1 727 1714 1696 1691 1692 1753 1169 22 1U 1074 38 5 3 324 2740 2534 2478 2 465 2503 258 0 1210 23 1287 4 35 3510 2 870 2682 2 610 2599 2638 27 1 9 1190 24 1 5 08 470 3 618 2920 2690 2 637 2627 2 664 2747 1177 25 18 07 525 4 088 3235 2962 2905 2910 2988 3130 1169
z ())
TABLE X Continued
Run No Position CFM I tc1 tc 2
Thermocouple Readings te3 tc4 tc5
(mv) tc6 tc7 tcair
26 c 10~29 6 32 2340 2~092 2032 2060 2~097 2152 2~213 1211 27 12 66 679 2270 2 047 1993 2013 2069 2142 2 210 1 182 28 1430 723 2336 2097 2033 2080 2153 2~255 2 356 1 138 29 1729 8 52 2318 2070 1980 2061 2158 2279 2367 1121 30 12D 1054 570 1520 1 4 20 1402 1400 1396 1400 1 443 1159 31 1294 6 69 1599 1469 1444 1439 1433 1 442 1485 1168 32 1430 7 88 1720 1562 1536 1532 1528 1537 158 0 118 5 33 1770 8 81 1641 1488 1450 1~441 1 441 1_466 1518 1 163 34 1D 1058 548 1579 1498 1495 1526 1553 1_557 1 571 1 276 35 1263 640 1609 1509 1515 1570 1599 1598 1 598 1 266 36 18 36 8 47 1538 1452 1483 1553 1602 1 590 1 558 1195 37 1 12D 1029 5 41 1 578 1499 148 4 1473 1461 1465 1-512 1200 38 1315 6 30 159 1 1504 1493 1482 1470 1470 1505 118 5 39 1 4 26 743 1765 168 1666 1660 1645 1642 1678 1270 40 1757 8 54 1744 1648 1634 1620 1598 1 593 - 1612 1223 41 2D 1080 5 30 1734 1604 1570 1 570 1570 1 588 1 640 128 1 42 1305 6 40 1744 1622 1589 1 608 1593 1 609 1 661 1240 43 1434 750 1798 1687 1658 1 636 -1641 1 661 1 711 1_220 44 18 04 8 41 1 764 1666 1607 1605 1614 1 635 1 675 1205 45 12nu 1088 415 2614 2295 2195 2 169 2174 2217 2256 1171 46 1318 477 2805 2477 2371 2342 2364 2 401 2 438 1 163 47 1413 5 28 2930 2 646 2 555 2 526 2532 2570 2 577 1 199 48 1773 550 2740 2518 2450 2431 2448 2 479 2 480 1 170 49 1 11 U 1054 380 3175 2670 2505 2 461 2467 2 534 2 621 1 258 50 1240 420 3268 2738 2 546 2 510 2 508 258 2 2 649 1214 51 1419 451 3364 2B07 2 632 2590 2 590 2 651 2773 1 215 52 1 12U 1032 360 3 165 2 629 2 450 2402 2403 2 473 2 bull568 1 163
--I lt0
TABLE X Continued
Run No Position CFM I tc1 tc2
lhermocoup1e Reading s tc3 tc4 t c 5
(mv) tc6 tc7 tc a ir
5 3 1314 38 9 3178 2592 2411 2367 2361 2432 2555 1140 54 1448 403 3095 2544 238 1 2336 2336 2390 2476 1158 55 178 2 427 3006 2434 2286 2253 255 3 2299 2397 1154 56 2 11U 1061 360 3369 2814 2619 2567 2560 2650 2833 1220 57 1216 360 3044 2512 2338 2290 2288 2374 2566 1150 58 1322 387 3196 2614 2425 2383 2382 2472 2670 1138 59 1639 403 3020 2438 2272 2238 2238 2318 2502 1127
60 1D 1068 612 1552 1424 1400 1395 1396 1426 1745 0945 61 1399 612 1355 1246 1230 1229 1230 1250 1509 0872 62 1669 710 1436 1293 1272 1265 1266 1286 1551 0847 63 1959 900 159 5 1468 1444 14 38 1432 1446 1720 0851 64 2295 730 1169 1105 1098 1099 1108 1100 1298 0781 65 2636 8 80 1202 1129 1121 1126 1 138 1115 1342 0748 66 3390 9 35 1060 o 9s7 0999 1001 1017 0971 1154 0703 67 1nu 1190 370 2225 2188 2104 2080 2120 2209 2 7 15 0990 68 1559 368 2005 1950 1871 18 48 1876 1951 2408 0916 69 1904 368 1870 18 1 4 17 34 1711 1730 18 07 2238 0875 70 22 bull11 471 228 6 2 204 2099 2063 2092 218 $ 2732 0840 71 2289 471 2030 2000 1925 1895 18 96 19 5 2498 0785 72 2727 4 71 1854 18 23 1753 17 23 1716 3758 2241 0743 73 3210 471 1680 1651 158 6 1559 1551 158 1 1950 omiddot7o9 74 2uD 1210 404 1261 1212 1198 1197 1205 1222 139 1 0978 75 14 20 540 1321 1260 1242 1 240 1249 1268 148 7 0918 76 1692 7 18 1467 138 6 1364 1361 1376 1405 1678 0883 77 18 94 903 1708 1 591 1565 1560 1575 1603 1948 0 857 78 2301 903 1530 1432 1407 1402 1415 1432 1738 0815
ro 0
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc117 tcair
79 2621 6 50 1069 1 020 1009 1009 1009 1007 1~189 o739 80 3230 901 1200 1128 1113 1119 1119 1086 1341 0694 81 82
l2D 1155 1689
360 575
1191 1345
1142 1252
1122 1218
1118 1210
1118 1209
1132 1228
1292 1446
0916 0822
83 1244 430 1163 1134 1131 1130 1129 1132 1292 0877 84 2100 645 1175 1135 1147 1 142 1138 1122 1286 0757 85 2292 8 25 1 354 1310 1327 1330 1323 1285 148 6 0728 86 2907 8 23 1180 1138 1151 1158 1149 1107 1268 0687 87 3380 902 1113 1049 1025 1011 1006 1042 1178 0673 88 89
1 12D 1427 1875
480 615
118 2 1140
1140 1095
1124 1077
1125 1075
1129 1072
1137 1072
1290 1243
0880 0790
90 2259 8 41 1296 1231 1207 1206 1203 1182 1419 0757 91 2682 8 80 1231 1170 1149 1147 1142 1112 1350 0731 92 3417 940 1142 1092 1076 1076 1069 1021 1252 0693 93 c 15 17 431 1321 1298 1268 1249 1250 1273 1522 0841 94 2034 505 1285 1263 1235 1209 1205 1206 1464 0759 95 2348 6 10 1395 1379 1334 1302 1286 1268 1536 0732 96 2716 706 1486 1480 1427 1383 1358 1311 1572 0 700 97 3247 7 56 1417 1430 1375 1320 1284 1223 1450 0660 98 1135 400 1425 1388 1352 1329 1330 1 364 1651 0893 99 14 06 440 1379 1341 1304 128 2 1281 1305 1583 0 831
100 2311 680 1602 1593 1553 1514 1502 1480 1 7 27 0 802 101 2666 680 1471 1469 1428 1390 1372 1335 1564 0761 102 3392 798 1491 1 509 1449 1395 1372 1305 1534 0 719
103 1U 1235 410 2469 2295 2173 2165 2226 2361 3120 0 897 104 2010 410 2017 1848 1 737 1706 1747 1865 2582 0753 105 28 14 410 1682 1535 1457 1427 1437 1520 2109 0 660
00 t-
TABLE X Continued
Ru n Thermocouple Rea ding s (mv No Positi on CFM I tc1 tc2 tc3 tc4 tc5 tc6 tc7 tcair
106 3492 440 1649 1499 1420 1391 1390 1470 2042 0620 107 4395 550 18 33 1679 1597 1564 1570 1640 2223 0583 108 5075 588 1779 1642 1580 1550 1552 1 615 2 191 0548 109 c 1344 398 1464 1 399 1364 1353 1350 1380 1689 0 907 110 1936 459 1369 1290 1253 1242 1 237 1259 1574 078 2 111 2846 580 1347 128 5 1251 1232 1220 1215 1 5 23 0 683 112 34 8 4 700 1392 1369 1339 1317 1299 1259 1599 0 636 113 4066 8 13 1449 1458 1427 1391 1363 1270 1595 0 591 114 5012 930 1484 1530 1500 1453 1420 1272 1580 0 580 115 1D 1362 513 1269 1218 1 217 1214 1220 1238 1460 0 893 116 19 58 600 1187 1122 1121 1120 1124 1133 1352 0798 117 2812 705 1052 1008 1015 1010 1011 1001 1218 0691 118 34 32 913 1105 1075 1085 1081 1086 1047 1301 0645 119 4022 980 1038 1021 1026 1023 1029 0983 1211 0 609 120 5026 982 0 8 61 0839 0836 0836 0837 0791 0955 0570 121 2D 1244 475 1320 1246 1233 1240 1255 1275 1434 0925 122 1 9 60 5 50 1160 1088 1074 1079 1089 1100 1260 078 7 123 2817 6 80 1096 1024 1 013 1018 1029 1022 1201 0 700 124 3491 960 1248 1175 1163 1172 1192 1153 1435 0 658 125 4096 989 1141 1089 1078 108 9 1105 1051 1310 0629 126 50 37 989 0983 0933 0929 0 936 0949 0880 1090 0 602 127 128
12D 1278 1947
402 545
1270 1261
1 230 1216
1228 1216
1230 1 215
1235 1223
1242 1219
1483 1514
0 913 0778shy
129 2769 695 1273 1234 1237 1221 1251 1212 1525 0678 130 131 132
34 39 4103 4978
8 40 9 80 9 80
1336 1448 1271
1322 1458 1 288
1328 1 462 1286
1 259 1 356 1157
1353 1492 1311
1261 1329 1138
1 555 160 7 1343
0 629 0 600 0599
(l) l)
TABLE X Continued
Run No Position CFM I tel tc 2
Thermocouple Readings tc3 tc4 tc5
( mv) tc6 tc7 tcair
133 1 l2D 1299 5 16 1 28 1 1212 1196 1195 1205 1221 1478 0869 134 1973 6 15 1163 1098 1073 1071 1079 1083 1343 0751 135 136
27 88 34 73
802 9 -_78
1187 1214
1099 1131
1069 1104
1066 1101
1075 1~110
1l061 1066
1370 1360
0662 0618
137 4118 9 81 1084 1010 0983 0979 0982 o937 1209 0581 138 4973 98 1 0969 0897 0 868 0855 0860 0799 1041 0572
139 1D 1253 409 1371 1293 1298 1301 1309 1321 1578 0928 140 2366 480 1130 1 090 1 121 1130 1137 1132 1390 0744 141 34 61 6 38 1081 1086 1152 1161 1147 1069 1382 0644 142 143 144
4325 5677 6759
7 90 939 998
1110 1115 1034
1161 1208 1139
1253 1268 1180
1265 1302 1215
1228 1230 1123
1080 1056 0970
13$913r12 8
0601 0561 0542
145 84 08 989 0863 0961 0934 0895 0871 0 785 09 9 0530 146 86 54 9 80 0808 0901 0 872 0821 0809 0733 0891 0498 147 7376 9 80 0 927 1032 1027 1 040 0961 0889 1032 0511 148 2D 4254 776 1 050 0 981 0965 0961 0962 0922 1155 0579 149 5708 991 1102 1031 1014 1009 1010 0931 1227 0528 150 69 78 990 0914 0853 0839 0 839 0843 0759 0996 0521 151 1254 490 1 479 1352 1329 1334 1351 1379 1607 0930 152 2713 7 00 1310 1220 1201 1201 1211 1209 1516 0723 153 8730 991 0809 0756 0742 0745 0 748 0663 0874 0543 154 5811 966 1219 1108 108 6 1081 1079 1033 1330 0650 155 42 46 8 02 1248 1136 1114 1114 1118 1103 1376 0 699 156 c 1270 429 1671 1571 1551 1545 1563 1600 1933 0929 157 2714 488 1398 1285 1 267 1258 1262 1275 1628 0729 158 4310 642 1424 1318 1299 1282 1283 1261 1683 0617
co ~
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc7 tc a 1r
159 60 12 780 1461 1388 1370 1349 1343 1279 1700 0 573 160 72 79 8 60 1402 1344 1330 1312 1292 1189 1 566 0 520 161 8690 982 1472 1442 1437 1 422 1392 1224 1602 0 521 162 163
12D 4368 5833
6 30 8 30
1195 1368
1105 1270
1111 1283
1117 1294
1131 1313
1081 1194
1369 1553
0613 0 553
164 76 43 959 1428 1338 1348 1341 1371 1180 1488 0535 165 8739 984 1345 1272 1272 1208 129 3 1059 1361 0550 166 1268 459 1701 1548 1541 1547 1589 1 625 1976 0 973 167 2678 570 1485 1351 1349 1356 138 1 1 385 1795 0760 168 169
1 12D 128 3 2729
448 650
1664 1314
1501 1232
1425 1233
1428 1229
1491 1229
1527 1232
1869 1571
0 962 0767
170 4345 847 1245 1179 1187 1182 1172 1132 1476 0 650 171 6036 9 76 1139 1109 1117 1114 1095 1020 1332 0588 172 6578 9 72 0982 0949 0942 0938 0926 0 8 50 1079 0560 173 87 84 9 72 0880 0854 0 8 36 0822 0818 0 749 0941 0585 174 1278 480 1564 1416 1397 1403 1417 1445 1733 0998 175 2711 590 128 3 1175 4 1178 1182 1187 1195 1493 0796 176 4351 8 90 1331 1259 1266 1275 1272 1235 1592 0 682 177 5994 9 60 1228 1152 1150 1151 1143 1075 1 360 0644 178 lU 1223 408 2282 2140 2052 2052 2106 2188 2626 0 878 179 2351 408 178 1 1623 158 5 1519 1556 1634 2068 0717 180 3448 482 1888 1675 1570 1541 1572 1665 2199 0629 181 4513 563 2026 1797 168 4 1644 1670 1770 2385 0583 182 5714 589 1913 1700 1610 1568 1580 1 682 2382 0551 middot 183 6997 653 1903 1718 1643 1611 1612 1700 2326 0 549 184 8709 6 80 1738 158 3 1543 1510 1498 1519 1 912 0577 185 186
2 12D 4249 5737
660 9 74
1055 1221
0 979 1122
0960 1093
0 952 1088
0959 1090
0 956 1054
1147 1350
0661 0602
187 7432 9 8 1 1065 0981 0951 0942 0 939 0881 1135 0582 CD ~
TABLE X Continued
Run No Position CFM I t o1 to 2
188 87 23 9 83 0944 0 879 189 1435 585 18 26 1630 190 2718 690 1433 1298 191 7507 950 1070 0961 192 85 44 964 0982 0 881 193 1287 600 1806 1668 194 2717 7 80 1579 1444 195 4253 8 81 1371 1260 196 60 68 9 78 1252 1152 197 73 89 975 1100 1000 198 86 88 973 0953 0 871 199 58 64 9 81 1269 1155 200 2D 4 1 77 915 1362 1251 201 5712 975 1213 1111 202 7363 9 78 1036 0 951 203 8 604 973 0932 0861 204 1268 6 95 2015 18 20 205 2659 6 96 1405 1295 206 39 80 7 98 1261 1174
No 207 Orifice 114 96 509 1325 1148 208 94 33 509 1477 1243 209 7487 5 09 1686 1409 210 5236 505 2094 1691 211 3309 428 2188 1 778 212 1293 392 2976 2560
Thermo ooup1e Readin g s (mv) to 3 to4 to
5 to
6 to7 toair
0 851 0847 0 8 29 0759 0987 0592 158 4 1583 1611 1647 1993 0986 1270 1266 1 279 1298 1604 0 789 0916 0908 0900 0 858 1115 0602 08 39 0 823 0 818 0 770 1035 0602 1609 1602 1629 1676 2153 0979 139 1 1385 1400 1 430 1938 0776 1212 1201 1205 1201 1601 0669 1 105 1086 1086 1 052 1371 0621 0952 0936 0923 0870 1195 0582 0 8 20 0 801 078 1 0 729 1044 0569 1108 1090 108 2 1043 1407 0610 1218 1221 1241 1202 1582 0659 1081 1083 1084 1031 1 368 0622 0921 0924 0919 0 841 1111 0 610 08 34 0831 0 821 0 751 1003 0 630 1761 1761 1 809 1861 2399 0966 1271 1271 1295 1311 1650 0797 1150 1150 1161 1149 1440 0703
1083 1057 1053 1109 1566 0~530 1158 1125 1138 1217 1763 0 526 1291 1250 1278 1383 2038 0542 1518 1478 1519 1657 2420 0 589 1596 1557 1601 1737 2441 0688 2370 2344 2409 2561 3 297 0921
()) (11
TABLE X Continued
Run Thermocouple Readings (mv) No Position CFM I tc 1 tc2 tc3 tc4 tc tc tc tc i5 6 7 a r
C of 2nd 213 516 1235 4 63 1 432 1291 1265 1258 1 268 1 308 1550 0 971 214 1919 6 17 1357 1223 1196 1191 1199 1211 1461 0 851 215 27 12 8 35 1401 1259 1278 1220 1230 1218 1511 0 762 216 3320 981 1439 1305 1270 1259 1275 1238 1450 0719 217 41 53 980 1251 1142 1132 1094 1121 1088 1305 0 695 218 404 987 1102 1042 1030 1 bull006 1014 0960 1133 0681
Supplementary Equations
Calculating temperatures from thermocouple readings
t = -026tc)2 + 3512(tc) + 3201 (26)
where t is the temp in deg F and tc is the thermocouple reading in millishyvolts
Calculation of the thermal conductivity of air
k = 00000245ta + 0 0132 (27)
where k is the thermal conductivity in Btuhr rt2 degFft and ta is the air temp 1n OF
I I
bull co m
ACKNOWLEDGMENTS
The author wishes to express his gratitude to
Dr James G Knudsen for his guidance during the course
of this research to the National Science Foundation for
financing the project and to Mr Azimuddin Faruqui and
Mr K Nar ayanan for their help in constructing the
equipment and taking the i n itial data
TABLE OF CONTENTS
Chapter Page
I Introduction bull bull bull bull bull 1
II Theory and Previous Work bull bull 4
III Experimental Apparatus bull 8
Test Section bull bull bull bull bull bull 8 Sen sing Probe Assembly bull bull bull bull 11 Power Source bull bull bull bull bull bull 12 Temperature Measuring bull bull 12 Air Source bull bull bull bull bull bull bull bull bull 15 Pressure Probe bull bull bull bull bull bull bull bull bull 16
IV Experimental Program bull bull bull 17
v Experimental Procedure bull 20
VI Calculation of Experimental Data bull 22
VII Analysis of Data bull bull 27
Variat ion of Heat Transfer Rate with Distance from the Baffle bull bull 27
Rate of Heat Transfer at the Point
Effect of Upstream Baffles on Heat
Heat Transfer in the Test Sect ion
Heat Transfer at the Baff le and Maximum Point as a Function of
Correlation of Data at the Baff le bull 36
of Maximum Heat Trans f er bull bull bull bull 39
Transfer at the Orifice Center bull bull bull 42
with No Orifice bull bull bull bull bull bull bull bull 42 Pressure Drop Data bull bull bull bull bull bull 44
Pressure Drop bull bull bull bull bull bull bull 47
VIII Summary of Re sults 51
IX Re commendations 53
Nomenclature 54
Bibliography bull 56
Append ix 57
LIST OF FIGURES
Figure Page
1 Cross Section of Test Section and Probe bull bull bull bull bull bull bull bull bull bull bull bull 9
2 Experimental Apparatus 10
3 Sensing Probe bull bull bull 13
4 Drawing of Assembled Probe 14
5 Variation of Heat Transfer Rate with Distance from Baffle - 1 364 11 and 1 216 Sizes bull bull bull bull bull bull bull bull bull bull 29
6 Variation of Heat Transfer Rate with Distance from Baffle - 1 316 11 Size bull 30
7 Variation of Heat Transfer Rate with Distance from Baffle - 1 516 Size bullbull 31
8 Effect of Orifice Size on Position and Value of Maximum Heat Transfer bull bull 34
9 Correlation of the Point of Maximum Heat Transfer with Orifice Size bullbull 35
10 Rate of Heat Transfer at Baffle Center 37
11 Correlation of Heat Transfer Data at Baffle Center bull bull bull bull bull bullbull 38
12 Rate of Heat Transfer at the Point of Maximum Heat Transf er bull bull bull bull bull bull bull bull 40
13 Correlation of Heat Transfer Data at the Point of Maximum Heat Transfer 41
14 Effect of Upstream Baffles on Heat Transfer at Baff le Center bull bull bull bull bull 43
15 Heat Transfer with No Baffle 4 5
16 Orifice Pressure Drop Function versus Reynolds number bull bull bull bull bull bull bull bull bull bull bull bull bull bull 46
17 Heat Transfer at the Baffle and Maximum Point as a Function of Ori fice Pressure DIO p bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 48
18
Fi gure Pa ge
Var iation of Heat Transfer Rate and Pressure Drop with Orific e Size at a Con stant Flow Rate bull bull bull bull bull bull 50
bull bull bull bull bull bull bull bull
bull bull
I
II
III
IV
v
VI
VII
VIII
I X
z
LIST OF TABLES
Pa ge
Summary of Experimental Program bull bull 19
Position of Maximum Heat Transfer 32
Calculated Heat Transfer Data 57
Pressure Profile Data bull bull bull 67
Rate of Heat Tr ansfer at the Baffle Center middot bull bull bull bull bull 70
Rate of Heat Transfer at the Point of Maximum Heat Transfer bull bull bull bull bull bull bull bull bull bull bull bull 72
Effect of Upstream Baffles on Heat Trar1sfer bull bull bull bull bull bull bull bull bull bull bull 74
Heat Transfer in the Test Section without Orifice bullbullbullbullbullbullbullbull 75
Pressure Drop Function 76
71bull r ntal bull bull bull bull bull bull bull bull bull bull bull bull
HEAT TRANSFER AND PRESSURE PROFILRS IN THE VICINITY OF ANNULAR ORIFICES
- CHAPTER I
INTRODUCTION
The most common type of industrial heat transfer
equipment is the shell and tube heat exchanger which
consists of a bundle of tubes contained in a cylindrical
shell Heat is transferred from the hot fluid to the cold
fluid through the tube walls as one fluid flows through
the tubes and the other flows through the shell surroundshy
ing the tubes
Most commercial multitube heat exchangers contain
bafflesmiddot to guide the fluid through the equipment and to
prevent stagnant regions from forming in the shell As a
result the flow pattern in the shell is very complicated
and considerable variation of the local rate of heat transshy
fer occurs because of the various types of flow which exist
in the baffled passage The research described in this
thesis concerns a study of one small portion of the shell
side of a heat exchanger
There are three main types of baffles used in commershy
cial heat exchangers
1middot Orifice baffles extend through the cross section
of the shell and all of the shellbullside flow is
through the annular orifice formed at each point
where the tube passes through the baffle
2
2 Disk and doughnut baffles consist of disks and
doughnuts or annular rings placed alternately
along the length of the tube bundle~ There is
some flow through the annular orifices formed
where the tubes pass through the baffles but a
large portion of the flow is around the baffles
3 Segmental baffles are segments of a circle and
Bre arranged so that the fluid flows back and
forth across the tube bank There is still some
f~ow through the small area where each tube goes
through the baffle
In the case of disk and doughnut and segmental baffles
small annular clearances must be allowed at the point where
the tube goes through the baffle so that the bundle may be
assembled easily Thus in all of the types of exchangers
some shell-side fluid flows through the annular orifice
where the tubes pass through the baffles It has been
shown that this is an area of high rate of heat transfer
but its effect on the overall performance of the heat exshy
changer is not well known Also the prediction of rates
of heat transfer 1n these orifices is not yet possible
The purpose of this research was to make an extensive
study of the heat transfer rates in the vicinity of these
annular orifices and to determine the effect of orifice
size flow rate and upstream conditions The work was
5
performed in a onebulltube single orifice type baffle heat
exchanger and provision was made to measure local rates
of heat transfer in the vicinity of the baffle
4
CHAPTER II
THEORY AND PREVI OUS WORK
In 1701 Newton defined the heat transfer rate qc
from a surface of a solid to a fluid by the equat ion
= ~A(tw - t) (1)q0
where hm is the coefficient of heat transfer from the surshy
face to the fluid excluding any radiation A is the area
of the surface tw is the surface temperature of the wall
and t is the bulk temperature of the fluid The equation
for the point of local surface coefficient h is given by
dqdA = h(tw- t) (2)
The mechan ism and the laws covering heat transfer by
true conduction in solids and by radiation through transshy
parent media are well known However with heat transfer
from a solid to a fluid the situation is far more complex
The mechanism of flow of the fluid to a large extent deshy
termines the rate of heat transfer for a given temperature
difference
In addition the coefficient hm depends on certain
physical properties of the flowing fluid the dimensions
of the apparatus the velocity of the fluid past the surshy
face and frequently the temperature potential AT
It was the purpose of t his research to measure the
local shell -side heat transfer coefficient and correlate
it with the several variables mentioned a bove
5
The heat transfer coefficient for fluids flowing inshy
side tubes is more e a sily measured and correlated due to
the simple geometry of t he tube i nterior Much work has
been done on the tube-side coefficients with one of the
more useful e quations being the Dittus - Boelter equation
( 4 p 450) ~
0 023 (---ctwGJbulla (~np M ( 3 ) M k
with the following cond itions satisfied
(1) Fluid properties evaluated at the arithmetic
mean bulk temperature
(2 Reynolds number gt10000
(3) 0 7 lt Pr lt 100
(4) n = 04 for heating and 0 3 for cooling
(5) Ldw gt60
Colburn (3 p 197) obtained an equation for tubeshy
side heat transfer coefficients in which the Stanton
number is used instead of the Nusselt number
hm ) (~~ 23 _ (dwG) 0 2 ( GC k - 0 bull 023 U (4)
p
Much of the research done on average shell-side heat
transfer coefficients has resulted in empirical correlashy
tions of the form of equations (3) and (4) above Several
investigations have been made for a certain set of phys~al
6
variables but the r esults have ne ver satisf a ctorily been
correlated to appl y for all types of heat exchangers
Some basic 1ork has been done recently however on
the local shell-side coefficients Ambrose (1) studied
the local heat transfer coefficients i n a model heat exshy
changer with segmental baffles This study was fairly
extensive at the baffle center but the data were quite
limited for the space between the baffles Gurushankar1ah
(5) further extended Ambroses work by studying a single
baffle space in detail
The results of these two studies indicated a need for
detailed information 1n the vicinity of the baffle Hence
Lee () investigated a single baffle s pace between two
orifice baffles and obtained considerable information on
the rates of heat transfer in the annular orifices Since
his work was carried out in a multitube mode l heat ex~
changer the determination of the rate of flow through the
individual orifice was difficult because of t he outer
clearances existing in the exchanger For this reason the
present research was undertaken to study the rate of heat
transfer in a single annular orifice through which the flow
could be accurately determined
Bell and Bergelin (2) have studied i n detail the pres shy
sure drop coeff icients for the annular orifices formed beshy
tween a circular disk and a circular tube These results
also appl y to the annular orifioe formed when a rod extends
7
through a circular hole in a plata This study was extenshy
sive in the fact that it considered the baffle thickness as
well as the orifice size but no heat transfer data were
presented
Sullivan and Bergelin (9) studied flow through a
single annular orifice through multiple annular orifices
i n parallel and flow around a single baffle both with and
without leakage through the baffle A generalized expres shy
sion is presented for the pressure drop across one baffle
section of a tubular exchanger with leakage through the
tube holes in the baffle but the effect of leakage area
upon heat transfer is only discussed qualitatively The
pressure drop data is correlated by plotting cent as a funcshy
tion of the Reynolds number where cent equals
d1 )22( ~ P) s c e (d2 -
M-2
8
CHAPTER III
~PERI1ffiNTAL APr ARATUS
The heat transfer test section was essentially a
single tube heat exchanger The inner tube was a l-in
OD aluminum tube with an electrically heated probe midshy
way between the two ends of the tube
Test Section
The shell as constructed from lucite plastic tubing
2 5-in I D and 3-in O D The te t section d a total
lengt h of 54 58 inches I t consisted of two sections
The upstream section was 40 i n ches in length in order to
assure freedom from entrance effects and the downstream
section was 13 12 inches in length To further assure
uniform flow a bundle of short copper tubes was placed a
few inches downstream from the entrance Both of these
sections had 12 i nch flanges on one end so t hat a 18
i nch thick orifice plate could be clamped between them
Heat transfer coefficients were measured in the vicinity of
t h is orifice A cross section of the center of the test
section is shown in Figure 1 and the experimental appara~
tus is shown in Figure 2
Cooled air supplied by a Roots -type blower was used
as the shell-side fluid throughout this study It entered
the test section through a l-in ID 1 12-in OD plasshy
tic pipe at the upstream end of the calming section Tbs
j Jl l 6- 11 BOLTS II I nbull middot~11 I HEATING ELEMENTS
J T ( T
-f-shy - - - f-_- __L
7 777 _y A
IT 1] I
I
FIGURE I CROSS SECTION OF TEST SECTION AND PROBE
10
FIGURE 2 EXPERIMENTAL APP1Ub~fUS
11
air left the test section through nine equally spaced 12
ineh holes placed around the side of the tube at the exit
end
Sensing Probe Assembly
The sensing probe was designed to measure the local
heat transfer coefficients at any point along the tube and
around the tube in the test section The tube was designed
so that it could be easily moved up- and downstream to
measure the heat transfer coefficients at various positions
in relation to the orifice
The sensing tube assembly consisted of the sensing
probe the thermoctmple lead s and selector switch the
power lines and the two aluminum tubes between which the
probe was centered
Imbedded in the sensing probe were seven iron-constanshy
tan thermocouples for measuring the temperatures around the
tube The lead wires from these thermocouples were conshy
nected to a seleotor switch at the downstream end or the
aluminum tube A layer of Saran wrap was placed around the
tube over the t hermocouple and three lengths of Trophet C
resistance ribbon were wrapped around the tube nd conshy
nected in series to the power leads
The heating surface of the probe was formed by these
three one inch wide strips of Trophet C resistance ribbons
The ribbons were 0002 inches thick and had a resistance of
12
0 271 ohms per foot and a thermal conductivity of 763
Btuhr ft 2 degFft They were held in position by four
copper bars placed in four parallel longitudinal slots
These copper bars served as connectors for the electrical
leads A photograph of the sensing probe is shown in
Figura 3 and a drawing of the assembled probe is given in
Figure 4
Power Source
Direct current was used to heat the resistance ribbon
on the sensing probe The current was regulated by a slide
wire resistor The po er source consisted of a Raytheon
Voltage Stabilizer to stabilize the city power source at
115 volts and an automatic selenium rectifier with an alshy
ternating current input of 115 volts at 60 cycles per
second and an output of 12 volts and 35 amperes direct
current
Temperature Measuring
The temperatures around the sensing probe were calcushy
lated from the emf readings of the ironbulloonstantan thermoshy
couples The emf measuring system consisted of the seven
probe thermocouples a separate thermocouple for measuring
the inlet air temperature a thermocouple selector switch
a cold junction and a Leeds and Northrup Type K Potentishy
ometer The potentiometer was placed on a Fischer
13
THERMOCOUPLE JUNCTIONS~ ~------- HOLES FOR THERMOCOUPLE LEADS
~----- SCREWS
~ff+--- CONNECTING BARS
END VIEW
POWER LEADS SOLDERED TO LOWER CONNECTING BAR
iER PLASTIC PIECE
RESISTANCE RIBBONS LOCATION OF THERMOCOUPLES
FIGURE 4 DRAWING OF ASSEMBLED SENSING PROBE
15
Vibradamp support to absorb the vibrations produced by the
air blower
Air Source
Air was used as the shell-side cooling fluid during
the study The air was pumped through the test section by
a Roots type air blower with a rating of 280 ofm at 3 12
psig outlet pressure The hot air leaving the blower was
passed tbxfugh two finned-tube box-type coolers and one
tubular edoler to oool it to approximately room temperature
The air flow rate was measured by passing it through a
flow measuring orifice in the line Two sharpbull edged orishy
ficas were used f or flow measurements The calibration
curves for these orifices were presented by Ambrose (1
p 166)
The pressure taps on each side of the orifice were
connected to two differential manometers containing 0 83
and 2 95 specific gravity fluids respectively The presshy
sure drop through the test section and test orifice was
measured by a pressure tap placed 13 inches upstream and
one placed 6 12 inches downstream from the orifice Two
pressure ga ges were used to measure the pressure at the
inlet to the flow orifice and to indicate the statio pres~
sure at the test section inlet
16
Pressure Probe
A probe was designed to measure the pressure drop
between the pressure tap 13 i nches upstream from the ori shy
fice baff le and any point downstream from the tap The
probe eonsisted of a l~in OD copper tube with six 132
i n ch holes even l y s paced around the tube The upstream
pressure tap and the pressure probe were connected to a
differential manometer so the pressure drop to various
points up- and downstream of the orifice could be measshy
ured
17
CHAPTER IV
EXPERIMENTAL PROGRAM
The experimental program was designed to measure the
heat transfer coefficients and pressure drops in the vicinshy
ity of annular orifices The four orifice sizes studied
were 1 364 1 216 l 316 and 1 516 inches~ The inner
tube used in each case was a 1-in OD alumintim tube
Hence tube to baffle clearances were respectively 3128
232 332 and 532 of an inch
Heat transfer coefficients were measured at poait~ons
1 i nch upstream at the orifice center and at 12 1
1 12 and 2 inches downstream for all orifices In addishy
middottion the heat transfer coefficient at a point 2 12
inches downstream from the 1 516 inch orifice was measured
and at the points 12 l 12 and 2 inches upstream from
the 1 364 inch orifice
The heat transfer coefficients at each point were
measured at five different flow rates for the 1 364 inch
orifice and at six different flow rates for the other orishy
fice sizes The high pressure drop through the small orishy
fice size limited the number of flow rates which could be
studied
The flow rate was calculated from the pressure drop
across the flow orifice This flow was corrected to cubic
feet per minute at 68degF and one atmosphere pressure by
18
using the orifice pressure and the test section pressure
which were measured by pressure gages
It was desired to determine a relationship between the
heat transfer coefficient and the total pressure drop for
each orifice size The pressure drop across each orifice
at various flow rates was measured by means of the presshy
sure probe described in Chapter III It was also desired
to obtain pressure profiles for each orifice size since
these might be similar to the heat transfer profiles The
pressure drop was measured from a point 13 inches upstream
of the orifice to points at 1 and 12 ineh upstream the
orifice center 12 1 1 12 and 2 inches downstream
The experimental program is summarized in Table I
TABLE I
SUla~RY OF EXPER IMENTAL PROGRAM
Position Investigated-Distance from Orifice-Inches
Orifice Range of Flow Rate Size Heat Transfer Pressure Drop CFM at 68degF amp 1 atm
1 364 2U 1 12U 1U 12U c 12U C 12D lD 10 - 18 l2D lD 1 12D 2D 1 12D 2D
1 216 1U c 12D lD 1 l2D 2D 12U c 12D lD 10 - 35
1 316 1U c 12D lD 1 l2D 2D l2U C 12D lD 12 - 50
1 516 1U c x2D lD 1 l2D 1U 12U C 12D 12 - 90 2D 2 1 2D l D 1 l2D 2D 2 12D
20
CHAPTER v
EXPERI MENTAL PROCEDURE
The experimental procedure for measuring the heat
transfer coefficients ~d corresponding flow rates reshy
quired the following procedure
(1) Install the orifice size to be studied in the
test section
(2) Place the heat transfer probe in the position up
or downstream from the orifice where the middot heat
transfer rate is to be studied
(3) Fill the cold junction thermos with cracked ice
(4) Measure the atmospheric pressure
(5 Open bypass line from blower and close line to
test section
(6) Turn on the cooling water for the exchangers used
to cool the air leaving the blower
(7) Start the automatic selen ium rectifier by turning
on the t 1mer bull
(8 ) Connect the voltage stabilizer to the wall outlet
(9) middot Set the slide wire resistor to the maximum re shy
s1atanee I
(10) Start the blower
(11 Open the line to the test section until the de shy
sired flow rate is obtained
(12) Switch on the probe direct current power source
21
(13) Adjust the slide wire resistor to obtain the
desired current
(14) After the thermocouples have reached equilibrium
values record the e m bullf across each of the
seven probe thermocouples and also the entering
air thermocouple
(15) Record the direct current amperage
(16) Record the gage pressure at the flow orifice and
the entrance to the test section
(17) Record the manometer measurement of the pressure
drop across the flow orifice and also the presshy
sure drop through the test section
22
CHAPTER VI
CALCULAT ION OF EXPERIMENTAL DATA
The local heat transfer coefficients were calculated
from the temperatures measured on the probe surface the
air temperature and the current input The results were
calculated by using the Alwae III-E computer
The general expression for calculation of the heat
transfer coefficients was derived by Ambrose (1 p 79)
The equation is derived by making an energy balance around
a small increment of the center resistance heating ribbon
The two ribbons tnstalled adjacent to the center ribbon
reduced the amount of logitudinal conduction and assured
little longitudinal temperature variation in the center
ribbon
A heat balan ce on this small increment of resistance
ribbon yields the following
(the heat conducted in) + (heat generated) = (heat
conducted out) +(Heat convected to the fluid) + (heat
radiated to the surroundings) + (Heat conducted into
the plastic center of the probe)
This gives the equation
kzw dtdS + 12RdS kzws [ t + (~) ds] + hwdS (t-ta )
+ ~Aad wd o middot+ qcAond 1 -~- wdS 5 )
23
Hence solving for h gi~ea
i2R kz d2t Qrad qcond w + -d$2 - ~- A
h = ( 6)t - ta
Since S = re where 9 equals the enclosed angle ~n radians
dS rd9 ( 7)
and
dt - dt (8)dS - rd9
Differentiating with respect to S
d2t (9)rd9dS
from which
(10)
Substitut1ng into the equation for heat transfer coeffishy
cient gives
h = i2R Qcond A (11)
w
The rate of radial heat conduction into the plastic
tube making up the probe was assumed to have negligible
effect on the heat transfer coefficient It was also
assumed that the heat loss by radiation from the ribbon
was negligible since all data were obtained with the ribbon
at a temperature less than 125degF
24
When t he rad iation and conduction terms are neglected
Eq (11) becomes
(12)
The following con stants are known
R = 0 271 ohmsft
w = 100 i n ches
k = 763 Btuhr rt2 degFft
z = 0 002 inches
r = 12 inch
Eq (12) putting 9 in degrees then reduces to
1110 12 + 2404 d 2t d92
( 15)h = ------~--~-------t - ta
Thi s equation was programed for the Alwac III- E comshy
puter and used to calculate the local heat transfer coefshy
ficients from the observed data
The average heat transfer coefficient around the tube
at a given position in the t est section was calculated by
averaging the local coefficients calculated from Eq (13 )
It was found 1n the course of the experimental work
that thermocouple numbers 1 and 7 were indicating higher
temperatures than would be expected This resulted in h1
and ~ being lower than the other local coefficients around
the tube Since the fluid was flowing parallel to the axis
of the probe the circumferential variation i n rate of heat
25
transfer should be small Hence in obtaining the average
coefficient around the tube the values of h1 and h7 were
not used even though they were calculated and are tabulated
1n Table I II in the Appendix
Then
(14
A Nusselt number as calculated from this aver age heat
transfer coefficient using the tube diameter as the characshy
teristic dimension
(15)
The air flow rates through the test section were calshy
culated by measuring the pressure drop across the flow orishy
fice the air temperature the pressure at the flow orifice
and the pressure at the entrance to the test section The
orifice calibration curves (1 p 166 ) were used to obtain
a value of the orifice coefficient f8e where Q equals
the flow in cubic feet per minute at 68deg F and one atmosmiddot
phere pressure and te is the density of air at the exchanger
and e the density of the air at the flow orifice The
den sity of the air can be expressed by
e = 2 703 p (16)T
where T equals the temperature in OR and P equals the absoshy
lUte pressure i n lb1n2 Using the value of e Qfo from
26
the calibration charts as A and Eq (16) solving for Q
gives
( 17
This equation was used to calculate the flow rate for
each flow studied
The Reynolds number used i n the correlation of the
data was the equivalent Reynolds number defined as
Re)eb ~ d2 - dl)Uf ( 18 ) lL
where d1 is the outside diameter of the inner tube and d2
is the orifice diameter U is the flow velocity through the
annular orifice e is the density of the air and U- is t he
viscosity of the air This equation can be transformed t o
(Re) b = 1611 Q (19) e dl + d2
where d1 and d2 are in inches
The pressure drop data were calculated i nto a dimenshy
sionless pressure drop function cent where
d1 )22( ~ P)gc f av(d2 shycent 2 bull (20
M-
For air this equation reduces to
where d2 and d1 are in i nches D P is expressed i n inches of
2 95 specific gravity fluid and P av is expressed as lbft3
27
CHAPTER VII
ANALYSIS OF DATA
In analyzing the heat transfer data an attempt was
made to correlate it 1n terms of the dimensionless groups
(Nusselt number Prandtl number and Reynolds number) which
appear in Eqs (3) and (4) Consequently all of the av~
erage heat transfer coefficients hav were brought into
the form ( Nu)( Pr)~3 bull The Nusselt number was based on the
tube diameter and the thermal conductivity of the air at
the flowing temperature The tube diameter was used in the
Nusselt number because comparison could then be made with
previous experimental work on heat exchangers which have
commonly used the Nusselt number defined as in Eq (15)
From the standpoint of dimensional analysis this is
equivalent to considering the tube diameter as the characshy
teristic length so far as the heat transfer is concerned
The Prandtl number of the air was taken as 0 7 in all
cases
Variation of Heat Transfer Rate with Distance from the Baffle
Considerable variation was observed in the rate of
heat transfer in the vicinity of the baffle In order to
obtain the variation with respect to position the term
(Nu)(Pr)-13 was plotted versus the flow rate Q for each
position and orifice studied Cros s plots were then made
28
at constant flow rates in order to obtain the variation of
(Nu)(Pr) -13 with position The resulting cross plots are
shown 1n Fi gures 5 6 and 7 for the four orifices studshy
ied
About one inch upstream from the orifice the heat
transfer coefficient begins to rise rapidly and continues
to do so until it reaches a maximum some distance downshy
stream After the maximum point the heat transfer coef fi shy
cient decreased slowly The heat transfer rate was found
to reach a maximum at a different position downstream for
each orifice size These figures also show that for a
given orifice size the maximum heat transfer rate occurs
a pproximately at the same point for all flow rates The
position of the maximum point f or each or ifice size is
shown in Table II
The region immediately downstream from the orifice is
one of h i gh turbulence due to the jetting action of the air
flowing through the orifice As the air flows t hrough the
orifice the streamlines continue to converge for some dis shy
tance downstream The point of maximum heat transfer is
probably at the point where the streamlines be gin to diverge
and a boundary layer begins to build up on the tube Tle
decreasing heat transfer coefficient beyond the maximum
point indicated the formation of a boundary layer
Since the position of the maximum point is independent
of flow rate middot it is possible to correlate it with respect
_ ct 11shyz-
100
0 136 ORIFICE
(
I 0
I )
~ 00
~p 0
I 0
--r--- ~
ISCFIII
-_ OCFM
rbull abull
~ middot~ a-1 z-
12fORIFICE
100
200
100
0 0 UPITRAM ORIFICE DISTANCE CENTER
CFM
h I DOWNSTREAM
DISTANCE
FIGURE 5 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLpound
30
too
700
800
100 ~ f gtf
400
z ~
100
100
100
0
13fORIFICE
~ -~ -- ---
)
~
~
-
I ~ ~OCFM
I vI~-~ OCFM
J ---
Iamp CFM
I 0 I I UPSTREAM ORIFICE DOWNSTREAM DIITANOE GENTER DIITANCI
FIGURE 6 VARIATION OF HEAT TRANSFER RATE WITH DISllNCE FROM BAFFLE
--
--- --
31
100
100
700
100
_ 100
f 9- 400 z-
100
tOO
100
0 - I 0 I I I UHTRIAM OAtfiCI DOWIIITMAM
+ I tyl6 ORIFICE
v I
~~ ~CFM
I v ~CFMI
v v 7
~~ v ~ iOCFM
- ~~ I-shy1-shy ~ICFM
DIITMCI OINTIR DIITANCI
FIGURE 7 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLE
32
TABLE II
POSITION OF MAXIMUM HEAT TRANSFER
Position of Maximum Orifice Size Heat Transfer
(inches) (inches downstream)
1 364 050
1 216 100
1 316 125
1 516 200
33
to orifice size Figure 8 shows the effect of the orifice
size on the position and value of the maximum heat transfer
at a constant flow rate of 15 cubic feet per minute It
can be seen that the larger the orifice size the further
downstream the point of maximum heat transfer occurs
Also as the orifice size increased the rate of heat
transfer decreased for a given flow rate The broken line
indicates the variation of the point of maximum heat transshy
fer with position and size The position of the point of
maximum heat transfer rate downstream from the orifice was
correlated with orifice size by means of the dimensionless
groups (Lde) and (d1de) where L is the distance downshy
stream from the orifice where the maximum rate of heat
transfer occurs d1 is the outside diameter of the inner
tube and de is the equivalent diameter of the orifice
ie de = d2-dlbull
Figure 9 shows a plot of Ld 6 versus d1d6 for the
four orifice sizes studied The four points on this logshy
log plot are approximately in a straight line and the
equation of this line is
Lde = 0 44 d1de)028 (22)
Although the above relationship represents a correlashy
tion of dimensionless groups it is based upon only one
tube diameter and needs to be substantiated further by
studying other tube diameters and other orifice sizes
34
aoo
400
aoo ~
-~ middot-CLshyJ z
200 -
100
0
ORIFICE CENTER
l~
l
t
I J~
1pound~
I
0 I I~
AT 15 CFM
-
bull ~ 1~6~
~ v~
~
~--~~6
~~~ ___ v v V -_
~ o q
~ I 16
v
~
ogWNSTREANI STANCE
FIGURE 8 EFFECT OF ORIFICE SIZE ON POSITION AND VALUE OF MAXIMUM HEAT TRANSFER
35
50
loshy____ -~
~ ~ -shylltl-shy~ r0
2 10 30
FIGURE 9 CORRELATION OF THE POINT OF MAXIMUM HEAT TRANSFER WITH
ORIFICE SIZE
36
Correlation of Data at the Baffle
The heat transfer data were correlated by obtaining a
relationship between the group (Nu)(Pr)-13 and a
Reynolds number based on twice the clearance (d2 - d1
between the tube and the baffle It was found that the
most satisfactory correlation could be obtained when the
term - d1 was used as the length term in the Reynoldsd2
number
Figure 10 shows the variation of the heat transfer
rate at the center of the orifice e xpressed as a function
of Reynolds number and the orifice size This shows that
for a given Reynolds number the heat transfer at the center
of the orifice is greatest for the smallest orifice size
In order to obtain a general correlation of the data
shown i n F1gure 10 the effect of the dimensionless ratio
d1de was considered This ratio considers all of the
geometric factor s needed to describe the annular orifice
The thiclaless of the orifice plate is also a factor but
was constant i n this i nvestigation
The data for the heat transfer at the baffle center
are shown in Figure 11 in which (Nu)( Pr)-13 is plotted
versus (Re)ebd1 de) 0 55 This data on a log-log plot
lies on a straight line for (Re)eb( dld8 )0 55 greater
than 3 x 104 The equation for cor relating the heat
37
4XI~middot~-r~------~--~~------~
Icf t--to_+--_c-c-________ SYMBOL SIZE
0 1~4
6 ~~
9 ~~ -o ~
(Re)eb
FIGURE 10 RATE OF HEAT TRANSFER AT BAFFLE CENTER
38
500
0
4 0 lcf
~ ~
~ ~iC-
~ ~
~IL 0~ 0 SYMBOL SIZE-
p 0 1364-
r 6 1~16 -~ -
9 1~16 --o 1~16
I I
FIGURE II CORRELATION OF HEAT TRANSFER DATA AT BAFFLE CENTER
39
transfer at the center bullOf the a nnular orifice was found by
the method of least s quares to be
(Nu)( Pr)-1 3 = 0018 ( Re)ebO Bl( dlde)04~ (23)
3 x 104 ltRe)eb(a1de)055 lt 105)
Rate of Heat Transfer at the Point of Maximum Heat Transfer-The heat transfer rate at the point of maximum heat
transfer is plotted in Figure 12 to show the variation with
Reynolds number and the size of the orifice It is shown
gives the h1gh st heat transfer ~ate at its point of maxibull
that for a given Reynolds number the smallest orifice size yen il
mum heat transfer
The data ~or the maximum poi~t could be correlated by
plotting (Nu) Pr)-13 versus (Re)eb(d1de)06 This plot
is shown 1n Figure 13 and the resulting eurve shows that
(Nu(Pr)-13 is not a simple p0wer function of the Reynolds
number as was the case for heat transfer at the baffle
center The reason for this is probably because other
factors such as intensity and scala of turbulence should
be considered At the orifice center the streamlines of
the flowing stream are converging_ and thus the flow is
quite stable Downstream from the orifice is a region of
large eddy currents and probably large scale turbulence
These factors could con ceivably cause the results which
were obtained for the point of maximum heat transfer
40
If)
~middotshy Q_-I z_
10~~~--------r----~~--~--
SYMBOL SIZE
0 13$4
6 1~8
Q 13-18
-o 1~8
7)(104
(Re)eb
FIGURE 12 RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
41
Ia ~
0 I
c ~ ~ c v
~ ~lt w ~
17
~ b
v ~ ( SYMBOL SIZE
-~ 0 f-64 -v ~ 6 t211e
~ Q I~~~
-o - l~rs I I
FIGURE 13 CORRELATION OF HEAT TRANSFER DATA AT THE POINT OF MAXIMUM HEAT TRANSFER
4 2
Effect of Upstream Baffles on Heat Transfer at the Orifice Center
The heat transfer rate at the orifice center using the
single orifice in a test section is a pproximately 13 of the
value that was obtained by Lee (7) using a model heat exshy
changer with orifice baffles Lee investigated the cent r al
baffles of the heat exchanger and thus the coeff icients he
obtained would be affected by the presence of a number of
upstream baffles To determine the effect of upstream
baffles an additional l 516 inch baffle was placed four
inches upstream 1n the test section The resulting data are
shown in Figure 14 where (Nu)(Prmiddot)-13 is plotted versus
(Re) eb for the case of a single baffle 1n the test section
and also the case of an additional baffle placed four inches
upstream Comparison is made with the results obtained by
Lee middot(7) using a four-baffle and a ten-baffle model heat exshy
changer Good a greement is obtained with Lees work and the
results show the marked effect that upstream baffles have on
the downstream heat transfer rate The additional up tream
ba ffle caused sufficient turbulence 1n the test section to
i n crease the heat transfer rate nearly three-fold at the
center of the next baffle
Heat Transfer i n the Test Section with No Orifice
In order to check the accuracy 6f the equipment the
orifice baffle was removed and the heat transfer mea sured
with the probe in the empty test section The data were
43
~~BAFFLES
0 l BAFFLE -shy
ll_9 2 BAFFLES
V 4 BAFFLES-LEE
4 10 BAFFLES- LEE lJf ~
~rv ~~ ~ v flvv ~~
I ~ J ~ L v
0
v
( V
40 3XIo 7XIa
(Re)eb
FIGURE 14 EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER AT BAFFLE CENTER
44
compared with heat transfe r coefficients predicted by the
equations for annuli which are recommended in the litera shy9
ture The two equa~ ions u sed tor comparison were
(hfe)=0 023 (rltGr e (~~ur4 (~r45 (24)
which was presente~ by Wiegant (10)
and ( h ) (cnM~5(M~l o14 o 023 CPG k j Mij - (de GJMb )0 2 ( 2 5)
which was presented by McAdams (8 p 242) The comparshy
i son is s hown in Figure 15 lq (25) gives a value which
is low by about ten percent while Eq (24) g ives values
which are high by as much as twenty -five percent when comshy
pared with the experimental data The se equations are gembull
erally considered to give coefficients with an accuracy of
about twenty percent Therefore the present experimental
data are within the accuracy of these equations Also the
plot indicate s that for a Reynold s number greater than 2 x
104 the slope of the line is the same for the experimental
data as for the equations
Pressure Drop Data
The total pressure drop across the orifice was measured
as a function of the flow rate and the orifice size The
pressure drop was expressed as a d1mens1onleas quantity r)
which ie plCltted ver sus the Reynolds number in Figure 18
The pressure drop function cent correlates for all or1f1oe
45
200
100
s z
10 5XI10 10
0 EXPERIMENTAL
--McADAMS
-WIEGAND L
V
~ ~ ~
P ~ ~
LL~ L
v~
~
v v
v 1 ~ ~ v
v -gt
~
~ ~
~
6Xid
FIGURE 15 HEAT TRANSFER WITH NO BAFFLE
46
0 1~4 -~ a 6 t216
Q t316 lJ J
-0 as a )t
A LEE I -shy SULLIVAN 8
p
10bull
BERGELIN
I _ll I
I ~
i I
~middot
lo II
f fl
J j
~middot
A)101
1q
I Ill
1 I3 X 10ao1
FIGURE 16 ORIFICE PRESSURE DROP FUNCTION VS REYNOLDS NUMBER
47
sizes- The present data extends the range covered by preshy
vious workers and agrees well with their work The preshy
vious work of Lee () for a heat exchanger containing 10
orifice baffles and also the data of Su livan and Bergelin
(9) for pressure drop in a model heat exchanger with a
single baffle is shown 1n Figure 16 long with the present
results~ This figure may be used to predict the preseure
drop from the equivalent Reynolds number of the annular
orifice
The pressure drop between individual points 1n the
vicinity of the orifice and an upstream pressure tap wa s
measured to obtain a pressure drop profile As might be
expected 1n all cases the profiles showed a rapid decrea e
in static pressure immediately upstream from the orifice
There was however little or no recovery of the pressure
loss downstream The 1 364 inch orifice did show a maxishy
mum point in the pressure drop but this maximum occurred at
the orifice center and total recovery was reached about 12
inch downstream
Heat Transfer at the Baffle and Maximum Point as a Function of Pressure Drop
In order to compare the effect of the total pressure
drop on the heat transfer at the baffle and the point of
maximum heat transfer Figure 17 was plotted showing
(Nu)(Pr)-13 as a function of the total pressure drop This
shows that for a given pressure drop the largest orifice
48
1200
1000
~ a -sshyz-
100
60 100 700
AT MAXIMUM POINT I 15116 2 13116 3 1~6 4 1364
AT ORIFICE CENTER
60
1
v
r ~ ~ ~
5
~
8 7
13116
8
~
1364
v
~
e6
1~6
v
~~ v ~ ~ -~ ~
~
~ v
l
~
vamp
I ~ ~
~
v L ~
v
I-
5
k= ~~
~ ~ ~
--I
v ~
FIGURE 17 HEAT TRANSFER AT THE BAFFLE AND MAXIMUM POINT AS A FUNCTION OF
ORIFICE PRESSURE DROP
49
size has the greatest heat transfer coefficient This is
true at both the orifice center and at the point of maxishy
mum heat transfer
Another comparison can be made by plotting the heat
transfer coefficient and the pressure drop versus the orishy
fice size at a constant flow rate Figure 18 shows this
plot This graph shows that at a constant flow rate the
pressure drop as well as the heat transfer coefficient
increases as the size of the orifice is decreased In
choosing an orifice size for maximum efficiency 1t would
be necessary to know the pumping power available as well
as the heat transfer desired
70 I I 700
AT 15 CFM 60 ---
~ aug
50 ---
NV
40 ~
~ ~ ~
~ _
MAXIMUM POINT ---- --- ~
1-----t---~ _
~00Qj ~
~t--- ORIFICE CENTER 10 1100
1---~ n
u0 01 02 03 Q35
a ltl
de inches
FIGURE 18 VARIATION OF HEAT TRANSFER RATE AND PRESSURE DROP WITH ORIFICE SIZE AT A CONSTANT FLOW RATE
cn 0
51
CHAPTER VI II
SUMMARY OF RESULTS
This study revealed several significant facts about
the heat transfer in the vicinity of annular orifices
Probably the most important contribution was the presshy
entation of the heat transfer profiles in the vicinity ot
the annular orifice ~ r s shown that t~ local heat
transfer coeffieient re~ches a maximum at a point downshy
stream from the orifice The distance downstream at which
this maximum oocurs is t1ven by the equation
22
The heat transfer coefficients at the center of the
orifice were correlated and found to follow the equation
(Nu)(Pr)-13 = 00176 (Re)eb08l(d 1de) 0 middot4~ (23)
3 x 104 lt( Re) 9 b( d1d6 )055 ltlo5 )
The heat transfer at the point of maximum heat trans
fer for each orifice size was correlated and presented in
Figure 13 as a plot of (Nu)(Pr)-l3 versus (Re)eb(d1de) 06
No simple po-orer relationship exists between the terms
Intensity and scale of turbulence downstream from the orishy
fice are probably important factors which affect the heat
transfer
The large effect of an upstream orifice on the heat
transfer rate at the second orifice was demonstrated by the
52
study of two 1 516 inch orifices in the test section The
added turbulence at the center of the second orifice was
found to raise the heat transfer rate almost three times
over that obtained for a single baffle
The pressure profiles in the vicinity of the orifice
indicate that nearly all the pressure drop occurs at the
orifice center~ Total pressure drop data were correlated
by a pressure drop function cent as a function of the Reynolds
number and good agreement obtained with the results of other
workers
The pressure drop and heat transfer data were correbull
lated by plotting the heat transfer as a function of the
pressure drop for each orifice size It was shown that for
a given pressure drop the largest orifice size gives the
greatest heat transfer coefficient
As a final presentation it was shown that the pressure
drop and the heat transfer coefficient both i ncrease i n
value at a constant flow rate as the orifice size is de shy
creased This is important in choosing the optimum clearshy
ance for orifice baffles
53
CHAPTER IX
RECOMMENDATIONS
A great deal of work remains to be done in the field of
evaluating shellmiddotside heat transfer coefficients This
study included only one tube size and air was the only f luid
used It is recommended that further studies be conducted
using other fluids and tube sizes It will also be necessary
to study several baffle types
The adde d turbulence due to a s e cond baffle placed upbull
s t ream would suggest that the heat transfer coef ficients at
a certain position i n relation to a baffle would increase as
the flow progressed through the exchanger It is recomshy
mended that an extensive s t udy should be made between baffles
the full length of a model heat exchanger
It is further recommended that the pressure drop study
be continued to include other fluids tube sizes and baffle
arrangements
Effects of turbulence downstream from the baff le should
be studied by i n vestigations with hot-wire anemometer equipshy
ment to determi ne t urbulence scale and i ntensity
54
NOMENCLATURE
Area of heat transfer
Heat capacity of the fluid
Outside diameter of the tube
Orifice diameter
Equivalent diameter of the orifice (d2 - dl)
Inside diameter of the test section
Inside diameter of the tube
Gravitational constant
G Mass velocity
h Local heat transfer coefficient
Coefficient of heat transfer from surface to fluid
i Direct current amperes
k Thermal conductivity of the fluid
L Distance downstream of the point of maximum heat transfer
p Absolute pressure
L P Total pressure drop across the orifice
Q Flow in cubio feet per minute at 1 atmosphere and 680 F
q Heat transferred
Thermal energy conducted into the sensing probe
Thermal energy radiated from the resistance ribbon
Resistivity of the resistance ribbon
s Length of the resistance ribbon
T Temperature oR
55
t Temperature of the resistance ribbon deg F
ta Temperature of the bulk stream oF
tw Wall temperature of the tube OF
U Veloc ity of the fluid
w Width of the resistance ribbon
z Thickness of the resistance ribbon
eeuro Density of the fluid in the test section
Density of the fluid at the flow orificef 0
AL Viscosity of the fluid
E9 Angle measured around the tube
Dimensionl ess groups
(Nu) Nusselt number hd1k
(Pr Prandtl number C~k
(Re)eb Equivalent Reynolds number at the baffle (d2 - d1 )uejt-Lshy
(Re)e Equivalent Reynolds number in the test section ( d 8 - d 1 )U fu
cent Orifice pressure drop function 2(~P ) gc~av(d2 - d1) 2
Al
56
BI BLIOGRAPHY
1 Ambrose Tommy W Local shell-side heat transfer coefshyficients in baffled tubular heat exchanger PhD thesis Corvallis Oregon State College 1957 183 numb leaves
2 Bell K J and o P Bergelin Flow through annular orif ices Transactions of the American Society of Mechanical Engineers 70593-601 1957
3 Colburn Allan P A method of correlating forced con shyvection heat transfer data and a comparison with fluid friction Transactions of the American Institute of Chemical Engineers 24 174-210 1933
4 Dittus F w and L M K Boelter Heat transfer 1n automobile radiators of the tubular type University of California Publications in Engineering 2443-461 1930
5 Gurushankariah M s Local shell-side heat transfer coefficients in the vicinity of baffles in tubular heat exchangers Masters thesis Corvallis Ore gon State Colle ge 1958 97 numb leaves
6 Knudsen James G and Donald L Katz Fluid dynamics and heat transfer New York McGraw-Hill 1958 576 p
7 Lee Kyu Sung Local shell-side heat transfer coeffishycients and pressure drop in a tubular heat exchanger with orifice baffles Masters thesis Corvallis Oregon State College 1959 118 numb leaves
8 McAdams William H Heat transmission 3d ed New York McGra ~-Hill 1954 532 p
9 Sullivan F W and 0 P Bergelin Heat transfer and fluid friction in a shell-andbulltube exchanger with a single baffle Chemica l Engineer ing Progress Symposium Series 52 ( 18) 85-94 1956
10 Wiegand J H Discussion on annular heat transfer coshyef f icients for turbulent flow Transactions of American Institut e of Chemical Eng i n eers 41147-153 1945
AP PENDIX
57
TABLE III
CALCULATED HEAT TRANSFER DATA
Baffle Hole Diameter Run No (inches)
1 - 59 1 364
60 - 102 1 216
103 - 138 1 316
139 - 206 1 516
207 - 212 No orifice
213 - 218 2nd - 1 516
TABLE III
CALCULATED HEAT TRANSFER DATA
Local Heat Transfer Coefficients Run
T0 bull Po s ition CFM hr h2 h3 h4 hs he ~ hav Nuav
1 c 1026 10 59 1476 16 09 1559 1510 1435 1203 1518 8511 2 1290 1369 1738 1878 18 05 1755 1689 1515 1773 9964 3 1416 1636 198 1 2068 1977 1924 1845 1715 1959 11030 4 1627 1991 2301 2382 2268 2194 20 ~98 1929 2249 12664 5 1776 2252 2669 2863 2713 2517 2338 2126 2620 14759 6 l2ttD 1109 2311 3317 3386 3373 3387 3394 3071 3371 18888 7 1258 3089 4583 4866 4683 4701 4643 4194 4695 26301 8 1433 38 8 5 55 83 5791 5495 5430 5436 5008 5547 31192 9 1681 4992 7378 7649 6980 6864 6870 64 28 7148 40180
10 1 D 1102 2371 3332 3511 3356 3342 3427 3102 3394 19012 11 1308 3218 4379 45 24 42 53 4255 4373 3965 43 57 24446 12 14 64 38 58 5146 5142 4839 4787 4903 4597 4963 278 79 13 1706 5218 6664 6269 58 81 5884 6237 5973 61 87 34718 14 15
1 l2D 1115 1275
2131 2661
2955 3638
2972 3720
2941 3675
2913 3576
28 22 34 74
2613 3278
2921 36 17
163 09 20246
16 1498 34 87 4644 4503 4441 4371 4343 4194 4460 25010 17 1695 4449 5743 5324 5222 5154 5157 5015 5320 298 97 18 2D 1049 1715 23 90 2550 2610 2656 2624 2208 2566 14363 19 1241 2117 2964 3145 3218 3221 3203 2759 3150 17757 20 1532 28 67 3936 4100 4188 4201 4167 3676 4118 23224 21 1674 3459 4508 4598 4746 4795 4792 4299 4688 26337 22 lU 1074 253 340 380 3 86 388 377 354 374 2097 23 1287 292 392 433 440 441 429 406 427 2394 24 1508 322 439 492 498 499 487 461 48 3 2713 25 18 07 3 38 464 519 5 24 520 499 463 5 05 28 40
~~ (]I agt
TABLE III Continued
Run No Position CFM h 1 h2 ~3 h4 h5 h6 ~ h
av Nu
av 26 c 1029 1171 1491 1589 15 28 1 4 62 1377 1293 1489 83 44 27 1266 1395 1746 1853 18 02 1685 1556 1453 1728 9704 28 1430 1637 2037 2175 2060 1909 1735 1591 1983 11159 29 1729 1982 24 96 2751 2507 2268 2030 1886 2410 13579 30 12D 1054 2934 4041 4321 4326 4423 4359 3706 4298 24160 31 1294 3385 4 8 26 52 42 5326 5450 5277 4566 52 24 293 50 32 1431 3784 5347 5721 57 bull75 58 44 5700 5084 5677 31870 33 1770 52 75 7 7 33 87 35 9005 9007 8267 7059 85 49 48050 34 lD 1058 3235 4401 4444 3877 3496 3451 3294 3934 21973 35 1263 38 98 5484 5330 4347 3964 3981 3987 4621 25823 36 18 36 6701 89 17 7855 6369 5597 5769 6283 69 01 38718 37 1 12D 1029 2404 31 8 2 3333 3459 3624 3577 3045 3435 19264 38 1315 3182 4033 4162 4310 4496 4502 4015 4301 24142 39 1426 3628 4389 4510 4573 4760 4804 43 8 5 4607 25678 40 1757 4547 5559 5(35 5931 6282 63 70 6060 5975 33471 41 2 11D 1080 2034 28 38 3155 3144 3145 2966 2540 3050 17027 42 1305 2650 3 4 87 3aoz 3595 3751 3595 3153 36 46 20405 43 1434 3167 39 07 4156 4371 4320 4126 3709 4176 23395 44 1804 4096 4 9 66 5691 5714 5586 53 15 48 65 5454 30582 45 12U 1088 409 516 557 564 5 60 535 513 5 46 30 67 46 1318 470 579 6 22 631 6 17 5 97 579 6 09 3422 47 14 13 540 640 676 6 86 681 6 60 6 54 6 69 3754 48 1773 641 740 774 782 7 69 749 746 763 42 87 49 l 11 U 1054 270 356 391 397 393 3 71 346 38 2 2133 50 1240 303 399 446 449 447 4 21 398 432 2420 51 1419 361 476 522 530 528 507 467 493 2760 52 1 1(2U 1032 236 311 342 347 344 325 301 334 18 78 53 1314 270 366 403 407 408 386 351 394 2217
(Tt tO
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ h av Nu av
54 1448 301 408 447 454 452 431 403 438 24 61 55 1782 353 494 548 544 415 529 531 506 2843 56 2U 10 61 220 287 316 320 322 303 268 310 1735 57 1216 249 335 370 377 378 353 307 363 2044 58 1322 263 356 394 398 399 374 327 384 2159 59 1639 310 433 478 481 482 452 393 465 2617
60 1D 10 68 2011 2536 2657 2681 2694 2560 15 62 2625 14938 61 1399 2520 3239 3369 3371 33r82 32 39 1946 3320 18968 62 1669 2781 3655 3820 38 76 3883 3738 2355 3794 21712 63 1959 3524 42 37 4399 4438 4497 4417 3047 4397 25156 64 2295 4426 5288 5396 5372 5240 5410 3369 5341 30680 65 2636 5490 6531 6662 6565 6379 6820 4249 6591 37938 66 3390 7869 9538 9462 9387 8924 10508 62 91 9564 59601 67 1U 1190 352 368 401 413 407 395 293 397 2256 68 1559 397 422 462 475 471 456 331 4 57 2603 69 1904 434 465 5 13 529 528 504 358 508 2901 70 2211 493 526 573 5 92 588 564 4 15 569 3257 71 2289 569 587 6 30 649 6 61 6 49 460 635 36 44 72 2727 637 6 60 7 09 733 751 743 521 719 4140 73 3210 728 755 8 15 8 43 8 62 8 54 616 826 4765 74 2nD 1210 181 2256 2393 2399 2333 2206 1325 2317 13158 75 1420 2340 2752 2899 2913 2850 2728 1701 2828 16121 76 1692 2853 3306 3452 3471 3379 3217 2134 3365 19217 77 1894 3102 3588 3713 3736 3670 3557 2455 3653 20892 78 2301 3682 4259 4433 4467 43 83 4289 2892 4366 250 30 79 2621 4117 4828 5017 5012 5030 5109 3071 4999 28785
m 0
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ hav Nuav
80 3230 5158 6006 62 13 61 18 6134 6695 4094 6233 359 87 8 1 12nD 1155 15 27 1854 2028 2064 20 85 1987 1164 1968 118 31 82 1689 2046 24 8 2 2688 2739 2760 2658 1749 2665 152 73 83 1244 2088 2317 2339 2345 2373 2381 1487 2351 13432 84 2100 3211 3539 34 21 3462 3512 3696 2575 3526 20284 85 2292 3 5 05 3761 3648 36 25 36 79 3957 2933 3734 21517 86 2907 4420 48 22 4679 46 04 4705 5206 3792 48 03 27741 87 33 80 59 35 69 38 7404 77 10 7 8 36 7 0 86 5190 7394 427 44 88 1 12D 1 4 27 2 4 58 28 31 3037 3021 2987 2927 18 57 2 9 61 16913 89 18 75 34 75 3 9 87 4230 4255 4317 4337 2734 4225 24258 90 22 59 4221 4796 5046 5052 51 01 5389 3491 5077 29206 91 2682 4978 5664 5943 5966 6054 6573 408 1 60 40 34795 92 3417 63 16 71 02 7 3 93 7385 75 40 8 6 95 51 45 7623 44017 93 c 1 5 17 1240 1305 1399 1467 1479 1429 9 26 1423 8251 94 20 34 1554 1623 1720 18 21 18 53 18 72 1215 1778 10229 95 2 3 48 1795 1843 198 5 2097 2171 2274 1540 2074 11947 96 2716 2028 2048 22 01 2 3 44 2444 2661 18 90 2340 13505 97 3247 2410 2375 2663 2778 2949 3298 2378 2793 1615 98 11 35 967 1040 1124 1186 1200 1142 728 1138 6496 99 14 06 1135 1220 1318 1384 1403 1 3 61 8 77 1336 7656
100 2311 1 8 54 18 78 1980 20 90 2136 2227 1653 2062 118 31 10 1 2666 2085 2094 2227 2 3 62 2438 2626 1902 2349 13508 102 3392 2635 2582 28 01 3026 3141 3529 2567 3016 17390
103 1 U 1235 349 395 434 436 4 28 411 286 423 2416 104 20 10 434 5 02 559 577 569 5 37 345 552 3177 105 28 14 538 626 685 711 7 21 682 424 6 8 6 3966
Q) j-J
TABIE III Continued
Run No Position CFM h1 h2 h3 h4 h5 hu h7 hav Nuav
106 3492 614 7 1 6 7 84 8 13 8 33 7 85 4 88 7 87 4562 107 4395 7 86 894 964 996 1005 9 64 640 9 65 56 06 108 50 75 9 11 10 22 1081 1112 1125 1085 7 24 1085 63 16 109 G 1344 9 22 1042 1120 1 1 46 1173 1131 7 04 1120 63 87 110 1936 1162 1340 1442 1474 1509 14 7 3 9 09 1441 82 77 111 2846 1631 1797 1902 1966 2027 2079 1342 19 2 3 11108 112 3484 207e 2144 2236 2307 2385 2574 1694 2268 13138 113 4066 24 65 24 42 2535 2648 2757 31 71 2178 2 5 96 15078 114 50 12 3059 2916 30 1 5 3176 3312 4059 2849 3105 180 46 115 1D 1362 2268 26 13 2613 26 35 2605 2503 15 46 2617 14934 116 1958 2993 3580 3580 3586 3539 3 5 02 2144 3571 20492 117 2812 4430 50 32 4913 4 9 86 4991 5196 3088 4981 287 66 118 3432 58 16 62 13 6067 61 18 60 66 6698 4143 61 16 354 16 119 40 22 71 71 7 4 62 7369 7419 7329 82 74 51 8 1 7395 42909 120 5026 105 95 11456 115 81 11574 11548 14010 80 91 11540 671 15 121 2D 1244 18 57 2277 2363 2305 2210 2107 1466 2289 13038 122 1960 2622 3240 3388 33 23 3226 31 40 2)99 3294 18919 123 2817 3762 45 87 4739 46 56 45 14 4 6 47 30 15 4624 26689 124 3491 50 22 5723 58 53 57 44 5542 60 18 3871 57 16 330 73 125 4096 61 29 68 16 69 79 6805 65 90 74 79 4677 67 98 39400 126 5037 82 27 94 60 95 69 93 57 9023 11324 65 05 93 52 542 83 127 12D 1278 14 70 1 6 48 1652 1638 1 6 34 1641 9 73 1 6 43 9369 128 1947 19 63 2155 2149 2151 2131 2190 1347 2147 12342 129 2769 2615 2791 2773 28 52 2716 2954 18 96 2783 1 60 82 130 3439 3208 3265 3239 3593 3133 3624 2515 3308 19174 131 4103 3637 35 88 3577 4077 3459 42 66 3138 3676 21343 132 49 78 45 82 44 60 44 8 1 55 17 43 25 5749 4227 4700 27288
Q) tlgt
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
133 1 12D 1299 2094 2507 2622 2625 2567 2489 1465 2578 14736 134 1973 29 56 3505 3772 3790 3718 3718 2115 3700 21290 135 2788 3941 4727 5069 5099 5 0 07 5231 2984 4976 28781 136 3473 5155 59 81 6308 6339 62 39 68 96 4204 6217 36052 137 4118 6135 71 8 6 7662 7731 76 91 87 16 49 8 5 7568 43985 138 4973 7765 94 75 10396 10861 10694 13646 66 64 10357 602 25
139 1ttn 1253 1242 1493 1460 1442 1431 1424 8 84 1457 83 01 140 2366 1942 2150 1961 1910 1897 19 62 1206 1980 11400 141 3461 3007 2957 2562 2513 2606 3143 18 51 2660 15400 142 4325 3942 3571 3060 2999 3198 4248 2631 3207 18618 143 5677 508 6 4359 39 88 3800 42 29 57 78 36 26 4094 23824 144 67 59 64 55 5330 4988 47 25 5494 2517 48 09 5134 29906 145 84 08 9326 72 26 7726 85 56 9172 12319 7733 8170 47626 146 86 54 9831 7582 818 9 94 90 9869 13116 78 97 8783 512 96 147 7376 7335 58 7 6 5941 5796 68 29 81 65 5954 6111 35662 148 2 11 D 4254 4106 48 02 4994 5038 5042 56 78 3419 4969 28881 149 5708 5487 6253 6466 6524 6527 78 63 45 8 2 64 43 37566 150 69 7 8 7983 9440 9848 98 34 97 32 13249 6701 9714 566 59 151 1254 1434 18 53 1947 1915 1850 1760 1186 1891 10772 152 2713 2696 3175 32 94 3288 3237 3288 20 44 3249 18728 153 87 30 118 07 14733 15758 15504 15305 26297 9617 15325 892 71 154 5811 5278 6543 6861 69 30 69 82 7 8 74 4478 68 29 39531 155 4246 3780 4736 4975 49 66 4936 5162 3113 4903 28301 156 (v 1270 8 15 935 959 966 9 51 9 23 6 35 953 5430 157 2714 1164 1390 1427 1447 1454 1455 9 08 1430 8242 158 4310 1655 18 96 1942 1988 2002 2111 1305 1957 11349
(j) ~
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 fry hav Nuav
159 6012 2208 2400 2450 2513 2548 28 20 18 00 2478 14416 160 7279 2696 2881 2927 2989 3081 3599 2340 2970 17326 161 86 90 3257 3360 3 3 76 34 26 3558 4455 2943 3430 2000 162 12D 4368 2209 2600 2558 2518 2466 2774 1753 2536 14713 163 5833 2730 3092 3028 2974 2913 3501 2287 3002 174 78 164 7643 3320 3681 3630 3651 3530 4623 3181 3623 21116 165 87 39 3920 4303 4300 4708 4178 61 60 3937 4372 25456 166 1268 962 1203 1205 1186 1118 1084 725 1178 6693 167 2678 14 67 1785 1779 1752 1698 1726 10 70 1754 88 49 168 1 12D 12 83 936 1217 1414 1397 1239 1190 7 65 1317 7484 169 2729 2502 2930 2914 2934 2956 2979 17 52 2934 16866 170 4345 3884 4357 4283 4318 4421 4836 28 59 4345 25151 171 6036 5546 5858 5764 5791 6028 7129 4184 5860 34045 172 6578 7167 7769 7907 79 82 8263 10492 5915 7980 46437 173 87 84 10237 112 23 120 26 12727 12968 185 19 85 98 12236 71103 174 1278 1344 1803 18 72 1835 1790 1712 1063 1825 10355 175 2711 2328 2972 2932 2893 28 78 2863 1667 2919 167 51 176 4351 3934 4414 4353 4281 4321 4654 28 63 4342 25088 177 5994 5076 5824 5838 5818 59 29 6914 4205 5852 33885 178 1 11 U 1223 388 432 465 464 449 435 338 453 2585 179 2351 521 602 6 22 675 6 57 619 436 639 3687 180 34 48 6 05 1725 803 8 27 8 11 760 518 792 4593 181 4513 718 850 934 9 68 9 57 8 99 609 9 27 5386 18 2 5714 8 32 981 1060 1102 11 06 1034 6 59 1062 61 82 183 6997 1025 1182 1258 1295 1309 1234 8 18 1261 7 3 44 184 8709 1295 1487 1 5 42 1594 1626 1612 1156 1562 9080
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
185 2 12D 4249 3560 4400 4670 4791 4695 47 81 2931 4639 268 37 186 5737 4926 58 54 61 92 6248 62 38 67 78 4134 6131 35590 187 7432 6390 7726 83 46 85 44 86 34 10371 5658 8313 48310 188 8723 7718 107 88 11933 12099 13046 186 22 79 39 119 67 69505 189 1 4 35 1340 1735 18 57 18 52 17 81 1711 1144 18 06 10256 190 2718 2399 3023 3187 3207 3138 30 53 1931 3139 18025 191 7 5 07 6189 80 11 9200 9427 9703 11364 5720 9085 527 38 192 8544 78 42 10666 125 42 13312 13775 178 20 6976 125 74 729 86 193 1287 1417 16 97 18 7 18 69 18 08 1720 1046 1800 10223 194 27 17 2450 2940 3187 3214 3157 3054 1749 3125 17954 195 42 53 3560 4222 45 90 4679 46 63 4743 2741 4539 26247 196 6068 48 69 57 79 6335 65 8 6 66 04 7172 4338 63 26 366 78 197 7389 58 86 72 8 6 82 23 8584 8936 10658 50 60 8257 4798 6 198 86 88 78 91 100 27 120 56 130 29 14299 190 81 6492 12353 71850 199 5864 4694 5 6 67 61 94 6419 65 48 7192 3950 6207 360 14 200 2 D 4177 38 36 4547 48 09 4775 4628 5006 2715 46 90 261 30 201 5712 5170 62 39 66 38 6599 6604 7518 4167 65 20 378 00 202 73 63 7201 8986 98 43 9733 9914 13353 6219 9619 55810 203 8604 10043 13118 148 41 150 42 158 66 25206 82 5 3 14717 85290 204 12 68 1506 18 41 1971 1966 1868 1799 11 42 1913 10880 205 2659 2571 3127 3276 32 50 3130 3069 18 80 3196 18 350 206 39 80 36 76 4347 4573 45~67 4473 46 34 28 37 4490 25910
o 207 Orifice 11496 10 64 1360 15 39 1 5 80 1 6 15 1496 8 58 15 24 88 83 208 9433 8 95 11 78 13 26 1394 1386 1263 727 1346 78 48 209 7387 746 9 77 1123 1184 1159 1048 6 11 1111 64 74 210 52 36 566 7 66 900 934 909 8 21 499 8 27 48 02
0) CJ1
TABLE III Continued
Run No Position CFM h 1 h2 hs h4 h5 h6 h7 hav Nuav
211 212
3309 1293
414 257
563 3 19
6 68 3 57
6 91 3 37
6 72 351
7 37 337
38 4 2 46
4 40 341
3748 1942
213 214 215 216 217 218
c of 2nd 1 516 1235
1919 2712 3320 4153 4704
1532 2447 35 46 4312 5567 74 29
2 1 87 3312 4225 52 86 6902 8 6 50
2360 3555 4340 56 12 7 0 49 8 9 40
2409 3598 4 8 85 5718 7713 9593
2347 2101 35 33 3453 48 00 49 62 5562 59 86 72~6 7 8 79 93 76 11237
1243 20 64 3054 4 2 8 1 5114 6983
2326 35 00 4638 5545 7225 91 40
132 13 200 27 26672 31968 41711 52811
bull
67
TABLE IV
PRESSURE PROFILE DATA
Baffle Flow Qpening Rate ~p
(Inches) Position (CFM) (Inches 295 S G Fluid)
1 364 l2 11 U 1012 0 254 1248 0197 1493 0 141 1718 0112
c 1000 9 80 1210 1710 1436 28 75 1746 4320 1011 1080 1277 2050 1393 3020 1 6 28 4450
12D 1011 9 75 1236 1520 1450 2510 1603 3450
1 D 1011 975 1256 1700 1480 2690 158 1 4070
1 12D 1010 950 1259 1750 1462 2650 1631 3710
2 11 D 1124 1315 1360 2130 1505 2850 1689 4125
1 216 12U 1294 045 1949 0324 2374 0282 2704 0225 3367 0169
c 1326 265 18 81 5 90 2313 990 2731 1480 3439 2660
12D 1272 2 49 1957 661
68
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Pos ition (CPM) Inches 2 95 S G Fluid)
2559 1275 3033 1940 3639 3025
1 216 1nD 1257 242 16 96 476 2117 8 05 2561 1280 2990 1895 3431 26 bull00
1 316 12U 1309 0 479 2004 0422 28 28 0 352 3526 0281 42 28 0225 5199 0225
c 1308 1 43 1998 272 28 14 5 10 3478 795 4248 1235 5048 1885
l2D 1286 140 2005 3 45 2831 725 3495 1180 4194 1805 5046 2945
1 11D 1322 150 2039 352 2841 735 43 77 1980 5378 3440
1 516 12U 1278 0493 2732 0493 4315 0408 5744 0352 7494 0352 8932 0422
c 1300 0 506 2731 1985 4310 348 6080 6 45
69
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Position (CPM) (Inches 295 SG Fluid)
7607 1090 8830 1585
l2D 1343 0549 2738 225 4566 583 6112 1195 7536 2055 9043 3415
1 516 1uD 1249 0464 2713 224 4155 579 5620 1150 7428 2115 90 70 3405
1 12D 1301 0493 2735 220 4501 616 61 50 1235 7440 2065 8862 3445
2D 1265 0 478 2750 226 4366 594 6578 1270 7678 2240 8945 5280
2 12D 1295 0493 2725 222 4293 600 5807 1120 7568 2200 9070 3615
TABLE V
RATE OF HEAT TR AN SFER Ar THE BAFFL~~ CID-TT ER
Orifice Size
(Inches)
Flow Rate
( CFM)
Re d e G tU
R~) 055 Nuav NuPr-l3
1 364 10 26 12 90
8 075 10015
43400 54 600
85 11 99 64
95 83 112 19
1416 11 140 59 900 110 30 124 20 16 27 12 800 68 900 126 64 142 60 17 29 13 610 73 200 135 79 152 90 17 76 13980 75 200 147 59 166 19
1 216 11 35 14 06
8 600 10 660
27000 33500
6 4 96 76 56
73 14 8 6 12
1517 11500 36100 82 51 9291 20 34 15400 48400 10229 115 18 23 11 17500 55000 118 31 13322 2348 17 800 55900 11947 13452 2666 20 200 63400 13508 15210 27 16 20 600 64700 135 05 152 07 32 47 24600 77200 161 57 18 193 3392 25 700 80700 17390 195 8 1
1 316 1344 19 36
9898 14 260
24800 35 700
63 8 7 8 2 77
71 92 93 20
28 46 20 9 60 52 500 111 08 125 08 34 84 25 660 64200 131 38 147 93 40 66 50 12
29900 36900
74800 92400
150 78 18046
169 78 203 20
~ 0
TABLE V Continued
Orifice Flow Re Size Rate d e G R~rmiddot55 NuPr-13(Inches) (CFM) U Nuav
1 516 12 70 8 847 16800 54 ~0 61 14 2 14 18 900 35800 82 42 92 80 43 10 30 000 56900 11349 127 79 60 12 41900 79400 14416 16232 7279 50700 96100 17326 19509 86 90 60540 115000 20098 22529
TABLE VI
RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
Orifice Size
(Inches)
1 364
1 216
1 316
Flow Rate
(CFM)
1054 1294 1431 1681 1770
1068 1399 1669 1959 2295 2636 3390
1299 1973 2788 34 73 4118 4973
Re deG Mshy
8 300 9870
11260 13200 13 930
8100 10600 12650 14850 17400 19980 25700
9 570 14500 20500 25600 30300 36600
R~r-6 51900 61700 70500 82 500 87 100
28200 36900 44000 51700 60 600 69500 89400
26100 39600 56000 69900 82700 99 900
Nuav
2416 293 5 3187 4018 4805
14938 18968 21712 25156 30680 37938 59601
14736 21290 28781 36052 439 85 60225
Uu Pr-1 3
27204 33050 3589 4524 541 0
16820 21358 24448 28326 34546 427 18 67111
16593 23973 32407 40595 495 1 678 13
TABLE VI Continued
Orifice Flow Re Size Rate deG R~rmiddot6 NuPr-13(Inches) (CFM ) M- Nuav
1 516 1268 88 30 17700 108 8 1225 2689 18700 37400 1835 2066 3980 27700 55700 2591 2917 4177 29100 58 500 2713 3055 5712 39800 80000 378 0 425 6 7362 51300 103000 5581 6284 8 604 59 900 120000 8529 9604
74
TABLE VII
EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER
l 516 Inch Orifice
Center ot 2nd Baffle 4 Downstream
Plow Rate (CFM)
1235 1919 2712 3320 4153 4704
Flow Rate (CFM)
1270 2714 4310 6012 7279 8690
(Re)eb -8600 1321
13400 2003 18900 2687 23100 5197 28900 4171 32800 5281
Center ot Single Battle
-8847 543
18900 824 30000 1135 41900 1442 50700 1733 60540 2001
(Nu)(Pr)-l3
1487 2255 3003 3600 4697 5946
(Nu)(Pr)-13
611 928
1278 1623 1951 2253
75
ABLE VIII
HEAT TRANSFER IN THE TEST SECTION WITHOUT ORIFICE
CFM Ute) 0b h Nu
1293 5-951 3 41 1942
33 09 15251 649 3746
5236 24193 827 4802
7387 34001 1111 6474
9433 43419 1346 7848
11496 52-914 1524 8883
76
TABLE IX
PRESSURE DROP FUNCTION
Orltlee Size Flow Rate incbea ~CFM (Re)eb X 10bull8
1 364 1011 7957 0808 1256 9885 1468 1480 11648 2765 1581 12443 4160 1689 1_3293 4 020
1 216 1257 9530 1327 1696 12858 2663 2117 16049 4615 2561 19415 7581 2990 22668 11560 3431 26011 16440
l 316 1322 9736 1819 2039 15016 4332 2845 20952 9275 3495 25739 15300 4377 32014 26800 5378 39607 50100
1 516 1011 7 957 oaos 1256 9885 1469 1480 11646 2765 1581 12443 4160 1689 13293 4020
77
TABLE X
EXPERIMENTAL DATA
Baffle Hole Diameter Run No
1 - 59
60 - 102
103 - 138
139 - 206
207 - 212
213 - 218
(Inches)
1 364
1 216
1 316
1 516
No Baffle
2nd - 1 516
TABLE X
EXPERIMENTAL DATA
Run Thermocouple Reading s (mv) No Position CFM I tc1 tc2 tc3 tc4 t c 5 tc6 tc7 tcair
1 c 1026 530 2055 1825 1768 1782 1802 1837 1965 1198 2 1290 612 2059 18 65 1809 18 32 1851 1880 1965 1160 3 1416 714 2151 1970 1931 1965 1988 2026 209 5 1130 4 1627 8 21 2235 2084 2 049 2093 2126 2173 2266 1130 5 1776 865 2203 2033 1970 2015 2084 2159 2 264 1121 6 12D 1109 542 1636 1507 1499 1499 1498 1498 1528 1218 7 1258 651 1670 1522 1503 1513 1513 1516 1548 1221 8 1433 750 1625 1480 1467 148 3 1487 1487 1516 1153 9 168 1 8 73 1656 1494 148 1 1511 1517 1517 1543 1159
10 1rtD 1102 485 1545 1450 1437 1446 1447 1442 1466 1220 11 13 08 6 10 1571 1470 1460 1476 1476 1469 1498 1194 12 1464 730 1 623 1509 1508 1528 1 5 32 1524 1548 1173 13 11 06 8 71 1663 1559 158 1 1606 160 6 1 583 1601 1190 14 1 12D 1115 520 1698 1579 1575 1 577 1580 1590 1615 1280 15 1275 6 10 1692 1567 1558 1 561 1570 1580 1601 1234 16 1498 770 1760 1619 1630 1 635 1642 1645 1661 1204 17 1695 912 1775 1635 1670 1689 1686 168 6 1701 1165 18 2D 1049 510 1736 15~2 1567 1558 1 553 1558 1620 1236 19 12 41 610 1655 1517 149 1 148 1 148 1 148 4 1546 1108 20 1 5 32 7 35 1720 1550 1530 1520 1519 1523 158 0 1104 21 16 74 8 8 0 1900 1 727 1714 1696 1691 1692 1753 1169 22 1U 1074 38 5 3 324 2740 2534 2478 2 465 2503 258 0 1210 23 1287 4 35 3510 2 870 2682 2 610 2599 2638 27 1 9 1190 24 1 5 08 470 3 618 2920 2690 2 637 2627 2 664 2747 1177 25 18 07 525 4 088 3235 2962 2905 2910 2988 3130 1169
z ())
TABLE X Continued
Run No Position CFM I tc1 tc 2
Thermocouple Readings te3 tc4 tc5
(mv) tc6 tc7 tcair
26 c 10~29 6 32 2340 2~092 2032 2060 2~097 2152 2~213 1211 27 12 66 679 2270 2 047 1993 2013 2069 2142 2 210 1 182 28 1430 723 2336 2097 2033 2080 2153 2~255 2 356 1 138 29 1729 8 52 2318 2070 1980 2061 2158 2279 2367 1121 30 12D 1054 570 1520 1 4 20 1402 1400 1396 1400 1 443 1159 31 1294 6 69 1599 1469 1444 1439 1433 1 442 1485 1168 32 1430 7 88 1720 1562 1536 1532 1528 1537 158 0 118 5 33 1770 8 81 1641 1488 1450 1~441 1 441 1_466 1518 1 163 34 1D 1058 548 1579 1498 1495 1526 1553 1_557 1 571 1 276 35 1263 640 1609 1509 1515 1570 1599 1598 1 598 1 266 36 18 36 8 47 1538 1452 1483 1553 1602 1 590 1 558 1195 37 1 12D 1029 5 41 1 578 1499 148 4 1473 1461 1465 1-512 1200 38 1315 6 30 159 1 1504 1493 1482 1470 1470 1505 118 5 39 1 4 26 743 1765 168 1666 1660 1645 1642 1678 1270 40 1757 8 54 1744 1648 1634 1620 1598 1 593 - 1612 1223 41 2D 1080 5 30 1734 1604 1570 1 570 1570 1 588 1 640 128 1 42 1305 6 40 1744 1622 1589 1 608 1593 1 609 1 661 1240 43 1434 750 1798 1687 1658 1 636 -1641 1 661 1 711 1_220 44 18 04 8 41 1 764 1666 1607 1605 1614 1 635 1 675 1205 45 12nu 1088 415 2614 2295 2195 2 169 2174 2217 2256 1171 46 1318 477 2805 2477 2371 2342 2364 2 401 2 438 1 163 47 1413 5 28 2930 2 646 2 555 2 526 2532 2570 2 577 1 199 48 1773 550 2740 2518 2450 2431 2448 2 479 2 480 1 170 49 1 11 U 1054 380 3175 2670 2505 2 461 2467 2 534 2 621 1 258 50 1240 420 3268 2738 2 546 2 510 2 508 258 2 2 649 1214 51 1419 451 3364 2B07 2 632 2590 2 590 2 651 2773 1 215 52 1 12U 1032 360 3 165 2 629 2 450 2402 2403 2 473 2 bull568 1 163
--I lt0
TABLE X Continued
Run No Position CFM I tc1 tc2
lhermocoup1e Reading s tc3 tc4 t c 5
(mv) tc6 tc7 tc a ir
5 3 1314 38 9 3178 2592 2411 2367 2361 2432 2555 1140 54 1448 403 3095 2544 238 1 2336 2336 2390 2476 1158 55 178 2 427 3006 2434 2286 2253 255 3 2299 2397 1154 56 2 11U 1061 360 3369 2814 2619 2567 2560 2650 2833 1220 57 1216 360 3044 2512 2338 2290 2288 2374 2566 1150 58 1322 387 3196 2614 2425 2383 2382 2472 2670 1138 59 1639 403 3020 2438 2272 2238 2238 2318 2502 1127
60 1D 1068 612 1552 1424 1400 1395 1396 1426 1745 0945 61 1399 612 1355 1246 1230 1229 1230 1250 1509 0872 62 1669 710 1436 1293 1272 1265 1266 1286 1551 0847 63 1959 900 159 5 1468 1444 14 38 1432 1446 1720 0851 64 2295 730 1169 1105 1098 1099 1108 1100 1298 0781 65 2636 8 80 1202 1129 1121 1126 1 138 1115 1342 0748 66 3390 9 35 1060 o 9s7 0999 1001 1017 0971 1154 0703 67 1nu 1190 370 2225 2188 2104 2080 2120 2209 2 7 15 0990 68 1559 368 2005 1950 1871 18 48 1876 1951 2408 0916 69 1904 368 1870 18 1 4 17 34 1711 1730 18 07 2238 0875 70 22 bull11 471 228 6 2 204 2099 2063 2092 218 $ 2732 0840 71 2289 471 2030 2000 1925 1895 18 96 19 5 2498 0785 72 2727 4 71 1854 18 23 1753 17 23 1716 3758 2241 0743 73 3210 471 1680 1651 158 6 1559 1551 158 1 1950 omiddot7o9 74 2uD 1210 404 1261 1212 1198 1197 1205 1222 139 1 0978 75 14 20 540 1321 1260 1242 1 240 1249 1268 148 7 0918 76 1692 7 18 1467 138 6 1364 1361 1376 1405 1678 0883 77 18 94 903 1708 1 591 1565 1560 1575 1603 1948 0 857 78 2301 903 1530 1432 1407 1402 1415 1432 1738 0815
ro 0
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc117 tcair
79 2621 6 50 1069 1 020 1009 1009 1009 1007 1~189 o739 80 3230 901 1200 1128 1113 1119 1119 1086 1341 0694 81 82
l2D 1155 1689
360 575
1191 1345
1142 1252
1122 1218
1118 1210
1118 1209
1132 1228
1292 1446
0916 0822
83 1244 430 1163 1134 1131 1130 1129 1132 1292 0877 84 2100 645 1175 1135 1147 1 142 1138 1122 1286 0757 85 2292 8 25 1 354 1310 1327 1330 1323 1285 148 6 0728 86 2907 8 23 1180 1138 1151 1158 1149 1107 1268 0687 87 3380 902 1113 1049 1025 1011 1006 1042 1178 0673 88 89
1 12D 1427 1875
480 615
118 2 1140
1140 1095
1124 1077
1125 1075
1129 1072
1137 1072
1290 1243
0880 0790
90 2259 8 41 1296 1231 1207 1206 1203 1182 1419 0757 91 2682 8 80 1231 1170 1149 1147 1142 1112 1350 0731 92 3417 940 1142 1092 1076 1076 1069 1021 1252 0693 93 c 15 17 431 1321 1298 1268 1249 1250 1273 1522 0841 94 2034 505 1285 1263 1235 1209 1205 1206 1464 0759 95 2348 6 10 1395 1379 1334 1302 1286 1268 1536 0732 96 2716 706 1486 1480 1427 1383 1358 1311 1572 0 700 97 3247 7 56 1417 1430 1375 1320 1284 1223 1450 0660 98 1135 400 1425 1388 1352 1329 1330 1 364 1651 0893 99 14 06 440 1379 1341 1304 128 2 1281 1305 1583 0 831
100 2311 680 1602 1593 1553 1514 1502 1480 1 7 27 0 802 101 2666 680 1471 1469 1428 1390 1372 1335 1564 0761 102 3392 798 1491 1 509 1449 1395 1372 1305 1534 0 719
103 1U 1235 410 2469 2295 2173 2165 2226 2361 3120 0 897 104 2010 410 2017 1848 1 737 1706 1747 1865 2582 0753 105 28 14 410 1682 1535 1457 1427 1437 1520 2109 0 660
00 t-
TABLE X Continued
Ru n Thermocouple Rea ding s (mv No Positi on CFM I tc1 tc2 tc3 tc4 tc5 tc6 tc7 tcair
106 3492 440 1649 1499 1420 1391 1390 1470 2042 0620 107 4395 550 18 33 1679 1597 1564 1570 1640 2223 0583 108 5075 588 1779 1642 1580 1550 1552 1 615 2 191 0548 109 c 1344 398 1464 1 399 1364 1353 1350 1380 1689 0 907 110 1936 459 1369 1290 1253 1242 1 237 1259 1574 078 2 111 2846 580 1347 128 5 1251 1232 1220 1215 1 5 23 0 683 112 34 8 4 700 1392 1369 1339 1317 1299 1259 1599 0 636 113 4066 8 13 1449 1458 1427 1391 1363 1270 1595 0 591 114 5012 930 1484 1530 1500 1453 1420 1272 1580 0 580 115 1D 1362 513 1269 1218 1 217 1214 1220 1238 1460 0 893 116 19 58 600 1187 1122 1121 1120 1124 1133 1352 0798 117 2812 705 1052 1008 1015 1010 1011 1001 1218 0691 118 34 32 913 1105 1075 1085 1081 1086 1047 1301 0645 119 4022 980 1038 1021 1026 1023 1029 0983 1211 0 609 120 5026 982 0 8 61 0839 0836 0836 0837 0791 0955 0570 121 2D 1244 475 1320 1246 1233 1240 1255 1275 1434 0925 122 1 9 60 5 50 1160 1088 1074 1079 1089 1100 1260 078 7 123 2817 6 80 1096 1024 1 013 1018 1029 1022 1201 0 700 124 3491 960 1248 1175 1163 1172 1192 1153 1435 0 658 125 4096 989 1141 1089 1078 108 9 1105 1051 1310 0629 126 50 37 989 0983 0933 0929 0 936 0949 0880 1090 0 602 127 128
12D 1278 1947
402 545
1270 1261
1 230 1216
1228 1216
1230 1 215
1235 1223
1242 1219
1483 1514
0 913 0778shy
129 2769 695 1273 1234 1237 1221 1251 1212 1525 0678 130 131 132
34 39 4103 4978
8 40 9 80 9 80
1336 1448 1271
1322 1458 1 288
1328 1 462 1286
1 259 1 356 1157
1353 1492 1311
1261 1329 1138
1 555 160 7 1343
0 629 0 600 0599
(l) l)
TABLE X Continued
Run No Position CFM I tel tc 2
Thermocouple Readings tc3 tc4 tc5
( mv) tc6 tc7 tcair
133 1 l2D 1299 5 16 1 28 1 1212 1196 1195 1205 1221 1478 0869 134 1973 6 15 1163 1098 1073 1071 1079 1083 1343 0751 135 136
27 88 34 73
802 9 -_78
1187 1214
1099 1131
1069 1104
1066 1101
1075 1~110
1l061 1066
1370 1360
0662 0618
137 4118 9 81 1084 1010 0983 0979 0982 o937 1209 0581 138 4973 98 1 0969 0897 0 868 0855 0860 0799 1041 0572
139 1D 1253 409 1371 1293 1298 1301 1309 1321 1578 0928 140 2366 480 1130 1 090 1 121 1130 1137 1132 1390 0744 141 34 61 6 38 1081 1086 1152 1161 1147 1069 1382 0644 142 143 144
4325 5677 6759
7 90 939 998
1110 1115 1034
1161 1208 1139
1253 1268 1180
1265 1302 1215
1228 1230 1123
1080 1056 0970
13$913r12 8
0601 0561 0542
145 84 08 989 0863 0961 0934 0895 0871 0 785 09 9 0530 146 86 54 9 80 0808 0901 0 872 0821 0809 0733 0891 0498 147 7376 9 80 0 927 1032 1027 1 040 0961 0889 1032 0511 148 2D 4254 776 1 050 0 981 0965 0961 0962 0922 1155 0579 149 5708 991 1102 1031 1014 1009 1010 0931 1227 0528 150 69 78 990 0914 0853 0839 0 839 0843 0759 0996 0521 151 1254 490 1 479 1352 1329 1334 1351 1379 1607 0930 152 2713 7 00 1310 1220 1201 1201 1211 1209 1516 0723 153 8730 991 0809 0756 0742 0745 0 748 0663 0874 0543 154 5811 966 1219 1108 108 6 1081 1079 1033 1330 0650 155 42 46 8 02 1248 1136 1114 1114 1118 1103 1376 0 699 156 c 1270 429 1671 1571 1551 1545 1563 1600 1933 0929 157 2714 488 1398 1285 1 267 1258 1262 1275 1628 0729 158 4310 642 1424 1318 1299 1282 1283 1261 1683 0617
co ~
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc7 tc a 1r
159 60 12 780 1461 1388 1370 1349 1343 1279 1700 0 573 160 72 79 8 60 1402 1344 1330 1312 1292 1189 1 566 0 520 161 8690 982 1472 1442 1437 1 422 1392 1224 1602 0 521 162 163
12D 4368 5833
6 30 8 30
1195 1368
1105 1270
1111 1283
1117 1294
1131 1313
1081 1194
1369 1553
0613 0 553
164 76 43 959 1428 1338 1348 1341 1371 1180 1488 0535 165 8739 984 1345 1272 1272 1208 129 3 1059 1361 0550 166 1268 459 1701 1548 1541 1547 1589 1 625 1976 0 973 167 2678 570 1485 1351 1349 1356 138 1 1 385 1795 0760 168 169
1 12D 128 3 2729
448 650
1664 1314
1501 1232
1425 1233
1428 1229
1491 1229
1527 1232
1869 1571
0 962 0767
170 4345 847 1245 1179 1187 1182 1172 1132 1476 0 650 171 6036 9 76 1139 1109 1117 1114 1095 1020 1332 0588 172 6578 9 72 0982 0949 0942 0938 0926 0 8 50 1079 0560 173 87 84 9 72 0880 0854 0 8 36 0822 0818 0 749 0941 0585 174 1278 480 1564 1416 1397 1403 1417 1445 1733 0998 175 2711 590 128 3 1175 4 1178 1182 1187 1195 1493 0796 176 4351 8 90 1331 1259 1266 1275 1272 1235 1592 0 682 177 5994 9 60 1228 1152 1150 1151 1143 1075 1 360 0644 178 lU 1223 408 2282 2140 2052 2052 2106 2188 2626 0 878 179 2351 408 178 1 1623 158 5 1519 1556 1634 2068 0717 180 3448 482 1888 1675 1570 1541 1572 1665 2199 0629 181 4513 563 2026 1797 168 4 1644 1670 1770 2385 0583 182 5714 589 1913 1700 1610 1568 1580 1 682 2382 0551 middot 183 6997 653 1903 1718 1643 1611 1612 1700 2326 0 549 184 8709 6 80 1738 158 3 1543 1510 1498 1519 1 912 0577 185 186
2 12D 4249 5737
660 9 74
1055 1221
0 979 1122
0960 1093
0 952 1088
0959 1090
0 956 1054
1147 1350
0661 0602
187 7432 9 8 1 1065 0981 0951 0942 0 939 0881 1135 0582 CD ~
TABLE X Continued
Run No Position CFM I t o1 to 2
188 87 23 9 83 0944 0 879 189 1435 585 18 26 1630 190 2718 690 1433 1298 191 7507 950 1070 0961 192 85 44 964 0982 0 881 193 1287 600 1806 1668 194 2717 7 80 1579 1444 195 4253 8 81 1371 1260 196 60 68 9 78 1252 1152 197 73 89 975 1100 1000 198 86 88 973 0953 0 871 199 58 64 9 81 1269 1155 200 2D 4 1 77 915 1362 1251 201 5712 975 1213 1111 202 7363 9 78 1036 0 951 203 8 604 973 0932 0861 204 1268 6 95 2015 18 20 205 2659 6 96 1405 1295 206 39 80 7 98 1261 1174
No 207 Orifice 114 96 509 1325 1148 208 94 33 509 1477 1243 209 7487 5 09 1686 1409 210 5236 505 2094 1691 211 3309 428 2188 1 778 212 1293 392 2976 2560
Thermo ooup1e Readin g s (mv) to 3 to4 to
5 to
6 to7 toair
0 851 0847 0 8 29 0759 0987 0592 158 4 1583 1611 1647 1993 0986 1270 1266 1 279 1298 1604 0 789 0916 0908 0900 0 858 1115 0602 08 39 0 823 0 818 0 770 1035 0602 1609 1602 1629 1676 2153 0979 139 1 1385 1400 1 430 1938 0776 1212 1201 1205 1201 1601 0669 1 105 1086 1086 1 052 1371 0621 0952 0936 0923 0870 1195 0582 0 8 20 0 801 078 1 0 729 1044 0569 1108 1090 108 2 1043 1407 0610 1218 1221 1241 1202 1582 0659 1081 1083 1084 1031 1 368 0622 0921 0924 0919 0 841 1111 0 610 08 34 0831 0 821 0 751 1003 0 630 1761 1761 1 809 1861 2399 0966 1271 1271 1295 1311 1650 0797 1150 1150 1161 1149 1440 0703
1083 1057 1053 1109 1566 0~530 1158 1125 1138 1217 1763 0 526 1291 1250 1278 1383 2038 0542 1518 1478 1519 1657 2420 0 589 1596 1557 1601 1737 2441 0688 2370 2344 2409 2561 3 297 0921
()) (11
TABLE X Continued
Run Thermocouple Readings (mv) No Position CFM I tc 1 tc2 tc3 tc4 tc tc tc tc i5 6 7 a r
C of 2nd 213 516 1235 4 63 1 432 1291 1265 1258 1 268 1 308 1550 0 971 214 1919 6 17 1357 1223 1196 1191 1199 1211 1461 0 851 215 27 12 8 35 1401 1259 1278 1220 1230 1218 1511 0 762 216 3320 981 1439 1305 1270 1259 1275 1238 1450 0719 217 41 53 980 1251 1142 1132 1094 1121 1088 1305 0 695 218 404 987 1102 1042 1030 1 bull006 1014 0960 1133 0681
Supplementary Equations
Calculating temperatures from thermocouple readings
t = -026tc)2 + 3512(tc) + 3201 (26)
where t is the temp in deg F and tc is the thermocouple reading in millishyvolts
Calculation of the thermal conductivity of air
k = 00000245ta + 0 0132 (27)
where k is the thermal conductivity in Btuhr rt2 degFft and ta is the air temp 1n OF
I I
bull co m
TABLE OF CONTENTS
Chapter Page
I Introduction bull bull bull bull bull 1
II Theory and Previous Work bull bull 4
III Experimental Apparatus bull 8
Test Section bull bull bull bull bull bull 8 Sen sing Probe Assembly bull bull bull bull 11 Power Source bull bull bull bull bull bull 12 Temperature Measuring bull bull 12 Air Source bull bull bull bull bull bull bull bull bull 15 Pressure Probe bull bull bull bull bull bull bull bull bull 16
IV Experimental Program bull bull bull 17
v Experimental Procedure bull 20
VI Calculation of Experimental Data bull 22
VII Analysis of Data bull bull 27
Variat ion of Heat Transfer Rate with Distance from the Baffle bull bull 27
Rate of Heat Transfer at the Point
Effect of Upstream Baffles on Heat
Heat Transfer in the Test Sect ion
Heat Transfer at the Baff le and Maximum Point as a Function of
Correlation of Data at the Baff le bull 36
of Maximum Heat Trans f er bull bull bull bull 39
Transfer at the Orifice Center bull bull bull 42
with No Orifice bull bull bull bull bull bull bull bull 42 Pressure Drop Data bull bull bull bull bull bull 44
Pressure Drop bull bull bull bull bull bull bull 47
VIII Summary of Re sults 51
IX Re commendations 53
Nomenclature 54
Bibliography bull 56
Append ix 57
LIST OF FIGURES
Figure Page
1 Cross Section of Test Section and Probe bull bull bull bull bull bull bull bull bull bull bull bull 9
2 Experimental Apparatus 10
3 Sensing Probe bull bull bull 13
4 Drawing of Assembled Probe 14
5 Variation of Heat Transfer Rate with Distance from Baffle - 1 364 11 and 1 216 Sizes bull bull bull bull bull bull bull bull bull bull 29
6 Variation of Heat Transfer Rate with Distance from Baffle - 1 316 11 Size bull 30
7 Variation of Heat Transfer Rate with Distance from Baffle - 1 516 Size bullbull 31
8 Effect of Orifice Size on Position and Value of Maximum Heat Transfer bull bull 34
9 Correlation of the Point of Maximum Heat Transfer with Orifice Size bullbull 35
10 Rate of Heat Transfer at Baffle Center 37
11 Correlation of Heat Transfer Data at Baffle Center bull bull bull bull bull bullbull 38
12 Rate of Heat Transfer at the Point of Maximum Heat Transf er bull bull bull bull bull bull bull bull 40
13 Correlation of Heat Transfer Data at the Point of Maximum Heat Transfer 41
14 Effect of Upstream Baffles on Heat Transfer at Baff le Center bull bull bull bull bull 43
15 Heat Transfer with No Baffle 4 5
16 Orifice Pressure Drop Function versus Reynolds number bull bull bull bull bull bull bull bull bull bull bull bull bull bull 46
17 Heat Transfer at the Baffle and Maximum Point as a Function of Ori fice Pressure DIO p bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 48
18
Fi gure Pa ge
Var iation of Heat Transfer Rate and Pressure Drop with Orific e Size at a Con stant Flow Rate bull bull bull bull bull bull 50
bull bull bull bull bull bull bull bull
bull bull
I
II
III
IV
v
VI
VII
VIII
I X
z
LIST OF TABLES
Pa ge
Summary of Experimental Program bull bull 19
Position of Maximum Heat Transfer 32
Calculated Heat Transfer Data 57
Pressure Profile Data bull bull bull 67
Rate of Heat Tr ansfer at the Baffle Center middot bull bull bull bull bull 70
Rate of Heat Transfer at the Point of Maximum Heat Transfer bull bull bull bull bull bull bull bull bull bull bull bull 72
Effect of Upstream Baffles on Heat Trar1sfer bull bull bull bull bull bull bull bull bull bull bull 74
Heat Transfer in the Test Section without Orifice bullbullbullbullbullbullbullbull 75
Pressure Drop Function 76
71bull r ntal bull bull bull bull bull bull bull bull bull bull bull bull
HEAT TRANSFER AND PRESSURE PROFILRS IN THE VICINITY OF ANNULAR ORIFICES
- CHAPTER I
INTRODUCTION
The most common type of industrial heat transfer
equipment is the shell and tube heat exchanger which
consists of a bundle of tubes contained in a cylindrical
shell Heat is transferred from the hot fluid to the cold
fluid through the tube walls as one fluid flows through
the tubes and the other flows through the shell surroundshy
ing the tubes
Most commercial multitube heat exchangers contain
bafflesmiddot to guide the fluid through the equipment and to
prevent stagnant regions from forming in the shell As a
result the flow pattern in the shell is very complicated
and considerable variation of the local rate of heat transshy
fer occurs because of the various types of flow which exist
in the baffled passage The research described in this
thesis concerns a study of one small portion of the shell
side of a heat exchanger
There are three main types of baffles used in commershy
cial heat exchangers
1middot Orifice baffles extend through the cross section
of the shell and all of the shellbullside flow is
through the annular orifice formed at each point
where the tube passes through the baffle
2
2 Disk and doughnut baffles consist of disks and
doughnuts or annular rings placed alternately
along the length of the tube bundle~ There is
some flow through the annular orifices formed
where the tubes pass through the baffles but a
large portion of the flow is around the baffles
3 Segmental baffles are segments of a circle and
Bre arranged so that the fluid flows back and
forth across the tube bank There is still some
f~ow through the small area where each tube goes
through the baffle
In the case of disk and doughnut and segmental baffles
small annular clearances must be allowed at the point where
the tube goes through the baffle so that the bundle may be
assembled easily Thus in all of the types of exchangers
some shell-side fluid flows through the annular orifice
where the tubes pass through the baffles It has been
shown that this is an area of high rate of heat transfer
but its effect on the overall performance of the heat exshy
changer is not well known Also the prediction of rates
of heat transfer 1n these orifices is not yet possible
The purpose of this research was to make an extensive
study of the heat transfer rates in the vicinity of these
annular orifices and to determine the effect of orifice
size flow rate and upstream conditions The work was
5
performed in a onebulltube single orifice type baffle heat
exchanger and provision was made to measure local rates
of heat transfer in the vicinity of the baffle
4
CHAPTER II
THEORY AND PREVI OUS WORK
In 1701 Newton defined the heat transfer rate qc
from a surface of a solid to a fluid by the equat ion
= ~A(tw - t) (1)q0
where hm is the coefficient of heat transfer from the surshy
face to the fluid excluding any radiation A is the area
of the surface tw is the surface temperature of the wall
and t is the bulk temperature of the fluid The equation
for the point of local surface coefficient h is given by
dqdA = h(tw- t) (2)
The mechan ism and the laws covering heat transfer by
true conduction in solids and by radiation through transshy
parent media are well known However with heat transfer
from a solid to a fluid the situation is far more complex
The mechanism of flow of the fluid to a large extent deshy
termines the rate of heat transfer for a given temperature
difference
In addition the coefficient hm depends on certain
physical properties of the flowing fluid the dimensions
of the apparatus the velocity of the fluid past the surshy
face and frequently the temperature potential AT
It was the purpose of t his research to measure the
local shell -side heat transfer coefficient and correlate
it with the several variables mentioned a bove
5
The heat transfer coefficient for fluids flowing inshy
side tubes is more e a sily measured and correlated due to
the simple geometry of t he tube i nterior Much work has
been done on the tube-side coefficients with one of the
more useful e quations being the Dittus - Boelter equation
( 4 p 450) ~
0 023 (---ctwGJbulla (~np M ( 3 ) M k
with the following cond itions satisfied
(1) Fluid properties evaluated at the arithmetic
mean bulk temperature
(2 Reynolds number gt10000
(3) 0 7 lt Pr lt 100
(4) n = 04 for heating and 0 3 for cooling
(5) Ldw gt60
Colburn (3 p 197) obtained an equation for tubeshy
side heat transfer coefficients in which the Stanton
number is used instead of the Nusselt number
hm ) (~~ 23 _ (dwG) 0 2 ( GC k - 0 bull 023 U (4)
p
Much of the research done on average shell-side heat
transfer coefficients has resulted in empirical correlashy
tions of the form of equations (3) and (4) above Several
investigations have been made for a certain set of phys~al
6
variables but the r esults have ne ver satisf a ctorily been
correlated to appl y for all types of heat exchangers
Some basic 1ork has been done recently however on
the local shell-side coefficients Ambrose (1) studied
the local heat transfer coefficients i n a model heat exshy
changer with segmental baffles This study was fairly
extensive at the baffle center but the data were quite
limited for the space between the baffles Gurushankar1ah
(5) further extended Ambroses work by studying a single
baffle space in detail
The results of these two studies indicated a need for
detailed information 1n the vicinity of the baffle Hence
Lee () investigated a single baffle s pace between two
orifice baffles and obtained considerable information on
the rates of heat transfer in the annular orifices Since
his work was carried out in a multitube mode l heat ex~
changer the determination of the rate of flow through the
individual orifice was difficult because of t he outer
clearances existing in the exchanger For this reason the
present research was undertaken to study the rate of heat
transfer in a single annular orifice through which the flow
could be accurately determined
Bell and Bergelin (2) have studied i n detail the pres shy
sure drop coeff icients for the annular orifices formed beshy
tween a circular disk and a circular tube These results
also appl y to the annular orifioe formed when a rod extends
7
through a circular hole in a plata This study was extenshy
sive in the fact that it considered the baffle thickness as
well as the orifice size but no heat transfer data were
presented
Sullivan and Bergelin (9) studied flow through a
single annular orifice through multiple annular orifices
i n parallel and flow around a single baffle both with and
without leakage through the baffle A generalized expres shy
sion is presented for the pressure drop across one baffle
section of a tubular exchanger with leakage through the
tube holes in the baffle but the effect of leakage area
upon heat transfer is only discussed qualitatively The
pressure drop data is correlated by plotting cent as a funcshy
tion of the Reynolds number where cent equals
d1 )22( ~ P) s c e (d2 -
M-2
8
CHAPTER III
~PERI1ffiNTAL APr ARATUS
The heat transfer test section was essentially a
single tube heat exchanger The inner tube was a l-in
OD aluminum tube with an electrically heated probe midshy
way between the two ends of the tube
Test Section
The shell as constructed from lucite plastic tubing
2 5-in I D and 3-in O D The te t section d a total
lengt h of 54 58 inches I t consisted of two sections
The upstream section was 40 i n ches in length in order to
assure freedom from entrance effects and the downstream
section was 13 12 inches in length To further assure
uniform flow a bundle of short copper tubes was placed a
few inches downstream from the entrance Both of these
sections had 12 i nch flanges on one end so t hat a 18
i nch thick orifice plate could be clamped between them
Heat transfer coefficients were measured in the vicinity of
t h is orifice A cross section of the center of the test
section is shown in Figure 1 and the experimental appara~
tus is shown in Figure 2
Cooled air supplied by a Roots -type blower was used
as the shell-side fluid throughout this study It entered
the test section through a l-in ID 1 12-in OD plasshy
tic pipe at the upstream end of the calming section Tbs
j Jl l 6- 11 BOLTS II I nbull middot~11 I HEATING ELEMENTS
J T ( T
-f-shy - - - f-_- __L
7 777 _y A
IT 1] I
I
FIGURE I CROSS SECTION OF TEST SECTION AND PROBE
10
FIGURE 2 EXPERIMENTAL APP1Ub~fUS
11
air left the test section through nine equally spaced 12
ineh holes placed around the side of the tube at the exit
end
Sensing Probe Assembly
The sensing probe was designed to measure the local
heat transfer coefficients at any point along the tube and
around the tube in the test section The tube was designed
so that it could be easily moved up- and downstream to
measure the heat transfer coefficients at various positions
in relation to the orifice
The sensing tube assembly consisted of the sensing
probe the thermoctmple lead s and selector switch the
power lines and the two aluminum tubes between which the
probe was centered
Imbedded in the sensing probe were seven iron-constanshy
tan thermocouples for measuring the temperatures around the
tube The lead wires from these thermocouples were conshy
nected to a seleotor switch at the downstream end or the
aluminum tube A layer of Saran wrap was placed around the
tube over the t hermocouple and three lengths of Trophet C
resistance ribbon were wrapped around the tube nd conshy
nected in series to the power leads
The heating surface of the probe was formed by these
three one inch wide strips of Trophet C resistance ribbons
The ribbons were 0002 inches thick and had a resistance of
12
0 271 ohms per foot and a thermal conductivity of 763
Btuhr ft 2 degFft They were held in position by four
copper bars placed in four parallel longitudinal slots
These copper bars served as connectors for the electrical
leads A photograph of the sensing probe is shown in
Figura 3 and a drawing of the assembled probe is given in
Figure 4
Power Source
Direct current was used to heat the resistance ribbon
on the sensing probe The current was regulated by a slide
wire resistor The po er source consisted of a Raytheon
Voltage Stabilizer to stabilize the city power source at
115 volts and an automatic selenium rectifier with an alshy
ternating current input of 115 volts at 60 cycles per
second and an output of 12 volts and 35 amperes direct
current
Temperature Measuring
The temperatures around the sensing probe were calcushy
lated from the emf readings of the ironbulloonstantan thermoshy
couples The emf measuring system consisted of the seven
probe thermocouples a separate thermocouple for measuring
the inlet air temperature a thermocouple selector switch
a cold junction and a Leeds and Northrup Type K Potentishy
ometer The potentiometer was placed on a Fischer
13
THERMOCOUPLE JUNCTIONS~ ~------- HOLES FOR THERMOCOUPLE LEADS
~----- SCREWS
~ff+--- CONNECTING BARS
END VIEW
POWER LEADS SOLDERED TO LOWER CONNECTING BAR
iER PLASTIC PIECE
RESISTANCE RIBBONS LOCATION OF THERMOCOUPLES
FIGURE 4 DRAWING OF ASSEMBLED SENSING PROBE
15
Vibradamp support to absorb the vibrations produced by the
air blower
Air Source
Air was used as the shell-side cooling fluid during
the study The air was pumped through the test section by
a Roots type air blower with a rating of 280 ofm at 3 12
psig outlet pressure The hot air leaving the blower was
passed tbxfugh two finned-tube box-type coolers and one
tubular edoler to oool it to approximately room temperature
The air flow rate was measured by passing it through a
flow measuring orifice in the line Two sharpbull edged orishy
ficas were used f or flow measurements The calibration
curves for these orifices were presented by Ambrose (1
p 166)
The pressure taps on each side of the orifice were
connected to two differential manometers containing 0 83
and 2 95 specific gravity fluids respectively The presshy
sure drop through the test section and test orifice was
measured by a pressure tap placed 13 inches upstream and
one placed 6 12 inches downstream from the orifice Two
pressure ga ges were used to measure the pressure at the
inlet to the flow orifice and to indicate the statio pres~
sure at the test section inlet
16
Pressure Probe
A probe was designed to measure the pressure drop
between the pressure tap 13 i nches upstream from the ori shy
fice baff le and any point downstream from the tap The
probe eonsisted of a l~in OD copper tube with six 132
i n ch holes even l y s paced around the tube The upstream
pressure tap and the pressure probe were connected to a
differential manometer so the pressure drop to various
points up- and downstream of the orifice could be measshy
ured
17
CHAPTER IV
EXPERIMENTAL PROGRAM
The experimental program was designed to measure the
heat transfer coefficients and pressure drops in the vicinshy
ity of annular orifices The four orifice sizes studied
were 1 364 1 216 l 316 and 1 516 inches~ The inner
tube used in each case was a 1-in OD alumintim tube
Hence tube to baffle clearances were respectively 3128
232 332 and 532 of an inch
Heat transfer coefficients were measured at poait~ons
1 i nch upstream at the orifice center and at 12 1
1 12 and 2 inches downstream for all orifices In addishy
middottion the heat transfer coefficient at a point 2 12
inches downstream from the 1 516 inch orifice was measured
and at the points 12 l 12 and 2 inches upstream from
the 1 364 inch orifice
The heat transfer coefficients at each point were
measured at five different flow rates for the 1 364 inch
orifice and at six different flow rates for the other orishy
fice sizes The high pressure drop through the small orishy
fice size limited the number of flow rates which could be
studied
The flow rate was calculated from the pressure drop
across the flow orifice This flow was corrected to cubic
feet per minute at 68degF and one atmosphere pressure by
18
using the orifice pressure and the test section pressure
which were measured by pressure gages
It was desired to determine a relationship between the
heat transfer coefficient and the total pressure drop for
each orifice size The pressure drop across each orifice
at various flow rates was measured by means of the presshy
sure probe described in Chapter III It was also desired
to obtain pressure profiles for each orifice size since
these might be similar to the heat transfer profiles The
pressure drop was measured from a point 13 inches upstream
of the orifice to points at 1 and 12 ineh upstream the
orifice center 12 1 1 12 and 2 inches downstream
The experimental program is summarized in Table I
TABLE I
SUla~RY OF EXPER IMENTAL PROGRAM
Position Investigated-Distance from Orifice-Inches
Orifice Range of Flow Rate Size Heat Transfer Pressure Drop CFM at 68degF amp 1 atm
1 364 2U 1 12U 1U 12U c 12U C 12D lD 10 - 18 l2D lD 1 12D 2D 1 12D 2D
1 216 1U c 12D lD 1 l2D 2D 12U c 12D lD 10 - 35
1 316 1U c 12D lD 1 l2D 2D l2U C 12D lD 12 - 50
1 516 1U c x2D lD 1 l2D 1U 12U C 12D 12 - 90 2D 2 1 2D l D 1 l2D 2D 2 12D
20
CHAPTER v
EXPERI MENTAL PROCEDURE
The experimental procedure for measuring the heat
transfer coefficients ~d corresponding flow rates reshy
quired the following procedure
(1) Install the orifice size to be studied in the
test section
(2) Place the heat transfer probe in the position up
or downstream from the orifice where the middot heat
transfer rate is to be studied
(3) Fill the cold junction thermos with cracked ice
(4) Measure the atmospheric pressure
(5 Open bypass line from blower and close line to
test section
(6) Turn on the cooling water for the exchangers used
to cool the air leaving the blower
(7) Start the automatic selen ium rectifier by turning
on the t 1mer bull
(8 ) Connect the voltage stabilizer to the wall outlet
(9) middot Set the slide wire resistor to the maximum re shy
s1atanee I
(10) Start the blower
(11 Open the line to the test section until the de shy
sired flow rate is obtained
(12) Switch on the probe direct current power source
21
(13) Adjust the slide wire resistor to obtain the
desired current
(14) After the thermocouples have reached equilibrium
values record the e m bullf across each of the
seven probe thermocouples and also the entering
air thermocouple
(15) Record the direct current amperage
(16) Record the gage pressure at the flow orifice and
the entrance to the test section
(17) Record the manometer measurement of the pressure
drop across the flow orifice and also the presshy
sure drop through the test section
22
CHAPTER VI
CALCULAT ION OF EXPERIMENTAL DATA
The local heat transfer coefficients were calculated
from the temperatures measured on the probe surface the
air temperature and the current input The results were
calculated by using the Alwae III-E computer
The general expression for calculation of the heat
transfer coefficients was derived by Ambrose (1 p 79)
The equation is derived by making an energy balance around
a small increment of the center resistance heating ribbon
The two ribbons tnstalled adjacent to the center ribbon
reduced the amount of logitudinal conduction and assured
little longitudinal temperature variation in the center
ribbon
A heat balan ce on this small increment of resistance
ribbon yields the following
(the heat conducted in) + (heat generated) = (heat
conducted out) +(Heat convected to the fluid) + (heat
radiated to the surroundings) + (Heat conducted into
the plastic center of the probe)
This gives the equation
kzw dtdS + 12RdS kzws [ t + (~) ds] + hwdS (t-ta )
+ ~Aad wd o middot+ qcAond 1 -~- wdS 5 )
23
Hence solving for h gi~ea
i2R kz d2t Qrad qcond w + -d$2 - ~- A
h = ( 6)t - ta
Since S = re where 9 equals the enclosed angle ~n radians
dS rd9 ( 7)
and
dt - dt (8)dS - rd9
Differentiating with respect to S
d2t (9)rd9dS
from which
(10)
Substitut1ng into the equation for heat transfer coeffishy
cient gives
h = i2R Qcond A (11)
w
The rate of radial heat conduction into the plastic
tube making up the probe was assumed to have negligible
effect on the heat transfer coefficient It was also
assumed that the heat loss by radiation from the ribbon
was negligible since all data were obtained with the ribbon
at a temperature less than 125degF
24
When t he rad iation and conduction terms are neglected
Eq (11) becomes
(12)
The following con stants are known
R = 0 271 ohmsft
w = 100 i n ches
k = 763 Btuhr rt2 degFft
z = 0 002 inches
r = 12 inch
Eq (12) putting 9 in degrees then reduces to
1110 12 + 2404 d 2t d92
( 15)h = ------~--~-------t - ta
Thi s equation was programed for the Alwac III- E comshy
puter and used to calculate the local heat transfer coefshy
ficients from the observed data
The average heat transfer coefficient around the tube
at a given position in the t est section was calculated by
averaging the local coefficients calculated from Eq (13 )
It was found 1n the course of the experimental work
that thermocouple numbers 1 and 7 were indicating higher
temperatures than would be expected This resulted in h1
and ~ being lower than the other local coefficients around
the tube Since the fluid was flowing parallel to the axis
of the probe the circumferential variation i n rate of heat
25
transfer should be small Hence in obtaining the average
coefficient around the tube the values of h1 and h7 were
not used even though they were calculated and are tabulated
1n Table I II in the Appendix
Then
(14
A Nusselt number as calculated from this aver age heat
transfer coefficient using the tube diameter as the characshy
teristic dimension
(15)
The air flow rates through the test section were calshy
culated by measuring the pressure drop across the flow orishy
fice the air temperature the pressure at the flow orifice
and the pressure at the entrance to the test section The
orifice calibration curves (1 p 166 ) were used to obtain
a value of the orifice coefficient f8e where Q equals
the flow in cubic feet per minute at 68deg F and one atmosmiddot
phere pressure and te is the density of air at the exchanger
and e the density of the air at the flow orifice The
den sity of the air can be expressed by
e = 2 703 p (16)T
where T equals the temperature in OR and P equals the absoshy
lUte pressure i n lb1n2 Using the value of e Qfo from
26
the calibration charts as A and Eq (16) solving for Q
gives
( 17
This equation was used to calculate the flow rate for
each flow studied
The Reynolds number used i n the correlation of the
data was the equivalent Reynolds number defined as
Re)eb ~ d2 - dl)Uf ( 18 ) lL
where d1 is the outside diameter of the inner tube and d2
is the orifice diameter U is the flow velocity through the
annular orifice e is the density of the air and U- is t he
viscosity of the air This equation can be transformed t o
(Re) b = 1611 Q (19) e dl + d2
where d1 and d2 are in inches
The pressure drop data were calculated i nto a dimenshy
sionless pressure drop function cent where
d1 )22( ~ P)gc f av(d2 shycent 2 bull (20
M-
For air this equation reduces to
where d2 and d1 are in i nches D P is expressed i n inches of
2 95 specific gravity fluid and P av is expressed as lbft3
27
CHAPTER VII
ANALYSIS OF DATA
In analyzing the heat transfer data an attempt was
made to correlate it 1n terms of the dimensionless groups
(Nusselt number Prandtl number and Reynolds number) which
appear in Eqs (3) and (4) Consequently all of the av~
erage heat transfer coefficients hav were brought into
the form ( Nu)( Pr)~3 bull The Nusselt number was based on the
tube diameter and the thermal conductivity of the air at
the flowing temperature The tube diameter was used in the
Nusselt number because comparison could then be made with
previous experimental work on heat exchangers which have
commonly used the Nusselt number defined as in Eq (15)
From the standpoint of dimensional analysis this is
equivalent to considering the tube diameter as the characshy
teristic length so far as the heat transfer is concerned
The Prandtl number of the air was taken as 0 7 in all
cases
Variation of Heat Transfer Rate with Distance from the Baffle
Considerable variation was observed in the rate of
heat transfer in the vicinity of the baffle In order to
obtain the variation with respect to position the term
(Nu)(Pr)-13 was plotted versus the flow rate Q for each
position and orifice studied Cros s plots were then made
28
at constant flow rates in order to obtain the variation of
(Nu)(Pr) -13 with position The resulting cross plots are
shown 1n Fi gures 5 6 and 7 for the four orifices studshy
ied
About one inch upstream from the orifice the heat
transfer coefficient begins to rise rapidly and continues
to do so until it reaches a maximum some distance downshy
stream After the maximum point the heat transfer coef fi shy
cient decreased slowly The heat transfer rate was found
to reach a maximum at a different position downstream for
each orifice size These figures also show that for a
given orifice size the maximum heat transfer rate occurs
a pproximately at the same point for all flow rates The
position of the maximum point f or each or ifice size is
shown in Table II
The region immediately downstream from the orifice is
one of h i gh turbulence due to the jetting action of the air
flowing through the orifice As the air flows t hrough the
orifice the streamlines continue to converge for some dis shy
tance downstream The point of maximum heat transfer is
probably at the point where the streamlines be gin to diverge
and a boundary layer begins to build up on the tube Tle
decreasing heat transfer coefficient beyond the maximum
point indicated the formation of a boundary layer
Since the position of the maximum point is independent
of flow rate middot it is possible to correlate it with respect
_ ct 11shyz-
100
0 136 ORIFICE
(
I 0
I )
~ 00
~p 0
I 0
--r--- ~
ISCFIII
-_ OCFM
rbull abull
~ middot~ a-1 z-
12fORIFICE
100
200
100
0 0 UPITRAM ORIFICE DISTANCE CENTER
CFM
h I DOWNSTREAM
DISTANCE
FIGURE 5 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLpound
30
too
700
800
100 ~ f gtf
400
z ~
100
100
100
0
13fORIFICE
~ -~ -- ---
)
~
~
-
I ~ ~OCFM
I vI~-~ OCFM
J ---
Iamp CFM
I 0 I I UPSTREAM ORIFICE DOWNSTREAM DIITANOE GENTER DIITANCI
FIGURE 6 VARIATION OF HEAT TRANSFER RATE WITH DISllNCE FROM BAFFLE
--
--- --
31
100
100
700
100
_ 100
f 9- 400 z-
100
tOO
100
0 - I 0 I I I UHTRIAM OAtfiCI DOWIIITMAM
+ I tyl6 ORIFICE
v I
~~ ~CFM
I v ~CFMI
v v 7
~~ v ~ iOCFM
- ~~ I-shy1-shy ~ICFM
DIITMCI OINTIR DIITANCI
FIGURE 7 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLE
32
TABLE II
POSITION OF MAXIMUM HEAT TRANSFER
Position of Maximum Orifice Size Heat Transfer
(inches) (inches downstream)
1 364 050
1 216 100
1 316 125
1 516 200
33
to orifice size Figure 8 shows the effect of the orifice
size on the position and value of the maximum heat transfer
at a constant flow rate of 15 cubic feet per minute It
can be seen that the larger the orifice size the further
downstream the point of maximum heat transfer occurs
Also as the orifice size increased the rate of heat
transfer decreased for a given flow rate The broken line
indicates the variation of the point of maximum heat transshy
fer with position and size The position of the point of
maximum heat transfer rate downstream from the orifice was
correlated with orifice size by means of the dimensionless
groups (Lde) and (d1de) where L is the distance downshy
stream from the orifice where the maximum rate of heat
transfer occurs d1 is the outside diameter of the inner
tube and de is the equivalent diameter of the orifice
ie de = d2-dlbull
Figure 9 shows a plot of Ld 6 versus d1d6 for the
four orifice sizes studied The four points on this logshy
log plot are approximately in a straight line and the
equation of this line is
Lde = 0 44 d1de)028 (22)
Although the above relationship represents a correlashy
tion of dimensionless groups it is based upon only one
tube diameter and needs to be substantiated further by
studying other tube diameters and other orifice sizes
34
aoo
400
aoo ~
-~ middot-CLshyJ z
200 -
100
0
ORIFICE CENTER
l~
l
t
I J~
1pound~
I
0 I I~
AT 15 CFM
-
bull ~ 1~6~
~ v~
~
~--~~6
~~~ ___ v v V -_
~ o q
~ I 16
v
~
ogWNSTREANI STANCE
FIGURE 8 EFFECT OF ORIFICE SIZE ON POSITION AND VALUE OF MAXIMUM HEAT TRANSFER
35
50
loshy____ -~
~ ~ -shylltl-shy~ r0
2 10 30
FIGURE 9 CORRELATION OF THE POINT OF MAXIMUM HEAT TRANSFER WITH
ORIFICE SIZE
36
Correlation of Data at the Baffle
The heat transfer data were correlated by obtaining a
relationship between the group (Nu)(Pr)-13 and a
Reynolds number based on twice the clearance (d2 - d1
between the tube and the baffle It was found that the
most satisfactory correlation could be obtained when the
term - d1 was used as the length term in the Reynoldsd2
number
Figure 10 shows the variation of the heat transfer
rate at the center of the orifice e xpressed as a function
of Reynolds number and the orifice size This shows that
for a given Reynolds number the heat transfer at the center
of the orifice is greatest for the smallest orifice size
In order to obtain a general correlation of the data
shown i n F1gure 10 the effect of the dimensionless ratio
d1de was considered This ratio considers all of the
geometric factor s needed to describe the annular orifice
The thiclaless of the orifice plate is also a factor but
was constant i n this i nvestigation
The data for the heat transfer at the baffle center
are shown in Figure 11 in which (Nu)( Pr)-13 is plotted
versus (Re)ebd1 de) 0 55 This data on a log-log plot
lies on a straight line for (Re)eb( dld8 )0 55 greater
than 3 x 104 The equation for cor relating the heat
37
4XI~middot~-r~------~--~~------~
Icf t--to_+--_c-c-________ SYMBOL SIZE
0 1~4
6 ~~
9 ~~ -o ~
(Re)eb
FIGURE 10 RATE OF HEAT TRANSFER AT BAFFLE CENTER
38
500
0
4 0 lcf
~ ~
~ ~iC-
~ ~
~IL 0~ 0 SYMBOL SIZE-
p 0 1364-
r 6 1~16 -~ -
9 1~16 --o 1~16
I I
FIGURE II CORRELATION OF HEAT TRANSFER DATA AT BAFFLE CENTER
39
transfer at the center bullOf the a nnular orifice was found by
the method of least s quares to be
(Nu)( Pr)-1 3 = 0018 ( Re)ebO Bl( dlde)04~ (23)
3 x 104 ltRe)eb(a1de)055 lt 105)
Rate of Heat Transfer at the Point of Maximum Heat Transfer-The heat transfer rate at the point of maximum heat
transfer is plotted in Figure 12 to show the variation with
Reynolds number and the size of the orifice It is shown
gives the h1gh st heat transfer ~ate at its point of maxibull
that for a given Reynolds number the smallest orifice size yen il
mum heat transfer
The data ~or the maximum poi~t could be correlated by
plotting (Nu) Pr)-13 versus (Re)eb(d1de)06 This plot
is shown 1n Figure 13 and the resulting eurve shows that
(Nu(Pr)-13 is not a simple p0wer function of the Reynolds
number as was the case for heat transfer at the baffle
center The reason for this is probably because other
factors such as intensity and scala of turbulence should
be considered At the orifice center the streamlines of
the flowing stream are converging_ and thus the flow is
quite stable Downstream from the orifice is a region of
large eddy currents and probably large scale turbulence
These factors could con ceivably cause the results which
were obtained for the point of maximum heat transfer
40
If)
~middotshy Q_-I z_
10~~~--------r----~~--~--
SYMBOL SIZE
0 13$4
6 1~8
Q 13-18
-o 1~8
7)(104
(Re)eb
FIGURE 12 RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
41
Ia ~
0 I
c ~ ~ c v
~ ~lt w ~
17
~ b
v ~ ( SYMBOL SIZE
-~ 0 f-64 -v ~ 6 t211e
~ Q I~~~
-o - l~rs I I
FIGURE 13 CORRELATION OF HEAT TRANSFER DATA AT THE POINT OF MAXIMUM HEAT TRANSFER
4 2
Effect of Upstream Baffles on Heat Transfer at the Orifice Center
The heat transfer rate at the orifice center using the
single orifice in a test section is a pproximately 13 of the
value that was obtained by Lee (7) using a model heat exshy
changer with orifice baffles Lee investigated the cent r al
baffles of the heat exchanger and thus the coeff icients he
obtained would be affected by the presence of a number of
upstream baffles To determine the effect of upstream
baffles an additional l 516 inch baffle was placed four
inches upstream 1n the test section The resulting data are
shown in Figure 14 where (Nu)(Prmiddot)-13 is plotted versus
(Re) eb for the case of a single baffle 1n the test section
and also the case of an additional baffle placed four inches
upstream Comparison is made with the results obtained by
Lee middot(7) using a four-baffle and a ten-baffle model heat exshy
changer Good a greement is obtained with Lees work and the
results show the marked effect that upstream baffles have on
the downstream heat transfer rate The additional up tream
ba ffle caused sufficient turbulence 1n the test section to
i n crease the heat transfer rate nearly three-fold at the
center of the next baffle
Heat Transfer i n the Test Section with No Orifice
In order to check the accuracy 6f the equipment the
orifice baffle was removed and the heat transfer mea sured
with the probe in the empty test section The data were
43
~~BAFFLES
0 l BAFFLE -shy
ll_9 2 BAFFLES
V 4 BAFFLES-LEE
4 10 BAFFLES- LEE lJf ~
~rv ~~ ~ v flvv ~~
I ~ J ~ L v
0
v
( V
40 3XIo 7XIa
(Re)eb
FIGURE 14 EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER AT BAFFLE CENTER
44
compared with heat transfe r coefficients predicted by the
equations for annuli which are recommended in the litera shy9
ture The two equa~ ions u sed tor comparison were
(hfe)=0 023 (rltGr e (~~ur4 (~r45 (24)
which was presente~ by Wiegant (10)
and ( h ) (cnM~5(M~l o14 o 023 CPG k j Mij - (de GJMb )0 2 ( 2 5)
which was presented by McAdams (8 p 242) The comparshy
i son is s hown in Figure 15 lq (25) gives a value which
is low by about ten percent while Eq (24) g ives values
which are high by as much as twenty -five percent when comshy
pared with the experimental data The se equations are gembull
erally considered to give coefficients with an accuracy of
about twenty percent Therefore the present experimental
data are within the accuracy of these equations Also the
plot indicate s that for a Reynold s number greater than 2 x
104 the slope of the line is the same for the experimental
data as for the equations
Pressure Drop Data
The total pressure drop across the orifice was measured
as a function of the flow rate and the orifice size The
pressure drop was expressed as a d1mens1onleas quantity r)
which ie plCltted ver sus the Reynolds number in Figure 18
The pressure drop function cent correlates for all or1f1oe
45
200
100
s z
10 5XI10 10
0 EXPERIMENTAL
--McADAMS
-WIEGAND L
V
~ ~ ~
P ~ ~
LL~ L
v~
~
v v
v 1 ~ ~ v
v -gt
~
~ ~
~
6Xid
FIGURE 15 HEAT TRANSFER WITH NO BAFFLE
46
0 1~4 -~ a 6 t216
Q t316 lJ J
-0 as a )t
A LEE I -shy SULLIVAN 8
p
10bull
BERGELIN
I _ll I
I ~
i I
~middot
lo II
f fl
J j
~middot
A)101
1q
I Ill
1 I3 X 10ao1
FIGURE 16 ORIFICE PRESSURE DROP FUNCTION VS REYNOLDS NUMBER
47
sizes- The present data extends the range covered by preshy
vious workers and agrees well with their work The preshy
vious work of Lee () for a heat exchanger containing 10
orifice baffles and also the data of Su livan and Bergelin
(9) for pressure drop in a model heat exchanger with a
single baffle is shown 1n Figure 16 long with the present
results~ This figure may be used to predict the preseure
drop from the equivalent Reynolds number of the annular
orifice
The pressure drop between individual points 1n the
vicinity of the orifice and an upstream pressure tap wa s
measured to obtain a pressure drop profile As might be
expected 1n all cases the profiles showed a rapid decrea e
in static pressure immediately upstream from the orifice
There was however little or no recovery of the pressure
loss downstream The 1 364 inch orifice did show a maxishy
mum point in the pressure drop but this maximum occurred at
the orifice center and total recovery was reached about 12
inch downstream
Heat Transfer at the Baffle and Maximum Point as a Function of Pressure Drop
In order to compare the effect of the total pressure
drop on the heat transfer at the baffle and the point of
maximum heat transfer Figure 17 was plotted showing
(Nu)(Pr)-13 as a function of the total pressure drop This
shows that for a given pressure drop the largest orifice
48
1200
1000
~ a -sshyz-
100
60 100 700
AT MAXIMUM POINT I 15116 2 13116 3 1~6 4 1364
AT ORIFICE CENTER
60
1
v
r ~ ~ ~
5
~
8 7
13116
8
~
1364
v
~
e6
1~6
v
~~ v ~ ~ -~ ~
~
~ v
l
~
vamp
I ~ ~
~
v L ~
v
I-
5
k= ~~
~ ~ ~
--I
v ~
FIGURE 17 HEAT TRANSFER AT THE BAFFLE AND MAXIMUM POINT AS A FUNCTION OF
ORIFICE PRESSURE DROP
49
size has the greatest heat transfer coefficient This is
true at both the orifice center and at the point of maxishy
mum heat transfer
Another comparison can be made by plotting the heat
transfer coefficient and the pressure drop versus the orishy
fice size at a constant flow rate Figure 18 shows this
plot This graph shows that at a constant flow rate the
pressure drop as well as the heat transfer coefficient
increases as the size of the orifice is decreased In
choosing an orifice size for maximum efficiency 1t would
be necessary to know the pumping power available as well
as the heat transfer desired
70 I I 700
AT 15 CFM 60 ---
~ aug
50 ---
NV
40 ~
~ ~ ~
~ _
MAXIMUM POINT ---- --- ~
1-----t---~ _
~00Qj ~
~t--- ORIFICE CENTER 10 1100
1---~ n
u0 01 02 03 Q35
a ltl
de inches
FIGURE 18 VARIATION OF HEAT TRANSFER RATE AND PRESSURE DROP WITH ORIFICE SIZE AT A CONSTANT FLOW RATE
cn 0
51
CHAPTER VI II
SUMMARY OF RESULTS
This study revealed several significant facts about
the heat transfer in the vicinity of annular orifices
Probably the most important contribution was the presshy
entation of the heat transfer profiles in the vicinity ot
the annular orifice ~ r s shown that t~ local heat
transfer coeffieient re~ches a maximum at a point downshy
stream from the orifice The distance downstream at which
this maximum oocurs is t1ven by the equation
22
The heat transfer coefficients at the center of the
orifice were correlated and found to follow the equation
(Nu)(Pr)-13 = 00176 (Re)eb08l(d 1de) 0 middot4~ (23)
3 x 104 lt( Re) 9 b( d1d6 )055 ltlo5 )
The heat transfer at the point of maximum heat trans
fer for each orifice size was correlated and presented in
Figure 13 as a plot of (Nu)(Pr)-l3 versus (Re)eb(d1de) 06
No simple po-orer relationship exists between the terms
Intensity and scale of turbulence downstream from the orishy
fice are probably important factors which affect the heat
transfer
The large effect of an upstream orifice on the heat
transfer rate at the second orifice was demonstrated by the
52
study of two 1 516 inch orifices in the test section The
added turbulence at the center of the second orifice was
found to raise the heat transfer rate almost three times
over that obtained for a single baffle
The pressure profiles in the vicinity of the orifice
indicate that nearly all the pressure drop occurs at the
orifice center~ Total pressure drop data were correlated
by a pressure drop function cent as a function of the Reynolds
number and good agreement obtained with the results of other
workers
The pressure drop and heat transfer data were correbull
lated by plotting the heat transfer as a function of the
pressure drop for each orifice size It was shown that for
a given pressure drop the largest orifice size gives the
greatest heat transfer coefficient
As a final presentation it was shown that the pressure
drop and the heat transfer coefficient both i ncrease i n
value at a constant flow rate as the orifice size is de shy
creased This is important in choosing the optimum clearshy
ance for orifice baffles
53
CHAPTER IX
RECOMMENDATIONS
A great deal of work remains to be done in the field of
evaluating shellmiddotside heat transfer coefficients This
study included only one tube size and air was the only f luid
used It is recommended that further studies be conducted
using other fluids and tube sizes It will also be necessary
to study several baffle types
The adde d turbulence due to a s e cond baffle placed upbull
s t ream would suggest that the heat transfer coef ficients at
a certain position i n relation to a baffle would increase as
the flow progressed through the exchanger It is recomshy
mended that an extensive s t udy should be made between baffles
the full length of a model heat exchanger
It is further recommended that the pressure drop study
be continued to include other fluids tube sizes and baffle
arrangements
Effects of turbulence downstream from the baff le should
be studied by i n vestigations with hot-wire anemometer equipshy
ment to determi ne t urbulence scale and i ntensity
54
NOMENCLATURE
Area of heat transfer
Heat capacity of the fluid
Outside diameter of the tube
Orifice diameter
Equivalent diameter of the orifice (d2 - dl)
Inside diameter of the test section
Inside diameter of the tube
Gravitational constant
G Mass velocity
h Local heat transfer coefficient
Coefficient of heat transfer from surface to fluid
i Direct current amperes
k Thermal conductivity of the fluid
L Distance downstream of the point of maximum heat transfer
p Absolute pressure
L P Total pressure drop across the orifice
Q Flow in cubio feet per minute at 1 atmosphere and 680 F
q Heat transferred
Thermal energy conducted into the sensing probe
Thermal energy radiated from the resistance ribbon
Resistivity of the resistance ribbon
s Length of the resistance ribbon
T Temperature oR
55
t Temperature of the resistance ribbon deg F
ta Temperature of the bulk stream oF
tw Wall temperature of the tube OF
U Veloc ity of the fluid
w Width of the resistance ribbon
z Thickness of the resistance ribbon
eeuro Density of the fluid in the test section
Density of the fluid at the flow orificef 0
AL Viscosity of the fluid
E9 Angle measured around the tube
Dimensionl ess groups
(Nu) Nusselt number hd1k
(Pr Prandtl number C~k
(Re)eb Equivalent Reynolds number at the baffle (d2 - d1 )uejt-Lshy
(Re)e Equivalent Reynolds number in the test section ( d 8 - d 1 )U fu
cent Orifice pressure drop function 2(~P ) gc~av(d2 - d1) 2
Al
56
BI BLIOGRAPHY
1 Ambrose Tommy W Local shell-side heat transfer coefshyficients in baffled tubular heat exchanger PhD thesis Corvallis Oregon State College 1957 183 numb leaves
2 Bell K J and o P Bergelin Flow through annular orif ices Transactions of the American Society of Mechanical Engineers 70593-601 1957
3 Colburn Allan P A method of correlating forced con shyvection heat transfer data and a comparison with fluid friction Transactions of the American Institute of Chemical Engineers 24 174-210 1933
4 Dittus F w and L M K Boelter Heat transfer 1n automobile radiators of the tubular type University of California Publications in Engineering 2443-461 1930
5 Gurushankariah M s Local shell-side heat transfer coefficients in the vicinity of baffles in tubular heat exchangers Masters thesis Corvallis Ore gon State Colle ge 1958 97 numb leaves
6 Knudsen James G and Donald L Katz Fluid dynamics and heat transfer New York McGraw-Hill 1958 576 p
7 Lee Kyu Sung Local shell-side heat transfer coeffishycients and pressure drop in a tubular heat exchanger with orifice baffles Masters thesis Corvallis Oregon State College 1959 118 numb leaves
8 McAdams William H Heat transmission 3d ed New York McGra ~-Hill 1954 532 p
9 Sullivan F W and 0 P Bergelin Heat transfer and fluid friction in a shell-andbulltube exchanger with a single baffle Chemica l Engineer ing Progress Symposium Series 52 ( 18) 85-94 1956
10 Wiegand J H Discussion on annular heat transfer coshyef f icients for turbulent flow Transactions of American Institut e of Chemical Eng i n eers 41147-153 1945
AP PENDIX
57
TABLE III
CALCULATED HEAT TRANSFER DATA
Baffle Hole Diameter Run No (inches)
1 - 59 1 364
60 - 102 1 216
103 - 138 1 316
139 - 206 1 516
207 - 212 No orifice
213 - 218 2nd - 1 516
TABLE III
CALCULATED HEAT TRANSFER DATA
Local Heat Transfer Coefficients Run
T0 bull Po s ition CFM hr h2 h3 h4 hs he ~ hav Nuav
1 c 1026 10 59 1476 16 09 1559 1510 1435 1203 1518 8511 2 1290 1369 1738 1878 18 05 1755 1689 1515 1773 9964 3 1416 1636 198 1 2068 1977 1924 1845 1715 1959 11030 4 1627 1991 2301 2382 2268 2194 20 ~98 1929 2249 12664 5 1776 2252 2669 2863 2713 2517 2338 2126 2620 14759 6 l2ttD 1109 2311 3317 3386 3373 3387 3394 3071 3371 18888 7 1258 3089 4583 4866 4683 4701 4643 4194 4695 26301 8 1433 38 8 5 55 83 5791 5495 5430 5436 5008 5547 31192 9 1681 4992 7378 7649 6980 6864 6870 64 28 7148 40180
10 1 D 1102 2371 3332 3511 3356 3342 3427 3102 3394 19012 11 1308 3218 4379 45 24 42 53 4255 4373 3965 43 57 24446 12 14 64 38 58 5146 5142 4839 4787 4903 4597 4963 278 79 13 1706 5218 6664 6269 58 81 5884 6237 5973 61 87 34718 14 15
1 l2D 1115 1275
2131 2661
2955 3638
2972 3720
2941 3675
2913 3576
28 22 34 74
2613 3278
2921 36 17
163 09 20246
16 1498 34 87 4644 4503 4441 4371 4343 4194 4460 25010 17 1695 4449 5743 5324 5222 5154 5157 5015 5320 298 97 18 2D 1049 1715 23 90 2550 2610 2656 2624 2208 2566 14363 19 1241 2117 2964 3145 3218 3221 3203 2759 3150 17757 20 1532 28 67 3936 4100 4188 4201 4167 3676 4118 23224 21 1674 3459 4508 4598 4746 4795 4792 4299 4688 26337 22 lU 1074 253 340 380 3 86 388 377 354 374 2097 23 1287 292 392 433 440 441 429 406 427 2394 24 1508 322 439 492 498 499 487 461 48 3 2713 25 18 07 3 38 464 519 5 24 520 499 463 5 05 28 40
~~ (]I agt
TABLE III Continued
Run No Position CFM h 1 h2 ~3 h4 h5 h6 ~ h
av Nu
av 26 c 1029 1171 1491 1589 15 28 1 4 62 1377 1293 1489 83 44 27 1266 1395 1746 1853 18 02 1685 1556 1453 1728 9704 28 1430 1637 2037 2175 2060 1909 1735 1591 1983 11159 29 1729 1982 24 96 2751 2507 2268 2030 1886 2410 13579 30 12D 1054 2934 4041 4321 4326 4423 4359 3706 4298 24160 31 1294 3385 4 8 26 52 42 5326 5450 5277 4566 52 24 293 50 32 1431 3784 5347 5721 57 bull75 58 44 5700 5084 5677 31870 33 1770 52 75 7 7 33 87 35 9005 9007 8267 7059 85 49 48050 34 lD 1058 3235 4401 4444 3877 3496 3451 3294 3934 21973 35 1263 38 98 5484 5330 4347 3964 3981 3987 4621 25823 36 18 36 6701 89 17 7855 6369 5597 5769 6283 69 01 38718 37 1 12D 1029 2404 31 8 2 3333 3459 3624 3577 3045 3435 19264 38 1315 3182 4033 4162 4310 4496 4502 4015 4301 24142 39 1426 3628 4389 4510 4573 4760 4804 43 8 5 4607 25678 40 1757 4547 5559 5(35 5931 6282 63 70 6060 5975 33471 41 2 11D 1080 2034 28 38 3155 3144 3145 2966 2540 3050 17027 42 1305 2650 3 4 87 3aoz 3595 3751 3595 3153 36 46 20405 43 1434 3167 39 07 4156 4371 4320 4126 3709 4176 23395 44 1804 4096 4 9 66 5691 5714 5586 53 15 48 65 5454 30582 45 12U 1088 409 516 557 564 5 60 535 513 5 46 30 67 46 1318 470 579 6 22 631 6 17 5 97 579 6 09 3422 47 14 13 540 640 676 6 86 681 6 60 6 54 6 69 3754 48 1773 641 740 774 782 7 69 749 746 763 42 87 49 l 11 U 1054 270 356 391 397 393 3 71 346 38 2 2133 50 1240 303 399 446 449 447 4 21 398 432 2420 51 1419 361 476 522 530 528 507 467 493 2760 52 1 1(2U 1032 236 311 342 347 344 325 301 334 18 78 53 1314 270 366 403 407 408 386 351 394 2217
(Tt tO
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ h av Nu av
54 1448 301 408 447 454 452 431 403 438 24 61 55 1782 353 494 548 544 415 529 531 506 2843 56 2U 10 61 220 287 316 320 322 303 268 310 1735 57 1216 249 335 370 377 378 353 307 363 2044 58 1322 263 356 394 398 399 374 327 384 2159 59 1639 310 433 478 481 482 452 393 465 2617
60 1D 10 68 2011 2536 2657 2681 2694 2560 15 62 2625 14938 61 1399 2520 3239 3369 3371 33r82 32 39 1946 3320 18968 62 1669 2781 3655 3820 38 76 3883 3738 2355 3794 21712 63 1959 3524 42 37 4399 4438 4497 4417 3047 4397 25156 64 2295 4426 5288 5396 5372 5240 5410 3369 5341 30680 65 2636 5490 6531 6662 6565 6379 6820 4249 6591 37938 66 3390 7869 9538 9462 9387 8924 10508 62 91 9564 59601 67 1U 1190 352 368 401 413 407 395 293 397 2256 68 1559 397 422 462 475 471 456 331 4 57 2603 69 1904 434 465 5 13 529 528 504 358 508 2901 70 2211 493 526 573 5 92 588 564 4 15 569 3257 71 2289 569 587 6 30 649 6 61 6 49 460 635 36 44 72 2727 637 6 60 7 09 733 751 743 521 719 4140 73 3210 728 755 8 15 8 43 8 62 8 54 616 826 4765 74 2nD 1210 181 2256 2393 2399 2333 2206 1325 2317 13158 75 1420 2340 2752 2899 2913 2850 2728 1701 2828 16121 76 1692 2853 3306 3452 3471 3379 3217 2134 3365 19217 77 1894 3102 3588 3713 3736 3670 3557 2455 3653 20892 78 2301 3682 4259 4433 4467 43 83 4289 2892 4366 250 30 79 2621 4117 4828 5017 5012 5030 5109 3071 4999 28785
m 0
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ hav Nuav
80 3230 5158 6006 62 13 61 18 6134 6695 4094 6233 359 87 8 1 12nD 1155 15 27 1854 2028 2064 20 85 1987 1164 1968 118 31 82 1689 2046 24 8 2 2688 2739 2760 2658 1749 2665 152 73 83 1244 2088 2317 2339 2345 2373 2381 1487 2351 13432 84 2100 3211 3539 34 21 3462 3512 3696 2575 3526 20284 85 2292 3 5 05 3761 3648 36 25 36 79 3957 2933 3734 21517 86 2907 4420 48 22 4679 46 04 4705 5206 3792 48 03 27741 87 33 80 59 35 69 38 7404 77 10 7 8 36 7 0 86 5190 7394 427 44 88 1 12D 1 4 27 2 4 58 28 31 3037 3021 2987 2927 18 57 2 9 61 16913 89 18 75 34 75 3 9 87 4230 4255 4317 4337 2734 4225 24258 90 22 59 4221 4796 5046 5052 51 01 5389 3491 5077 29206 91 2682 4978 5664 5943 5966 6054 6573 408 1 60 40 34795 92 3417 63 16 71 02 7 3 93 7385 75 40 8 6 95 51 45 7623 44017 93 c 1 5 17 1240 1305 1399 1467 1479 1429 9 26 1423 8251 94 20 34 1554 1623 1720 18 21 18 53 18 72 1215 1778 10229 95 2 3 48 1795 1843 198 5 2097 2171 2274 1540 2074 11947 96 2716 2028 2048 22 01 2 3 44 2444 2661 18 90 2340 13505 97 3247 2410 2375 2663 2778 2949 3298 2378 2793 1615 98 11 35 967 1040 1124 1186 1200 1142 728 1138 6496 99 14 06 1135 1220 1318 1384 1403 1 3 61 8 77 1336 7656
100 2311 1 8 54 18 78 1980 20 90 2136 2227 1653 2062 118 31 10 1 2666 2085 2094 2227 2 3 62 2438 2626 1902 2349 13508 102 3392 2635 2582 28 01 3026 3141 3529 2567 3016 17390
103 1 U 1235 349 395 434 436 4 28 411 286 423 2416 104 20 10 434 5 02 559 577 569 5 37 345 552 3177 105 28 14 538 626 685 711 7 21 682 424 6 8 6 3966
Q) j-J
TABIE III Continued
Run No Position CFM h1 h2 h3 h4 h5 hu h7 hav Nuav
106 3492 614 7 1 6 7 84 8 13 8 33 7 85 4 88 7 87 4562 107 4395 7 86 894 964 996 1005 9 64 640 9 65 56 06 108 50 75 9 11 10 22 1081 1112 1125 1085 7 24 1085 63 16 109 G 1344 9 22 1042 1120 1 1 46 1173 1131 7 04 1120 63 87 110 1936 1162 1340 1442 1474 1509 14 7 3 9 09 1441 82 77 111 2846 1631 1797 1902 1966 2027 2079 1342 19 2 3 11108 112 3484 207e 2144 2236 2307 2385 2574 1694 2268 13138 113 4066 24 65 24 42 2535 2648 2757 31 71 2178 2 5 96 15078 114 50 12 3059 2916 30 1 5 3176 3312 4059 2849 3105 180 46 115 1D 1362 2268 26 13 2613 26 35 2605 2503 15 46 2617 14934 116 1958 2993 3580 3580 3586 3539 3 5 02 2144 3571 20492 117 2812 4430 50 32 4913 4 9 86 4991 5196 3088 4981 287 66 118 3432 58 16 62 13 6067 61 18 60 66 6698 4143 61 16 354 16 119 40 22 71 71 7 4 62 7369 7419 7329 82 74 51 8 1 7395 42909 120 5026 105 95 11456 115 81 11574 11548 14010 80 91 11540 671 15 121 2D 1244 18 57 2277 2363 2305 2210 2107 1466 2289 13038 122 1960 2622 3240 3388 33 23 3226 31 40 2)99 3294 18919 123 2817 3762 45 87 4739 46 56 45 14 4 6 47 30 15 4624 26689 124 3491 50 22 5723 58 53 57 44 5542 60 18 3871 57 16 330 73 125 4096 61 29 68 16 69 79 6805 65 90 74 79 4677 67 98 39400 126 5037 82 27 94 60 95 69 93 57 9023 11324 65 05 93 52 542 83 127 12D 1278 14 70 1 6 48 1652 1638 1 6 34 1641 9 73 1 6 43 9369 128 1947 19 63 2155 2149 2151 2131 2190 1347 2147 12342 129 2769 2615 2791 2773 28 52 2716 2954 18 96 2783 1 60 82 130 3439 3208 3265 3239 3593 3133 3624 2515 3308 19174 131 4103 3637 35 88 3577 4077 3459 42 66 3138 3676 21343 132 49 78 45 82 44 60 44 8 1 55 17 43 25 5749 4227 4700 27288
Q) tlgt
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
133 1 12D 1299 2094 2507 2622 2625 2567 2489 1465 2578 14736 134 1973 29 56 3505 3772 3790 3718 3718 2115 3700 21290 135 2788 3941 4727 5069 5099 5 0 07 5231 2984 4976 28781 136 3473 5155 59 81 6308 6339 62 39 68 96 4204 6217 36052 137 4118 6135 71 8 6 7662 7731 76 91 87 16 49 8 5 7568 43985 138 4973 7765 94 75 10396 10861 10694 13646 66 64 10357 602 25
139 1ttn 1253 1242 1493 1460 1442 1431 1424 8 84 1457 83 01 140 2366 1942 2150 1961 1910 1897 19 62 1206 1980 11400 141 3461 3007 2957 2562 2513 2606 3143 18 51 2660 15400 142 4325 3942 3571 3060 2999 3198 4248 2631 3207 18618 143 5677 508 6 4359 39 88 3800 42 29 57 78 36 26 4094 23824 144 67 59 64 55 5330 4988 47 25 5494 2517 48 09 5134 29906 145 84 08 9326 72 26 7726 85 56 9172 12319 7733 8170 47626 146 86 54 9831 7582 818 9 94 90 9869 13116 78 97 8783 512 96 147 7376 7335 58 7 6 5941 5796 68 29 81 65 5954 6111 35662 148 2 11 D 4254 4106 48 02 4994 5038 5042 56 78 3419 4969 28881 149 5708 5487 6253 6466 6524 6527 78 63 45 8 2 64 43 37566 150 69 7 8 7983 9440 9848 98 34 97 32 13249 6701 9714 566 59 151 1254 1434 18 53 1947 1915 1850 1760 1186 1891 10772 152 2713 2696 3175 32 94 3288 3237 3288 20 44 3249 18728 153 87 30 118 07 14733 15758 15504 15305 26297 9617 15325 892 71 154 5811 5278 6543 6861 69 30 69 82 7 8 74 4478 68 29 39531 155 4246 3780 4736 4975 49 66 4936 5162 3113 4903 28301 156 (v 1270 8 15 935 959 966 9 51 9 23 6 35 953 5430 157 2714 1164 1390 1427 1447 1454 1455 9 08 1430 8242 158 4310 1655 18 96 1942 1988 2002 2111 1305 1957 11349
(j) ~
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 fry hav Nuav
159 6012 2208 2400 2450 2513 2548 28 20 18 00 2478 14416 160 7279 2696 2881 2927 2989 3081 3599 2340 2970 17326 161 86 90 3257 3360 3 3 76 34 26 3558 4455 2943 3430 2000 162 12D 4368 2209 2600 2558 2518 2466 2774 1753 2536 14713 163 5833 2730 3092 3028 2974 2913 3501 2287 3002 174 78 164 7643 3320 3681 3630 3651 3530 4623 3181 3623 21116 165 87 39 3920 4303 4300 4708 4178 61 60 3937 4372 25456 166 1268 962 1203 1205 1186 1118 1084 725 1178 6693 167 2678 14 67 1785 1779 1752 1698 1726 10 70 1754 88 49 168 1 12D 12 83 936 1217 1414 1397 1239 1190 7 65 1317 7484 169 2729 2502 2930 2914 2934 2956 2979 17 52 2934 16866 170 4345 3884 4357 4283 4318 4421 4836 28 59 4345 25151 171 6036 5546 5858 5764 5791 6028 7129 4184 5860 34045 172 6578 7167 7769 7907 79 82 8263 10492 5915 7980 46437 173 87 84 10237 112 23 120 26 12727 12968 185 19 85 98 12236 71103 174 1278 1344 1803 18 72 1835 1790 1712 1063 1825 10355 175 2711 2328 2972 2932 2893 28 78 2863 1667 2919 167 51 176 4351 3934 4414 4353 4281 4321 4654 28 63 4342 25088 177 5994 5076 5824 5838 5818 59 29 6914 4205 5852 33885 178 1 11 U 1223 388 432 465 464 449 435 338 453 2585 179 2351 521 602 6 22 675 6 57 619 436 639 3687 180 34 48 6 05 1725 803 8 27 8 11 760 518 792 4593 181 4513 718 850 934 9 68 9 57 8 99 609 9 27 5386 18 2 5714 8 32 981 1060 1102 11 06 1034 6 59 1062 61 82 183 6997 1025 1182 1258 1295 1309 1234 8 18 1261 7 3 44 184 8709 1295 1487 1 5 42 1594 1626 1612 1156 1562 9080
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
185 2 12D 4249 3560 4400 4670 4791 4695 47 81 2931 4639 268 37 186 5737 4926 58 54 61 92 6248 62 38 67 78 4134 6131 35590 187 7432 6390 7726 83 46 85 44 86 34 10371 5658 8313 48310 188 8723 7718 107 88 11933 12099 13046 186 22 79 39 119 67 69505 189 1 4 35 1340 1735 18 57 18 52 17 81 1711 1144 18 06 10256 190 2718 2399 3023 3187 3207 3138 30 53 1931 3139 18025 191 7 5 07 6189 80 11 9200 9427 9703 11364 5720 9085 527 38 192 8544 78 42 10666 125 42 13312 13775 178 20 6976 125 74 729 86 193 1287 1417 16 97 18 7 18 69 18 08 1720 1046 1800 10223 194 27 17 2450 2940 3187 3214 3157 3054 1749 3125 17954 195 42 53 3560 4222 45 90 4679 46 63 4743 2741 4539 26247 196 6068 48 69 57 79 6335 65 8 6 66 04 7172 4338 63 26 366 78 197 7389 58 86 72 8 6 82 23 8584 8936 10658 50 60 8257 4798 6 198 86 88 78 91 100 27 120 56 130 29 14299 190 81 6492 12353 71850 199 5864 4694 5 6 67 61 94 6419 65 48 7192 3950 6207 360 14 200 2 D 4177 38 36 4547 48 09 4775 4628 5006 2715 46 90 261 30 201 5712 5170 62 39 66 38 6599 6604 7518 4167 65 20 378 00 202 73 63 7201 8986 98 43 9733 9914 13353 6219 9619 55810 203 8604 10043 13118 148 41 150 42 158 66 25206 82 5 3 14717 85290 204 12 68 1506 18 41 1971 1966 1868 1799 11 42 1913 10880 205 2659 2571 3127 3276 32 50 3130 3069 18 80 3196 18 350 206 39 80 36 76 4347 4573 45~67 4473 46 34 28 37 4490 25910
o 207 Orifice 11496 10 64 1360 15 39 1 5 80 1 6 15 1496 8 58 15 24 88 83 208 9433 8 95 11 78 13 26 1394 1386 1263 727 1346 78 48 209 7387 746 9 77 1123 1184 1159 1048 6 11 1111 64 74 210 52 36 566 7 66 900 934 909 8 21 499 8 27 48 02
0) CJ1
TABLE III Continued
Run No Position CFM h 1 h2 hs h4 h5 h6 h7 hav Nuav
211 212
3309 1293
414 257
563 3 19
6 68 3 57
6 91 3 37
6 72 351
7 37 337
38 4 2 46
4 40 341
3748 1942
213 214 215 216 217 218
c of 2nd 1 516 1235
1919 2712 3320 4153 4704
1532 2447 35 46 4312 5567 74 29
2 1 87 3312 4225 52 86 6902 8 6 50
2360 3555 4340 56 12 7 0 49 8 9 40
2409 3598 4 8 85 5718 7713 9593
2347 2101 35 33 3453 48 00 49 62 5562 59 86 72~6 7 8 79 93 76 11237
1243 20 64 3054 4 2 8 1 5114 6983
2326 35 00 4638 5545 7225 91 40
132 13 200 27 26672 31968 41711 52811
bull
67
TABLE IV
PRESSURE PROFILE DATA
Baffle Flow Qpening Rate ~p
(Inches) Position (CFM) (Inches 295 S G Fluid)
1 364 l2 11 U 1012 0 254 1248 0197 1493 0 141 1718 0112
c 1000 9 80 1210 1710 1436 28 75 1746 4320 1011 1080 1277 2050 1393 3020 1 6 28 4450
12D 1011 9 75 1236 1520 1450 2510 1603 3450
1 D 1011 975 1256 1700 1480 2690 158 1 4070
1 12D 1010 950 1259 1750 1462 2650 1631 3710
2 11 D 1124 1315 1360 2130 1505 2850 1689 4125
1 216 12U 1294 045 1949 0324 2374 0282 2704 0225 3367 0169
c 1326 265 18 81 5 90 2313 990 2731 1480 3439 2660
12D 1272 2 49 1957 661
68
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Pos ition (CPM) Inches 2 95 S G Fluid)
2559 1275 3033 1940 3639 3025
1 216 1nD 1257 242 16 96 476 2117 8 05 2561 1280 2990 1895 3431 26 bull00
1 316 12U 1309 0 479 2004 0422 28 28 0 352 3526 0281 42 28 0225 5199 0225
c 1308 1 43 1998 272 28 14 5 10 3478 795 4248 1235 5048 1885
l2D 1286 140 2005 3 45 2831 725 3495 1180 4194 1805 5046 2945
1 11D 1322 150 2039 352 2841 735 43 77 1980 5378 3440
1 516 12U 1278 0493 2732 0493 4315 0408 5744 0352 7494 0352 8932 0422
c 1300 0 506 2731 1985 4310 348 6080 6 45
69
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Position (CPM) (Inches 295 SG Fluid)
7607 1090 8830 1585
l2D 1343 0549 2738 225 4566 583 6112 1195 7536 2055 9043 3415
1 516 1uD 1249 0464 2713 224 4155 579 5620 1150 7428 2115 90 70 3405
1 12D 1301 0493 2735 220 4501 616 61 50 1235 7440 2065 8862 3445
2D 1265 0 478 2750 226 4366 594 6578 1270 7678 2240 8945 5280
2 12D 1295 0493 2725 222 4293 600 5807 1120 7568 2200 9070 3615
TABLE V
RATE OF HEAT TR AN SFER Ar THE BAFFL~~ CID-TT ER
Orifice Size
(Inches)
Flow Rate
( CFM)
Re d e G tU
R~) 055 Nuav NuPr-l3
1 364 10 26 12 90
8 075 10015
43400 54 600
85 11 99 64
95 83 112 19
1416 11 140 59 900 110 30 124 20 16 27 12 800 68 900 126 64 142 60 17 29 13 610 73 200 135 79 152 90 17 76 13980 75 200 147 59 166 19
1 216 11 35 14 06
8 600 10 660
27000 33500
6 4 96 76 56
73 14 8 6 12
1517 11500 36100 82 51 9291 20 34 15400 48400 10229 115 18 23 11 17500 55000 118 31 13322 2348 17 800 55900 11947 13452 2666 20 200 63400 13508 15210 27 16 20 600 64700 135 05 152 07 32 47 24600 77200 161 57 18 193 3392 25 700 80700 17390 195 8 1
1 316 1344 19 36
9898 14 260
24800 35 700
63 8 7 8 2 77
71 92 93 20
28 46 20 9 60 52 500 111 08 125 08 34 84 25 660 64200 131 38 147 93 40 66 50 12
29900 36900
74800 92400
150 78 18046
169 78 203 20
~ 0
TABLE V Continued
Orifice Flow Re Size Rate d e G R~rmiddot55 NuPr-13(Inches) (CFM) U Nuav
1 516 12 70 8 847 16800 54 ~0 61 14 2 14 18 900 35800 82 42 92 80 43 10 30 000 56900 11349 127 79 60 12 41900 79400 14416 16232 7279 50700 96100 17326 19509 86 90 60540 115000 20098 22529
TABLE VI
RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
Orifice Size
(Inches)
1 364
1 216
1 316
Flow Rate
(CFM)
1054 1294 1431 1681 1770
1068 1399 1669 1959 2295 2636 3390
1299 1973 2788 34 73 4118 4973
Re deG Mshy
8 300 9870
11260 13200 13 930
8100 10600 12650 14850 17400 19980 25700
9 570 14500 20500 25600 30300 36600
R~r-6 51900 61700 70500 82 500 87 100
28200 36900 44000 51700 60 600 69500 89400
26100 39600 56000 69900 82700 99 900
Nuav
2416 293 5 3187 4018 4805
14938 18968 21712 25156 30680 37938 59601
14736 21290 28781 36052 439 85 60225
Uu Pr-1 3
27204 33050 3589 4524 541 0
16820 21358 24448 28326 34546 427 18 67111
16593 23973 32407 40595 495 1 678 13
TABLE VI Continued
Orifice Flow Re Size Rate deG R~rmiddot6 NuPr-13(Inches) (CFM ) M- Nuav
1 516 1268 88 30 17700 108 8 1225 2689 18700 37400 1835 2066 3980 27700 55700 2591 2917 4177 29100 58 500 2713 3055 5712 39800 80000 378 0 425 6 7362 51300 103000 5581 6284 8 604 59 900 120000 8529 9604
74
TABLE VII
EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER
l 516 Inch Orifice
Center ot 2nd Baffle 4 Downstream
Plow Rate (CFM)
1235 1919 2712 3320 4153 4704
Flow Rate (CFM)
1270 2714 4310 6012 7279 8690
(Re)eb -8600 1321
13400 2003 18900 2687 23100 5197 28900 4171 32800 5281
Center ot Single Battle
-8847 543
18900 824 30000 1135 41900 1442 50700 1733 60540 2001
(Nu)(Pr)-l3
1487 2255 3003 3600 4697 5946
(Nu)(Pr)-13
611 928
1278 1623 1951 2253
75
ABLE VIII
HEAT TRANSFER IN THE TEST SECTION WITHOUT ORIFICE
CFM Ute) 0b h Nu
1293 5-951 3 41 1942
33 09 15251 649 3746
5236 24193 827 4802
7387 34001 1111 6474
9433 43419 1346 7848
11496 52-914 1524 8883
76
TABLE IX
PRESSURE DROP FUNCTION
Orltlee Size Flow Rate incbea ~CFM (Re)eb X 10bull8
1 364 1011 7957 0808 1256 9885 1468 1480 11648 2765 1581 12443 4160 1689 1_3293 4 020
1 216 1257 9530 1327 1696 12858 2663 2117 16049 4615 2561 19415 7581 2990 22668 11560 3431 26011 16440
l 316 1322 9736 1819 2039 15016 4332 2845 20952 9275 3495 25739 15300 4377 32014 26800 5378 39607 50100
1 516 1011 7 957 oaos 1256 9885 1469 1480 11646 2765 1581 12443 4160 1689 13293 4020
77
TABLE X
EXPERIMENTAL DATA
Baffle Hole Diameter Run No
1 - 59
60 - 102
103 - 138
139 - 206
207 - 212
213 - 218
(Inches)
1 364
1 216
1 316
1 516
No Baffle
2nd - 1 516
TABLE X
EXPERIMENTAL DATA
Run Thermocouple Reading s (mv) No Position CFM I tc1 tc2 tc3 tc4 t c 5 tc6 tc7 tcair
1 c 1026 530 2055 1825 1768 1782 1802 1837 1965 1198 2 1290 612 2059 18 65 1809 18 32 1851 1880 1965 1160 3 1416 714 2151 1970 1931 1965 1988 2026 209 5 1130 4 1627 8 21 2235 2084 2 049 2093 2126 2173 2266 1130 5 1776 865 2203 2033 1970 2015 2084 2159 2 264 1121 6 12D 1109 542 1636 1507 1499 1499 1498 1498 1528 1218 7 1258 651 1670 1522 1503 1513 1513 1516 1548 1221 8 1433 750 1625 1480 1467 148 3 1487 1487 1516 1153 9 168 1 8 73 1656 1494 148 1 1511 1517 1517 1543 1159
10 1rtD 1102 485 1545 1450 1437 1446 1447 1442 1466 1220 11 13 08 6 10 1571 1470 1460 1476 1476 1469 1498 1194 12 1464 730 1 623 1509 1508 1528 1 5 32 1524 1548 1173 13 11 06 8 71 1663 1559 158 1 1606 160 6 1 583 1601 1190 14 1 12D 1115 520 1698 1579 1575 1 577 1580 1590 1615 1280 15 1275 6 10 1692 1567 1558 1 561 1570 1580 1601 1234 16 1498 770 1760 1619 1630 1 635 1642 1645 1661 1204 17 1695 912 1775 1635 1670 1689 1686 168 6 1701 1165 18 2D 1049 510 1736 15~2 1567 1558 1 553 1558 1620 1236 19 12 41 610 1655 1517 149 1 148 1 148 1 148 4 1546 1108 20 1 5 32 7 35 1720 1550 1530 1520 1519 1523 158 0 1104 21 16 74 8 8 0 1900 1 727 1714 1696 1691 1692 1753 1169 22 1U 1074 38 5 3 324 2740 2534 2478 2 465 2503 258 0 1210 23 1287 4 35 3510 2 870 2682 2 610 2599 2638 27 1 9 1190 24 1 5 08 470 3 618 2920 2690 2 637 2627 2 664 2747 1177 25 18 07 525 4 088 3235 2962 2905 2910 2988 3130 1169
z ())
TABLE X Continued
Run No Position CFM I tc1 tc 2
Thermocouple Readings te3 tc4 tc5
(mv) tc6 tc7 tcair
26 c 10~29 6 32 2340 2~092 2032 2060 2~097 2152 2~213 1211 27 12 66 679 2270 2 047 1993 2013 2069 2142 2 210 1 182 28 1430 723 2336 2097 2033 2080 2153 2~255 2 356 1 138 29 1729 8 52 2318 2070 1980 2061 2158 2279 2367 1121 30 12D 1054 570 1520 1 4 20 1402 1400 1396 1400 1 443 1159 31 1294 6 69 1599 1469 1444 1439 1433 1 442 1485 1168 32 1430 7 88 1720 1562 1536 1532 1528 1537 158 0 118 5 33 1770 8 81 1641 1488 1450 1~441 1 441 1_466 1518 1 163 34 1D 1058 548 1579 1498 1495 1526 1553 1_557 1 571 1 276 35 1263 640 1609 1509 1515 1570 1599 1598 1 598 1 266 36 18 36 8 47 1538 1452 1483 1553 1602 1 590 1 558 1195 37 1 12D 1029 5 41 1 578 1499 148 4 1473 1461 1465 1-512 1200 38 1315 6 30 159 1 1504 1493 1482 1470 1470 1505 118 5 39 1 4 26 743 1765 168 1666 1660 1645 1642 1678 1270 40 1757 8 54 1744 1648 1634 1620 1598 1 593 - 1612 1223 41 2D 1080 5 30 1734 1604 1570 1 570 1570 1 588 1 640 128 1 42 1305 6 40 1744 1622 1589 1 608 1593 1 609 1 661 1240 43 1434 750 1798 1687 1658 1 636 -1641 1 661 1 711 1_220 44 18 04 8 41 1 764 1666 1607 1605 1614 1 635 1 675 1205 45 12nu 1088 415 2614 2295 2195 2 169 2174 2217 2256 1171 46 1318 477 2805 2477 2371 2342 2364 2 401 2 438 1 163 47 1413 5 28 2930 2 646 2 555 2 526 2532 2570 2 577 1 199 48 1773 550 2740 2518 2450 2431 2448 2 479 2 480 1 170 49 1 11 U 1054 380 3175 2670 2505 2 461 2467 2 534 2 621 1 258 50 1240 420 3268 2738 2 546 2 510 2 508 258 2 2 649 1214 51 1419 451 3364 2B07 2 632 2590 2 590 2 651 2773 1 215 52 1 12U 1032 360 3 165 2 629 2 450 2402 2403 2 473 2 bull568 1 163
--I lt0
TABLE X Continued
Run No Position CFM I tc1 tc2
lhermocoup1e Reading s tc3 tc4 t c 5
(mv) tc6 tc7 tc a ir
5 3 1314 38 9 3178 2592 2411 2367 2361 2432 2555 1140 54 1448 403 3095 2544 238 1 2336 2336 2390 2476 1158 55 178 2 427 3006 2434 2286 2253 255 3 2299 2397 1154 56 2 11U 1061 360 3369 2814 2619 2567 2560 2650 2833 1220 57 1216 360 3044 2512 2338 2290 2288 2374 2566 1150 58 1322 387 3196 2614 2425 2383 2382 2472 2670 1138 59 1639 403 3020 2438 2272 2238 2238 2318 2502 1127
60 1D 1068 612 1552 1424 1400 1395 1396 1426 1745 0945 61 1399 612 1355 1246 1230 1229 1230 1250 1509 0872 62 1669 710 1436 1293 1272 1265 1266 1286 1551 0847 63 1959 900 159 5 1468 1444 14 38 1432 1446 1720 0851 64 2295 730 1169 1105 1098 1099 1108 1100 1298 0781 65 2636 8 80 1202 1129 1121 1126 1 138 1115 1342 0748 66 3390 9 35 1060 o 9s7 0999 1001 1017 0971 1154 0703 67 1nu 1190 370 2225 2188 2104 2080 2120 2209 2 7 15 0990 68 1559 368 2005 1950 1871 18 48 1876 1951 2408 0916 69 1904 368 1870 18 1 4 17 34 1711 1730 18 07 2238 0875 70 22 bull11 471 228 6 2 204 2099 2063 2092 218 $ 2732 0840 71 2289 471 2030 2000 1925 1895 18 96 19 5 2498 0785 72 2727 4 71 1854 18 23 1753 17 23 1716 3758 2241 0743 73 3210 471 1680 1651 158 6 1559 1551 158 1 1950 omiddot7o9 74 2uD 1210 404 1261 1212 1198 1197 1205 1222 139 1 0978 75 14 20 540 1321 1260 1242 1 240 1249 1268 148 7 0918 76 1692 7 18 1467 138 6 1364 1361 1376 1405 1678 0883 77 18 94 903 1708 1 591 1565 1560 1575 1603 1948 0 857 78 2301 903 1530 1432 1407 1402 1415 1432 1738 0815
ro 0
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc117 tcair
79 2621 6 50 1069 1 020 1009 1009 1009 1007 1~189 o739 80 3230 901 1200 1128 1113 1119 1119 1086 1341 0694 81 82
l2D 1155 1689
360 575
1191 1345
1142 1252
1122 1218
1118 1210
1118 1209
1132 1228
1292 1446
0916 0822
83 1244 430 1163 1134 1131 1130 1129 1132 1292 0877 84 2100 645 1175 1135 1147 1 142 1138 1122 1286 0757 85 2292 8 25 1 354 1310 1327 1330 1323 1285 148 6 0728 86 2907 8 23 1180 1138 1151 1158 1149 1107 1268 0687 87 3380 902 1113 1049 1025 1011 1006 1042 1178 0673 88 89
1 12D 1427 1875
480 615
118 2 1140
1140 1095
1124 1077
1125 1075
1129 1072
1137 1072
1290 1243
0880 0790
90 2259 8 41 1296 1231 1207 1206 1203 1182 1419 0757 91 2682 8 80 1231 1170 1149 1147 1142 1112 1350 0731 92 3417 940 1142 1092 1076 1076 1069 1021 1252 0693 93 c 15 17 431 1321 1298 1268 1249 1250 1273 1522 0841 94 2034 505 1285 1263 1235 1209 1205 1206 1464 0759 95 2348 6 10 1395 1379 1334 1302 1286 1268 1536 0732 96 2716 706 1486 1480 1427 1383 1358 1311 1572 0 700 97 3247 7 56 1417 1430 1375 1320 1284 1223 1450 0660 98 1135 400 1425 1388 1352 1329 1330 1 364 1651 0893 99 14 06 440 1379 1341 1304 128 2 1281 1305 1583 0 831
100 2311 680 1602 1593 1553 1514 1502 1480 1 7 27 0 802 101 2666 680 1471 1469 1428 1390 1372 1335 1564 0761 102 3392 798 1491 1 509 1449 1395 1372 1305 1534 0 719
103 1U 1235 410 2469 2295 2173 2165 2226 2361 3120 0 897 104 2010 410 2017 1848 1 737 1706 1747 1865 2582 0753 105 28 14 410 1682 1535 1457 1427 1437 1520 2109 0 660
00 t-
TABLE X Continued
Ru n Thermocouple Rea ding s (mv No Positi on CFM I tc1 tc2 tc3 tc4 tc5 tc6 tc7 tcair
106 3492 440 1649 1499 1420 1391 1390 1470 2042 0620 107 4395 550 18 33 1679 1597 1564 1570 1640 2223 0583 108 5075 588 1779 1642 1580 1550 1552 1 615 2 191 0548 109 c 1344 398 1464 1 399 1364 1353 1350 1380 1689 0 907 110 1936 459 1369 1290 1253 1242 1 237 1259 1574 078 2 111 2846 580 1347 128 5 1251 1232 1220 1215 1 5 23 0 683 112 34 8 4 700 1392 1369 1339 1317 1299 1259 1599 0 636 113 4066 8 13 1449 1458 1427 1391 1363 1270 1595 0 591 114 5012 930 1484 1530 1500 1453 1420 1272 1580 0 580 115 1D 1362 513 1269 1218 1 217 1214 1220 1238 1460 0 893 116 19 58 600 1187 1122 1121 1120 1124 1133 1352 0798 117 2812 705 1052 1008 1015 1010 1011 1001 1218 0691 118 34 32 913 1105 1075 1085 1081 1086 1047 1301 0645 119 4022 980 1038 1021 1026 1023 1029 0983 1211 0 609 120 5026 982 0 8 61 0839 0836 0836 0837 0791 0955 0570 121 2D 1244 475 1320 1246 1233 1240 1255 1275 1434 0925 122 1 9 60 5 50 1160 1088 1074 1079 1089 1100 1260 078 7 123 2817 6 80 1096 1024 1 013 1018 1029 1022 1201 0 700 124 3491 960 1248 1175 1163 1172 1192 1153 1435 0 658 125 4096 989 1141 1089 1078 108 9 1105 1051 1310 0629 126 50 37 989 0983 0933 0929 0 936 0949 0880 1090 0 602 127 128
12D 1278 1947
402 545
1270 1261
1 230 1216
1228 1216
1230 1 215
1235 1223
1242 1219
1483 1514
0 913 0778shy
129 2769 695 1273 1234 1237 1221 1251 1212 1525 0678 130 131 132
34 39 4103 4978
8 40 9 80 9 80
1336 1448 1271
1322 1458 1 288
1328 1 462 1286
1 259 1 356 1157
1353 1492 1311
1261 1329 1138
1 555 160 7 1343
0 629 0 600 0599
(l) l)
TABLE X Continued
Run No Position CFM I tel tc 2
Thermocouple Readings tc3 tc4 tc5
( mv) tc6 tc7 tcair
133 1 l2D 1299 5 16 1 28 1 1212 1196 1195 1205 1221 1478 0869 134 1973 6 15 1163 1098 1073 1071 1079 1083 1343 0751 135 136
27 88 34 73
802 9 -_78
1187 1214
1099 1131
1069 1104
1066 1101
1075 1~110
1l061 1066
1370 1360
0662 0618
137 4118 9 81 1084 1010 0983 0979 0982 o937 1209 0581 138 4973 98 1 0969 0897 0 868 0855 0860 0799 1041 0572
139 1D 1253 409 1371 1293 1298 1301 1309 1321 1578 0928 140 2366 480 1130 1 090 1 121 1130 1137 1132 1390 0744 141 34 61 6 38 1081 1086 1152 1161 1147 1069 1382 0644 142 143 144
4325 5677 6759
7 90 939 998
1110 1115 1034
1161 1208 1139
1253 1268 1180
1265 1302 1215
1228 1230 1123
1080 1056 0970
13$913r12 8
0601 0561 0542
145 84 08 989 0863 0961 0934 0895 0871 0 785 09 9 0530 146 86 54 9 80 0808 0901 0 872 0821 0809 0733 0891 0498 147 7376 9 80 0 927 1032 1027 1 040 0961 0889 1032 0511 148 2D 4254 776 1 050 0 981 0965 0961 0962 0922 1155 0579 149 5708 991 1102 1031 1014 1009 1010 0931 1227 0528 150 69 78 990 0914 0853 0839 0 839 0843 0759 0996 0521 151 1254 490 1 479 1352 1329 1334 1351 1379 1607 0930 152 2713 7 00 1310 1220 1201 1201 1211 1209 1516 0723 153 8730 991 0809 0756 0742 0745 0 748 0663 0874 0543 154 5811 966 1219 1108 108 6 1081 1079 1033 1330 0650 155 42 46 8 02 1248 1136 1114 1114 1118 1103 1376 0 699 156 c 1270 429 1671 1571 1551 1545 1563 1600 1933 0929 157 2714 488 1398 1285 1 267 1258 1262 1275 1628 0729 158 4310 642 1424 1318 1299 1282 1283 1261 1683 0617
co ~
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc7 tc a 1r
159 60 12 780 1461 1388 1370 1349 1343 1279 1700 0 573 160 72 79 8 60 1402 1344 1330 1312 1292 1189 1 566 0 520 161 8690 982 1472 1442 1437 1 422 1392 1224 1602 0 521 162 163
12D 4368 5833
6 30 8 30
1195 1368
1105 1270
1111 1283
1117 1294
1131 1313
1081 1194
1369 1553
0613 0 553
164 76 43 959 1428 1338 1348 1341 1371 1180 1488 0535 165 8739 984 1345 1272 1272 1208 129 3 1059 1361 0550 166 1268 459 1701 1548 1541 1547 1589 1 625 1976 0 973 167 2678 570 1485 1351 1349 1356 138 1 1 385 1795 0760 168 169
1 12D 128 3 2729
448 650
1664 1314
1501 1232
1425 1233
1428 1229
1491 1229
1527 1232
1869 1571
0 962 0767
170 4345 847 1245 1179 1187 1182 1172 1132 1476 0 650 171 6036 9 76 1139 1109 1117 1114 1095 1020 1332 0588 172 6578 9 72 0982 0949 0942 0938 0926 0 8 50 1079 0560 173 87 84 9 72 0880 0854 0 8 36 0822 0818 0 749 0941 0585 174 1278 480 1564 1416 1397 1403 1417 1445 1733 0998 175 2711 590 128 3 1175 4 1178 1182 1187 1195 1493 0796 176 4351 8 90 1331 1259 1266 1275 1272 1235 1592 0 682 177 5994 9 60 1228 1152 1150 1151 1143 1075 1 360 0644 178 lU 1223 408 2282 2140 2052 2052 2106 2188 2626 0 878 179 2351 408 178 1 1623 158 5 1519 1556 1634 2068 0717 180 3448 482 1888 1675 1570 1541 1572 1665 2199 0629 181 4513 563 2026 1797 168 4 1644 1670 1770 2385 0583 182 5714 589 1913 1700 1610 1568 1580 1 682 2382 0551 middot 183 6997 653 1903 1718 1643 1611 1612 1700 2326 0 549 184 8709 6 80 1738 158 3 1543 1510 1498 1519 1 912 0577 185 186
2 12D 4249 5737
660 9 74
1055 1221
0 979 1122
0960 1093
0 952 1088
0959 1090
0 956 1054
1147 1350
0661 0602
187 7432 9 8 1 1065 0981 0951 0942 0 939 0881 1135 0582 CD ~
TABLE X Continued
Run No Position CFM I t o1 to 2
188 87 23 9 83 0944 0 879 189 1435 585 18 26 1630 190 2718 690 1433 1298 191 7507 950 1070 0961 192 85 44 964 0982 0 881 193 1287 600 1806 1668 194 2717 7 80 1579 1444 195 4253 8 81 1371 1260 196 60 68 9 78 1252 1152 197 73 89 975 1100 1000 198 86 88 973 0953 0 871 199 58 64 9 81 1269 1155 200 2D 4 1 77 915 1362 1251 201 5712 975 1213 1111 202 7363 9 78 1036 0 951 203 8 604 973 0932 0861 204 1268 6 95 2015 18 20 205 2659 6 96 1405 1295 206 39 80 7 98 1261 1174
No 207 Orifice 114 96 509 1325 1148 208 94 33 509 1477 1243 209 7487 5 09 1686 1409 210 5236 505 2094 1691 211 3309 428 2188 1 778 212 1293 392 2976 2560
Thermo ooup1e Readin g s (mv) to 3 to4 to
5 to
6 to7 toair
0 851 0847 0 8 29 0759 0987 0592 158 4 1583 1611 1647 1993 0986 1270 1266 1 279 1298 1604 0 789 0916 0908 0900 0 858 1115 0602 08 39 0 823 0 818 0 770 1035 0602 1609 1602 1629 1676 2153 0979 139 1 1385 1400 1 430 1938 0776 1212 1201 1205 1201 1601 0669 1 105 1086 1086 1 052 1371 0621 0952 0936 0923 0870 1195 0582 0 8 20 0 801 078 1 0 729 1044 0569 1108 1090 108 2 1043 1407 0610 1218 1221 1241 1202 1582 0659 1081 1083 1084 1031 1 368 0622 0921 0924 0919 0 841 1111 0 610 08 34 0831 0 821 0 751 1003 0 630 1761 1761 1 809 1861 2399 0966 1271 1271 1295 1311 1650 0797 1150 1150 1161 1149 1440 0703
1083 1057 1053 1109 1566 0~530 1158 1125 1138 1217 1763 0 526 1291 1250 1278 1383 2038 0542 1518 1478 1519 1657 2420 0 589 1596 1557 1601 1737 2441 0688 2370 2344 2409 2561 3 297 0921
()) (11
TABLE X Continued
Run Thermocouple Readings (mv) No Position CFM I tc 1 tc2 tc3 tc4 tc tc tc tc i5 6 7 a r
C of 2nd 213 516 1235 4 63 1 432 1291 1265 1258 1 268 1 308 1550 0 971 214 1919 6 17 1357 1223 1196 1191 1199 1211 1461 0 851 215 27 12 8 35 1401 1259 1278 1220 1230 1218 1511 0 762 216 3320 981 1439 1305 1270 1259 1275 1238 1450 0719 217 41 53 980 1251 1142 1132 1094 1121 1088 1305 0 695 218 404 987 1102 1042 1030 1 bull006 1014 0960 1133 0681
Supplementary Equations
Calculating temperatures from thermocouple readings
t = -026tc)2 + 3512(tc) + 3201 (26)
where t is the temp in deg F and tc is the thermocouple reading in millishyvolts
Calculation of the thermal conductivity of air
k = 00000245ta + 0 0132 (27)
where k is the thermal conductivity in Btuhr rt2 degFft and ta is the air temp 1n OF
I I
bull co m
LIST OF FIGURES
Figure Page
1 Cross Section of Test Section and Probe bull bull bull bull bull bull bull bull bull bull bull bull 9
2 Experimental Apparatus 10
3 Sensing Probe bull bull bull 13
4 Drawing of Assembled Probe 14
5 Variation of Heat Transfer Rate with Distance from Baffle - 1 364 11 and 1 216 Sizes bull bull bull bull bull bull bull bull bull bull 29
6 Variation of Heat Transfer Rate with Distance from Baffle - 1 316 11 Size bull 30
7 Variation of Heat Transfer Rate with Distance from Baffle - 1 516 Size bullbull 31
8 Effect of Orifice Size on Position and Value of Maximum Heat Transfer bull bull 34
9 Correlation of the Point of Maximum Heat Transfer with Orifice Size bullbull 35
10 Rate of Heat Transfer at Baffle Center 37
11 Correlation of Heat Transfer Data at Baffle Center bull bull bull bull bull bullbull 38
12 Rate of Heat Transfer at the Point of Maximum Heat Transf er bull bull bull bull bull bull bull bull 40
13 Correlation of Heat Transfer Data at the Point of Maximum Heat Transfer 41
14 Effect of Upstream Baffles on Heat Transfer at Baff le Center bull bull bull bull bull 43
15 Heat Transfer with No Baffle 4 5
16 Orifice Pressure Drop Function versus Reynolds number bull bull bull bull bull bull bull bull bull bull bull bull bull bull 46
17 Heat Transfer at the Baffle and Maximum Point as a Function of Ori fice Pressure DIO p bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull bull 48
18
Fi gure Pa ge
Var iation of Heat Transfer Rate and Pressure Drop with Orific e Size at a Con stant Flow Rate bull bull bull bull bull bull 50
bull bull bull bull bull bull bull bull
bull bull
I
II
III
IV
v
VI
VII
VIII
I X
z
LIST OF TABLES
Pa ge
Summary of Experimental Program bull bull 19
Position of Maximum Heat Transfer 32
Calculated Heat Transfer Data 57
Pressure Profile Data bull bull bull 67
Rate of Heat Tr ansfer at the Baffle Center middot bull bull bull bull bull 70
Rate of Heat Transfer at the Point of Maximum Heat Transfer bull bull bull bull bull bull bull bull bull bull bull bull 72
Effect of Upstream Baffles on Heat Trar1sfer bull bull bull bull bull bull bull bull bull bull bull 74
Heat Transfer in the Test Section without Orifice bullbullbullbullbullbullbullbull 75
Pressure Drop Function 76
71bull r ntal bull bull bull bull bull bull bull bull bull bull bull bull
HEAT TRANSFER AND PRESSURE PROFILRS IN THE VICINITY OF ANNULAR ORIFICES
- CHAPTER I
INTRODUCTION
The most common type of industrial heat transfer
equipment is the shell and tube heat exchanger which
consists of a bundle of tubes contained in a cylindrical
shell Heat is transferred from the hot fluid to the cold
fluid through the tube walls as one fluid flows through
the tubes and the other flows through the shell surroundshy
ing the tubes
Most commercial multitube heat exchangers contain
bafflesmiddot to guide the fluid through the equipment and to
prevent stagnant regions from forming in the shell As a
result the flow pattern in the shell is very complicated
and considerable variation of the local rate of heat transshy
fer occurs because of the various types of flow which exist
in the baffled passage The research described in this
thesis concerns a study of one small portion of the shell
side of a heat exchanger
There are three main types of baffles used in commershy
cial heat exchangers
1middot Orifice baffles extend through the cross section
of the shell and all of the shellbullside flow is
through the annular orifice formed at each point
where the tube passes through the baffle
2
2 Disk and doughnut baffles consist of disks and
doughnuts or annular rings placed alternately
along the length of the tube bundle~ There is
some flow through the annular orifices formed
where the tubes pass through the baffles but a
large portion of the flow is around the baffles
3 Segmental baffles are segments of a circle and
Bre arranged so that the fluid flows back and
forth across the tube bank There is still some
f~ow through the small area where each tube goes
through the baffle
In the case of disk and doughnut and segmental baffles
small annular clearances must be allowed at the point where
the tube goes through the baffle so that the bundle may be
assembled easily Thus in all of the types of exchangers
some shell-side fluid flows through the annular orifice
where the tubes pass through the baffles It has been
shown that this is an area of high rate of heat transfer
but its effect on the overall performance of the heat exshy
changer is not well known Also the prediction of rates
of heat transfer 1n these orifices is not yet possible
The purpose of this research was to make an extensive
study of the heat transfer rates in the vicinity of these
annular orifices and to determine the effect of orifice
size flow rate and upstream conditions The work was
5
performed in a onebulltube single orifice type baffle heat
exchanger and provision was made to measure local rates
of heat transfer in the vicinity of the baffle
4
CHAPTER II
THEORY AND PREVI OUS WORK
In 1701 Newton defined the heat transfer rate qc
from a surface of a solid to a fluid by the equat ion
= ~A(tw - t) (1)q0
where hm is the coefficient of heat transfer from the surshy
face to the fluid excluding any radiation A is the area
of the surface tw is the surface temperature of the wall
and t is the bulk temperature of the fluid The equation
for the point of local surface coefficient h is given by
dqdA = h(tw- t) (2)
The mechan ism and the laws covering heat transfer by
true conduction in solids and by radiation through transshy
parent media are well known However with heat transfer
from a solid to a fluid the situation is far more complex
The mechanism of flow of the fluid to a large extent deshy
termines the rate of heat transfer for a given temperature
difference
In addition the coefficient hm depends on certain
physical properties of the flowing fluid the dimensions
of the apparatus the velocity of the fluid past the surshy
face and frequently the temperature potential AT
It was the purpose of t his research to measure the
local shell -side heat transfer coefficient and correlate
it with the several variables mentioned a bove
5
The heat transfer coefficient for fluids flowing inshy
side tubes is more e a sily measured and correlated due to
the simple geometry of t he tube i nterior Much work has
been done on the tube-side coefficients with one of the
more useful e quations being the Dittus - Boelter equation
( 4 p 450) ~
0 023 (---ctwGJbulla (~np M ( 3 ) M k
with the following cond itions satisfied
(1) Fluid properties evaluated at the arithmetic
mean bulk temperature
(2 Reynolds number gt10000
(3) 0 7 lt Pr lt 100
(4) n = 04 for heating and 0 3 for cooling
(5) Ldw gt60
Colburn (3 p 197) obtained an equation for tubeshy
side heat transfer coefficients in which the Stanton
number is used instead of the Nusselt number
hm ) (~~ 23 _ (dwG) 0 2 ( GC k - 0 bull 023 U (4)
p
Much of the research done on average shell-side heat
transfer coefficients has resulted in empirical correlashy
tions of the form of equations (3) and (4) above Several
investigations have been made for a certain set of phys~al
6
variables but the r esults have ne ver satisf a ctorily been
correlated to appl y for all types of heat exchangers
Some basic 1ork has been done recently however on
the local shell-side coefficients Ambrose (1) studied
the local heat transfer coefficients i n a model heat exshy
changer with segmental baffles This study was fairly
extensive at the baffle center but the data were quite
limited for the space between the baffles Gurushankar1ah
(5) further extended Ambroses work by studying a single
baffle space in detail
The results of these two studies indicated a need for
detailed information 1n the vicinity of the baffle Hence
Lee () investigated a single baffle s pace between two
orifice baffles and obtained considerable information on
the rates of heat transfer in the annular orifices Since
his work was carried out in a multitube mode l heat ex~
changer the determination of the rate of flow through the
individual orifice was difficult because of t he outer
clearances existing in the exchanger For this reason the
present research was undertaken to study the rate of heat
transfer in a single annular orifice through which the flow
could be accurately determined
Bell and Bergelin (2) have studied i n detail the pres shy
sure drop coeff icients for the annular orifices formed beshy
tween a circular disk and a circular tube These results
also appl y to the annular orifioe formed when a rod extends
7
through a circular hole in a plata This study was extenshy
sive in the fact that it considered the baffle thickness as
well as the orifice size but no heat transfer data were
presented
Sullivan and Bergelin (9) studied flow through a
single annular orifice through multiple annular orifices
i n parallel and flow around a single baffle both with and
without leakage through the baffle A generalized expres shy
sion is presented for the pressure drop across one baffle
section of a tubular exchanger with leakage through the
tube holes in the baffle but the effect of leakage area
upon heat transfer is only discussed qualitatively The
pressure drop data is correlated by plotting cent as a funcshy
tion of the Reynolds number where cent equals
d1 )22( ~ P) s c e (d2 -
M-2
8
CHAPTER III
~PERI1ffiNTAL APr ARATUS
The heat transfer test section was essentially a
single tube heat exchanger The inner tube was a l-in
OD aluminum tube with an electrically heated probe midshy
way between the two ends of the tube
Test Section
The shell as constructed from lucite plastic tubing
2 5-in I D and 3-in O D The te t section d a total
lengt h of 54 58 inches I t consisted of two sections
The upstream section was 40 i n ches in length in order to
assure freedom from entrance effects and the downstream
section was 13 12 inches in length To further assure
uniform flow a bundle of short copper tubes was placed a
few inches downstream from the entrance Both of these
sections had 12 i nch flanges on one end so t hat a 18
i nch thick orifice plate could be clamped between them
Heat transfer coefficients were measured in the vicinity of
t h is orifice A cross section of the center of the test
section is shown in Figure 1 and the experimental appara~
tus is shown in Figure 2
Cooled air supplied by a Roots -type blower was used
as the shell-side fluid throughout this study It entered
the test section through a l-in ID 1 12-in OD plasshy
tic pipe at the upstream end of the calming section Tbs
j Jl l 6- 11 BOLTS II I nbull middot~11 I HEATING ELEMENTS
J T ( T
-f-shy - - - f-_- __L
7 777 _y A
IT 1] I
I
FIGURE I CROSS SECTION OF TEST SECTION AND PROBE
10
FIGURE 2 EXPERIMENTAL APP1Ub~fUS
11
air left the test section through nine equally spaced 12
ineh holes placed around the side of the tube at the exit
end
Sensing Probe Assembly
The sensing probe was designed to measure the local
heat transfer coefficients at any point along the tube and
around the tube in the test section The tube was designed
so that it could be easily moved up- and downstream to
measure the heat transfer coefficients at various positions
in relation to the orifice
The sensing tube assembly consisted of the sensing
probe the thermoctmple lead s and selector switch the
power lines and the two aluminum tubes between which the
probe was centered
Imbedded in the sensing probe were seven iron-constanshy
tan thermocouples for measuring the temperatures around the
tube The lead wires from these thermocouples were conshy
nected to a seleotor switch at the downstream end or the
aluminum tube A layer of Saran wrap was placed around the
tube over the t hermocouple and three lengths of Trophet C
resistance ribbon were wrapped around the tube nd conshy
nected in series to the power leads
The heating surface of the probe was formed by these
three one inch wide strips of Trophet C resistance ribbons
The ribbons were 0002 inches thick and had a resistance of
12
0 271 ohms per foot and a thermal conductivity of 763
Btuhr ft 2 degFft They were held in position by four
copper bars placed in four parallel longitudinal slots
These copper bars served as connectors for the electrical
leads A photograph of the sensing probe is shown in
Figura 3 and a drawing of the assembled probe is given in
Figure 4
Power Source
Direct current was used to heat the resistance ribbon
on the sensing probe The current was regulated by a slide
wire resistor The po er source consisted of a Raytheon
Voltage Stabilizer to stabilize the city power source at
115 volts and an automatic selenium rectifier with an alshy
ternating current input of 115 volts at 60 cycles per
second and an output of 12 volts and 35 amperes direct
current
Temperature Measuring
The temperatures around the sensing probe were calcushy
lated from the emf readings of the ironbulloonstantan thermoshy
couples The emf measuring system consisted of the seven
probe thermocouples a separate thermocouple for measuring
the inlet air temperature a thermocouple selector switch
a cold junction and a Leeds and Northrup Type K Potentishy
ometer The potentiometer was placed on a Fischer
13
THERMOCOUPLE JUNCTIONS~ ~------- HOLES FOR THERMOCOUPLE LEADS
~----- SCREWS
~ff+--- CONNECTING BARS
END VIEW
POWER LEADS SOLDERED TO LOWER CONNECTING BAR
iER PLASTIC PIECE
RESISTANCE RIBBONS LOCATION OF THERMOCOUPLES
FIGURE 4 DRAWING OF ASSEMBLED SENSING PROBE
15
Vibradamp support to absorb the vibrations produced by the
air blower
Air Source
Air was used as the shell-side cooling fluid during
the study The air was pumped through the test section by
a Roots type air blower with a rating of 280 ofm at 3 12
psig outlet pressure The hot air leaving the blower was
passed tbxfugh two finned-tube box-type coolers and one
tubular edoler to oool it to approximately room temperature
The air flow rate was measured by passing it through a
flow measuring orifice in the line Two sharpbull edged orishy
ficas were used f or flow measurements The calibration
curves for these orifices were presented by Ambrose (1
p 166)
The pressure taps on each side of the orifice were
connected to two differential manometers containing 0 83
and 2 95 specific gravity fluids respectively The presshy
sure drop through the test section and test orifice was
measured by a pressure tap placed 13 inches upstream and
one placed 6 12 inches downstream from the orifice Two
pressure ga ges were used to measure the pressure at the
inlet to the flow orifice and to indicate the statio pres~
sure at the test section inlet
16
Pressure Probe
A probe was designed to measure the pressure drop
between the pressure tap 13 i nches upstream from the ori shy
fice baff le and any point downstream from the tap The
probe eonsisted of a l~in OD copper tube with six 132
i n ch holes even l y s paced around the tube The upstream
pressure tap and the pressure probe were connected to a
differential manometer so the pressure drop to various
points up- and downstream of the orifice could be measshy
ured
17
CHAPTER IV
EXPERIMENTAL PROGRAM
The experimental program was designed to measure the
heat transfer coefficients and pressure drops in the vicinshy
ity of annular orifices The four orifice sizes studied
were 1 364 1 216 l 316 and 1 516 inches~ The inner
tube used in each case was a 1-in OD alumintim tube
Hence tube to baffle clearances were respectively 3128
232 332 and 532 of an inch
Heat transfer coefficients were measured at poait~ons
1 i nch upstream at the orifice center and at 12 1
1 12 and 2 inches downstream for all orifices In addishy
middottion the heat transfer coefficient at a point 2 12
inches downstream from the 1 516 inch orifice was measured
and at the points 12 l 12 and 2 inches upstream from
the 1 364 inch orifice
The heat transfer coefficients at each point were
measured at five different flow rates for the 1 364 inch
orifice and at six different flow rates for the other orishy
fice sizes The high pressure drop through the small orishy
fice size limited the number of flow rates which could be
studied
The flow rate was calculated from the pressure drop
across the flow orifice This flow was corrected to cubic
feet per minute at 68degF and one atmosphere pressure by
18
using the orifice pressure and the test section pressure
which were measured by pressure gages
It was desired to determine a relationship between the
heat transfer coefficient and the total pressure drop for
each orifice size The pressure drop across each orifice
at various flow rates was measured by means of the presshy
sure probe described in Chapter III It was also desired
to obtain pressure profiles for each orifice size since
these might be similar to the heat transfer profiles The
pressure drop was measured from a point 13 inches upstream
of the orifice to points at 1 and 12 ineh upstream the
orifice center 12 1 1 12 and 2 inches downstream
The experimental program is summarized in Table I
TABLE I
SUla~RY OF EXPER IMENTAL PROGRAM
Position Investigated-Distance from Orifice-Inches
Orifice Range of Flow Rate Size Heat Transfer Pressure Drop CFM at 68degF amp 1 atm
1 364 2U 1 12U 1U 12U c 12U C 12D lD 10 - 18 l2D lD 1 12D 2D 1 12D 2D
1 216 1U c 12D lD 1 l2D 2D 12U c 12D lD 10 - 35
1 316 1U c 12D lD 1 l2D 2D l2U C 12D lD 12 - 50
1 516 1U c x2D lD 1 l2D 1U 12U C 12D 12 - 90 2D 2 1 2D l D 1 l2D 2D 2 12D
20
CHAPTER v
EXPERI MENTAL PROCEDURE
The experimental procedure for measuring the heat
transfer coefficients ~d corresponding flow rates reshy
quired the following procedure
(1) Install the orifice size to be studied in the
test section
(2) Place the heat transfer probe in the position up
or downstream from the orifice where the middot heat
transfer rate is to be studied
(3) Fill the cold junction thermos with cracked ice
(4) Measure the atmospheric pressure
(5 Open bypass line from blower and close line to
test section
(6) Turn on the cooling water for the exchangers used
to cool the air leaving the blower
(7) Start the automatic selen ium rectifier by turning
on the t 1mer bull
(8 ) Connect the voltage stabilizer to the wall outlet
(9) middot Set the slide wire resistor to the maximum re shy
s1atanee I
(10) Start the blower
(11 Open the line to the test section until the de shy
sired flow rate is obtained
(12) Switch on the probe direct current power source
21
(13) Adjust the slide wire resistor to obtain the
desired current
(14) After the thermocouples have reached equilibrium
values record the e m bullf across each of the
seven probe thermocouples and also the entering
air thermocouple
(15) Record the direct current amperage
(16) Record the gage pressure at the flow orifice and
the entrance to the test section
(17) Record the manometer measurement of the pressure
drop across the flow orifice and also the presshy
sure drop through the test section
22
CHAPTER VI
CALCULAT ION OF EXPERIMENTAL DATA
The local heat transfer coefficients were calculated
from the temperatures measured on the probe surface the
air temperature and the current input The results were
calculated by using the Alwae III-E computer
The general expression for calculation of the heat
transfer coefficients was derived by Ambrose (1 p 79)
The equation is derived by making an energy balance around
a small increment of the center resistance heating ribbon
The two ribbons tnstalled adjacent to the center ribbon
reduced the amount of logitudinal conduction and assured
little longitudinal temperature variation in the center
ribbon
A heat balan ce on this small increment of resistance
ribbon yields the following
(the heat conducted in) + (heat generated) = (heat
conducted out) +(Heat convected to the fluid) + (heat
radiated to the surroundings) + (Heat conducted into
the plastic center of the probe)
This gives the equation
kzw dtdS + 12RdS kzws [ t + (~) ds] + hwdS (t-ta )
+ ~Aad wd o middot+ qcAond 1 -~- wdS 5 )
23
Hence solving for h gi~ea
i2R kz d2t Qrad qcond w + -d$2 - ~- A
h = ( 6)t - ta
Since S = re where 9 equals the enclosed angle ~n radians
dS rd9 ( 7)
and
dt - dt (8)dS - rd9
Differentiating with respect to S
d2t (9)rd9dS
from which
(10)
Substitut1ng into the equation for heat transfer coeffishy
cient gives
h = i2R Qcond A (11)
w
The rate of radial heat conduction into the plastic
tube making up the probe was assumed to have negligible
effect on the heat transfer coefficient It was also
assumed that the heat loss by radiation from the ribbon
was negligible since all data were obtained with the ribbon
at a temperature less than 125degF
24
When t he rad iation and conduction terms are neglected
Eq (11) becomes
(12)
The following con stants are known
R = 0 271 ohmsft
w = 100 i n ches
k = 763 Btuhr rt2 degFft
z = 0 002 inches
r = 12 inch
Eq (12) putting 9 in degrees then reduces to
1110 12 + 2404 d 2t d92
( 15)h = ------~--~-------t - ta
Thi s equation was programed for the Alwac III- E comshy
puter and used to calculate the local heat transfer coefshy
ficients from the observed data
The average heat transfer coefficient around the tube
at a given position in the t est section was calculated by
averaging the local coefficients calculated from Eq (13 )
It was found 1n the course of the experimental work
that thermocouple numbers 1 and 7 were indicating higher
temperatures than would be expected This resulted in h1
and ~ being lower than the other local coefficients around
the tube Since the fluid was flowing parallel to the axis
of the probe the circumferential variation i n rate of heat
25
transfer should be small Hence in obtaining the average
coefficient around the tube the values of h1 and h7 were
not used even though they were calculated and are tabulated
1n Table I II in the Appendix
Then
(14
A Nusselt number as calculated from this aver age heat
transfer coefficient using the tube diameter as the characshy
teristic dimension
(15)
The air flow rates through the test section were calshy
culated by measuring the pressure drop across the flow orishy
fice the air temperature the pressure at the flow orifice
and the pressure at the entrance to the test section The
orifice calibration curves (1 p 166 ) were used to obtain
a value of the orifice coefficient f8e where Q equals
the flow in cubic feet per minute at 68deg F and one atmosmiddot
phere pressure and te is the density of air at the exchanger
and e the density of the air at the flow orifice The
den sity of the air can be expressed by
e = 2 703 p (16)T
where T equals the temperature in OR and P equals the absoshy
lUte pressure i n lb1n2 Using the value of e Qfo from
26
the calibration charts as A and Eq (16) solving for Q
gives
( 17
This equation was used to calculate the flow rate for
each flow studied
The Reynolds number used i n the correlation of the
data was the equivalent Reynolds number defined as
Re)eb ~ d2 - dl)Uf ( 18 ) lL
where d1 is the outside diameter of the inner tube and d2
is the orifice diameter U is the flow velocity through the
annular orifice e is the density of the air and U- is t he
viscosity of the air This equation can be transformed t o
(Re) b = 1611 Q (19) e dl + d2
where d1 and d2 are in inches
The pressure drop data were calculated i nto a dimenshy
sionless pressure drop function cent where
d1 )22( ~ P)gc f av(d2 shycent 2 bull (20
M-
For air this equation reduces to
where d2 and d1 are in i nches D P is expressed i n inches of
2 95 specific gravity fluid and P av is expressed as lbft3
27
CHAPTER VII
ANALYSIS OF DATA
In analyzing the heat transfer data an attempt was
made to correlate it 1n terms of the dimensionless groups
(Nusselt number Prandtl number and Reynolds number) which
appear in Eqs (3) and (4) Consequently all of the av~
erage heat transfer coefficients hav were brought into
the form ( Nu)( Pr)~3 bull The Nusselt number was based on the
tube diameter and the thermal conductivity of the air at
the flowing temperature The tube diameter was used in the
Nusselt number because comparison could then be made with
previous experimental work on heat exchangers which have
commonly used the Nusselt number defined as in Eq (15)
From the standpoint of dimensional analysis this is
equivalent to considering the tube diameter as the characshy
teristic length so far as the heat transfer is concerned
The Prandtl number of the air was taken as 0 7 in all
cases
Variation of Heat Transfer Rate with Distance from the Baffle
Considerable variation was observed in the rate of
heat transfer in the vicinity of the baffle In order to
obtain the variation with respect to position the term
(Nu)(Pr)-13 was plotted versus the flow rate Q for each
position and orifice studied Cros s plots were then made
28
at constant flow rates in order to obtain the variation of
(Nu)(Pr) -13 with position The resulting cross plots are
shown 1n Fi gures 5 6 and 7 for the four orifices studshy
ied
About one inch upstream from the orifice the heat
transfer coefficient begins to rise rapidly and continues
to do so until it reaches a maximum some distance downshy
stream After the maximum point the heat transfer coef fi shy
cient decreased slowly The heat transfer rate was found
to reach a maximum at a different position downstream for
each orifice size These figures also show that for a
given orifice size the maximum heat transfer rate occurs
a pproximately at the same point for all flow rates The
position of the maximum point f or each or ifice size is
shown in Table II
The region immediately downstream from the orifice is
one of h i gh turbulence due to the jetting action of the air
flowing through the orifice As the air flows t hrough the
orifice the streamlines continue to converge for some dis shy
tance downstream The point of maximum heat transfer is
probably at the point where the streamlines be gin to diverge
and a boundary layer begins to build up on the tube Tle
decreasing heat transfer coefficient beyond the maximum
point indicated the formation of a boundary layer
Since the position of the maximum point is independent
of flow rate middot it is possible to correlate it with respect
_ ct 11shyz-
100
0 136 ORIFICE
(
I 0
I )
~ 00
~p 0
I 0
--r--- ~
ISCFIII
-_ OCFM
rbull abull
~ middot~ a-1 z-
12fORIFICE
100
200
100
0 0 UPITRAM ORIFICE DISTANCE CENTER
CFM
h I DOWNSTREAM
DISTANCE
FIGURE 5 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLpound
30
too
700
800
100 ~ f gtf
400
z ~
100
100
100
0
13fORIFICE
~ -~ -- ---
)
~
~
-
I ~ ~OCFM
I vI~-~ OCFM
J ---
Iamp CFM
I 0 I I UPSTREAM ORIFICE DOWNSTREAM DIITANOE GENTER DIITANCI
FIGURE 6 VARIATION OF HEAT TRANSFER RATE WITH DISllNCE FROM BAFFLE
--
--- --
31
100
100
700
100
_ 100
f 9- 400 z-
100
tOO
100
0 - I 0 I I I UHTRIAM OAtfiCI DOWIIITMAM
+ I tyl6 ORIFICE
v I
~~ ~CFM
I v ~CFMI
v v 7
~~ v ~ iOCFM
- ~~ I-shy1-shy ~ICFM
DIITMCI OINTIR DIITANCI
FIGURE 7 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLE
32
TABLE II
POSITION OF MAXIMUM HEAT TRANSFER
Position of Maximum Orifice Size Heat Transfer
(inches) (inches downstream)
1 364 050
1 216 100
1 316 125
1 516 200
33
to orifice size Figure 8 shows the effect of the orifice
size on the position and value of the maximum heat transfer
at a constant flow rate of 15 cubic feet per minute It
can be seen that the larger the orifice size the further
downstream the point of maximum heat transfer occurs
Also as the orifice size increased the rate of heat
transfer decreased for a given flow rate The broken line
indicates the variation of the point of maximum heat transshy
fer with position and size The position of the point of
maximum heat transfer rate downstream from the orifice was
correlated with orifice size by means of the dimensionless
groups (Lde) and (d1de) where L is the distance downshy
stream from the orifice where the maximum rate of heat
transfer occurs d1 is the outside diameter of the inner
tube and de is the equivalent diameter of the orifice
ie de = d2-dlbull
Figure 9 shows a plot of Ld 6 versus d1d6 for the
four orifice sizes studied The four points on this logshy
log plot are approximately in a straight line and the
equation of this line is
Lde = 0 44 d1de)028 (22)
Although the above relationship represents a correlashy
tion of dimensionless groups it is based upon only one
tube diameter and needs to be substantiated further by
studying other tube diameters and other orifice sizes
34
aoo
400
aoo ~
-~ middot-CLshyJ z
200 -
100
0
ORIFICE CENTER
l~
l
t
I J~
1pound~
I
0 I I~
AT 15 CFM
-
bull ~ 1~6~
~ v~
~
~--~~6
~~~ ___ v v V -_
~ o q
~ I 16
v
~
ogWNSTREANI STANCE
FIGURE 8 EFFECT OF ORIFICE SIZE ON POSITION AND VALUE OF MAXIMUM HEAT TRANSFER
35
50
loshy____ -~
~ ~ -shylltl-shy~ r0
2 10 30
FIGURE 9 CORRELATION OF THE POINT OF MAXIMUM HEAT TRANSFER WITH
ORIFICE SIZE
36
Correlation of Data at the Baffle
The heat transfer data were correlated by obtaining a
relationship between the group (Nu)(Pr)-13 and a
Reynolds number based on twice the clearance (d2 - d1
between the tube and the baffle It was found that the
most satisfactory correlation could be obtained when the
term - d1 was used as the length term in the Reynoldsd2
number
Figure 10 shows the variation of the heat transfer
rate at the center of the orifice e xpressed as a function
of Reynolds number and the orifice size This shows that
for a given Reynolds number the heat transfer at the center
of the orifice is greatest for the smallest orifice size
In order to obtain a general correlation of the data
shown i n F1gure 10 the effect of the dimensionless ratio
d1de was considered This ratio considers all of the
geometric factor s needed to describe the annular orifice
The thiclaless of the orifice plate is also a factor but
was constant i n this i nvestigation
The data for the heat transfer at the baffle center
are shown in Figure 11 in which (Nu)( Pr)-13 is plotted
versus (Re)ebd1 de) 0 55 This data on a log-log plot
lies on a straight line for (Re)eb( dld8 )0 55 greater
than 3 x 104 The equation for cor relating the heat
37
4XI~middot~-r~------~--~~------~
Icf t--to_+--_c-c-________ SYMBOL SIZE
0 1~4
6 ~~
9 ~~ -o ~
(Re)eb
FIGURE 10 RATE OF HEAT TRANSFER AT BAFFLE CENTER
38
500
0
4 0 lcf
~ ~
~ ~iC-
~ ~
~IL 0~ 0 SYMBOL SIZE-
p 0 1364-
r 6 1~16 -~ -
9 1~16 --o 1~16
I I
FIGURE II CORRELATION OF HEAT TRANSFER DATA AT BAFFLE CENTER
39
transfer at the center bullOf the a nnular orifice was found by
the method of least s quares to be
(Nu)( Pr)-1 3 = 0018 ( Re)ebO Bl( dlde)04~ (23)
3 x 104 ltRe)eb(a1de)055 lt 105)
Rate of Heat Transfer at the Point of Maximum Heat Transfer-The heat transfer rate at the point of maximum heat
transfer is plotted in Figure 12 to show the variation with
Reynolds number and the size of the orifice It is shown
gives the h1gh st heat transfer ~ate at its point of maxibull
that for a given Reynolds number the smallest orifice size yen il
mum heat transfer
The data ~or the maximum poi~t could be correlated by
plotting (Nu) Pr)-13 versus (Re)eb(d1de)06 This plot
is shown 1n Figure 13 and the resulting eurve shows that
(Nu(Pr)-13 is not a simple p0wer function of the Reynolds
number as was the case for heat transfer at the baffle
center The reason for this is probably because other
factors such as intensity and scala of turbulence should
be considered At the orifice center the streamlines of
the flowing stream are converging_ and thus the flow is
quite stable Downstream from the orifice is a region of
large eddy currents and probably large scale turbulence
These factors could con ceivably cause the results which
were obtained for the point of maximum heat transfer
40
If)
~middotshy Q_-I z_
10~~~--------r----~~--~--
SYMBOL SIZE
0 13$4
6 1~8
Q 13-18
-o 1~8
7)(104
(Re)eb
FIGURE 12 RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
41
Ia ~
0 I
c ~ ~ c v
~ ~lt w ~
17
~ b
v ~ ( SYMBOL SIZE
-~ 0 f-64 -v ~ 6 t211e
~ Q I~~~
-o - l~rs I I
FIGURE 13 CORRELATION OF HEAT TRANSFER DATA AT THE POINT OF MAXIMUM HEAT TRANSFER
4 2
Effect of Upstream Baffles on Heat Transfer at the Orifice Center
The heat transfer rate at the orifice center using the
single orifice in a test section is a pproximately 13 of the
value that was obtained by Lee (7) using a model heat exshy
changer with orifice baffles Lee investigated the cent r al
baffles of the heat exchanger and thus the coeff icients he
obtained would be affected by the presence of a number of
upstream baffles To determine the effect of upstream
baffles an additional l 516 inch baffle was placed four
inches upstream 1n the test section The resulting data are
shown in Figure 14 where (Nu)(Prmiddot)-13 is plotted versus
(Re) eb for the case of a single baffle 1n the test section
and also the case of an additional baffle placed four inches
upstream Comparison is made with the results obtained by
Lee middot(7) using a four-baffle and a ten-baffle model heat exshy
changer Good a greement is obtained with Lees work and the
results show the marked effect that upstream baffles have on
the downstream heat transfer rate The additional up tream
ba ffle caused sufficient turbulence 1n the test section to
i n crease the heat transfer rate nearly three-fold at the
center of the next baffle
Heat Transfer i n the Test Section with No Orifice
In order to check the accuracy 6f the equipment the
orifice baffle was removed and the heat transfer mea sured
with the probe in the empty test section The data were
43
~~BAFFLES
0 l BAFFLE -shy
ll_9 2 BAFFLES
V 4 BAFFLES-LEE
4 10 BAFFLES- LEE lJf ~
~rv ~~ ~ v flvv ~~
I ~ J ~ L v
0
v
( V
40 3XIo 7XIa
(Re)eb
FIGURE 14 EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER AT BAFFLE CENTER
44
compared with heat transfe r coefficients predicted by the
equations for annuli which are recommended in the litera shy9
ture The two equa~ ions u sed tor comparison were
(hfe)=0 023 (rltGr e (~~ur4 (~r45 (24)
which was presente~ by Wiegant (10)
and ( h ) (cnM~5(M~l o14 o 023 CPG k j Mij - (de GJMb )0 2 ( 2 5)
which was presented by McAdams (8 p 242) The comparshy
i son is s hown in Figure 15 lq (25) gives a value which
is low by about ten percent while Eq (24) g ives values
which are high by as much as twenty -five percent when comshy
pared with the experimental data The se equations are gembull
erally considered to give coefficients with an accuracy of
about twenty percent Therefore the present experimental
data are within the accuracy of these equations Also the
plot indicate s that for a Reynold s number greater than 2 x
104 the slope of the line is the same for the experimental
data as for the equations
Pressure Drop Data
The total pressure drop across the orifice was measured
as a function of the flow rate and the orifice size The
pressure drop was expressed as a d1mens1onleas quantity r)
which ie plCltted ver sus the Reynolds number in Figure 18
The pressure drop function cent correlates for all or1f1oe
45
200
100
s z
10 5XI10 10
0 EXPERIMENTAL
--McADAMS
-WIEGAND L
V
~ ~ ~
P ~ ~
LL~ L
v~
~
v v
v 1 ~ ~ v
v -gt
~
~ ~
~
6Xid
FIGURE 15 HEAT TRANSFER WITH NO BAFFLE
46
0 1~4 -~ a 6 t216
Q t316 lJ J
-0 as a )t
A LEE I -shy SULLIVAN 8
p
10bull
BERGELIN
I _ll I
I ~
i I
~middot
lo II
f fl
J j
~middot
A)101
1q
I Ill
1 I3 X 10ao1
FIGURE 16 ORIFICE PRESSURE DROP FUNCTION VS REYNOLDS NUMBER
47
sizes- The present data extends the range covered by preshy
vious workers and agrees well with their work The preshy
vious work of Lee () for a heat exchanger containing 10
orifice baffles and also the data of Su livan and Bergelin
(9) for pressure drop in a model heat exchanger with a
single baffle is shown 1n Figure 16 long with the present
results~ This figure may be used to predict the preseure
drop from the equivalent Reynolds number of the annular
orifice
The pressure drop between individual points 1n the
vicinity of the orifice and an upstream pressure tap wa s
measured to obtain a pressure drop profile As might be
expected 1n all cases the profiles showed a rapid decrea e
in static pressure immediately upstream from the orifice
There was however little or no recovery of the pressure
loss downstream The 1 364 inch orifice did show a maxishy
mum point in the pressure drop but this maximum occurred at
the orifice center and total recovery was reached about 12
inch downstream
Heat Transfer at the Baffle and Maximum Point as a Function of Pressure Drop
In order to compare the effect of the total pressure
drop on the heat transfer at the baffle and the point of
maximum heat transfer Figure 17 was plotted showing
(Nu)(Pr)-13 as a function of the total pressure drop This
shows that for a given pressure drop the largest orifice
48
1200
1000
~ a -sshyz-
100
60 100 700
AT MAXIMUM POINT I 15116 2 13116 3 1~6 4 1364
AT ORIFICE CENTER
60
1
v
r ~ ~ ~
5
~
8 7
13116
8
~
1364
v
~
e6
1~6
v
~~ v ~ ~ -~ ~
~
~ v
l
~
vamp
I ~ ~
~
v L ~
v
I-
5
k= ~~
~ ~ ~
--I
v ~
FIGURE 17 HEAT TRANSFER AT THE BAFFLE AND MAXIMUM POINT AS A FUNCTION OF
ORIFICE PRESSURE DROP
49
size has the greatest heat transfer coefficient This is
true at both the orifice center and at the point of maxishy
mum heat transfer
Another comparison can be made by plotting the heat
transfer coefficient and the pressure drop versus the orishy
fice size at a constant flow rate Figure 18 shows this
plot This graph shows that at a constant flow rate the
pressure drop as well as the heat transfer coefficient
increases as the size of the orifice is decreased In
choosing an orifice size for maximum efficiency 1t would
be necessary to know the pumping power available as well
as the heat transfer desired
70 I I 700
AT 15 CFM 60 ---
~ aug
50 ---
NV
40 ~
~ ~ ~
~ _
MAXIMUM POINT ---- --- ~
1-----t---~ _
~00Qj ~
~t--- ORIFICE CENTER 10 1100
1---~ n
u0 01 02 03 Q35
a ltl
de inches
FIGURE 18 VARIATION OF HEAT TRANSFER RATE AND PRESSURE DROP WITH ORIFICE SIZE AT A CONSTANT FLOW RATE
cn 0
51
CHAPTER VI II
SUMMARY OF RESULTS
This study revealed several significant facts about
the heat transfer in the vicinity of annular orifices
Probably the most important contribution was the presshy
entation of the heat transfer profiles in the vicinity ot
the annular orifice ~ r s shown that t~ local heat
transfer coeffieient re~ches a maximum at a point downshy
stream from the orifice The distance downstream at which
this maximum oocurs is t1ven by the equation
22
The heat transfer coefficients at the center of the
orifice were correlated and found to follow the equation
(Nu)(Pr)-13 = 00176 (Re)eb08l(d 1de) 0 middot4~ (23)
3 x 104 lt( Re) 9 b( d1d6 )055 ltlo5 )
The heat transfer at the point of maximum heat trans
fer for each orifice size was correlated and presented in
Figure 13 as a plot of (Nu)(Pr)-l3 versus (Re)eb(d1de) 06
No simple po-orer relationship exists between the terms
Intensity and scale of turbulence downstream from the orishy
fice are probably important factors which affect the heat
transfer
The large effect of an upstream orifice on the heat
transfer rate at the second orifice was demonstrated by the
52
study of two 1 516 inch orifices in the test section The
added turbulence at the center of the second orifice was
found to raise the heat transfer rate almost three times
over that obtained for a single baffle
The pressure profiles in the vicinity of the orifice
indicate that nearly all the pressure drop occurs at the
orifice center~ Total pressure drop data were correlated
by a pressure drop function cent as a function of the Reynolds
number and good agreement obtained with the results of other
workers
The pressure drop and heat transfer data were correbull
lated by plotting the heat transfer as a function of the
pressure drop for each orifice size It was shown that for
a given pressure drop the largest orifice size gives the
greatest heat transfer coefficient
As a final presentation it was shown that the pressure
drop and the heat transfer coefficient both i ncrease i n
value at a constant flow rate as the orifice size is de shy
creased This is important in choosing the optimum clearshy
ance for orifice baffles
53
CHAPTER IX
RECOMMENDATIONS
A great deal of work remains to be done in the field of
evaluating shellmiddotside heat transfer coefficients This
study included only one tube size and air was the only f luid
used It is recommended that further studies be conducted
using other fluids and tube sizes It will also be necessary
to study several baffle types
The adde d turbulence due to a s e cond baffle placed upbull
s t ream would suggest that the heat transfer coef ficients at
a certain position i n relation to a baffle would increase as
the flow progressed through the exchanger It is recomshy
mended that an extensive s t udy should be made between baffles
the full length of a model heat exchanger
It is further recommended that the pressure drop study
be continued to include other fluids tube sizes and baffle
arrangements
Effects of turbulence downstream from the baff le should
be studied by i n vestigations with hot-wire anemometer equipshy
ment to determi ne t urbulence scale and i ntensity
54
NOMENCLATURE
Area of heat transfer
Heat capacity of the fluid
Outside diameter of the tube
Orifice diameter
Equivalent diameter of the orifice (d2 - dl)
Inside diameter of the test section
Inside diameter of the tube
Gravitational constant
G Mass velocity
h Local heat transfer coefficient
Coefficient of heat transfer from surface to fluid
i Direct current amperes
k Thermal conductivity of the fluid
L Distance downstream of the point of maximum heat transfer
p Absolute pressure
L P Total pressure drop across the orifice
Q Flow in cubio feet per minute at 1 atmosphere and 680 F
q Heat transferred
Thermal energy conducted into the sensing probe
Thermal energy radiated from the resistance ribbon
Resistivity of the resistance ribbon
s Length of the resistance ribbon
T Temperature oR
55
t Temperature of the resistance ribbon deg F
ta Temperature of the bulk stream oF
tw Wall temperature of the tube OF
U Veloc ity of the fluid
w Width of the resistance ribbon
z Thickness of the resistance ribbon
eeuro Density of the fluid in the test section
Density of the fluid at the flow orificef 0
AL Viscosity of the fluid
E9 Angle measured around the tube
Dimensionl ess groups
(Nu) Nusselt number hd1k
(Pr Prandtl number C~k
(Re)eb Equivalent Reynolds number at the baffle (d2 - d1 )uejt-Lshy
(Re)e Equivalent Reynolds number in the test section ( d 8 - d 1 )U fu
cent Orifice pressure drop function 2(~P ) gc~av(d2 - d1) 2
Al
56
BI BLIOGRAPHY
1 Ambrose Tommy W Local shell-side heat transfer coefshyficients in baffled tubular heat exchanger PhD thesis Corvallis Oregon State College 1957 183 numb leaves
2 Bell K J and o P Bergelin Flow through annular orif ices Transactions of the American Society of Mechanical Engineers 70593-601 1957
3 Colburn Allan P A method of correlating forced con shyvection heat transfer data and a comparison with fluid friction Transactions of the American Institute of Chemical Engineers 24 174-210 1933
4 Dittus F w and L M K Boelter Heat transfer 1n automobile radiators of the tubular type University of California Publications in Engineering 2443-461 1930
5 Gurushankariah M s Local shell-side heat transfer coefficients in the vicinity of baffles in tubular heat exchangers Masters thesis Corvallis Ore gon State Colle ge 1958 97 numb leaves
6 Knudsen James G and Donald L Katz Fluid dynamics and heat transfer New York McGraw-Hill 1958 576 p
7 Lee Kyu Sung Local shell-side heat transfer coeffishycients and pressure drop in a tubular heat exchanger with orifice baffles Masters thesis Corvallis Oregon State College 1959 118 numb leaves
8 McAdams William H Heat transmission 3d ed New York McGra ~-Hill 1954 532 p
9 Sullivan F W and 0 P Bergelin Heat transfer and fluid friction in a shell-andbulltube exchanger with a single baffle Chemica l Engineer ing Progress Symposium Series 52 ( 18) 85-94 1956
10 Wiegand J H Discussion on annular heat transfer coshyef f icients for turbulent flow Transactions of American Institut e of Chemical Eng i n eers 41147-153 1945
AP PENDIX
57
TABLE III
CALCULATED HEAT TRANSFER DATA
Baffle Hole Diameter Run No (inches)
1 - 59 1 364
60 - 102 1 216
103 - 138 1 316
139 - 206 1 516
207 - 212 No orifice
213 - 218 2nd - 1 516
TABLE III
CALCULATED HEAT TRANSFER DATA
Local Heat Transfer Coefficients Run
T0 bull Po s ition CFM hr h2 h3 h4 hs he ~ hav Nuav
1 c 1026 10 59 1476 16 09 1559 1510 1435 1203 1518 8511 2 1290 1369 1738 1878 18 05 1755 1689 1515 1773 9964 3 1416 1636 198 1 2068 1977 1924 1845 1715 1959 11030 4 1627 1991 2301 2382 2268 2194 20 ~98 1929 2249 12664 5 1776 2252 2669 2863 2713 2517 2338 2126 2620 14759 6 l2ttD 1109 2311 3317 3386 3373 3387 3394 3071 3371 18888 7 1258 3089 4583 4866 4683 4701 4643 4194 4695 26301 8 1433 38 8 5 55 83 5791 5495 5430 5436 5008 5547 31192 9 1681 4992 7378 7649 6980 6864 6870 64 28 7148 40180
10 1 D 1102 2371 3332 3511 3356 3342 3427 3102 3394 19012 11 1308 3218 4379 45 24 42 53 4255 4373 3965 43 57 24446 12 14 64 38 58 5146 5142 4839 4787 4903 4597 4963 278 79 13 1706 5218 6664 6269 58 81 5884 6237 5973 61 87 34718 14 15
1 l2D 1115 1275
2131 2661
2955 3638
2972 3720
2941 3675
2913 3576
28 22 34 74
2613 3278
2921 36 17
163 09 20246
16 1498 34 87 4644 4503 4441 4371 4343 4194 4460 25010 17 1695 4449 5743 5324 5222 5154 5157 5015 5320 298 97 18 2D 1049 1715 23 90 2550 2610 2656 2624 2208 2566 14363 19 1241 2117 2964 3145 3218 3221 3203 2759 3150 17757 20 1532 28 67 3936 4100 4188 4201 4167 3676 4118 23224 21 1674 3459 4508 4598 4746 4795 4792 4299 4688 26337 22 lU 1074 253 340 380 3 86 388 377 354 374 2097 23 1287 292 392 433 440 441 429 406 427 2394 24 1508 322 439 492 498 499 487 461 48 3 2713 25 18 07 3 38 464 519 5 24 520 499 463 5 05 28 40
~~ (]I agt
TABLE III Continued
Run No Position CFM h 1 h2 ~3 h4 h5 h6 ~ h
av Nu
av 26 c 1029 1171 1491 1589 15 28 1 4 62 1377 1293 1489 83 44 27 1266 1395 1746 1853 18 02 1685 1556 1453 1728 9704 28 1430 1637 2037 2175 2060 1909 1735 1591 1983 11159 29 1729 1982 24 96 2751 2507 2268 2030 1886 2410 13579 30 12D 1054 2934 4041 4321 4326 4423 4359 3706 4298 24160 31 1294 3385 4 8 26 52 42 5326 5450 5277 4566 52 24 293 50 32 1431 3784 5347 5721 57 bull75 58 44 5700 5084 5677 31870 33 1770 52 75 7 7 33 87 35 9005 9007 8267 7059 85 49 48050 34 lD 1058 3235 4401 4444 3877 3496 3451 3294 3934 21973 35 1263 38 98 5484 5330 4347 3964 3981 3987 4621 25823 36 18 36 6701 89 17 7855 6369 5597 5769 6283 69 01 38718 37 1 12D 1029 2404 31 8 2 3333 3459 3624 3577 3045 3435 19264 38 1315 3182 4033 4162 4310 4496 4502 4015 4301 24142 39 1426 3628 4389 4510 4573 4760 4804 43 8 5 4607 25678 40 1757 4547 5559 5(35 5931 6282 63 70 6060 5975 33471 41 2 11D 1080 2034 28 38 3155 3144 3145 2966 2540 3050 17027 42 1305 2650 3 4 87 3aoz 3595 3751 3595 3153 36 46 20405 43 1434 3167 39 07 4156 4371 4320 4126 3709 4176 23395 44 1804 4096 4 9 66 5691 5714 5586 53 15 48 65 5454 30582 45 12U 1088 409 516 557 564 5 60 535 513 5 46 30 67 46 1318 470 579 6 22 631 6 17 5 97 579 6 09 3422 47 14 13 540 640 676 6 86 681 6 60 6 54 6 69 3754 48 1773 641 740 774 782 7 69 749 746 763 42 87 49 l 11 U 1054 270 356 391 397 393 3 71 346 38 2 2133 50 1240 303 399 446 449 447 4 21 398 432 2420 51 1419 361 476 522 530 528 507 467 493 2760 52 1 1(2U 1032 236 311 342 347 344 325 301 334 18 78 53 1314 270 366 403 407 408 386 351 394 2217
(Tt tO
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ h av Nu av
54 1448 301 408 447 454 452 431 403 438 24 61 55 1782 353 494 548 544 415 529 531 506 2843 56 2U 10 61 220 287 316 320 322 303 268 310 1735 57 1216 249 335 370 377 378 353 307 363 2044 58 1322 263 356 394 398 399 374 327 384 2159 59 1639 310 433 478 481 482 452 393 465 2617
60 1D 10 68 2011 2536 2657 2681 2694 2560 15 62 2625 14938 61 1399 2520 3239 3369 3371 33r82 32 39 1946 3320 18968 62 1669 2781 3655 3820 38 76 3883 3738 2355 3794 21712 63 1959 3524 42 37 4399 4438 4497 4417 3047 4397 25156 64 2295 4426 5288 5396 5372 5240 5410 3369 5341 30680 65 2636 5490 6531 6662 6565 6379 6820 4249 6591 37938 66 3390 7869 9538 9462 9387 8924 10508 62 91 9564 59601 67 1U 1190 352 368 401 413 407 395 293 397 2256 68 1559 397 422 462 475 471 456 331 4 57 2603 69 1904 434 465 5 13 529 528 504 358 508 2901 70 2211 493 526 573 5 92 588 564 4 15 569 3257 71 2289 569 587 6 30 649 6 61 6 49 460 635 36 44 72 2727 637 6 60 7 09 733 751 743 521 719 4140 73 3210 728 755 8 15 8 43 8 62 8 54 616 826 4765 74 2nD 1210 181 2256 2393 2399 2333 2206 1325 2317 13158 75 1420 2340 2752 2899 2913 2850 2728 1701 2828 16121 76 1692 2853 3306 3452 3471 3379 3217 2134 3365 19217 77 1894 3102 3588 3713 3736 3670 3557 2455 3653 20892 78 2301 3682 4259 4433 4467 43 83 4289 2892 4366 250 30 79 2621 4117 4828 5017 5012 5030 5109 3071 4999 28785
m 0
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ hav Nuav
80 3230 5158 6006 62 13 61 18 6134 6695 4094 6233 359 87 8 1 12nD 1155 15 27 1854 2028 2064 20 85 1987 1164 1968 118 31 82 1689 2046 24 8 2 2688 2739 2760 2658 1749 2665 152 73 83 1244 2088 2317 2339 2345 2373 2381 1487 2351 13432 84 2100 3211 3539 34 21 3462 3512 3696 2575 3526 20284 85 2292 3 5 05 3761 3648 36 25 36 79 3957 2933 3734 21517 86 2907 4420 48 22 4679 46 04 4705 5206 3792 48 03 27741 87 33 80 59 35 69 38 7404 77 10 7 8 36 7 0 86 5190 7394 427 44 88 1 12D 1 4 27 2 4 58 28 31 3037 3021 2987 2927 18 57 2 9 61 16913 89 18 75 34 75 3 9 87 4230 4255 4317 4337 2734 4225 24258 90 22 59 4221 4796 5046 5052 51 01 5389 3491 5077 29206 91 2682 4978 5664 5943 5966 6054 6573 408 1 60 40 34795 92 3417 63 16 71 02 7 3 93 7385 75 40 8 6 95 51 45 7623 44017 93 c 1 5 17 1240 1305 1399 1467 1479 1429 9 26 1423 8251 94 20 34 1554 1623 1720 18 21 18 53 18 72 1215 1778 10229 95 2 3 48 1795 1843 198 5 2097 2171 2274 1540 2074 11947 96 2716 2028 2048 22 01 2 3 44 2444 2661 18 90 2340 13505 97 3247 2410 2375 2663 2778 2949 3298 2378 2793 1615 98 11 35 967 1040 1124 1186 1200 1142 728 1138 6496 99 14 06 1135 1220 1318 1384 1403 1 3 61 8 77 1336 7656
100 2311 1 8 54 18 78 1980 20 90 2136 2227 1653 2062 118 31 10 1 2666 2085 2094 2227 2 3 62 2438 2626 1902 2349 13508 102 3392 2635 2582 28 01 3026 3141 3529 2567 3016 17390
103 1 U 1235 349 395 434 436 4 28 411 286 423 2416 104 20 10 434 5 02 559 577 569 5 37 345 552 3177 105 28 14 538 626 685 711 7 21 682 424 6 8 6 3966
Q) j-J
TABIE III Continued
Run No Position CFM h1 h2 h3 h4 h5 hu h7 hav Nuav
106 3492 614 7 1 6 7 84 8 13 8 33 7 85 4 88 7 87 4562 107 4395 7 86 894 964 996 1005 9 64 640 9 65 56 06 108 50 75 9 11 10 22 1081 1112 1125 1085 7 24 1085 63 16 109 G 1344 9 22 1042 1120 1 1 46 1173 1131 7 04 1120 63 87 110 1936 1162 1340 1442 1474 1509 14 7 3 9 09 1441 82 77 111 2846 1631 1797 1902 1966 2027 2079 1342 19 2 3 11108 112 3484 207e 2144 2236 2307 2385 2574 1694 2268 13138 113 4066 24 65 24 42 2535 2648 2757 31 71 2178 2 5 96 15078 114 50 12 3059 2916 30 1 5 3176 3312 4059 2849 3105 180 46 115 1D 1362 2268 26 13 2613 26 35 2605 2503 15 46 2617 14934 116 1958 2993 3580 3580 3586 3539 3 5 02 2144 3571 20492 117 2812 4430 50 32 4913 4 9 86 4991 5196 3088 4981 287 66 118 3432 58 16 62 13 6067 61 18 60 66 6698 4143 61 16 354 16 119 40 22 71 71 7 4 62 7369 7419 7329 82 74 51 8 1 7395 42909 120 5026 105 95 11456 115 81 11574 11548 14010 80 91 11540 671 15 121 2D 1244 18 57 2277 2363 2305 2210 2107 1466 2289 13038 122 1960 2622 3240 3388 33 23 3226 31 40 2)99 3294 18919 123 2817 3762 45 87 4739 46 56 45 14 4 6 47 30 15 4624 26689 124 3491 50 22 5723 58 53 57 44 5542 60 18 3871 57 16 330 73 125 4096 61 29 68 16 69 79 6805 65 90 74 79 4677 67 98 39400 126 5037 82 27 94 60 95 69 93 57 9023 11324 65 05 93 52 542 83 127 12D 1278 14 70 1 6 48 1652 1638 1 6 34 1641 9 73 1 6 43 9369 128 1947 19 63 2155 2149 2151 2131 2190 1347 2147 12342 129 2769 2615 2791 2773 28 52 2716 2954 18 96 2783 1 60 82 130 3439 3208 3265 3239 3593 3133 3624 2515 3308 19174 131 4103 3637 35 88 3577 4077 3459 42 66 3138 3676 21343 132 49 78 45 82 44 60 44 8 1 55 17 43 25 5749 4227 4700 27288
Q) tlgt
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
133 1 12D 1299 2094 2507 2622 2625 2567 2489 1465 2578 14736 134 1973 29 56 3505 3772 3790 3718 3718 2115 3700 21290 135 2788 3941 4727 5069 5099 5 0 07 5231 2984 4976 28781 136 3473 5155 59 81 6308 6339 62 39 68 96 4204 6217 36052 137 4118 6135 71 8 6 7662 7731 76 91 87 16 49 8 5 7568 43985 138 4973 7765 94 75 10396 10861 10694 13646 66 64 10357 602 25
139 1ttn 1253 1242 1493 1460 1442 1431 1424 8 84 1457 83 01 140 2366 1942 2150 1961 1910 1897 19 62 1206 1980 11400 141 3461 3007 2957 2562 2513 2606 3143 18 51 2660 15400 142 4325 3942 3571 3060 2999 3198 4248 2631 3207 18618 143 5677 508 6 4359 39 88 3800 42 29 57 78 36 26 4094 23824 144 67 59 64 55 5330 4988 47 25 5494 2517 48 09 5134 29906 145 84 08 9326 72 26 7726 85 56 9172 12319 7733 8170 47626 146 86 54 9831 7582 818 9 94 90 9869 13116 78 97 8783 512 96 147 7376 7335 58 7 6 5941 5796 68 29 81 65 5954 6111 35662 148 2 11 D 4254 4106 48 02 4994 5038 5042 56 78 3419 4969 28881 149 5708 5487 6253 6466 6524 6527 78 63 45 8 2 64 43 37566 150 69 7 8 7983 9440 9848 98 34 97 32 13249 6701 9714 566 59 151 1254 1434 18 53 1947 1915 1850 1760 1186 1891 10772 152 2713 2696 3175 32 94 3288 3237 3288 20 44 3249 18728 153 87 30 118 07 14733 15758 15504 15305 26297 9617 15325 892 71 154 5811 5278 6543 6861 69 30 69 82 7 8 74 4478 68 29 39531 155 4246 3780 4736 4975 49 66 4936 5162 3113 4903 28301 156 (v 1270 8 15 935 959 966 9 51 9 23 6 35 953 5430 157 2714 1164 1390 1427 1447 1454 1455 9 08 1430 8242 158 4310 1655 18 96 1942 1988 2002 2111 1305 1957 11349
(j) ~
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 fry hav Nuav
159 6012 2208 2400 2450 2513 2548 28 20 18 00 2478 14416 160 7279 2696 2881 2927 2989 3081 3599 2340 2970 17326 161 86 90 3257 3360 3 3 76 34 26 3558 4455 2943 3430 2000 162 12D 4368 2209 2600 2558 2518 2466 2774 1753 2536 14713 163 5833 2730 3092 3028 2974 2913 3501 2287 3002 174 78 164 7643 3320 3681 3630 3651 3530 4623 3181 3623 21116 165 87 39 3920 4303 4300 4708 4178 61 60 3937 4372 25456 166 1268 962 1203 1205 1186 1118 1084 725 1178 6693 167 2678 14 67 1785 1779 1752 1698 1726 10 70 1754 88 49 168 1 12D 12 83 936 1217 1414 1397 1239 1190 7 65 1317 7484 169 2729 2502 2930 2914 2934 2956 2979 17 52 2934 16866 170 4345 3884 4357 4283 4318 4421 4836 28 59 4345 25151 171 6036 5546 5858 5764 5791 6028 7129 4184 5860 34045 172 6578 7167 7769 7907 79 82 8263 10492 5915 7980 46437 173 87 84 10237 112 23 120 26 12727 12968 185 19 85 98 12236 71103 174 1278 1344 1803 18 72 1835 1790 1712 1063 1825 10355 175 2711 2328 2972 2932 2893 28 78 2863 1667 2919 167 51 176 4351 3934 4414 4353 4281 4321 4654 28 63 4342 25088 177 5994 5076 5824 5838 5818 59 29 6914 4205 5852 33885 178 1 11 U 1223 388 432 465 464 449 435 338 453 2585 179 2351 521 602 6 22 675 6 57 619 436 639 3687 180 34 48 6 05 1725 803 8 27 8 11 760 518 792 4593 181 4513 718 850 934 9 68 9 57 8 99 609 9 27 5386 18 2 5714 8 32 981 1060 1102 11 06 1034 6 59 1062 61 82 183 6997 1025 1182 1258 1295 1309 1234 8 18 1261 7 3 44 184 8709 1295 1487 1 5 42 1594 1626 1612 1156 1562 9080
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
185 2 12D 4249 3560 4400 4670 4791 4695 47 81 2931 4639 268 37 186 5737 4926 58 54 61 92 6248 62 38 67 78 4134 6131 35590 187 7432 6390 7726 83 46 85 44 86 34 10371 5658 8313 48310 188 8723 7718 107 88 11933 12099 13046 186 22 79 39 119 67 69505 189 1 4 35 1340 1735 18 57 18 52 17 81 1711 1144 18 06 10256 190 2718 2399 3023 3187 3207 3138 30 53 1931 3139 18025 191 7 5 07 6189 80 11 9200 9427 9703 11364 5720 9085 527 38 192 8544 78 42 10666 125 42 13312 13775 178 20 6976 125 74 729 86 193 1287 1417 16 97 18 7 18 69 18 08 1720 1046 1800 10223 194 27 17 2450 2940 3187 3214 3157 3054 1749 3125 17954 195 42 53 3560 4222 45 90 4679 46 63 4743 2741 4539 26247 196 6068 48 69 57 79 6335 65 8 6 66 04 7172 4338 63 26 366 78 197 7389 58 86 72 8 6 82 23 8584 8936 10658 50 60 8257 4798 6 198 86 88 78 91 100 27 120 56 130 29 14299 190 81 6492 12353 71850 199 5864 4694 5 6 67 61 94 6419 65 48 7192 3950 6207 360 14 200 2 D 4177 38 36 4547 48 09 4775 4628 5006 2715 46 90 261 30 201 5712 5170 62 39 66 38 6599 6604 7518 4167 65 20 378 00 202 73 63 7201 8986 98 43 9733 9914 13353 6219 9619 55810 203 8604 10043 13118 148 41 150 42 158 66 25206 82 5 3 14717 85290 204 12 68 1506 18 41 1971 1966 1868 1799 11 42 1913 10880 205 2659 2571 3127 3276 32 50 3130 3069 18 80 3196 18 350 206 39 80 36 76 4347 4573 45~67 4473 46 34 28 37 4490 25910
o 207 Orifice 11496 10 64 1360 15 39 1 5 80 1 6 15 1496 8 58 15 24 88 83 208 9433 8 95 11 78 13 26 1394 1386 1263 727 1346 78 48 209 7387 746 9 77 1123 1184 1159 1048 6 11 1111 64 74 210 52 36 566 7 66 900 934 909 8 21 499 8 27 48 02
0) CJ1
TABLE III Continued
Run No Position CFM h 1 h2 hs h4 h5 h6 h7 hav Nuav
211 212
3309 1293
414 257
563 3 19
6 68 3 57
6 91 3 37
6 72 351
7 37 337
38 4 2 46
4 40 341
3748 1942
213 214 215 216 217 218
c of 2nd 1 516 1235
1919 2712 3320 4153 4704
1532 2447 35 46 4312 5567 74 29
2 1 87 3312 4225 52 86 6902 8 6 50
2360 3555 4340 56 12 7 0 49 8 9 40
2409 3598 4 8 85 5718 7713 9593
2347 2101 35 33 3453 48 00 49 62 5562 59 86 72~6 7 8 79 93 76 11237
1243 20 64 3054 4 2 8 1 5114 6983
2326 35 00 4638 5545 7225 91 40
132 13 200 27 26672 31968 41711 52811
bull
67
TABLE IV
PRESSURE PROFILE DATA
Baffle Flow Qpening Rate ~p
(Inches) Position (CFM) (Inches 295 S G Fluid)
1 364 l2 11 U 1012 0 254 1248 0197 1493 0 141 1718 0112
c 1000 9 80 1210 1710 1436 28 75 1746 4320 1011 1080 1277 2050 1393 3020 1 6 28 4450
12D 1011 9 75 1236 1520 1450 2510 1603 3450
1 D 1011 975 1256 1700 1480 2690 158 1 4070
1 12D 1010 950 1259 1750 1462 2650 1631 3710
2 11 D 1124 1315 1360 2130 1505 2850 1689 4125
1 216 12U 1294 045 1949 0324 2374 0282 2704 0225 3367 0169
c 1326 265 18 81 5 90 2313 990 2731 1480 3439 2660
12D 1272 2 49 1957 661
68
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Pos ition (CPM) Inches 2 95 S G Fluid)
2559 1275 3033 1940 3639 3025
1 216 1nD 1257 242 16 96 476 2117 8 05 2561 1280 2990 1895 3431 26 bull00
1 316 12U 1309 0 479 2004 0422 28 28 0 352 3526 0281 42 28 0225 5199 0225
c 1308 1 43 1998 272 28 14 5 10 3478 795 4248 1235 5048 1885
l2D 1286 140 2005 3 45 2831 725 3495 1180 4194 1805 5046 2945
1 11D 1322 150 2039 352 2841 735 43 77 1980 5378 3440
1 516 12U 1278 0493 2732 0493 4315 0408 5744 0352 7494 0352 8932 0422
c 1300 0 506 2731 1985 4310 348 6080 6 45
69
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Position (CPM) (Inches 295 SG Fluid)
7607 1090 8830 1585
l2D 1343 0549 2738 225 4566 583 6112 1195 7536 2055 9043 3415
1 516 1uD 1249 0464 2713 224 4155 579 5620 1150 7428 2115 90 70 3405
1 12D 1301 0493 2735 220 4501 616 61 50 1235 7440 2065 8862 3445
2D 1265 0 478 2750 226 4366 594 6578 1270 7678 2240 8945 5280
2 12D 1295 0493 2725 222 4293 600 5807 1120 7568 2200 9070 3615
TABLE V
RATE OF HEAT TR AN SFER Ar THE BAFFL~~ CID-TT ER
Orifice Size
(Inches)
Flow Rate
( CFM)
Re d e G tU
R~) 055 Nuav NuPr-l3
1 364 10 26 12 90
8 075 10015
43400 54 600
85 11 99 64
95 83 112 19
1416 11 140 59 900 110 30 124 20 16 27 12 800 68 900 126 64 142 60 17 29 13 610 73 200 135 79 152 90 17 76 13980 75 200 147 59 166 19
1 216 11 35 14 06
8 600 10 660
27000 33500
6 4 96 76 56
73 14 8 6 12
1517 11500 36100 82 51 9291 20 34 15400 48400 10229 115 18 23 11 17500 55000 118 31 13322 2348 17 800 55900 11947 13452 2666 20 200 63400 13508 15210 27 16 20 600 64700 135 05 152 07 32 47 24600 77200 161 57 18 193 3392 25 700 80700 17390 195 8 1
1 316 1344 19 36
9898 14 260
24800 35 700
63 8 7 8 2 77
71 92 93 20
28 46 20 9 60 52 500 111 08 125 08 34 84 25 660 64200 131 38 147 93 40 66 50 12
29900 36900
74800 92400
150 78 18046
169 78 203 20
~ 0
TABLE V Continued
Orifice Flow Re Size Rate d e G R~rmiddot55 NuPr-13(Inches) (CFM) U Nuav
1 516 12 70 8 847 16800 54 ~0 61 14 2 14 18 900 35800 82 42 92 80 43 10 30 000 56900 11349 127 79 60 12 41900 79400 14416 16232 7279 50700 96100 17326 19509 86 90 60540 115000 20098 22529
TABLE VI
RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
Orifice Size
(Inches)
1 364
1 216
1 316
Flow Rate
(CFM)
1054 1294 1431 1681 1770
1068 1399 1669 1959 2295 2636 3390
1299 1973 2788 34 73 4118 4973
Re deG Mshy
8 300 9870
11260 13200 13 930
8100 10600 12650 14850 17400 19980 25700
9 570 14500 20500 25600 30300 36600
R~r-6 51900 61700 70500 82 500 87 100
28200 36900 44000 51700 60 600 69500 89400
26100 39600 56000 69900 82700 99 900
Nuav
2416 293 5 3187 4018 4805
14938 18968 21712 25156 30680 37938 59601
14736 21290 28781 36052 439 85 60225
Uu Pr-1 3
27204 33050 3589 4524 541 0
16820 21358 24448 28326 34546 427 18 67111
16593 23973 32407 40595 495 1 678 13
TABLE VI Continued
Orifice Flow Re Size Rate deG R~rmiddot6 NuPr-13(Inches) (CFM ) M- Nuav
1 516 1268 88 30 17700 108 8 1225 2689 18700 37400 1835 2066 3980 27700 55700 2591 2917 4177 29100 58 500 2713 3055 5712 39800 80000 378 0 425 6 7362 51300 103000 5581 6284 8 604 59 900 120000 8529 9604
74
TABLE VII
EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER
l 516 Inch Orifice
Center ot 2nd Baffle 4 Downstream
Plow Rate (CFM)
1235 1919 2712 3320 4153 4704
Flow Rate (CFM)
1270 2714 4310 6012 7279 8690
(Re)eb -8600 1321
13400 2003 18900 2687 23100 5197 28900 4171 32800 5281
Center ot Single Battle
-8847 543
18900 824 30000 1135 41900 1442 50700 1733 60540 2001
(Nu)(Pr)-l3
1487 2255 3003 3600 4697 5946
(Nu)(Pr)-13
611 928
1278 1623 1951 2253
75
ABLE VIII
HEAT TRANSFER IN THE TEST SECTION WITHOUT ORIFICE
CFM Ute) 0b h Nu
1293 5-951 3 41 1942
33 09 15251 649 3746
5236 24193 827 4802
7387 34001 1111 6474
9433 43419 1346 7848
11496 52-914 1524 8883
76
TABLE IX
PRESSURE DROP FUNCTION
Orltlee Size Flow Rate incbea ~CFM (Re)eb X 10bull8
1 364 1011 7957 0808 1256 9885 1468 1480 11648 2765 1581 12443 4160 1689 1_3293 4 020
1 216 1257 9530 1327 1696 12858 2663 2117 16049 4615 2561 19415 7581 2990 22668 11560 3431 26011 16440
l 316 1322 9736 1819 2039 15016 4332 2845 20952 9275 3495 25739 15300 4377 32014 26800 5378 39607 50100
1 516 1011 7 957 oaos 1256 9885 1469 1480 11646 2765 1581 12443 4160 1689 13293 4020
77
TABLE X
EXPERIMENTAL DATA
Baffle Hole Diameter Run No
1 - 59
60 - 102
103 - 138
139 - 206
207 - 212
213 - 218
(Inches)
1 364
1 216
1 316
1 516
No Baffle
2nd - 1 516
TABLE X
EXPERIMENTAL DATA
Run Thermocouple Reading s (mv) No Position CFM I tc1 tc2 tc3 tc4 t c 5 tc6 tc7 tcair
1 c 1026 530 2055 1825 1768 1782 1802 1837 1965 1198 2 1290 612 2059 18 65 1809 18 32 1851 1880 1965 1160 3 1416 714 2151 1970 1931 1965 1988 2026 209 5 1130 4 1627 8 21 2235 2084 2 049 2093 2126 2173 2266 1130 5 1776 865 2203 2033 1970 2015 2084 2159 2 264 1121 6 12D 1109 542 1636 1507 1499 1499 1498 1498 1528 1218 7 1258 651 1670 1522 1503 1513 1513 1516 1548 1221 8 1433 750 1625 1480 1467 148 3 1487 1487 1516 1153 9 168 1 8 73 1656 1494 148 1 1511 1517 1517 1543 1159
10 1rtD 1102 485 1545 1450 1437 1446 1447 1442 1466 1220 11 13 08 6 10 1571 1470 1460 1476 1476 1469 1498 1194 12 1464 730 1 623 1509 1508 1528 1 5 32 1524 1548 1173 13 11 06 8 71 1663 1559 158 1 1606 160 6 1 583 1601 1190 14 1 12D 1115 520 1698 1579 1575 1 577 1580 1590 1615 1280 15 1275 6 10 1692 1567 1558 1 561 1570 1580 1601 1234 16 1498 770 1760 1619 1630 1 635 1642 1645 1661 1204 17 1695 912 1775 1635 1670 1689 1686 168 6 1701 1165 18 2D 1049 510 1736 15~2 1567 1558 1 553 1558 1620 1236 19 12 41 610 1655 1517 149 1 148 1 148 1 148 4 1546 1108 20 1 5 32 7 35 1720 1550 1530 1520 1519 1523 158 0 1104 21 16 74 8 8 0 1900 1 727 1714 1696 1691 1692 1753 1169 22 1U 1074 38 5 3 324 2740 2534 2478 2 465 2503 258 0 1210 23 1287 4 35 3510 2 870 2682 2 610 2599 2638 27 1 9 1190 24 1 5 08 470 3 618 2920 2690 2 637 2627 2 664 2747 1177 25 18 07 525 4 088 3235 2962 2905 2910 2988 3130 1169
z ())
TABLE X Continued
Run No Position CFM I tc1 tc 2
Thermocouple Readings te3 tc4 tc5
(mv) tc6 tc7 tcair
26 c 10~29 6 32 2340 2~092 2032 2060 2~097 2152 2~213 1211 27 12 66 679 2270 2 047 1993 2013 2069 2142 2 210 1 182 28 1430 723 2336 2097 2033 2080 2153 2~255 2 356 1 138 29 1729 8 52 2318 2070 1980 2061 2158 2279 2367 1121 30 12D 1054 570 1520 1 4 20 1402 1400 1396 1400 1 443 1159 31 1294 6 69 1599 1469 1444 1439 1433 1 442 1485 1168 32 1430 7 88 1720 1562 1536 1532 1528 1537 158 0 118 5 33 1770 8 81 1641 1488 1450 1~441 1 441 1_466 1518 1 163 34 1D 1058 548 1579 1498 1495 1526 1553 1_557 1 571 1 276 35 1263 640 1609 1509 1515 1570 1599 1598 1 598 1 266 36 18 36 8 47 1538 1452 1483 1553 1602 1 590 1 558 1195 37 1 12D 1029 5 41 1 578 1499 148 4 1473 1461 1465 1-512 1200 38 1315 6 30 159 1 1504 1493 1482 1470 1470 1505 118 5 39 1 4 26 743 1765 168 1666 1660 1645 1642 1678 1270 40 1757 8 54 1744 1648 1634 1620 1598 1 593 - 1612 1223 41 2D 1080 5 30 1734 1604 1570 1 570 1570 1 588 1 640 128 1 42 1305 6 40 1744 1622 1589 1 608 1593 1 609 1 661 1240 43 1434 750 1798 1687 1658 1 636 -1641 1 661 1 711 1_220 44 18 04 8 41 1 764 1666 1607 1605 1614 1 635 1 675 1205 45 12nu 1088 415 2614 2295 2195 2 169 2174 2217 2256 1171 46 1318 477 2805 2477 2371 2342 2364 2 401 2 438 1 163 47 1413 5 28 2930 2 646 2 555 2 526 2532 2570 2 577 1 199 48 1773 550 2740 2518 2450 2431 2448 2 479 2 480 1 170 49 1 11 U 1054 380 3175 2670 2505 2 461 2467 2 534 2 621 1 258 50 1240 420 3268 2738 2 546 2 510 2 508 258 2 2 649 1214 51 1419 451 3364 2B07 2 632 2590 2 590 2 651 2773 1 215 52 1 12U 1032 360 3 165 2 629 2 450 2402 2403 2 473 2 bull568 1 163
--I lt0
TABLE X Continued
Run No Position CFM I tc1 tc2
lhermocoup1e Reading s tc3 tc4 t c 5
(mv) tc6 tc7 tc a ir
5 3 1314 38 9 3178 2592 2411 2367 2361 2432 2555 1140 54 1448 403 3095 2544 238 1 2336 2336 2390 2476 1158 55 178 2 427 3006 2434 2286 2253 255 3 2299 2397 1154 56 2 11U 1061 360 3369 2814 2619 2567 2560 2650 2833 1220 57 1216 360 3044 2512 2338 2290 2288 2374 2566 1150 58 1322 387 3196 2614 2425 2383 2382 2472 2670 1138 59 1639 403 3020 2438 2272 2238 2238 2318 2502 1127
60 1D 1068 612 1552 1424 1400 1395 1396 1426 1745 0945 61 1399 612 1355 1246 1230 1229 1230 1250 1509 0872 62 1669 710 1436 1293 1272 1265 1266 1286 1551 0847 63 1959 900 159 5 1468 1444 14 38 1432 1446 1720 0851 64 2295 730 1169 1105 1098 1099 1108 1100 1298 0781 65 2636 8 80 1202 1129 1121 1126 1 138 1115 1342 0748 66 3390 9 35 1060 o 9s7 0999 1001 1017 0971 1154 0703 67 1nu 1190 370 2225 2188 2104 2080 2120 2209 2 7 15 0990 68 1559 368 2005 1950 1871 18 48 1876 1951 2408 0916 69 1904 368 1870 18 1 4 17 34 1711 1730 18 07 2238 0875 70 22 bull11 471 228 6 2 204 2099 2063 2092 218 $ 2732 0840 71 2289 471 2030 2000 1925 1895 18 96 19 5 2498 0785 72 2727 4 71 1854 18 23 1753 17 23 1716 3758 2241 0743 73 3210 471 1680 1651 158 6 1559 1551 158 1 1950 omiddot7o9 74 2uD 1210 404 1261 1212 1198 1197 1205 1222 139 1 0978 75 14 20 540 1321 1260 1242 1 240 1249 1268 148 7 0918 76 1692 7 18 1467 138 6 1364 1361 1376 1405 1678 0883 77 18 94 903 1708 1 591 1565 1560 1575 1603 1948 0 857 78 2301 903 1530 1432 1407 1402 1415 1432 1738 0815
ro 0
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc117 tcair
79 2621 6 50 1069 1 020 1009 1009 1009 1007 1~189 o739 80 3230 901 1200 1128 1113 1119 1119 1086 1341 0694 81 82
l2D 1155 1689
360 575
1191 1345
1142 1252
1122 1218
1118 1210
1118 1209
1132 1228
1292 1446
0916 0822
83 1244 430 1163 1134 1131 1130 1129 1132 1292 0877 84 2100 645 1175 1135 1147 1 142 1138 1122 1286 0757 85 2292 8 25 1 354 1310 1327 1330 1323 1285 148 6 0728 86 2907 8 23 1180 1138 1151 1158 1149 1107 1268 0687 87 3380 902 1113 1049 1025 1011 1006 1042 1178 0673 88 89
1 12D 1427 1875
480 615
118 2 1140
1140 1095
1124 1077
1125 1075
1129 1072
1137 1072
1290 1243
0880 0790
90 2259 8 41 1296 1231 1207 1206 1203 1182 1419 0757 91 2682 8 80 1231 1170 1149 1147 1142 1112 1350 0731 92 3417 940 1142 1092 1076 1076 1069 1021 1252 0693 93 c 15 17 431 1321 1298 1268 1249 1250 1273 1522 0841 94 2034 505 1285 1263 1235 1209 1205 1206 1464 0759 95 2348 6 10 1395 1379 1334 1302 1286 1268 1536 0732 96 2716 706 1486 1480 1427 1383 1358 1311 1572 0 700 97 3247 7 56 1417 1430 1375 1320 1284 1223 1450 0660 98 1135 400 1425 1388 1352 1329 1330 1 364 1651 0893 99 14 06 440 1379 1341 1304 128 2 1281 1305 1583 0 831
100 2311 680 1602 1593 1553 1514 1502 1480 1 7 27 0 802 101 2666 680 1471 1469 1428 1390 1372 1335 1564 0761 102 3392 798 1491 1 509 1449 1395 1372 1305 1534 0 719
103 1U 1235 410 2469 2295 2173 2165 2226 2361 3120 0 897 104 2010 410 2017 1848 1 737 1706 1747 1865 2582 0753 105 28 14 410 1682 1535 1457 1427 1437 1520 2109 0 660
00 t-
TABLE X Continued
Ru n Thermocouple Rea ding s (mv No Positi on CFM I tc1 tc2 tc3 tc4 tc5 tc6 tc7 tcair
106 3492 440 1649 1499 1420 1391 1390 1470 2042 0620 107 4395 550 18 33 1679 1597 1564 1570 1640 2223 0583 108 5075 588 1779 1642 1580 1550 1552 1 615 2 191 0548 109 c 1344 398 1464 1 399 1364 1353 1350 1380 1689 0 907 110 1936 459 1369 1290 1253 1242 1 237 1259 1574 078 2 111 2846 580 1347 128 5 1251 1232 1220 1215 1 5 23 0 683 112 34 8 4 700 1392 1369 1339 1317 1299 1259 1599 0 636 113 4066 8 13 1449 1458 1427 1391 1363 1270 1595 0 591 114 5012 930 1484 1530 1500 1453 1420 1272 1580 0 580 115 1D 1362 513 1269 1218 1 217 1214 1220 1238 1460 0 893 116 19 58 600 1187 1122 1121 1120 1124 1133 1352 0798 117 2812 705 1052 1008 1015 1010 1011 1001 1218 0691 118 34 32 913 1105 1075 1085 1081 1086 1047 1301 0645 119 4022 980 1038 1021 1026 1023 1029 0983 1211 0 609 120 5026 982 0 8 61 0839 0836 0836 0837 0791 0955 0570 121 2D 1244 475 1320 1246 1233 1240 1255 1275 1434 0925 122 1 9 60 5 50 1160 1088 1074 1079 1089 1100 1260 078 7 123 2817 6 80 1096 1024 1 013 1018 1029 1022 1201 0 700 124 3491 960 1248 1175 1163 1172 1192 1153 1435 0 658 125 4096 989 1141 1089 1078 108 9 1105 1051 1310 0629 126 50 37 989 0983 0933 0929 0 936 0949 0880 1090 0 602 127 128
12D 1278 1947
402 545
1270 1261
1 230 1216
1228 1216
1230 1 215
1235 1223
1242 1219
1483 1514
0 913 0778shy
129 2769 695 1273 1234 1237 1221 1251 1212 1525 0678 130 131 132
34 39 4103 4978
8 40 9 80 9 80
1336 1448 1271
1322 1458 1 288
1328 1 462 1286
1 259 1 356 1157
1353 1492 1311
1261 1329 1138
1 555 160 7 1343
0 629 0 600 0599
(l) l)
TABLE X Continued
Run No Position CFM I tel tc 2
Thermocouple Readings tc3 tc4 tc5
( mv) tc6 tc7 tcair
133 1 l2D 1299 5 16 1 28 1 1212 1196 1195 1205 1221 1478 0869 134 1973 6 15 1163 1098 1073 1071 1079 1083 1343 0751 135 136
27 88 34 73
802 9 -_78
1187 1214
1099 1131
1069 1104
1066 1101
1075 1~110
1l061 1066
1370 1360
0662 0618
137 4118 9 81 1084 1010 0983 0979 0982 o937 1209 0581 138 4973 98 1 0969 0897 0 868 0855 0860 0799 1041 0572
139 1D 1253 409 1371 1293 1298 1301 1309 1321 1578 0928 140 2366 480 1130 1 090 1 121 1130 1137 1132 1390 0744 141 34 61 6 38 1081 1086 1152 1161 1147 1069 1382 0644 142 143 144
4325 5677 6759
7 90 939 998
1110 1115 1034
1161 1208 1139
1253 1268 1180
1265 1302 1215
1228 1230 1123
1080 1056 0970
13$913r12 8
0601 0561 0542
145 84 08 989 0863 0961 0934 0895 0871 0 785 09 9 0530 146 86 54 9 80 0808 0901 0 872 0821 0809 0733 0891 0498 147 7376 9 80 0 927 1032 1027 1 040 0961 0889 1032 0511 148 2D 4254 776 1 050 0 981 0965 0961 0962 0922 1155 0579 149 5708 991 1102 1031 1014 1009 1010 0931 1227 0528 150 69 78 990 0914 0853 0839 0 839 0843 0759 0996 0521 151 1254 490 1 479 1352 1329 1334 1351 1379 1607 0930 152 2713 7 00 1310 1220 1201 1201 1211 1209 1516 0723 153 8730 991 0809 0756 0742 0745 0 748 0663 0874 0543 154 5811 966 1219 1108 108 6 1081 1079 1033 1330 0650 155 42 46 8 02 1248 1136 1114 1114 1118 1103 1376 0 699 156 c 1270 429 1671 1571 1551 1545 1563 1600 1933 0929 157 2714 488 1398 1285 1 267 1258 1262 1275 1628 0729 158 4310 642 1424 1318 1299 1282 1283 1261 1683 0617
co ~
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc7 tc a 1r
159 60 12 780 1461 1388 1370 1349 1343 1279 1700 0 573 160 72 79 8 60 1402 1344 1330 1312 1292 1189 1 566 0 520 161 8690 982 1472 1442 1437 1 422 1392 1224 1602 0 521 162 163
12D 4368 5833
6 30 8 30
1195 1368
1105 1270
1111 1283
1117 1294
1131 1313
1081 1194
1369 1553
0613 0 553
164 76 43 959 1428 1338 1348 1341 1371 1180 1488 0535 165 8739 984 1345 1272 1272 1208 129 3 1059 1361 0550 166 1268 459 1701 1548 1541 1547 1589 1 625 1976 0 973 167 2678 570 1485 1351 1349 1356 138 1 1 385 1795 0760 168 169
1 12D 128 3 2729
448 650
1664 1314
1501 1232
1425 1233
1428 1229
1491 1229
1527 1232
1869 1571
0 962 0767
170 4345 847 1245 1179 1187 1182 1172 1132 1476 0 650 171 6036 9 76 1139 1109 1117 1114 1095 1020 1332 0588 172 6578 9 72 0982 0949 0942 0938 0926 0 8 50 1079 0560 173 87 84 9 72 0880 0854 0 8 36 0822 0818 0 749 0941 0585 174 1278 480 1564 1416 1397 1403 1417 1445 1733 0998 175 2711 590 128 3 1175 4 1178 1182 1187 1195 1493 0796 176 4351 8 90 1331 1259 1266 1275 1272 1235 1592 0 682 177 5994 9 60 1228 1152 1150 1151 1143 1075 1 360 0644 178 lU 1223 408 2282 2140 2052 2052 2106 2188 2626 0 878 179 2351 408 178 1 1623 158 5 1519 1556 1634 2068 0717 180 3448 482 1888 1675 1570 1541 1572 1665 2199 0629 181 4513 563 2026 1797 168 4 1644 1670 1770 2385 0583 182 5714 589 1913 1700 1610 1568 1580 1 682 2382 0551 middot 183 6997 653 1903 1718 1643 1611 1612 1700 2326 0 549 184 8709 6 80 1738 158 3 1543 1510 1498 1519 1 912 0577 185 186
2 12D 4249 5737
660 9 74
1055 1221
0 979 1122
0960 1093
0 952 1088
0959 1090
0 956 1054
1147 1350
0661 0602
187 7432 9 8 1 1065 0981 0951 0942 0 939 0881 1135 0582 CD ~
TABLE X Continued
Run No Position CFM I t o1 to 2
188 87 23 9 83 0944 0 879 189 1435 585 18 26 1630 190 2718 690 1433 1298 191 7507 950 1070 0961 192 85 44 964 0982 0 881 193 1287 600 1806 1668 194 2717 7 80 1579 1444 195 4253 8 81 1371 1260 196 60 68 9 78 1252 1152 197 73 89 975 1100 1000 198 86 88 973 0953 0 871 199 58 64 9 81 1269 1155 200 2D 4 1 77 915 1362 1251 201 5712 975 1213 1111 202 7363 9 78 1036 0 951 203 8 604 973 0932 0861 204 1268 6 95 2015 18 20 205 2659 6 96 1405 1295 206 39 80 7 98 1261 1174
No 207 Orifice 114 96 509 1325 1148 208 94 33 509 1477 1243 209 7487 5 09 1686 1409 210 5236 505 2094 1691 211 3309 428 2188 1 778 212 1293 392 2976 2560
Thermo ooup1e Readin g s (mv) to 3 to4 to
5 to
6 to7 toair
0 851 0847 0 8 29 0759 0987 0592 158 4 1583 1611 1647 1993 0986 1270 1266 1 279 1298 1604 0 789 0916 0908 0900 0 858 1115 0602 08 39 0 823 0 818 0 770 1035 0602 1609 1602 1629 1676 2153 0979 139 1 1385 1400 1 430 1938 0776 1212 1201 1205 1201 1601 0669 1 105 1086 1086 1 052 1371 0621 0952 0936 0923 0870 1195 0582 0 8 20 0 801 078 1 0 729 1044 0569 1108 1090 108 2 1043 1407 0610 1218 1221 1241 1202 1582 0659 1081 1083 1084 1031 1 368 0622 0921 0924 0919 0 841 1111 0 610 08 34 0831 0 821 0 751 1003 0 630 1761 1761 1 809 1861 2399 0966 1271 1271 1295 1311 1650 0797 1150 1150 1161 1149 1440 0703
1083 1057 1053 1109 1566 0~530 1158 1125 1138 1217 1763 0 526 1291 1250 1278 1383 2038 0542 1518 1478 1519 1657 2420 0 589 1596 1557 1601 1737 2441 0688 2370 2344 2409 2561 3 297 0921
()) (11
TABLE X Continued
Run Thermocouple Readings (mv) No Position CFM I tc 1 tc2 tc3 tc4 tc tc tc tc i5 6 7 a r
C of 2nd 213 516 1235 4 63 1 432 1291 1265 1258 1 268 1 308 1550 0 971 214 1919 6 17 1357 1223 1196 1191 1199 1211 1461 0 851 215 27 12 8 35 1401 1259 1278 1220 1230 1218 1511 0 762 216 3320 981 1439 1305 1270 1259 1275 1238 1450 0719 217 41 53 980 1251 1142 1132 1094 1121 1088 1305 0 695 218 404 987 1102 1042 1030 1 bull006 1014 0960 1133 0681
Supplementary Equations
Calculating temperatures from thermocouple readings
t = -026tc)2 + 3512(tc) + 3201 (26)
where t is the temp in deg F and tc is the thermocouple reading in millishyvolts
Calculation of the thermal conductivity of air
k = 00000245ta + 0 0132 (27)
where k is the thermal conductivity in Btuhr rt2 degFft and ta is the air temp 1n OF
I I
bull co m
18
Fi gure Pa ge
Var iation of Heat Transfer Rate and Pressure Drop with Orific e Size at a Con stant Flow Rate bull bull bull bull bull bull 50
bull bull bull bull bull bull bull bull
bull bull
I
II
III
IV
v
VI
VII
VIII
I X
z
LIST OF TABLES
Pa ge
Summary of Experimental Program bull bull 19
Position of Maximum Heat Transfer 32
Calculated Heat Transfer Data 57
Pressure Profile Data bull bull bull 67
Rate of Heat Tr ansfer at the Baffle Center middot bull bull bull bull bull 70
Rate of Heat Transfer at the Point of Maximum Heat Transfer bull bull bull bull bull bull bull bull bull bull bull bull 72
Effect of Upstream Baffles on Heat Trar1sfer bull bull bull bull bull bull bull bull bull bull bull 74
Heat Transfer in the Test Section without Orifice bullbullbullbullbullbullbullbull 75
Pressure Drop Function 76
71bull r ntal bull bull bull bull bull bull bull bull bull bull bull bull
HEAT TRANSFER AND PRESSURE PROFILRS IN THE VICINITY OF ANNULAR ORIFICES
- CHAPTER I
INTRODUCTION
The most common type of industrial heat transfer
equipment is the shell and tube heat exchanger which
consists of a bundle of tubes contained in a cylindrical
shell Heat is transferred from the hot fluid to the cold
fluid through the tube walls as one fluid flows through
the tubes and the other flows through the shell surroundshy
ing the tubes
Most commercial multitube heat exchangers contain
bafflesmiddot to guide the fluid through the equipment and to
prevent stagnant regions from forming in the shell As a
result the flow pattern in the shell is very complicated
and considerable variation of the local rate of heat transshy
fer occurs because of the various types of flow which exist
in the baffled passage The research described in this
thesis concerns a study of one small portion of the shell
side of a heat exchanger
There are three main types of baffles used in commershy
cial heat exchangers
1middot Orifice baffles extend through the cross section
of the shell and all of the shellbullside flow is
through the annular orifice formed at each point
where the tube passes through the baffle
2
2 Disk and doughnut baffles consist of disks and
doughnuts or annular rings placed alternately
along the length of the tube bundle~ There is
some flow through the annular orifices formed
where the tubes pass through the baffles but a
large portion of the flow is around the baffles
3 Segmental baffles are segments of a circle and
Bre arranged so that the fluid flows back and
forth across the tube bank There is still some
f~ow through the small area where each tube goes
through the baffle
In the case of disk and doughnut and segmental baffles
small annular clearances must be allowed at the point where
the tube goes through the baffle so that the bundle may be
assembled easily Thus in all of the types of exchangers
some shell-side fluid flows through the annular orifice
where the tubes pass through the baffles It has been
shown that this is an area of high rate of heat transfer
but its effect on the overall performance of the heat exshy
changer is not well known Also the prediction of rates
of heat transfer 1n these orifices is not yet possible
The purpose of this research was to make an extensive
study of the heat transfer rates in the vicinity of these
annular orifices and to determine the effect of orifice
size flow rate and upstream conditions The work was
5
performed in a onebulltube single orifice type baffle heat
exchanger and provision was made to measure local rates
of heat transfer in the vicinity of the baffle
4
CHAPTER II
THEORY AND PREVI OUS WORK
In 1701 Newton defined the heat transfer rate qc
from a surface of a solid to a fluid by the equat ion
= ~A(tw - t) (1)q0
where hm is the coefficient of heat transfer from the surshy
face to the fluid excluding any radiation A is the area
of the surface tw is the surface temperature of the wall
and t is the bulk temperature of the fluid The equation
for the point of local surface coefficient h is given by
dqdA = h(tw- t) (2)
The mechan ism and the laws covering heat transfer by
true conduction in solids and by radiation through transshy
parent media are well known However with heat transfer
from a solid to a fluid the situation is far more complex
The mechanism of flow of the fluid to a large extent deshy
termines the rate of heat transfer for a given temperature
difference
In addition the coefficient hm depends on certain
physical properties of the flowing fluid the dimensions
of the apparatus the velocity of the fluid past the surshy
face and frequently the temperature potential AT
It was the purpose of t his research to measure the
local shell -side heat transfer coefficient and correlate
it with the several variables mentioned a bove
5
The heat transfer coefficient for fluids flowing inshy
side tubes is more e a sily measured and correlated due to
the simple geometry of t he tube i nterior Much work has
been done on the tube-side coefficients with one of the
more useful e quations being the Dittus - Boelter equation
( 4 p 450) ~
0 023 (---ctwGJbulla (~np M ( 3 ) M k
with the following cond itions satisfied
(1) Fluid properties evaluated at the arithmetic
mean bulk temperature
(2 Reynolds number gt10000
(3) 0 7 lt Pr lt 100
(4) n = 04 for heating and 0 3 for cooling
(5) Ldw gt60
Colburn (3 p 197) obtained an equation for tubeshy
side heat transfer coefficients in which the Stanton
number is used instead of the Nusselt number
hm ) (~~ 23 _ (dwG) 0 2 ( GC k - 0 bull 023 U (4)
p
Much of the research done on average shell-side heat
transfer coefficients has resulted in empirical correlashy
tions of the form of equations (3) and (4) above Several
investigations have been made for a certain set of phys~al
6
variables but the r esults have ne ver satisf a ctorily been
correlated to appl y for all types of heat exchangers
Some basic 1ork has been done recently however on
the local shell-side coefficients Ambrose (1) studied
the local heat transfer coefficients i n a model heat exshy
changer with segmental baffles This study was fairly
extensive at the baffle center but the data were quite
limited for the space between the baffles Gurushankar1ah
(5) further extended Ambroses work by studying a single
baffle space in detail
The results of these two studies indicated a need for
detailed information 1n the vicinity of the baffle Hence
Lee () investigated a single baffle s pace between two
orifice baffles and obtained considerable information on
the rates of heat transfer in the annular orifices Since
his work was carried out in a multitube mode l heat ex~
changer the determination of the rate of flow through the
individual orifice was difficult because of t he outer
clearances existing in the exchanger For this reason the
present research was undertaken to study the rate of heat
transfer in a single annular orifice through which the flow
could be accurately determined
Bell and Bergelin (2) have studied i n detail the pres shy
sure drop coeff icients for the annular orifices formed beshy
tween a circular disk and a circular tube These results
also appl y to the annular orifioe formed when a rod extends
7
through a circular hole in a plata This study was extenshy
sive in the fact that it considered the baffle thickness as
well as the orifice size but no heat transfer data were
presented
Sullivan and Bergelin (9) studied flow through a
single annular orifice through multiple annular orifices
i n parallel and flow around a single baffle both with and
without leakage through the baffle A generalized expres shy
sion is presented for the pressure drop across one baffle
section of a tubular exchanger with leakage through the
tube holes in the baffle but the effect of leakage area
upon heat transfer is only discussed qualitatively The
pressure drop data is correlated by plotting cent as a funcshy
tion of the Reynolds number where cent equals
d1 )22( ~ P) s c e (d2 -
M-2
8
CHAPTER III
~PERI1ffiNTAL APr ARATUS
The heat transfer test section was essentially a
single tube heat exchanger The inner tube was a l-in
OD aluminum tube with an electrically heated probe midshy
way between the two ends of the tube
Test Section
The shell as constructed from lucite plastic tubing
2 5-in I D and 3-in O D The te t section d a total
lengt h of 54 58 inches I t consisted of two sections
The upstream section was 40 i n ches in length in order to
assure freedom from entrance effects and the downstream
section was 13 12 inches in length To further assure
uniform flow a bundle of short copper tubes was placed a
few inches downstream from the entrance Both of these
sections had 12 i nch flanges on one end so t hat a 18
i nch thick orifice plate could be clamped between them
Heat transfer coefficients were measured in the vicinity of
t h is orifice A cross section of the center of the test
section is shown in Figure 1 and the experimental appara~
tus is shown in Figure 2
Cooled air supplied by a Roots -type blower was used
as the shell-side fluid throughout this study It entered
the test section through a l-in ID 1 12-in OD plasshy
tic pipe at the upstream end of the calming section Tbs
j Jl l 6- 11 BOLTS II I nbull middot~11 I HEATING ELEMENTS
J T ( T
-f-shy - - - f-_- __L
7 777 _y A
IT 1] I
I
FIGURE I CROSS SECTION OF TEST SECTION AND PROBE
10
FIGURE 2 EXPERIMENTAL APP1Ub~fUS
11
air left the test section through nine equally spaced 12
ineh holes placed around the side of the tube at the exit
end
Sensing Probe Assembly
The sensing probe was designed to measure the local
heat transfer coefficients at any point along the tube and
around the tube in the test section The tube was designed
so that it could be easily moved up- and downstream to
measure the heat transfer coefficients at various positions
in relation to the orifice
The sensing tube assembly consisted of the sensing
probe the thermoctmple lead s and selector switch the
power lines and the two aluminum tubes between which the
probe was centered
Imbedded in the sensing probe were seven iron-constanshy
tan thermocouples for measuring the temperatures around the
tube The lead wires from these thermocouples were conshy
nected to a seleotor switch at the downstream end or the
aluminum tube A layer of Saran wrap was placed around the
tube over the t hermocouple and three lengths of Trophet C
resistance ribbon were wrapped around the tube nd conshy
nected in series to the power leads
The heating surface of the probe was formed by these
three one inch wide strips of Trophet C resistance ribbons
The ribbons were 0002 inches thick and had a resistance of
12
0 271 ohms per foot and a thermal conductivity of 763
Btuhr ft 2 degFft They were held in position by four
copper bars placed in four parallel longitudinal slots
These copper bars served as connectors for the electrical
leads A photograph of the sensing probe is shown in
Figura 3 and a drawing of the assembled probe is given in
Figure 4
Power Source
Direct current was used to heat the resistance ribbon
on the sensing probe The current was regulated by a slide
wire resistor The po er source consisted of a Raytheon
Voltage Stabilizer to stabilize the city power source at
115 volts and an automatic selenium rectifier with an alshy
ternating current input of 115 volts at 60 cycles per
second and an output of 12 volts and 35 amperes direct
current
Temperature Measuring
The temperatures around the sensing probe were calcushy
lated from the emf readings of the ironbulloonstantan thermoshy
couples The emf measuring system consisted of the seven
probe thermocouples a separate thermocouple for measuring
the inlet air temperature a thermocouple selector switch
a cold junction and a Leeds and Northrup Type K Potentishy
ometer The potentiometer was placed on a Fischer
13
THERMOCOUPLE JUNCTIONS~ ~------- HOLES FOR THERMOCOUPLE LEADS
~----- SCREWS
~ff+--- CONNECTING BARS
END VIEW
POWER LEADS SOLDERED TO LOWER CONNECTING BAR
iER PLASTIC PIECE
RESISTANCE RIBBONS LOCATION OF THERMOCOUPLES
FIGURE 4 DRAWING OF ASSEMBLED SENSING PROBE
15
Vibradamp support to absorb the vibrations produced by the
air blower
Air Source
Air was used as the shell-side cooling fluid during
the study The air was pumped through the test section by
a Roots type air blower with a rating of 280 ofm at 3 12
psig outlet pressure The hot air leaving the blower was
passed tbxfugh two finned-tube box-type coolers and one
tubular edoler to oool it to approximately room temperature
The air flow rate was measured by passing it through a
flow measuring orifice in the line Two sharpbull edged orishy
ficas were used f or flow measurements The calibration
curves for these orifices were presented by Ambrose (1
p 166)
The pressure taps on each side of the orifice were
connected to two differential manometers containing 0 83
and 2 95 specific gravity fluids respectively The presshy
sure drop through the test section and test orifice was
measured by a pressure tap placed 13 inches upstream and
one placed 6 12 inches downstream from the orifice Two
pressure ga ges were used to measure the pressure at the
inlet to the flow orifice and to indicate the statio pres~
sure at the test section inlet
16
Pressure Probe
A probe was designed to measure the pressure drop
between the pressure tap 13 i nches upstream from the ori shy
fice baff le and any point downstream from the tap The
probe eonsisted of a l~in OD copper tube with six 132
i n ch holes even l y s paced around the tube The upstream
pressure tap and the pressure probe were connected to a
differential manometer so the pressure drop to various
points up- and downstream of the orifice could be measshy
ured
17
CHAPTER IV
EXPERIMENTAL PROGRAM
The experimental program was designed to measure the
heat transfer coefficients and pressure drops in the vicinshy
ity of annular orifices The four orifice sizes studied
were 1 364 1 216 l 316 and 1 516 inches~ The inner
tube used in each case was a 1-in OD alumintim tube
Hence tube to baffle clearances were respectively 3128
232 332 and 532 of an inch
Heat transfer coefficients were measured at poait~ons
1 i nch upstream at the orifice center and at 12 1
1 12 and 2 inches downstream for all orifices In addishy
middottion the heat transfer coefficient at a point 2 12
inches downstream from the 1 516 inch orifice was measured
and at the points 12 l 12 and 2 inches upstream from
the 1 364 inch orifice
The heat transfer coefficients at each point were
measured at five different flow rates for the 1 364 inch
orifice and at six different flow rates for the other orishy
fice sizes The high pressure drop through the small orishy
fice size limited the number of flow rates which could be
studied
The flow rate was calculated from the pressure drop
across the flow orifice This flow was corrected to cubic
feet per minute at 68degF and one atmosphere pressure by
18
using the orifice pressure and the test section pressure
which were measured by pressure gages
It was desired to determine a relationship between the
heat transfer coefficient and the total pressure drop for
each orifice size The pressure drop across each orifice
at various flow rates was measured by means of the presshy
sure probe described in Chapter III It was also desired
to obtain pressure profiles for each orifice size since
these might be similar to the heat transfer profiles The
pressure drop was measured from a point 13 inches upstream
of the orifice to points at 1 and 12 ineh upstream the
orifice center 12 1 1 12 and 2 inches downstream
The experimental program is summarized in Table I
TABLE I
SUla~RY OF EXPER IMENTAL PROGRAM
Position Investigated-Distance from Orifice-Inches
Orifice Range of Flow Rate Size Heat Transfer Pressure Drop CFM at 68degF amp 1 atm
1 364 2U 1 12U 1U 12U c 12U C 12D lD 10 - 18 l2D lD 1 12D 2D 1 12D 2D
1 216 1U c 12D lD 1 l2D 2D 12U c 12D lD 10 - 35
1 316 1U c 12D lD 1 l2D 2D l2U C 12D lD 12 - 50
1 516 1U c x2D lD 1 l2D 1U 12U C 12D 12 - 90 2D 2 1 2D l D 1 l2D 2D 2 12D
20
CHAPTER v
EXPERI MENTAL PROCEDURE
The experimental procedure for measuring the heat
transfer coefficients ~d corresponding flow rates reshy
quired the following procedure
(1) Install the orifice size to be studied in the
test section
(2) Place the heat transfer probe in the position up
or downstream from the orifice where the middot heat
transfer rate is to be studied
(3) Fill the cold junction thermos with cracked ice
(4) Measure the atmospheric pressure
(5 Open bypass line from blower and close line to
test section
(6) Turn on the cooling water for the exchangers used
to cool the air leaving the blower
(7) Start the automatic selen ium rectifier by turning
on the t 1mer bull
(8 ) Connect the voltage stabilizer to the wall outlet
(9) middot Set the slide wire resistor to the maximum re shy
s1atanee I
(10) Start the blower
(11 Open the line to the test section until the de shy
sired flow rate is obtained
(12) Switch on the probe direct current power source
21
(13) Adjust the slide wire resistor to obtain the
desired current
(14) After the thermocouples have reached equilibrium
values record the e m bullf across each of the
seven probe thermocouples and also the entering
air thermocouple
(15) Record the direct current amperage
(16) Record the gage pressure at the flow orifice and
the entrance to the test section
(17) Record the manometer measurement of the pressure
drop across the flow orifice and also the presshy
sure drop through the test section
22
CHAPTER VI
CALCULAT ION OF EXPERIMENTAL DATA
The local heat transfer coefficients were calculated
from the temperatures measured on the probe surface the
air temperature and the current input The results were
calculated by using the Alwae III-E computer
The general expression for calculation of the heat
transfer coefficients was derived by Ambrose (1 p 79)
The equation is derived by making an energy balance around
a small increment of the center resistance heating ribbon
The two ribbons tnstalled adjacent to the center ribbon
reduced the amount of logitudinal conduction and assured
little longitudinal temperature variation in the center
ribbon
A heat balan ce on this small increment of resistance
ribbon yields the following
(the heat conducted in) + (heat generated) = (heat
conducted out) +(Heat convected to the fluid) + (heat
radiated to the surroundings) + (Heat conducted into
the plastic center of the probe)
This gives the equation
kzw dtdS + 12RdS kzws [ t + (~) ds] + hwdS (t-ta )
+ ~Aad wd o middot+ qcAond 1 -~- wdS 5 )
23
Hence solving for h gi~ea
i2R kz d2t Qrad qcond w + -d$2 - ~- A
h = ( 6)t - ta
Since S = re where 9 equals the enclosed angle ~n radians
dS rd9 ( 7)
and
dt - dt (8)dS - rd9
Differentiating with respect to S
d2t (9)rd9dS
from which
(10)
Substitut1ng into the equation for heat transfer coeffishy
cient gives
h = i2R Qcond A (11)
w
The rate of radial heat conduction into the plastic
tube making up the probe was assumed to have negligible
effect on the heat transfer coefficient It was also
assumed that the heat loss by radiation from the ribbon
was negligible since all data were obtained with the ribbon
at a temperature less than 125degF
24
When t he rad iation and conduction terms are neglected
Eq (11) becomes
(12)
The following con stants are known
R = 0 271 ohmsft
w = 100 i n ches
k = 763 Btuhr rt2 degFft
z = 0 002 inches
r = 12 inch
Eq (12) putting 9 in degrees then reduces to
1110 12 + 2404 d 2t d92
( 15)h = ------~--~-------t - ta
Thi s equation was programed for the Alwac III- E comshy
puter and used to calculate the local heat transfer coefshy
ficients from the observed data
The average heat transfer coefficient around the tube
at a given position in the t est section was calculated by
averaging the local coefficients calculated from Eq (13 )
It was found 1n the course of the experimental work
that thermocouple numbers 1 and 7 were indicating higher
temperatures than would be expected This resulted in h1
and ~ being lower than the other local coefficients around
the tube Since the fluid was flowing parallel to the axis
of the probe the circumferential variation i n rate of heat
25
transfer should be small Hence in obtaining the average
coefficient around the tube the values of h1 and h7 were
not used even though they were calculated and are tabulated
1n Table I II in the Appendix
Then
(14
A Nusselt number as calculated from this aver age heat
transfer coefficient using the tube diameter as the characshy
teristic dimension
(15)
The air flow rates through the test section were calshy
culated by measuring the pressure drop across the flow orishy
fice the air temperature the pressure at the flow orifice
and the pressure at the entrance to the test section The
orifice calibration curves (1 p 166 ) were used to obtain
a value of the orifice coefficient f8e where Q equals
the flow in cubic feet per minute at 68deg F and one atmosmiddot
phere pressure and te is the density of air at the exchanger
and e the density of the air at the flow orifice The
den sity of the air can be expressed by
e = 2 703 p (16)T
where T equals the temperature in OR and P equals the absoshy
lUte pressure i n lb1n2 Using the value of e Qfo from
26
the calibration charts as A and Eq (16) solving for Q
gives
( 17
This equation was used to calculate the flow rate for
each flow studied
The Reynolds number used i n the correlation of the
data was the equivalent Reynolds number defined as
Re)eb ~ d2 - dl)Uf ( 18 ) lL
where d1 is the outside diameter of the inner tube and d2
is the orifice diameter U is the flow velocity through the
annular orifice e is the density of the air and U- is t he
viscosity of the air This equation can be transformed t o
(Re) b = 1611 Q (19) e dl + d2
where d1 and d2 are in inches
The pressure drop data were calculated i nto a dimenshy
sionless pressure drop function cent where
d1 )22( ~ P)gc f av(d2 shycent 2 bull (20
M-
For air this equation reduces to
where d2 and d1 are in i nches D P is expressed i n inches of
2 95 specific gravity fluid and P av is expressed as lbft3
27
CHAPTER VII
ANALYSIS OF DATA
In analyzing the heat transfer data an attempt was
made to correlate it 1n terms of the dimensionless groups
(Nusselt number Prandtl number and Reynolds number) which
appear in Eqs (3) and (4) Consequently all of the av~
erage heat transfer coefficients hav were brought into
the form ( Nu)( Pr)~3 bull The Nusselt number was based on the
tube diameter and the thermal conductivity of the air at
the flowing temperature The tube diameter was used in the
Nusselt number because comparison could then be made with
previous experimental work on heat exchangers which have
commonly used the Nusselt number defined as in Eq (15)
From the standpoint of dimensional analysis this is
equivalent to considering the tube diameter as the characshy
teristic length so far as the heat transfer is concerned
The Prandtl number of the air was taken as 0 7 in all
cases
Variation of Heat Transfer Rate with Distance from the Baffle
Considerable variation was observed in the rate of
heat transfer in the vicinity of the baffle In order to
obtain the variation with respect to position the term
(Nu)(Pr)-13 was plotted versus the flow rate Q for each
position and orifice studied Cros s plots were then made
28
at constant flow rates in order to obtain the variation of
(Nu)(Pr) -13 with position The resulting cross plots are
shown 1n Fi gures 5 6 and 7 for the four orifices studshy
ied
About one inch upstream from the orifice the heat
transfer coefficient begins to rise rapidly and continues
to do so until it reaches a maximum some distance downshy
stream After the maximum point the heat transfer coef fi shy
cient decreased slowly The heat transfer rate was found
to reach a maximum at a different position downstream for
each orifice size These figures also show that for a
given orifice size the maximum heat transfer rate occurs
a pproximately at the same point for all flow rates The
position of the maximum point f or each or ifice size is
shown in Table II
The region immediately downstream from the orifice is
one of h i gh turbulence due to the jetting action of the air
flowing through the orifice As the air flows t hrough the
orifice the streamlines continue to converge for some dis shy
tance downstream The point of maximum heat transfer is
probably at the point where the streamlines be gin to diverge
and a boundary layer begins to build up on the tube Tle
decreasing heat transfer coefficient beyond the maximum
point indicated the formation of a boundary layer
Since the position of the maximum point is independent
of flow rate middot it is possible to correlate it with respect
_ ct 11shyz-
100
0 136 ORIFICE
(
I 0
I )
~ 00
~p 0
I 0
--r--- ~
ISCFIII
-_ OCFM
rbull abull
~ middot~ a-1 z-
12fORIFICE
100
200
100
0 0 UPITRAM ORIFICE DISTANCE CENTER
CFM
h I DOWNSTREAM
DISTANCE
FIGURE 5 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLpound
30
too
700
800
100 ~ f gtf
400
z ~
100
100
100
0
13fORIFICE
~ -~ -- ---
)
~
~
-
I ~ ~OCFM
I vI~-~ OCFM
J ---
Iamp CFM
I 0 I I UPSTREAM ORIFICE DOWNSTREAM DIITANOE GENTER DIITANCI
FIGURE 6 VARIATION OF HEAT TRANSFER RATE WITH DISllNCE FROM BAFFLE
--
--- --
31
100
100
700
100
_ 100
f 9- 400 z-
100
tOO
100
0 - I 0 I I I UHTRIAM OAtfiCI DOWIIITMAM
+ I tyl6 ORIFICE
v I
~~ ~CFM
I v ~CFMI
v v 7
~~ v ~ iOCFM
- ~~ I-shy1-shy ~ICFM
DIITMCI OINTIR DIITANCI
FIGURE 7 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLE
32
TABLE II
POSITION OF MAXIMUM HEAT TRANSFER
Position of Maximum Orifice Size Heat Transfer
(inches) (inches downstream)
1 364 050
1 216 100
1 316 125
1 516 200
33
to orifice size Figure 8 shows the effect of the orifice
size on the position and value of the maximum heat transfer
at a constant flow rate of 15 cubic feet per minute It
can be seen that the larger the orifice size the further
downstream the point of maximum heat transfer occurs
Also as the orifice size increased the rate of heat
transfer decreased for a given flow rate The broken line
indicates the variation of the point of maximum heat transshy
fer with position and size The position of the point of
maximum heat transfer rate downstream from the orifice was
correlated with orifice size by means of the dimensionless
groups (Lde) and (d1de) where L is the distance downshy
stream from the orifice where the maximum rate of heat
transfer occurs d1 is the outside diameter of the inner
tube and de is the equivalent diameter of the orifice
ie de = d2-dlbull
Figure 9 shows a plot of Ld 6 versus d1d6 for the
four orifice sizes studied The four points on this logshy
log plot are approximately in a straight line and the
equation of this line is
Lde = 0 44 d1de)028 (22)
Although the above relationship represents a correlashy
tion of dimensionless groups it is based upon only one
tube diameter and needs to be substantiated further by
studying other tube diameters and other orifice sizes
34
aoo
400
aoo ~
-~ middot-CLshyJ z
200 -
100
0
ORIFICE CENTER
l~
l
t
I J~
1pound~
I
0 I I~
AT 15 CFM
-
bull ~ 1~6~
~ v~
~
~--~~6
~~~ ___ v v V -_
~ o q
~ I 16
v
~
ogWNSTREANI STANCE
FIGURE 8 EFFECT OF ORIFICE SIZE ON POSITION AND VALUE OF MAXIMUM HEAT TRANSFER
35
50
loshy____ -~
~ ~ -shylltl-shy~ r0
2 10 30
FIGURE 9 CORRELATION OF THE POINT OF MAXIMUM HEAT TRANSFER WITH
ORIFICE SIZE
36
Correlation of Data at the Baffle
The heat transfer data were correlated by obtaining a
relationship between the group (Nu)(Pr)-13 and a
Reynolds number based on twice the clearance (d2 - d1
between the tube and the baffle It was found that the
most satisfactory correlation could be obtained when the
term - d1 was used as the length term in the Reynoldsd2
number
Figure 10 shows the variation of the heat transfer
rate at the center of the orifice e xpressed as a function
of Reynolds number and the orifice size This shows that
for a given Reynolds number the heat transfer at the center
of the orifice is greatest for the smallest orifice size
In order to obtain a general correlation of the data
shown i n F1gure 10 the effect of the dimensionless ratio
d1de was considered This ratio considers all of the
geometric factor s needed to describe the annular orifice
The thiclaless of the orifice plate is also a factor but
was constant i n this i nvestigation
The data for the heat transfer at the baffle center
are shown in Figure 11 in which (Nu)( Pr)-13 is plotted
versus (Re)ebd1 de) 0 55 This data on a log-log plot
lies on a straight line for (Re)eb( dld8 )0 55 greater
than 3 x 104 The equation for cor relating the heat
37
4XI~middot~-r~------~--~~------~
Icf t--to_+--_c-c-________ SYMBOL SIZE
0 1~4
6 ~~
9 ~~ -o ~
(Re)eb
FIGURE 10 RATE OF HEAT TRANSFER AT BAFFLE CENTER
38
500
0
4 0 lcf
~ ~
~ ~iC-
~ ~
~IL 0~ 0 SYMBOL SIZE-
p 0 1364-
r 6 1~16 -~ -
9 1~16 --o 1~16
I I
FIGURE II CORRELATION OF HEAT TRANSFER DATA AT BAFFLE CENTER
39
transfer at the center bullOf the a nnular orifice was found by
the method of least s quares to be
(Nu)( Pr)-1 3 = 0018 ( Re)ebO Bl( dlde)04~ (23)
3 x 104 ltRe)eb(a1de)055 lt 105)
Rate of Heat Transfer at the Point of Maximum Heat Transfer-The heat transfer rate at the point of maximum heat
transfer is plotted in Figure 12 to show the variation with
Reynolds number and the size of the orifice It is shown
gives the h1gh st heat transfer ~ate at its point of maxibull
that for a given Reynolds number the smallest orifice size yen il
mum heat transfer
The data ~or the maximum poi~t could be correlated by
plotting (Nu) Pr)-13 versus (Re)eb(d1de)06 This plot
is shown 1n Figure 13 and the resulting eurve shows that
(Nu(Pr)-13 is not a simple p0wer function of the Reynolds
number as was the case for heat transfer at the baffle
center The reason for this is probably because other
factors such as intensity and scala of turbulence should
be considered At the orifice center the streamlines of
the flowing stream are converging_ and thus the flow is
quite stable Downstream from the orifice is a region of
large eddy currents and probably large scale turbulence
These factors could con ceivably cause the results which
were obtained for the point of maximum heat transfer
40
If)
~middotshy Q_-I z_
10~~~--------r----~~--~--
SYMBOL SIZE
0 13$4
6 1~8
Q 13-18
-o 1~8
7)(104
(Re)eb
FIGURE 12 RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
41
Ia ~
0 I
c ~ ~ c v
~ ~lt w ~
17
~ b
v ~ ( SYMBOL SIZE
-~ 0 f-64 -v ~ 6 t211e
~ Q I~~~
-o - l~rs I I
FIGURE 13 CORRELATION OF HEAT TRANSFER DATA AT THE POINT OF MAXIMUM HEAT TRANSFER
4 2
Effect of Upstream Baffles on Heat Transfer at the Orifice Center
The heat transfer rate at the orifice center using the
single orifice in a test section is a pproximately 13 of the
value that was obtained by Lee (7) using a model heat exshy
changer with orifice baffles Lee investigated the cent r al
baffles of the heat exchanger and thus the coeff icients he
obtained would be affected by the presence of a number of
upstream baffles To determine the effect of upstream
baffles an additional l 516 inch baffle was placed four
inches upstream 1n the test section The resulting data are
shown in Figure 14 where (Nu)(Prmiddot)-13 is plotted versus
(Re) eb for the case of a single baffle 1n the test section
and also the case of an additional baffle placed four inches
upstream Comparison is made with the results obtained by
Lee middot(7) using a four-baffle and a ten-baffle model heat exshy
changer Good a greement is obtained with Lees work and the
results show the marked effect that upstream baffles have on
the downstream heat transfer rate The additional up tream
ba ffle caused sufficient turbulence 1n the test section to
i n crease the heat transfer rate nearly three-fold at the
center of the next baffle
Heat Transfer i n the Test Section with No Orifice
In order to check the accuracy 6f the equipment the
orifice baffle was removed and the heat transfer mea sured
with the probe in the empty test section The data were
43
~~BAFFLES
0 l BAFFLE -shy
ll_9 2 BAFFLES
V 4 BAFFLES-LEE
4 10 BAFFLES- LEE lJf ~
~rv ~~ ~ v flvv ~~
I ~ J ~ L v
0
v
( V
40 3XIo 7XIa
(Re)eb
FIGURE 14 EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER AT BAFFLE CENTER
44
compared with heat transfe r coefficients predicted by the
equations for annuli which are recommended in the litera shy9
ture The two equa~ ions u sed tor comparison were
(hfe)=0 023 (rltGr e (~~ur4 (~r45 (24)
which was presente~ by Wiegant (10)
and ( h ) (cnM~5(M~l o14 o 023 CPG k j Mij - (de GJMb )0 2 ( 2 5)
which was presented by McAdams (8 p 242) The comparshy
i son is s hown in Figure 15 lq (25) gives a value which
is low by about ten percent while Eq (24) g ives values
which are high by as much as twenty -five percent when comshy
pared with the experimental data The se equations are gembull
erally considered to give coefficients with an accuracy of
about twenty percent Therefore the present experimental
data are within the accuracy of these equations Also the
plot indicate s that for a Reynold s number greater than 2 x
104 the slope of the line is the same for the experimental
data as for the equations
Pressure Drop Data
The total pressure drop across the orifice was measured
as a function of the flow rate and the orifice size The
pressure drop was expressed as a d1mens1onleas quantity r)
which ie plCltted ver sus the Reynolds number in Figure 18
The pressure drop function cent correlates for all or1f1oe
45
200
100
s z
10 5XI10 10
0 EXPERIMENTAL
--McADAMS
-WIEGAND L
V
~ ~ ~
P ~ ~
LL~ L
v~
~
v v
v 1 ~ ~ v
v -gt
~
~ ~
~
6Xid
FIGURE 15 HEAT TRANSFER WITH NO BAFFLE
46
0 1~4 -~ a 6 t216
Q t316 lJ J
-0 as a )t
A LEE I -shy SULLIVAN 8
p
10bull
BERGELIN
I _ll I
I ~
i I
~middot
lo II
f fl
J j
~middot
A)101
1q
I Ill
1 I3 X 10ao1
FIGURE 16 ORIFICE PRESSURE DROP FUNCTION VS REYNOLDS NUMBER
47
sizes- The present data extends the range covered by preshy
vious workers and agrees well with their work The preshy
vious work of Lee () for a heat exchanger containing 10
orifice baffles and also the data of Su livan and Bergelin
(9) for pressure drop in a model heat exchanger with a
single baffle is shown 1n Figure 16 long with the present
results~ This figure may be used to predict the preseure
drop from the equivalent Reynolds number of the annular
orifice
The pressure drop between individual points 1n the
vicinity of the orifice and an upstream pressure tap wa s
measured to obtain a pressure drop profile As might be
expected 1n all cases the profiles showed a rapid decrea e
in static pressure immediately upstream from the orifice
There was however little or no recovery of the pressure
loss downstream The 1 364 inch orifice did show a maxishy
mum point in the pressure drop but this maximum occurred at
the orifice center and total recovery was reached about 12
inch downstream
Heat Transfer at the Baffle and Maximum Point as a Function of Pressure Drop
In order to compare the effect of the total pressure
drop on the heat transfer at the baffle and the point of
maximum heat transfer Figure 17 was plotted showing
(Nu)(Pr)-13 as a function of the total pressure drop This
shows that for a given pressure drop the largest orifice
48
1200
1000
~ a -sshyz-
100
60 100 700
AT MAXIMUM POINT I 15116 2 13116 3 1~6 4 1364
AT ORIFICE CENTER
60
1
v
r ~ ~ ~
5
~
8 7
13116
8
~
1364
v
~
e6
1~6
v
~~ v ~ ~ -~ ~
~
~ v
l
~
vamp
I ~ ~
~
v L ~
v
I-
5
k= ~~
~ ~ ~
--I
v ~
FIGURE 17 HEAT TRANSFER AT THE BAFFLE AND MAXIMUM POINT AS A FUNCTION OF
ORIFICE PRESSURE DROP
49
size has the greatest heat transfer coefficient This is
true at both the orifice center and at the point of maxishy
mum heat transfer
Another comparison can be made by plotting the heat
transfer coefficient and the pressure drop versus the orishy
fice size at a constant flow rate Figure 18 shows this
plot This graph shows that at a constant flow rate the
pressure drop as well as the heat transfer coefficient
increases as the size of the orifice is decreased In
choosing an orifice size for maximum efficiency 1t would
be necessary to know the pumping power available as well
as the heat transfer desired
70 I I 700
AT 15 CFM 60 ---
~ aug
50 ---
NV
40 ~
~ ~ ~
~ _
MAXIMUM POINT ---- --- ~
1-----t---~ _
~00Qj ~
~t--- ORIFICE CENTER 10 1100
1---~ n
u0 01 02 03 Q35
a ltl
de inches
FIGURE 18 VARIATION OF HEAT TRANSFER RATE AND PRESSURE DROP WITH ORIFICE SIZE AT A CONSTANT FLOW RATE
cn 0
51
CHAPTER VI II
SUMMARY OF RESULTS
This study revealed several significant facts about
the heat transfer in the vicinity of annular orifices
Probably the most important contribution was the presshy
entation of the heat transfer profiles in the vicinity ot
the annular orifice ~ r s shown that t~ local heat
transfer coeffieient re~ches a maximum at a point downshy
stream from the orifice The distance downstream at which
this maximum oocurs is t1ven by the equation
22
The heat transfer coefficients at the center of the
orifice were correlated and found to follow the equation
(Nu)(Pr)-13 = 00176 (Re)eb08l(d 1de) 0 middot4~ (23)
3 x 104 lt( Re) 9 b( d1d6 )055 ltlo5 )
The heat transfer at the point of maximum heat trans
fer for each orifice size was correlated and presented in
Figure 13 as a plot of (Nu)(Pr)-l3 versus (Re)eb(d1de) 06
No simple po-orer relationship exists between the terms
Intensity and scale of turbulence downstream from the orishy
fice are probably important factors which affect the heat
transfer
The large effect of an upstream orifice on the heat
transfer rate at the second orifice was demonstrated by the
52
study of two 1 516 inch orifices in the test section The
added turbulence at the center of the second orifice was
found to raise the heat transfer rate almost three times
over that obtained for a single baffle
The pressure profiles in the vicinity of the orifice
indicate that nearly all the pressure drop occurs at the
orifice center~ Total pressure drop data were correlated
by a pressure drop function cent as a function of the Reynolds
number and good agreement obtained with the results of other
workers
The pressure drop and heat transfer data were correbull
lated by plotting the heat transfer as a function of the
pressure drop for each orifice size It was shown that for
a given pressure drop the largest orifice size gives the
greatest heat transfer coefficient
As a final presentation it was shown that the pressure
drop and the heat transfer coefficient both i ncrease i n
value at a constant flow rate as the orifice size is de shy
creased This is important in choosing the optimum clearshy
ance for orifice baffles
53
CHAPTER IX
RECOMMENDATIONS
A great deal of work remains to be done in the field of
evaluating shellmiddotside heat transfer coefficients This
study included only one tube size and air was the only f luid
used It is recommended that further studies be conducted
using other fluids and tube sizes It will also be necessary
to study several baffle types
The adde d turbulence due to a s e cond baffle placed upbull
s t ream would suggest that the heat transfer coef ficients at
a certain position i n relation to a baffle would increase as
the flow progressed through the exchanger It is recomshy
mended that an extensive s t udy should be made between baffles
the full length of a model heat exchanger
It is further recommended that the pressure drop study
be continued to include other fluids tube sizes and baffle
arrangements
Effects of turbulence downstream from the baff le should
be studied by i n vestigations with hot-wire anemometer equipshy
ment to determi ne t urbulence scale and i ntensity
54
NOMENCLATURE
Area of heat transfer
Heat capacity of the fluid
Outside diameter of the tube
Orifice diameter
Equivalent diameter of the orifice (d2 - dl)
Inside diameter of the test section
Inside diameter of the tube
Gravitational constant
G Mass velocity
h Local heat transfer coefficient
Coefficient of heat transfer from surface to fluid
i Direct current amperes
k Thermal conductivity of the fluid
L Distance downstream of the point of maximum heat transfer
p Absolute pressure
L P Total pressure drop across the orifice
Q Flow in cubio feet per minute at 1 atmosphere and 680 F
q Heat transferred
Thermal energy conducted into the sensing probe
Thermal energy radiated from the resistance ribbon
Resistivity of the resistance ribbon
s Length of the resistance ribbon
T Temperature oR
55
t Temperature of the resistance ribbon deg F
ta Temperature of the bulk stream oF
tw Wall temperature of the tube OF
U Veloc ity of the fluid
w Width of the resistance ribbon
z Thickness of the resistance ribbon
eeuro Density of the fluid in the test section
Density of the fluid at the flow orificef 0
AL Viscosity of the fluid
E9 Angle measured around the tube
Dimensionl ess groups
(Nu) Nusselt number hd1k
(Pr Prandtl number C~k
(Re)eb Equivalent Reynolds number at the baffle (d2 - d1 )uejt-Lshy
(Re)e Equivalent Reynolds number in the test section ( d 8 - d 1 )U fu
cent Orifice pressure drop function 2(~P ) gc~av(d2 - d1) 2
Al
56
BI BLIOGRAPHY
1 Ambrose Tommy W Local shell-side heat transfer coefshyficients in baffled tubular heat exchanger PhD thesis Corvallis Oregon State College 1957 183 numb leaves
2 Bell K J and o P Bergelin Flow through annular orif ices Transactions of the American Society of Mechanical Engineers 70593-601 1957
3 Colburn Allan P A method of correlating forced con shyvection heat transfer data and a comparison with fluid friction Transactions of the American Institute of Chemical Engineers 24 174-210 1933
4 Dittus F w and L M K Boelter Heat transfer 1n automobile radiators of the tubular type University of California Publications in Engineering 2443-461 1930
5 Gurushankariah M s Local shell-side heat transfer coefficients in the vicinity of baffles in tubular heat exchangers Masters thesis Corvallis Ore gon State Colle ge 1958 97 numb leaves
6 Knudsen James G and Donald L Katz Fluid dynamics and heat transfer New York McGraw-Hill 1958 576 p
7 Lee Kyu Sung Local shell-side heat transfer coeffishycients and pressure drop in a tubular heat exchanger with orifice baffles Masters thesis Corvallis Oregon State College 1959 118 numb leaves
8 McAdams William H Heat transmission 3d ed New York McGra ~-Hill 1954 532 p
9 Sullivan F W and 0 P Bergelin Heat transfer and fluid friction in a shell-andbulltube exchanger with a single baffle Chemica l Engineer ing Progress Symposium Series 52 ( 18) 85-94 1956
10 Wiegand J H Discussion on annular heat transfer coshyef f icients for turbulent flow Transactions of American Institut e of Chemical Eng i n eers 41147-153 1945
AP PENDIX
57
TABLE III
CALCULATED HEAT TRANSFER DATA
Baffle Hole Diameter Run No (inches)
1 - 59 1 364
60 - 102 1 216
103 - 138 1 316
139 - 206 1 516
207 - 212 No orifice
213 - 218 2nd - 1 516
TABLE III
CALCULATED HEAT TRANSFER DATA
Local Heat Transfer Coefficients Run
T0 bull Po s ition CFM hr h2 h3 h4 hs he ~ hav Nuav
1 c 1026 10 59 1476 16 09 1559 1510 1435 1203 1518 8511 2 1290 1369 1738 1878 18 05 1755 1689 1515 1773 9964 3 1416 1636 198 1 2068 1977 1924 1845 1715 1959 11030 4 1627 1991 2301 2382 2268 2194 20 ~98 1929 2249 12664 5 1776 2252 2669 2863 2713 2517 2338 2126 2620 14759 6 l2ttD 1109 2311 3317 3386 3373 3387 3394 3071 3371 18888 7 1258 3089 4583 4866 4683 4701 4643 4194 4695 26301 8 1433 38 8 5 55 83 5791 5495 5430 5436 5008 5547 31192 9 1681 4992 7378 7649 6980 6864 6870 64 28 7148 40180
10 1 D 1102 2371 3332 3511 3356 3342 3427 3102 3394 19012 11 1308 3218 4379 45 24 42 53 4255 4373 3965 43 57 24446 12 14 64 38 58 5146 5142 4839 4787 4903 4597 4963 278 79 13 1706 5218 6664 6269 58 81 5884 6237 5973 61 87 34718 14 15
1 l2D 1115 1275
2131 2661
2955 3638
2972 3720
2941 3675
2913 3576
28 22 34 74
2613 3278
2921 36 17
163 09 20246
16 1498 34 87 4644 4503 4441 4371 4343 4194 4460 25010 17 1695 4449 5743 5324 5222 5154 5157 5015 5320 298 97 18 2D 1049 1715 23 90 2550 2610 2656 2624 2208 2566 14363 19 1241 2117 2964 3145 3218 3221 3203 2759 3150 17757 20 1532 28 67 3936 4100 4188 4201 4167 3676 4118 23224 21 1674 3459 4508 4598 4746 4795 4792 4299 4688 26337 22 lU 1074 253 340 380 3 86 388 377 354 374 2097 23 1287 292 392 433 440 441 429 406 427 2394 24 1508 322 439 492 498 499 487 461 48 3 2713 25 18 07 3 38 464 519 5 24 520 499 463 5 05 28 40
~~ (]I agt
TABLE III Continued
Run No Position CFM h 1 h2 ~3 h4 h5 h6 ~ h
av Nu
av 26 c 1029 1171 1491 1589 15 28 1 4 62 1377 1293 1489 83 44 27 1266 1395 1746 1853 18 02 1685 1556 1453 1728 9704 28 1430 1637 2037 2175 2060 1909 1735 1591 1983 11159 29 1729 1982 24 96 2751 2507 2268 2030 1886 2410 13579 30 12D 1054 2934 4041 4321 4326 4423 4359 3706 4298 24160 31 1294 3385 4 8 26 52 42 5326 5450 5277 4566 52 24 293 50 32 1431 3784 5347 5721 57 bull75 58 44 5700 5084 5677 31870 33 1770 52 75 7 7 33 87 35 9005 9007 8267 7059 85 49 48050 34 lD 1058 3235 4401 4444 3877 3496 3451 3294 3934 21973 35 1263 38 98 5484 5330 4347 3964 3981 3987 4621 25823 36 18 36 6701 89 17 7855 6369 5597 5769 6283 69 01 38718 37 1 12D 1029 2404 31 8 2 3333 3459 3624 3577 3045 3435 19264 38 1315 3182 4033 4162 4310 4496 4502 4015 4301 24142 39 1426 3628 4389 4510 4573 4760 4804 43 8 5 4607 25678 40 1757 4547 5559 5(35 5931 6282 63 70 6060 5975 33471 41 2 11D 1080 2034 28 38 3155 3144 3145 2966 2540 3050 17027 42 1305 2650 3 4 87 3aoz 3595 3751 3595 3153 36 46 20405 43 1434 3167 39 07 4156 4371 4320 4126 3709 4176 23395 44 1804 4096 4 9 66 5691 5714 5586 53 15 48 65 5454 30582 45 12U 1088 409 516 557 564 5 60 535 513 5 46 30 67 46 1318 470 579 6 22 631 6 17 5 97 579 6 09 3422 47 14 13 540 640 676 6 86 681 6 60 6 54 6 69 3754 48 1773 641 740 774 782 7 69 749 746 763 42 87 49 l 11 U 1054 270 356 391 397 393 3 71 346 38 2 2133 50 1240 303 399 446 449 447 4 21 398 432 2420 51 1419 361 476 522 530 528 507 467 493 2760 52 1 1(2U 1032 236 311 342 347 344 325 301 334 18 78 53 1314 270 366 403 407 408 386 351 394 2217
(Tt tO
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ h av Nu av
54 1448 301 408 447 454 452 431 403 438 24 61 55 1782 353 494 548 544 415 529 531 506 2843 56 2U 10 61 220 287 316 320 322 303 268 310 1735 57 1216 249 335 370 377 378 353 307 363 2044 58 1322 263 356 394 398 399 374 327 384 2159 59 1639 310 433 478 481 482 452 393 465 2617
60 1D 10 68 2011 2536 2657 2681 2694 2560 15 62 2625 14938 61 1399 2520 3239 3369 3371 33r82 32 39 1946 3320 18968 62 1669 2781 3655 3820 38 76 3883 3738 2355 3794 21712 63 1959 3524 42 37 4399 4438 4497 4417 3047 4397 25156 64 2295 4426 5288 5396 5372 5240 5410 3369 5341 30680 65 2636 5490 6531 6662 6565 6379 6820 4249 6591 37938 66 3390 7869 9538 9462 9387 8924 10508 62 91 9564 59601 67 1U 1190 352 368 401 413 407 395 293 397 2256 68 1559 397 422 462 475 471 456 331 4 57 2603 69 1904 434 465 5 13 529 528 504 358 508 2901 70 2211 493 526 573 5 92 588 564 4 15 569 3257 71 2289 569 587 6 30 649 6 61 6 49 460 635 36 44 72 2727 637 6 60 7 09 733 751 743 521 719 4140 73 3210 728 755 8 15 8 43 8 62 8 54 616 826 4765 74 2nD 1210 181 2256 2393 2399 2333 2206 1325 2317 13158 75 1420 2340 2752 2899 2913 2850 2728 1701 2828 16121 76 1692 2853 3306 3452 3471 3379 3217 2134 3365 19217 77 1894 3102 3588 3713 3736 3670 3557 2455 3653 20892 78 2301 3682 4259 4433 4467 43 83 4289 2892 4366 250 30 79 2621 4117 4828 5017 5012 5030 5109 3071 4999 28785
m 0
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ hav Nuav
80 3230 5158 6006 62 13 61 18 6134 6695 4094 6233 359 87 8 1 12nD 1155 15 27 1854 2028 2064 20 85 1987 1164 1968 118 31 82 1689 2046 24 8 2 2688 2739 2760 2658 1749 2665 152 73 83 1244 2088 2317 2339 2345 2373 2381 1487 2351 13432 84 2100 3211 3539 34 21 3462 3512 3696 2575 3526 20284 85 2292 3 5 05 3761 3648 36 25 36 79 3957 2933 3734 21517 86 2907 4420 48 22 4679 46 04 4705 5206 3792 48 03 27741 87 33 80 59 35 69 38 7404 77 10 7 8 36 7 0 86 5190 7394 427 44 88 1 12D 1 4 27 2 4 58 28 31 3037 3021 2987 2927 18 57 2 9 61 16913 89 18 75 34 75 3 9 87 4230 4255 4317 4337 2734 4225 24258 90 22 59 4221 4796 5046 5052 51 01 5389 3491 5077 29206 91 2682 4978 5664 5943 5966 6054 6573 408 1 60 40 34795 92 3417 63 16 71 02 7 3 93 7385 75 40 8 6 95 51 45 7623 44017 93 c 1 5 17 1240 1305 1399 1467 1479 1429 9 26 1423 8251 94 20 34 1554 1623 1720 18 21 18 53 18 72 1215 1778 10229 95 2 3 48 1795 1843 198 5 2097 2171 2274 1540 2074 11947 96 2716 2028 2048 22 01 2 3 44 2444 2661 18 90 2340 13505 97 3247 2410 2375 2663 2778 2949 3298 2378 2793 1615 98 11 35 967 1040 1124 1186 1200 1142 728 1138 6496 99 14 06 1135 1220 1318 1384 1403 1 3 61 8 77 1336 7656
100 2311 1 8 54 18 78 1980 20 90 2136 2227 1653 2062 118 31 10 1 2666 2085 2094 2227 2 3 62 2438 2626 1902 2349 13508 102 3392 2635 2582 28 01 3026 3141 3529 2567 3016 17390
103 1 U 1235 349 395 434 436 4 28 411 286 423 2416 104 20 10 434 5 02 559 577 569 5 37 345 552 3177 105 28 14 538 626 685 711 7 21 682 424 6 8 6 3966
Q) j-J
TABIE III Continued
Run No Position CFM h1 h2 h3 h4 h5 hu h7 hav Nuav
106 3492 614 7 1 6 7 84 8 13 8 33 7 85 4 88 7 87 4562 107 4395 7 86 894 964 996 1005 9 64 640 9 65 56 06 108 50 75 9 11 10 22 1081 1112 1125 1085 7 24 1085 63 16 109 G 1344 9 22 1042 1120 1 1 46 1173 1131 7 04 1120 63 87 110 1936 1162 1340 1442 1474 1509 14 7 3 9 09 1441 82 77 111 2846 1631 1797 1902 1966 2027 2079 1342 19 2 3 11108 112 3484 207e 2144 2236 2307 2385 2574 1694 2268 13138 113 4066 24 65 24 42 2535 2648 2757 31 71 2178 2 5 96 15078 114 50 12 3059 2916 30 1 5 3176 3312 4059 2849 3105 180 46 115 1D 1362 2268 26 13 2613 26 35 2605 2503 15 46 2617 14934 116 1958 2993 3580 3580 3586 3539 3 5 02 2144 3571 20492 117 2812 4430 50 32 4913 4 9 86 4991 5196 3088 4981 287 66 118 3432 58 16 62 13 6067 61 18 60 66 6698 4143 61 16 354 16 119 40 22 71 71 7 4 62 7369 7419 7329 82 74 51 8 1 7395 42909 120 5026 105 95 11456 115 81 11574 11548 14010 80 91 11540 671 15 121 2D 1244 18 57 2277 2363 2305 2210 2107 1466 2289 13038 122 1960 2622 3240 3388 33 23 3226 31 40 2)99 3294 18919 123 2817 3762 45 87 4739 46 56 45 14 4 6 47 30 15 4624 26689 124 3491 50 22 5723 58 53 57 44 5542 60 18 3871 57 16 330 73 125 4096 61 29 68 16 69 79 6805 65 90 74 79 4677 67 98 39400 126 5037 82 27 94 60 95 69 93 57 9023 11324 65 05 93 52 542 83 127 12D 1278 14 70 1 6 48 1652 1638 1 6 34 1641 9 73 1 6 43 9369 128 1947 19 63 2155 2149 2151 2131 2190 1347 2147 12342 129 2769 2615 2791 2773 28 52 2716 2954 18 96 2783 1 60 82 130 3439 3208 3265 3239 3593 3133 3624 2515 3308 19174 131 4103 3637 35 88 3577 4077 3459 42 66 3138 3676 21343 132 49 78 45 82 44 60 44 8 1 55 17 43 25 5749 4227 4700 27288
Q) tlgt
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
133 1 12D 1299 2094 2507 2622 2625 2567 2489 1465 2578 14736 134 1973 29 56 3505 3772 3790 3718 3718 2115 3700 21290 135 2788 3941 4727 5069 5099 5 0 07 5231 2984 4976 28781 136 3473 5155 59 81 6308 6339 62 39 68 96 4204 6217 36052 137 4118 6135 71 8 6 7662 7731 76 91 87 16 49 8 5 7568 43985 138 4973 7765 94 75 10396 10861 10694 13646 66 64 10357 602 25
139 1ttn 1253 1242 1493 1460 1442 1431 1424 8 84 1457 83 01 140 2366 1942 2150 1961 1910 1897 19 62 1206 1980 11400 141 3461 3007 2957 2562 2513 2606 3143 18 51 2660 15400 142 4325 3942 3571 3060 2999 3198 4248 2631 3207 18618 143 5677 508 6 4359 39 88 3800 42 29 57 78 36 26 4094 23824 144 67 59 64 55 5330 4988 47 25 5494 2517 48 09 5134 29906 145 84 08 9326 72 26 7726 85 56 9172 12319 7733 8170 47626 146 86 54 9831 7582 818 9 94 90 9869 13116 78 97 8783 512 96 147 7376 7335 58 7 6 5941 5796 68 29 81 65 5954 6111 35662 148 2 11 D 4254 4106 48 02 4994 5038 5042 56 78 3419 4969 28881 149 5708 5487 6253 6466 6524 6527 78 63 45 8 2 64 43 37566 150 69 7 8 7983 9440 9848 98 34 97 32 13249 6701 9714 566 59 151 1254 1434 18 53 1947 1915 1850 1760 1186 1891 10772 152 2713 2696 3175 32 94 3288 3237 3288 20 44 3249 18728 153 87 30 118 07 14733 15758 15504 15305 26297 9617 15325 892 71 154 5811 5278 6543 6861 69 30 69 82 7 8 74 4478 68 29 39531 155 4246 3780 4736 4975 49 66 4936 5162 3113 4903 28301 156 (v 1270 8 15 935 959 966 9 51 9 23 6 35 953 5430 157 2714 1164 1390 1427 1447 1454 1455 9 08 1430 8242 158 4310 1655 18 96 1942 1988 2002 2111 1305 1957 11349
(j) ~
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 fry hav Nuav
159 6012 2208 2400 2450 2513 2548 28 20 18 00 2478 14416 160 7279 2696 2881 2927 2989 3081 3599 2340 2970 17326 161 86 90 3257 3360 3 3 76 34 26 3558 4455 2943 3430 2000 162 12D 4368 2209 2600 2558 2518 2466 2774 1753 2536 14713 163 5833 2730 3092 3028 2974 2913 3501 2287 3002 174 78 164 7643 3320 3681 3630 3651 3530 4623 3181 3623 21116 165 87 39 3920 4303 4300 4708 4178 61 60 3937 4372 25456 166 1268 962 1203 1205 1186 1118 1084 725 1178 6693 167 2678 14 67 1785 1779 1752 1698 1726 10 70 1754 88 49 168 1 12D 12 83 936 1217 1414 1397 1239 1190 7 65 1317 7484 169 2729 2502 2930 2914 2934 2956 2979 17 52 2934 16866 170 4345 3884 4357 4283 4318 4421 4836 28 59 4345 25151 171 6036 5546 5858 5764 5791 6028 7129 4184 5860 34045 172 6578 7167 7769 7907 79 82 8263 10492 5915 7980 46437 173 87 84 10237 112 23 120 26 12727 12968 185 19 85 98 12236 71103 174 1278 1344 1803 18 72 1835 1790 1712 1063 1825 10355 175 2711 2328 2972 2932 2893 28 78 2863 1667 2919 167 51 176 4351 3934 4414 4353 4281 4321 4654 28 63 4342 25088 177 5994 5076 5824 5838 5818 59 29 6914 4205 5852 33885 178 1 11 U 1223 388 432 465 464 449 435 338 453 2585 179 2351 521 602 6 22 675 6 57 619 436 639 3687 180 34 48 6 05 1725 803 8 27 8 11 760 518 792 4593 181 4513 718 850 934 9 68 9 57 8 99 609 9 27 5386 18 2 5714 8 32 981 1060 1102 11 06 1034 6 59 1062 61 82 183 6997 1025 1182 1258 1295 1309 1234 8 18 1261 7 3 44 184 8709 1295 1487 1 5 42 1594 1626 1612 1156 1562 9080
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
185 2 12D 4249 3560 4400 4670 4791 4695 47 81 2931 4639 268 37 186 5737 4926 58 54 61 92 6248 62 38 67 78 4134 6131 35590 187 7432 6390 7726 83 46 85 44 86 34 10371 5658 8313 48310 188 8723 7718 107 88 11933 12099 13046 186 22 79 39 119 67 69505 189 1 4 35 1340 1735 18 57 18 52 17 81 1711 1144 18 06 10256 190 2718 2399 3023 3187 3207 3138 30 53 1931 3139 18025 191 7 5 07 6189 80 11 9200 9427 9703 11364 5720 9085 527 38 192 8544 78 42 10666 125 42 13312 13775 178 20 6976 125 74 729 86 193 1287 1417 16 97 18 7 18 69 18 08 1720 1046 1800 10223 194 27 17 2450 2940 3187 3214 3157 3054 1749 3125 17954 195 42 53 3560 4222 45 90 4679 46 63 4743 2741 4539 26247 196 6068 48 69 57 79 6335 65 8 6 66 04 7172 4338 63 26 366 78 197 7389 58 86 72 8 6 82 23 8584 8936 10658 50 60 8257 4798 6 198 86 88 78 91 100 27 120 56 130 29 14299 190 81 6492 12353 71850 199 5864 4694 5 6 67 61 94 6419 65 48 7192 3950 6207 360 14 200 2 D 4177 38 36 4547 48 09 4775 4628 5006 2715 46 90 261 30 201 5712 5170 62 39 66 38 6599 6604 7518 4167 65 20 378 00 202 73 63 7201 8986 98 43 9733 9914 13353 6219 9619 55810 203 8604 10043 13118 148 41 150 42 158 66 25206 82 5 3 14717 85290 204 12 68 1506 18 41 1971 1966 1868 1799 11 42 1913 10880 205 2659 2571 3127 3276 32 50 3130 3069 18 80 3196 18 350 206 39 80 36 76 4347 4573 45~67 4473 46 34 28 37 4490 25910
o 207 Orifice 11496 10 64 1360 15 39 1 5 80 1 6 15 1496 8 58 15 24 88 83 208 9433 8 95 11 78 13 26 1394 1386 1263 727 1346 78 48 209 7387 746 9 77 1123 1184 1159 1048 6 11 1111 64 74 210 52 36 566 7 66 900 934 909 8 21 499 8 27 48 02
0) CJ1
TABLE III Continued
Run No Position CFM h 1 h2 hs h4 h5 h6 h7 hav Nuav
211 212
3309 1293
414 257
563 3 19
6 68 3 57
6 91 3 37
6 72 351
7 37 337
38 4 2 46
4 40 341
3748 1942
213 214 215 216 217 218
c of 2nd 1 516 1235
1919 2712 3320 4153 4704
1532 2447 35 46 4312 5567 74 29
2 1 87 3312 4225 52 86 6902 8 6 50
2360 3555 4340 56 12 7 0 49 8 9 40
2409 3598 4 8 85 5718 7713 9593
2347 2101 35 33 3453 48 00 49 62 5562 59 86 72~6 7 8 79 93 76 11237
1243 20 64 3054 4 2 8 1 5114 6983
2326 35 00 4638 5545 7225 91 40
132 13 200 27 26672 31968 41711 52811
bull
67
TABLE IV
PRESSURE PROFILE DATA
Baffle Flow Qpening Rate ~p
(Inches) Position (CFM) (Inches 295 S G Fluid)
1 364 l2 11 U 1012 0 254 1248 0197 1493 0 141 1718 0112
c 1000 9 80 1210 1710 1436 28 75 1746 4320 1011 1080 1277 2050 1393 3020 1 6 28 4450
12D 1011 9 75 1236 1520 1450 2510 1603 3450
1 D 1011 975 1256 1700 1480 2690 158 1 4070
1 12D 1010 950 1259 1750 1462 2650 1631 3710
2 11 D 1124 1315 1360 2130 1505 2850 1689 4125
1 216 12U 1294 045 1949 0324 2374 0282 2704 0225 3367 0169
c 1326 265 18 81 5 90 2313 990 2731 1480 3439 2660
12D 1272 2 49 1957 661
68
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Pos ition (CPM) Inches 2 95 S G Fluid)
2559 1275 3033 1940 3639 3025
1 216 1nD 1257 242 16 96 476 2117 8 05 2561 1280 2990 1895 3431 26 bull00
1 316 12U 1309 0 479 2004 0422 28 28 0 352 3526 0281 42 28 0225 5199 0225
c 1308 1 43 1998 272 28 14 5 10 3478 795 4248 1235 5048 1885
l2D 1286 140 2005 3 45 2831 725 3495 1180 4194 1805 5046 2945
1 11D 1322 150 2039 352 2841 735 43 77 1980 5378 3440
1 516 12U 1278 0493 2732 0493 4315 0408 5744 0352 7494 0352 8932 0422
c 1300 0 506 2731 1985 4310 348 6080 6 45
69
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Position (CPM) (Inches 295 SG Fluid)
7607 1090 8830 1585
l2D 1343 0549 2738 225 4566 583 6112 1195 7536 2055 9043 3415
1 516 1uD 1249 0464 2713 224 4155 579 5620 1150 7428 2115 90 70 3405
1 12D 1301 0493 2735 220 4501 616 61 50 1235 7440 2065 8862 3445
2D 1265 0 478 2750 226 4366 594 6578 1270 7678 2240 8945 5280
2 12D 1295 0493 2725 222 4293 600 5807 1120 7568 2200 9070 3615
TABLE V
RATE OF HEAT TR AN SFER Ar THE BAFFL~~ CID-TT ER
Orifice Size
(Inches)
Flow Rate
( CFM)
Re d e G tU
R~) 055 Nuav NuPr-l3
1 364 10 26 12 90
8 075 10015
43400 54 600
85 11 99 64
95 83 112 19
1416 11 140 59 900 110 30 124 20 16 27 12 800 68 900 126 64 142 60 17 29 13 610 73 200 135 79 152 90 17 76 13980 75 200 147 59 166 19
1 216 11 35 14 06
8 600 10 660
27000 33500
6 4 96 76 56
73 14 8 6 12
1517 11500 36100 82 51 9291 20 34 15400 48400 10229 115 18 23 11 17500 55000 118 31 13322 2348 17 800 55900 11947 13452 2666 20 200 63400 13508 15210 27 16 20 600 64700 135 05 152 07 32 47 24600 77200 161 57 18 193 3392 25 700 80700 17390 195 8 1
1 316 1344 19 36
9898 14 260
24800 35 700
63 8 7 8 2 77
71 92 93 20
28 46 20 9 60 52 500 111 08 125 08 34 84 25 660 64200 131 38 147 93 40 66 50 12
29900 36900
74800 92400
150 78 18046
169 78 203 20
~ 0
TABLE V Continued
Orifice Flow Re Size Rate d e G R~rmiddot55 NuPr-13(Inches) (CFM) U Nuav
1 516 12 70 8 847 16800 54 ~0 61 14 2 14 18 900 35800 82 42 92 80 43 10 30 000 56900 11349 127 79 60 12 41900 79400 14416 16232 7279 50700 96100 17326 19509 86 90 60540 115000 20098 22529
TABLE VI
RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
Orifice Size
(Inches)
1 364
1 216
1 316
Flow Rate
(CFM)
1054 1294 1431 1681 1770
1068 1399 1669 1959 2295 2636 3390
1299 1973 2788 34 73 4118 4973
Re deG Mshy
8 300 9870
11260 13200 13 930
8100 10600 12650 14850 17400 19980 25700
9 570 14500 20500 25600 30300 36600
R~r-6 51900 61700 70500 82 500 87 100
28200 36900 44000 51700 60 600 69500 89400
26100 39600 56000 69900 82700 99 900
Nuav
2416 293 5 3187 4018 4805
14938 18968 21712 25156 30680 37938 59601
14736 21290 28781 36052 439 85 60225
Uu Pr-1 3
27204 33050 3589 4524 541 0
16820 21358 24448 28326 34546 427 18 67111
16593 23973 32407 40595 495 1 678 13
TABLE VI Continued
Orifice Flow Re Size Rate deG R~rmiddot6 NuPr-13(Inches) (CFM ) M- Nuav
1 516 1268 88 30 17700 108 8 1225 2689 18700 37400 1835 2066 3980 27700 55700 2591 2917 4177 29100 58 500 2713 3055 5712 39800 80000 378 0 425 6 7362 51300 103000 5581 6284 8 604 59 900 120000 8529 9604
74
TABLE VII
EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER
l 516 Inch Orifice
Center ot 2nd Baffle 4 Downstream
Plow Rate (CFM)
1235 1919 2712 3320 4153 4704
Flow Rate (CFM)
1270 2714 4310 6012 7279 8690
(Re)eb -8600 1321
13400 2003 18900 2687 23100 5197 28900 4171 32800 5281
Center ot Single Battle
-8847 543
18900 824 30000 1135 41900 1442 50700 1733 60540 2001
(Nu)(Pr)-l3
1487 2255 3003 3600 4697 5946
(Nu)(Pr)-13
611 928
1278 1623 1951 2253
75
ABLE VIII
HEAT TRANSFER IN THE TEST SECTION WITHOUT ORIFICE
CFM Ute) 0b h Nu
1293 5-951 3 41 1942
33 09 15251 649 3746
5236 24193 827 4802
7387 34001 1111 6474
9433 43419 1346 7848
11496 52-914 1524 8883
76
TABLE IX
PRESSURE DROP FUNCTION
Orltlee Size Flow Rate incbea ~CFM (Re)eb X 10bull8
1 364 1011 7957 0808 1256 9885 1468 1480 11648 2765 1581 12443 4160 1689 1_3293 4 020
1 216 1257 9530 1327 1696 12858 2663 2117 16049 4615 2561 19415 7581 2990 22668 11560 3431 26011 16440
l 316 1322 9736 1819 2039 15016 4332 2845 20952 9275 3495 25739 15300 4377 32014 26800 5378 39607 50100
1 516 1011 7 957 oaos 1256 9885 1469 1480 11646 2765 1581 12443 4160 1689 13293 4020
77
TABLE X
EXPERIMENTAL DATA
Baffle Hole Diameter Run No
1 - 59
60 - 102
103 - 138
139 - 206
207 - 212
213 - 218
(Inches)
1 364
1 216
1 316
1 516
No Baffle
2nd - 1 516
TABLE X
EXPERIMENTAL DATA
Run Thermocouple Reading s (mv) No Position CFM I tc1 tc2 tc3 tc4 t c 5 tc6 tc7 tcair
1 c 1026 530 2055 1825 1768 1782 1802 1837 1965 1198 2 1290 612 2059 18 65 1809 18 32 1851 1880 1965 1160 3 1416 714 2151 1970 1931 1965 1988 2026 209 5 1130 4 1627 8 21 2235 2084 2 049 2093 2126 2173 2266 1130 5 1776 865 2203 2033 1970 2015 2084 2159 2 264 1121 6 12D 1109 542 1636 1507 1499 1499 1498 1498 1528 1218 7 1258 651 1670 1522 1503 1513 1513 1516 1548 1221 8 1433 750 1625 1480 1467 148 3 1487 1487 1516 1153 9 168 1 8 73 1656 1494 148 1 1511 1517 1517 1543 1159
10 1rtD 1102 485 1545 1450 1437 1446 1447 1442 1466 1220 11 13 08 6 10 1571 1470 1460 1476 1476 1469 1498 1194 12 1464 730 1 623 1509 1508 1528 1 5 32 1524 1548 1173 13 11 06 8 71 1663 1559 158 1 1606 160 6 1 583 1601 1190 14 1 12D 1115 520 1698 1579 1575 1 577 1580 1590 1615 1280 15 1275 6 10 1692 1567 1558 1 561 1570 1580 1601 1234 16 1498 770 1760 1619 1630 1 635 1642 1645 1661 1204 17 1695 912 1775 1635 1670 1689 1686 168 6 1701 1165 18 2D 1049 510 1736 15~2 1567 1558 1 553 1558 1620 1236 19 12 41 610 1655 1517 149 1 148 1 148 1 148 4 1546 1108 20 1 5 32 7 35 1720 1550 1530 1520 1519 1523 158 0 1104 21 16 74 8 8 0 1900 1 727 1714 1696 1691 1692 1753 1169 22 1U 1074 38 5 3 324 2740 2534 2478 2 465 2503 258 0 1210 23 1287 4 35 3510 2 870 2682 2 610 2599 2638 27 1 9 1190 24 1 5 08 470 3 618 2920 2690 2 637 2627 2 664 2747 1177 25 18 07 525 4 088 3235 2962 2905 2910 2988 3130 1169
z ())
TABLE X Continued
Run No Position CFM I tc1 tc 2
Thermocouple Readings te3 tc4 tc5
(mv) tc6 tc7 tcair
26 c 10~29 6 32 2340 2~092 2032 2060 2~097 2152 2~213 1211 27 12 66 679 2270 2 047 1993 2013 2069 2142 2 210 1 182 28 1430 723 2336 2097 2033 2080 2153 2~255 2 356 1 138 29 1729 8 52 2318 2070 1980 2061 2158 2279 2367 1121 30 12D 1054 570 1520 1 4 20 1402 1400 1396 1400 1 443 1159 31 1294 6 69 1599 1469 1444 1439 1433 1 442 1485 1168 32 1430 7 88 1720 1562 1536 1532 1528 1537 158 0 118 5 33 1770 8 81 1641 1488 1450 1~441 1 441 1_466 1518 1 163 34 1D 1058 548 1579 1498 1495 1526 1553 1_557 1 571 1 276 35 1263 640 1609 1509 1515 1570 1599 1598 1 598 1 266 36 18 36 8 47 1538 1452 1483 1553 1602 1 590 1 558 1195 37 1 12D 1029 5 41 1 578 1499 148 4 1473 1461 1465 1-512 1200 38 1315 6 30 159 1 1504 1493 1482 1470 1470 1505 118 5 39 1 4 26 743 1765 168 1666 1660 1645 1642 1678 1270 40 1757 8 54 1744 1648 1634 1620 1598 1 593 - 1612 1223 41 2D 1080 5 30 1734 1604 1570 1 570 1570 1 588 1 640 128 1 42 1305 6 40 1744 1622 1589 1 608 1593 1 609 1 661 1240 43 1434 750 1798 1687 1658 1 636 -1641 1 661 1 711 1_220 44 18 04 8 41 1 764 1666 1607 1605 1614 1 635 1 675 1205 45 12nu 1088 415 2614 2295 2195 2 169 2174 2217 2256 1171 46 1318 477 2805 2477 2371 2342 2364 2 401 2 438 1 163 47 1413 5 28 2930 2 646 2 555 2 526 2532 2570 2 577 1 199 48 1773 550 2740 2518 2450 2431 2448 2 479 2 480 1 170 49 1 11 U 1054 380 3175 2670 2505 2 461 2467 2 534 2 621 1 258 50 1240 420 3268 2738 2 546 2 510 2 508 258 2 2 649 1214 51 1419 451 3364 2B07 2 632 2590 2 590 2 651 2773 1 215 52 1 12U 1032 360 3 165 2 629 2 450 2402 2403 2 473 2 bull568 1 163
--I lt0
TABLE X Continued
Run No Position CFM I tc1 tc2
lhermocoup1e Reading s tc3 tc4 t c 5
(mv) tc6 tc7 tc a ir
5 3 1314 38 9 3178 2592 2411 2367 2361 2432 2555 1140 54 1448 403 3095 2544 238 1 2336 2336 2390 2476 1158 55 178 2 427 3006 2434 2286 2253 255 3 2299 2397 1154 56 2 11U 1061 360 3369 2814 2619 2567 2560 2650 2833 1220 57 1216 360 3044 2512 2338 2290 2288 2374 2566 1150 58 1322 387 3196 2614 2425 2383 2382 2472 2670 1138 59 1639 403 3020 2438 2272 2238 2238 2318 2502 1127
60 1D 1068 612 1552 1424 1400 1395 1396 1426 1745 0945 61 1399 612 1355 1246 1230 1229 1230 1250 1509 0872 62 1669 710 1436 1293 1272 1265 1266 1286 1551 0847 63 1959 900 159 5 1468 1444 14 38 1432 1446 1720 0851 64 2295 730 1169 1105 1098 1099 1108 1100 1298 0781 65 2636 8 80 1202 1129 1121 1126 1 138 1115 1342 0748 66 3390 9 35 1060 o 9s7 0999 1001 1017 0971 1154 0703 67 1nu 1190 370 2225 2188 2104 2080 2120 2209 2 7 15 0990 68 1559 368 2005 1950 1871 18 48 1876 1951 2408 0916 69 1904 368 1870 18 1 4 17 34 1711 1730 18 07 2238 0875 70 22 bull11 471 228 6 2 204 2099 2063 2092 218 $ 2732 0840 71 2289 471 2030 2000 1925 1895 18 96 19 5 2498 0785 72 2727 4 71 1854 18 23 1753 17 23 1716 3758 2241 0743 73 3210 471 1680 1651 158 6 1559 1551 158 1 1950 omiddot7o9 74 2uD 1210 404 1261 1212 1198 1197 1205 1222 139 1 0978 75 14 20 540 1321 1260 1242 1 240 1249 1268 148 7 0918 76 1692 7 18 1467 138 6 1364 1361 1376 1405 1678 0883 77 18 94 903 1708 1 591 1565 1560 1575 1603 1948 0 857 78 2301 903 1530 1432 1407 1402 1415 1432 1738 0815
ro 0
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc117 tcair
79 2621 6 50 1069 1 020 1009 1009 1009 1007 1~189 o739 80 3230 901 1200 1128 1113 1119 1119 1086 1341 0694 81 82
l2D 1155 1689
360 575
1191 1345
1142 1252
1122 1218
1118 1210
1118 1209
1132 1228
1292 1446
0916 0822
83 1244 430 1163 1134 1131 1130 1129 1132 1292 0877 84 2100 645 1175 1135 1147 1 142 1138 1122 1286 0757 85 2292 8 25 1 354 1310 1327 1330 1323 1285 148 6 0728 86 2907 8 23 1180 1138 1151 1158 1149 1107 1268 0687 87 3380 902 1113 1049 1025 1011 1006 1042 1178 0673 88 89
1 12D 1427 1875
480 615
118 2 1140
1140 1095
1124 1077
1125 1075
1129 1072
1137 1072
1290 1243
0880 0790
90 2259 8 41 1296 1231 1207 1206 1203 1182 1419 0757 91 2682 8 80 1231 1170 1149 1147 1142 1112 1350 0731 92 3417 940 1142 1092 1076 1076 1069 1021 1252 0693 93 c 15 17 431 1321 1298 1268 1249 1250 1273 1522 0841 94 2034 505 1285 1263 1235 1209 1205 1206 1464 0759 95 2348 6 10 1395 1379 1334 1302 1286 1268 1536 0732 96 2716 706 1486 1480 1427 1383 1358 1311 1572 0 700 97 3247 7 56 1417 1430 1375 1320 1284 1223 1450 0660 98 1135 400 1425 1388 1352 1329 1330 1 364 1651 0893 99 14 06 440 1379 1341 1304 128 2 1281 1305 1583 0 831
100 2311 680 1602 1593 1553 1514 1502 1480 1 7 27 0 802 101 2666 680 1471 1469 1428 1390 1372 1335 1564 0761 102 3392 798 1491 1 509 1449 1395 1372 1305 1534 0 719
103 1U 1235 410 2469 2295 2173 2165 2226 2361 3120 0 897 104 2010 410 2017 1848 1 737 1706 1747 1865 2582 0753 105 28 14 410 1682 1535 1457 1427 1437 1520 2109 0 660
00 t-
TABLE X Continued
Ru n Thermocouple Rea ding s (mv No Positi on CFM I tc1 tc2 tc3 tc4 tc5 tc6 tc7 tcair
106 3492 440 1649 1499 1420 1391 1390 1470 2042 0620 107 4395 550 18 33 1679 1597 1564 1570 1640 2223 0583 108 5075 588 1779 1642 1580 1550 1552 1 615 2 191 0548 109 c 1344 398 1464 1 399 1364 1353 1350 1380 1689 0 907 110 1936 459 1369 1290 1253 1242 1 237 1259 1574 078 2 111 2846 580 1347 128 5 1251 1232 1220 1215 1 5 23 0 683 112 34 8 4 700 1392 1369 1339 1317 1299 1259 1599 0 636 113 4066 8 13 1449 1458 1427 1391 1363 1270 1595 0 591 114 5012 930 1484 1530 1500 1453 1420 1272 1580 0 580 115 1D 1362 513 1269 1218 1 217 1214 1220 1238 1460 0 893 116 19 58 600 1187 1122 1121 1120 1124 1133 1352 0798 117 2812 705 1052 1008 1015 1010 1011 1001 1218 0691 118 34 32 913 1105 1075 1085 1081 1086 1047 1301 0645 119 4022 980 1038 1021 1026 1023 1029 0983 1211 0 609 120 5026 982 0 8 61 0839 0836 0836 0837 0791 0955 0570 121 2D 1244 475 1320 1246 1233 1240 1255 1275 1434 0925 122 1 9 60 5 50 1160 1088 1074 1079 1089 1100 1260 078 7 123 2817 6 80 1096 1024 1 013 1018 1029 1022 1201 0 700 124 3491 960 1248 1175 1163 1172 1192 1153 1435 0 658 125 4096 989 1141 1089 1078 108 9 1105 1051 1310 0629 126 50 37 989 0983 0933 0929 0 936 0949 0880 1090 0 602 127 128
12D 1278 1947
402 545
1270 1261
1 230 1216
1228 1216
1230 1 215
1235 1223
1242 1219
1483 1514
0 913 0778shy
129 2769 695 1273 1234 1237 1221 1251 1212 1525 0678 130 131 132
34 39 4103 4978
8 40 9 80 9 80
1336 1448 1271
1322 1458 1 288
1328 1 462 1286
1 259 1 356 1157
1353 1492 1311
1261 1329 1138
1 555 160 7 1343
0 629 0 600 0599
(l) l)
TABLE X Continued
Run No Position CFM I tel tc 2
Thermocouple Readings tc3 tc4 tc5
( mv) tc6 tc7 tcair
133 1 l2D 1299 5 16 1 28 1 1212 1196 1195 1205 1221 1478 0869 134 1973 6 15 1163 1098 1073 1071 1079 1083 1343 0751 135 136
27 88 34 73
802 9 -_78
1187 1214
1099 1131
1069 1104
1066 1101
1075 1~110
1l061 1066
1370 1360
0662 0618
137 4118 9 81 1084 1010 0983 0979 0982 o937 1209 0581 138 4973 98 1 0969 0897 0 868 0855 0860 0799 1041 0572
139 1D 1253 409 1371 1293 1298 1301 1309 1321 1578 0928 140 2366 480 1130 1 090 1 121 1130 1137 1132 1390 0744 141 34 61 6 38 1081 1086 1152 1161 1147 1069 1382 0644 142 143 144
4325 5677 6759
7 90 939 998
1110 1115 1034
1161 1208 1139
1253 1268 1180
1265 1302 1215
1228 1230 1123
1080 1056 0970
13$913r12 8
0601 0561 0542
145 84 08 989 0863 0961 0934 0895 0871 0 785 09 9 0530 146 86 54 9 80 0808 0901 0 872 0821 0809 0733 0891 0498 147 7376 9 80 0 927 1032 1027 1 040 0961 0889 1032 0511 148 2D 4254 776 1 050 0 981 0965 0961 0962 0922 1155 0579 149 5708 991 1102 1031 1014 1009 1010 0931 1227 0528 150 69 78 990 0914 0853 0839 0 839 0843 0759 0996 0521 151 1254 490 1 479 1352 1329 1334 1351 1379 1607 0930 152 2713 7 00 1310 1220 1201 1201 1211 1209 1516 0723 153 8730 991 0809 0756 0742 0745 0 748 0663 0874 0543 154 5811 966 1219 1108 108 6 1081 1079 1033 1330 0650 155 42 46 8 02 1248 1136 1114 1114 1118 1103 1376 0 699 156 c 1270 429 1671 1571 1551 1545 1563 1600 1933 0929 157 2714 488 1398 1285 1 267 1258 1262 1275 1628 0729 158 4310 642 1424 1318 1299 1282 1283 1261 1683 0617
co ~
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc7 tc a 1r
159 60 12 780 1461 1388 1370 1349 1343 1279 1700 0 573 160 72 79 8 60 1402 1344 1330 1312 1292 1189 1 566 0 520 161 8690 982 1472 1442 1437 1 422 1392 1224 1602 0 521 162 163
12D 4368 5833
6 30 8 30
1195 1368
1105 1270
1111 1283
1117 1294
1131 1313
1081 1194
1369 1553
0613 0 553
164 76 43 959 1428 1338 1348 1341 1371 1180 1488 0535 165 8739 984 1345 1272 1272 1208 129 3 1059 1361 0550 166 1268 459 1701 1548 1541 1547 1589 1 625 1976 0 973 167 2678 570 1485 1351 1349 1356 138 1 1 385 1795 0760 168 169
1 12D 128 3 2729
448 650
1664 1314
1501 1232
1425 1233
1428 1229
1491 1229
1527 1232
1869 1571
0 962 0767
170 4345 847 1245 1179 1187 1182 1172 1132 1476 0 650 171 6036 9 76 1139 1109 1117 1114 1095 1020 1332 0588 172 6578 9 72 0982 0949 0942 0938 0926 0 8 50 1079 0560 173 87 84 9 72 0880 0854 0 8 36 0822 0818 0 749 0941 0585 174 1278 480 1564 1416 1397 1403 1417 1445 1733 0998 175 2711 590 128 3 1175 4 1178 1182 1187 1195 1493 0796 176 4351 8 90 1331 1259 1266 1275 1272 1235 1592 0 682 177 5994 9 60 1228 1152 1150 1151 1143 1075 1 360 0644 178 lU 1223 408 2282 2140 2052 2052 2106 2188 2626 0 878 179 2351 408 178 1 1623 158 5 1519 1556 1634 2068 0717 180 3448 482 1888 1675 1570 1541 1572 1665 2199 0629 181 4513 563 2026 1797 168 4 1644 1670 1770 2385 0583 182 5714 589 1913 1700 1610 1568 1580 1 682 2382 0551 middot 183 6997 653 1903 1718 1643 1611 1612 1700 2326 0 549 184 8709 6 80 1738 158 3 1543 1510 1498 1519 1 912 0577 185 186
2 12D 4249 5737
660 9 74
1055 1221
0 979 1122
0960 1093
0 952 1088
0959 1090
0 956 1054
1147 1350
0661 0602
187 7432 9 8 1 1065 0981 0951 0942 0 939 0881 1135 0582 CD ~
TABLE X Continued
Run No Position CFM I t o1 to 2
188 87 23 9 83 0944 0 879 189 1435 585 18 26 1630 190 2718 690 1433 1298 191 7507 950 1070 0961 192 85 44 964 0982 0 881 193 1287 600 1806 1668 194 2717 7 80 1579 1444 195 4253 8 81 1371 1260 196 60 68 9 78 1252 1152 197 73 89 975 1100 1000 198 86 88 973 0953 0 871 199 58 64 9 81 1269 1155 200 2D 4 1 77 915 1362 1251 201 5712 975 1213 1111 202 7363 9 78 1036 0 951 203 8 604 973 0932 0861 204 1268 6 95 2015 18 20 205 2659 6 96 1405 1295 206 39 80 7 98 1261 1174
No 207 Orifice 114 96 509 1325 1148 208 94 33 509 1477 1243 209 7487 5 09 1686 1409 210 5236 505 2094 1691 211 3309 428 2188 1 778 212 1293 392 2976 2560
Thermo ooup1e Readin g s (mv) to 3 to4 to
5 to
6 to7 toair
0 851 0847 0 8 29 0759 0987 0592 158 4 1583 1611 1647 1993 0986 1270 1266 1 279 1298 1604 0 789 0916 0908 0900 0 858 1115 0602 08 39 0 823 0 818 0 770 1035 0602 1609 1602 1629 1676 2153 0979 139 1 1385 1400 1 430 1938 0776 1212 1201 1205 1201 1601 0669 1 105 1086 1086 1 052 1371 0621 0952 0936 0923 0870 1195 0582 0 8 20 0 801 078 1 0 729 1044 0569 1108 1090 108 2 1043 1407 0610 1218 1221 1241 1202 1582 0659 1081 1083 1084 1031 1 368 0622 0921 0924 0919 0 841 1111 0 610 08 34 0831 0 821 0 751 1003 0 630 1761 1761 1 809 1861 2399 0966 1271 1271 1295 1311 1650 0797 1150 1150 1161 1149 1440 0703
1083 1057 1053 1109 1566 0~530 1158 1125 1138 1217 1763 0 526 1291 1250 1278 1383 2038 0542 1518 1478 1519 1657 2420 0 589 1596 1557 1601 1737 2441 0688 2370 2344 2409 2561 3 297 0921
()) (11
TABLE X Continued
Run Thermocouple Readings (mv) No Position CFM I tc 1 tc2 tc3 tc4 tc tc tc tc i5 6 7 a r
C of 2nd 213 516 1235 4 63 1 432 1291 1265 1258 1 268 1 308 1550 0 971 214 1919 6 17 1357 1223 1196 1191 1199 1211 1461 0 851 215 27 12 8 35 1401 1259 1278 1220 1230 1218 1511 0 762 216 3320 981 1439 1305 1270 1259 1275 1238 1450 0719 217 41 53 980 1251 1142 1132 1094 1121 1088 1305 0 695 218 404 987 1102 1042 1030 1 bull006 1014 0960 1133 0681
Supplementary Equations
Calculating temperatures from thermocouple readings
t = -026tc)2 + 3512(tc) + 3201 (26)
where t is the temp in deg F and tc is the thermocouple reading in millishyvolts
Calculation of the thermal conductivity of air
k = 00000245ta + 0 0132 (27)
where k is the thermal conductivity in Btuhr rt2 degFft and ta is the air temp 1n OF
I I
bull co m
bull bull bull bull bull bull bull bull
bull bull
I
II
III
IV
v
VI
VII
VIII
I X
z
LIST OF TABLES
Pa ge
Summary of Experimental Program bull bull 19
Position of Maximum Heat Transfer 32
Calculated Heat Transfer Data 57
Pressure Profile Data bull bull bull 67
Rate of Heat Tr ansfer at the Baffle Center middot bull bull bull bull bull 70
Rate of Heat Transfer at the Point of Maximum Heat Transfer bull bull bull bull bull bull bull bull bull bull bull bull 72
Effect of Upstream Baffles on Heat Trar1sfer bull bull bull bull bull bull bull bull bull bull bull 74
Heat Transfer in the Test Section without Orifice bullbullbullbullbullbullbullbull 75
Pressure Drop Function 76
71bull r ntal bull bull bull bull bull bull bull bull bull bull bull bull
HEAT TRANSFER AND PRESSURE PROFILRS IN THE VICINITY OF ANNULAR ORIFICES
- CHAPTER I
INTRODUCTION
The most common type of industrial heat transfer
equipment is the shell and tube heat exchanger which
consists of a bundle of tubes contained in a cylindrical
shell Heat is transferred from the hot fluid to the cold
fluid through the tube walls as one fluid flows through
the tubes and the other flows through the shell surroundshy
ing the tubes
Most commercial multitube heat exchangers contain
bafflesmiddot to guide the fluid through the equipment and to
prevent stagnant regions from forming in the shell As a
result the flow pattern in the shell is very complicated
and considerable variation of the local rate of heat transshy
fer occurs because of the various types of flow which exist
in the baffled passage The research described in this
thesis concerns a study of one small portion of the shell
side of a heat exchanger
There are three main types of baffles used in commershy
cial heat exchangers
1middot Orifice baffles extend through the cross section
of the shell and all of the shellbullside flow is
through the annular orifice formed at each point
where the tube passes through the baffle
2
2 Disk and doughnut baffles consist of disks and
doughnuts or annular rings placed alternately
along the length of the tube bundle~ There is
some flow through the annular orifices formed
where the tubes pass through the baffles but a
large portion of the flow is around the baffles
3 Segmental baffles are segments of a circle and
Bre arranged so that the fluid flows back and
forth across the tube bank There is still some
f~ow through the small area where each tube goes
through the baffle
In the case of disk and doughnut and segmental baffles
small annular clearances must be allowed at the point where
the tube goes through the baffle so that the bundle may be
assembled easily Thus in all of the types of exchangers
some shell-side fluid flows through the annular orifice
where the tubes pass through the baffles It has been
shown that this is an area of high rate of heat transfer
but its effect on the overall performance of the heat exshy
changer is not well known Also the prediction of rates
of heat transfer 1n these orifices is not yet possible
The purpose of this research was to make an extensive
study of the heat transfer rates in the vicinity of these
annular orifices and to determine the effect of orifice
size flow rate and upstream conditions The work was
5
performed in a onebulltube single orifice type baffle heat
exchanger and provision was made to measure local rates
of heat transfer in the vicinity of the baffle
4
CHAPTER II
THEORY AND PREVI OUS WORK
In 1701 Newton defined the heat transfer rate qc
from a surface of a solid to a fluid by the equat ion
= ~A(tw - t) (1)q0
where hm is the coefficient of heat transfer from the surshy
face to the fluid excluding any radiation A is the area
of the surface tw is the surface temperature of the wall
and t is the bulk temperature of the fluid The equation
for the point of local surface coefficient h is given by
dqdA = h(tw- t) (2)
The mechan ism and the laws covering heat transfer by
true conduction in solids and by radiation through transshy
parent media are well known However with heat transfer
from a solid to a fluid the situation is far more complex
The mechanism of flow of the fluid to a large extent deshy
termines the rate of heat transfer for a given temperature
difference
In addition the coefficient hm depends on certain
physical properties of the flowing fluid the dimensions
of the apparatus the velocity of the fluid past the surshy
face and frequently the temperature potential AT
It was the purpose of t his research to measure the
local shell -side heat transfer coefficient and correlate
it with the several variables mentioned a bove
5
The heat transfer coefficient for fluids flowing inshy
side tubes is more e a sily measured and correlated due to
the simple geometry of t he tube i nterior Much work has
been done on the tube-side coefficients with one of the
more useful e quations being the Dittus - Boelter equation
( 4 p 450) ~
0 023 (---ctwGJbulla (~np M ( 3 ) M k
with the following cond itions satisfied
(1) Fluid properties evaluated at the arithmetic
mean bulk temperature
(2 Reynolds number gt10000
(3) 0 7 lt Pr lt 100
(4) n = 04 for heating and 0 3 for cooling
(5) Ldw gt60
Colburn (3 p 197) obtained an equation for tubeshy
side heat transfer coefficients in which the Stanton
number is used instead of the Nusselt number
hm ) (~~ 23 _ (dwG) 0 2 ( GC k - 0 bull 023 U (4)
p
Much of the research done on average shell-side heat
transfer coefficients has resulted in empirical correlashy
tions of the form of equations (3) and (4) above Several
investigations have been made for a certain set of phys~al
6
variables but the r esults have ne ver satisf a ctorily been
correlated to appl y for all types of heat exchangers
Some basic 1ork has been done recently however on
the local shell-side coefficients Ambrose (1) studied
the local heat transfer coefficients i n a model heat exshy
changer with segmental baffles This study was fairly
extensive at the baffle center but the data were quite
limited for the space between the baffles Gurushankar1ah
(5) further extended Ambroses work by studying a single
baffle space in detail
The results of these two studies indicated a need for
detailed information 1n the vicinity of the baffle Hence
Lee () investigated a single baffle s pace between two
orifice baffles and obtained considerable information on
the rates of heat transfer in the annular orifices Since
his work was carried out in a multitube mode l heat ex~
changer the determination of the rate of flow through the
individual orifice was difficult because of t he outer
clearances existing in the exchanger For this reason the
present research was undertaken to study the rate of heat
transfer in a single annular orifice through which the flow
could be accurately determined
Bell and Bergelin (2) have studied i n detail the pres shy
sure drop coeff icients for the annular orifices formed beshy
tween a circular disk and a circular tube These results
also appl y to the annular orifioe formed when a rod extends
7
through a circular hole in a plata This study was extenshy
sive in the fact that it considered the baffle thickness as
well as the orifice size but no heat transfer data were
presented
Sullivan and Bergelin (9) studied flow through a
single annular orifice through multiple annular orifices
i n parallel and flow around a single baffle both with and
without leakage through the baffle A generalized expres shy
sion is presented for the pressure drop across one baffle
section of a tubular exchanger with leakage through the
tube holes in the baffle but the effect of leakage area
upon heat transfer is only discussed qualitatively The
pressure drop data is correlated by plotting cent as a funcshy
tion of the Reynolds number where cent equals
d1 )22( ~ P) s c e (d2 -
M-2
8
CHAPTER III
~PERI1ffiNTAL APr ARATUS
The heat transfer test section was essentially a
single tube heat exchanger The inner tube was a l-in
OD aluminum tube with an electrically heated probe midshy
way between the two ends of the tube
Test Section
The shell as constructed from lucite plastic tubing
2 5-in I D and 3-in O D The te t section d a total
lengt h of 54 58 inches I t consisted of two sections
The upstream section was 40 i n ches in length in order to
assure freedom from entrance effects and the downstream
section was 13 12 inches in length To further assure
uniform flow a bundle of short copper tubes was placed a
few inches downstream from the entrance Both of these
sections had 12 i nch flanges on one end so t hat a 18
i nch thick orifice plate could be clamped between them
Heat transfer coefficients were measured in the vicinity of
t h is orifice A cross section of the center of the test
section is shown in Figure 1 and the experimental appara~
tus is shown in Figure 2
Cooled air supplied by a Roots -type blower was used
as the shell-side fluid throughout this study It entered
the test section through a l-in ID 1 12-in OD plasshy
tic pipe at the upstream end of the calming section Tbs
j Jl l 6- 11 BOLTS II I nbull middot~11 I HEATING ELEMENTS
J T ( T
-f-shy - - - f-_- __L
7 777 _y A
IT 1] I
I
FIGURE I CROSS SECTION OF TEST SECTION AND PROBE
10
FIGURE 2 EXPERIMENTAL APP1Ub~fUS
11
air left the test section through nine equally spaced 12
ineh holes placed around the side of the tube at the exit
end
Sensing Probe Assembly
The sensing probe was designed to measure the local
heat transfer coefficients at any point along the tube and
around the tube in the test section The tube was designed
so that it could be easily moved up- and downstream to
measure the heat transfer coefficients at various positions
in relation to the orifice
The sensing tube assembly consisted of the sensing
probe the thermoctmple lead s and selector switch the
power lines and the two aluminum tubes between which the
probe was centered
Imbedded in the sensing probe were seven iron-constanshy
tan thermocouples for measuring the temperatures around the
tube The lead wires from these thermocouples were conshy
nected to a seleotor switch at the downstream end or the
aluminum tube A layer of Saran wrap was placed around the
tube over the t hermocouple and three lengths of Trophet C
resistance ribbon were wrapped around the tube nd conshy
nected in series to the power leads
The heating surface of the probe was formed by these
three one inch wide strips of Trophet C resistance ribbons
The ribbons were 0002 inches thick and had a resistance of
12
0 271 ohms per foot and a thermal conductivity of 763
Btuhr ft 2 degFft They were held in position by four
copper bars placed in four parallel longitudinal slots
These copper bars served as connectors for the electrical
leads A photograph of the sensing probe is shown in
Figura 3 and a drawing of the assembled probe is given in
Figure 4
Power Source
Direct current was used to heat the resistance ribbon
on the sensing probe The current was regulated by a slide
wire resistor The po er source consisted of a Raytheon
Voltage Stabilizer to stabilize the city power source at
115 volts and an automatic selenium rectifier with an alshy
ternating current input of 115 volts at 60 cycles per
second and an output of 12 volts and 35 amperes direct
current
Temperature Measuring
The temperatures around the sensing probe were calcushy
lated from the emf readings of the ironbulloonstantan thermoshy
couples The emf measuring system consisted of the seven
probe thermocouples a separate thermocouple for measuring
the inlet air temperature a thermocouple selector switch
a cold junction and a Leeds and Northrup Type K Potentishy
ometer The potentiometer was placed on a Fischer
13
THERMOCOUPLE JUNCTIONS~ ~------- HOLES FOR THERMOCOUPLE LEADS
~----- SCREWS
~ff+--- CONNECTING BARS
END VIEW
POWER LEADS SOLDERED TO LOWER CONNECTING BAR
iER PLASTIC PIECE
RESISTANCE RIBBONS LOCATION OF THERMOCOUPLES
FIGURE 4 DRAWING OF ASSEMBLED SENSING PROBE
15
Vibradamp support to absorb the vibrations produced by the
air blower
Air Source
Air was used as the shell-side cooling fluid during
the study The air was pumped through the test section by
a Roots type air blower with a rating of 280 ofm at 3 12
psig outlet pressure The hot air leaving the blower was
passed tbxfugh two finned-tube box-type coolers and one
tubular edoler to oool it to approximately room temperature
The air flow rate was measured by passing it through a
flow measuring orifice in the line Two sharpbull edged orishy
ficas were used f or flow measurements The calibration
curves for these orifices were presented by Ambrose (1
p 166)
The pressure taps on each side of the orifice were
connected to two differential manometers containing 0 83
and 2 95 specific gravity fluids respectively The presshy
sure drop through the test section and test orifice was
measured by a pressure tap placed 13 inches upstream and
one placed 6 12 inches downstream from the orifice Two
pressure ga ges were used to measure the pressure at the
inlet to the flow orifice and to indicate the statio pres~
sure at the test section inlet
16
Pressure Probe
A probe was designed to measure the pressure drop
between the pressure tap 13 i nches upstream from the ori shy
fice baff le and any point downstream from the tap The
probe eonsisted of a l~in OD copper tube with six 132
i n ch holes even l y s paced around the tube The upstream
pressure tap and the pressure probe were connected to a
differential manometer so the pressure drop to various
points up- and downstream of the orifice could be measshy
ured
17
CHAPTER IV
EXPERIMENTAL PROGRAM
The experimental program was designed to measure the
heat transfer coefficients and pressure drops in the vicinshy
ity of annular orifices The four orifice sizes studied
were 1 364 1 216 l 316 and 1 516 inches~ The inner
tube used in each case was a 1-in OD alumintim tube
Hence tube to baffle clearances were respectively 3128
232 332 and 532 of an inch
Heat transfer coefficients were measured at poait~ons
1 i nch upstream at the orifice center and at 12 1
1 12 and 2 inches downstream for all orifices In addishy
middottion the heat transfer coefficient at a point 2 12
inches downstream from the 1 516 inch orifice was measured
and at the points 12 l 12 and 2 inches upstream from
the 1 364 inch orifice
The heat transfer coefficients at each point were
measured at five different flow rates for the 1 364 inch
orifice and at six different flow rates for the other orishy
fice sizes The high pressure drop through the small orishy
fice size limited the number of flow rates which could be
studied
The flow rate was calculated from the pressure drop
across the flow orifice This flow was corrected to cubic
feet per minute at 68degF and one atmosphere pressure by
18
using the orifice pressure and the test section pressure
which were measured by pressure gages
It was desired to determine a relationship between the
heat transfer coefficient and the total pressure drop for
each orifice size The pressure drop across each orifice
at various flow rates was measured by means of the presshy
sure probe described in Chapter III It was also desired
to obtain pressure profiles for each orifice size since
these might be similar to the heat transfer profiles The
pressure drop was measured from a point 13 inches upstream
of the orifice to points at 1 and 12 ineh upstream the
orifice center 12 1 1 12 and 2 inches downstream
The experimental program is summarized in Table I
TABLE I
SUla~RY OF EXPER IMENTAL PROGRAM
Position Investigated-Distance from Orifice-Inches
Orifice Range of Flow Rate Size Heat Transfer Pressure Drop CFM at 68degF amp 1 atm
1 364 2U 1 12U 1U 12U c 12U C 12D lD 10 - 18 l2D lD 1 12D 2D 1 12D 2D
1 216 1U c 12D lD 1 l2D 2D 12U c 12D lD 10 - 35
1 316 1U c 12D lD 1 l2D 2D l2U C 12D lD 12 - 50
1 516 1U c x2D lD 1 l2D 1U 12U C 12D 12 - 90 2D 2 1 2D l D 1 l2D 2D 2 12D
20
CHAPTER v
EXPERI MENTAL PROCEDURE
The experimental procedure for measuring the heat
transfer coefficients ~d corresponding flow rates reshy
quired the following procedure
(1) Install the orifice size to be studied in the
test section
(2) Place the heat transfer probe in the position up
or downstream from the orifice where the middot heat
transfer rate is to be studied
(3) Fill the cold junction thermos with cracked ice
(4) Measure the atmospheric pressure
(5 Open bypass line from blower and close line to
test section
(6) Turn on the cooling water for the exchangers used
to cool the air leaving the blower
(7) Start the automatic selen ium rectifier by turning
on the t 1mer bull
(8 ) Connect the voltage stabilizer to the wall outlet
(9) middot Set the slide wire resistor to the maximum re shy
s1atanee I
(10) Start the blower
(11 Open the line to the test section until the de shy
sired flow rate is obtained
(12) Switch on the probe direct current power source
21
(13) Adjust the slide wire resistor to obtain the
desired current
(14) After the thermocouples have reached equilibrium
values record the e m bullf across each of the
seven probe thermocouples and also the entering
air thermocouple
(15) Record the direct current amperage
(16) Record the gage pressure at the flow orifice and
the entrance to the test section
(17) Record the manometer measurement of the pressure
drop across the flow orifice and also the presshy
sure drop through the test section
22
CHAPTER VI
CALCULAT ION OF EXPERIMENTAL DATA
The local heat transfer coefficients were calculated
from the temperatures measured on the probe surface the
air temperature and the current input The results were
calculated by using the Alwae III-E computer
The general expression for calculation of the heat
transfer coefficients was derived by Ambrose (1 p 79)
The equation is derived by making an energy balance around
a small increment of the center resistance heating ribbon
The two ribbons tnstalled adjacent to the center ribbon
reduced the amount of logitudinal conduction and assured
little longitudinal temperature variation in the center
ribbon
A heat balan ce on this small increment of resistance
ribbon yields the following
(the heat conducted in) + (heat generated) = (heat
conducted out) +(Heat convected to the fluid) + (heat
radiated to the surroundings) + (Heat conducted into
the plastic center of the probe)
This gives the equation
kzw dtdS + 12RdS kzws [ t + (~) ds] + hwdS (t-ta )
+ ~Aad wd o middot+ qcAond 1 -~- wdS 5 )
23
Hence solving for h gi~ea
i2R kz d2t Qrad qcond w + -d$2 - ~- A
h = ( 6)t - ta
Since S = re where 9 equals the enclosed angle ~n radians
dS rd9 ( 7)
and
dt - dt (8)dS - rd9
Differentiating with respect to S
d2t (9)rd9dS
from which
(10)
Substitut1ng into the equation for heat transfer coeffishy
cient gives
h = i2R Qcond A (11)
w
The rate of radial heat conduction into the plastic
tube making up the probe was assumed to have negligible
effect on the heat transfer coefficient It was also
assumed that the heat loss by radiation from the ribbon
was negligible since all data were obtained with the ribbon
at a temperature less than 125degF
24
When t he rad iation and conduction terms are neglected
Eq (11) becomes
(12)
The following con stants are known
R = 0 271 ohmsft
w = 100 i n ches
k = 763 Btuhr rt2 degFft
z = 0 002 inches
r = 12 inch
Eq (12) putting 9 in degrees then reduces to
1110 12 + 2404 d 2t d92
( 15)h = ------~--~-------t - ta
Thi s equation was programed for the Alwac III- E comshy
puter and used to calculate the local heat transfer coefshy
ficients from the observed data
The average heat transfer coefficient around the tube
at a given position in the t est section was calculated by
averaging the local coefficients calculated from Eq (13 )
It was found 1n the course of the experimental work
that thermocouple numbers 1 and 7 were indicating higher
temperatures than would be expected This resulted in h1
and ~ being lower than the other local coefficients around
the tube Since the fluid was flowing parallel to the axis
of the probe the circumferential variation i n rate of heat
25
transfer should be small Hence in obtaining the average
coefficient around the tube the values of h1 and h7 were
not used even though they were calculated and are tabulated
1n Table I II in the Appendix
Then
(14
A Nusselt number as calculated from this aver age heat
transfer coefficient using the tube diameter as the characshy
teristic dimension
(15)
The air flow rates through the test section were calshy
culated by measuring the pressure drop across the flow orishy
fice the air temperature the pressure at the flow orifice
and the pressure at the entrance to the test section The
orifice calibration curves (1 p 166 ) were used to obtain
a value of the orifice coefficient f8e where Q equals
the flow in cubic feet per minute at 68deg F and one atmosmiddot
phere pressure and te is the density of air at the exchanger
and e the density of the air at the flow orifice The
den sity of the air can be expressed by
e = 2 703 p (16)T
where T equals the temperature in OR and P equals the absoshy
lUte pressure i n lb1n2 Using the value of e Qfo from
26
the calibration charts as A and Eq (16) solving for Q
gives
( 17
This equation was used to calculate the flow rate for
each flow studied
The Reynolds number used i n the correlation of the
data was the equivalent Reynolds number defined as
Re)eb ~ d2 - dl)Uf ( 18 ) lL
where d1 is the outside diameter of the inner tube and d2
is the orifice diameter U is the flow velocity through the
annular orifice e is the density of the air and U- is t he
viscosity of the air This equation can be transformed t o
(Re) b = 1611 Q (19) e dl + d2
where d1 and d2 are in inches
The pressure drop data were calculated i nto a dimenshy
sionless pressure drop function cent where
d1 )22( ~ P)gc f av(d2 shycent 2 bull (20
M-
For air this equation reduces to
where d2 and d1 are in i nches D P is expressed i n inches of
2 95 specific gravity fluid and P av is expressed as lbft3
27
CHAPTER VII
ANALYSIS OF DATA
In analyzing the heat transfer data an attempt was
made to correlate it 1n terms of the dimensionless groups
(Nusselt number Prandtl number and Reynolds number) which
appear in Eqs (3) and (4) Consequently all of the av~
erage heat transfer coefficients hav were brought into
the form ( Nu)( Pr)~3 bull The Nusselt number was based on the
tube diameter and the thermal conductivity of the air at
the flowing temperature The tube diameter was used in the
Nusselt number because comparison could then be made with
previous experimental work on heat exchangers which have
commonly used the Nusselt number defined as in Eq (15)
From the standpoint of dimensional analysis this is
equivalent to considering the tube diameter as the characshy
teristic length so far as the heat transfer is concerned
The Prandtl number of the air was taken as 0 7 in all
cases
Variation of Heat Transfer Rate with Distance from the Baffle
Considerable variation was observed in the rate of
heat transfer in the vicinity of the baffle In order to
obtain the variation with respect to position the term
(Nu)(Pr)-13 was plotted versus the flow rate Q for each
position and orifice studied Cros s plots were then made
28
at constant flow rates in order to obtain the variation of
(Nu)(Pr) -13 with position The resulting cross plots are
shown 1n Fi gures 5 6 and 7 for the four orifices studshy
ied
About one inch upstream from the orifice the heat
transfer coefficient begins to rise rapidly and continues
to do so until it reaches a maximum some distance downshy
stream After the maximum point the heat transfer coef fi shy
cient decreased slowly The heat transfer rate was found
to reach a maximum at a different position downstream for
each orifice size These figures also show that for a
given orifice size the maximum heat transfer rate occurs
a pproximately at the same point for all flow rates The
position of the maximum point f or each or ifice size is
shown in Table II
The region immediately downstream from the orifice is
one of h i gh turbulence due to the jetting action of the air
flowing through the orifice As the air flows t hrough the
orifice the streamlines continue to converge for some dis shy
tance downstream The point of maximum heat transfer is
probably at the point where the streamlines be gin to diverge
and a boundary layer begins to build up on the tube Tle
decreasing heat transfer coefficient beyond the maximum
point indicated the formation of a boundary layer
Since the position of the maximum point is independent
of flow rate middot it is possible to correlate it with respect
_ ct 11shyz-
100
0 136 ORIFICE
(
I 0
I )
~ 00
~p 0
I 0
--r--- ~
ISCFIII
-_ OCFM
rbull abull
~ middot~ a-1 z-
12fORIFICE
100
200
100
0 0 UPITRAM ORIFICE DISTANCE CENTER
CFM
h I DOWNSTREAM
DISTANCE
FIGURE 5 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLpound
30
too
700
800
100 ~ f gtf
400
z ~
100
100
100
0
13fORIFICE
~ -~ -- ---
)
~
~
-
I ~ ~OCFM
I vI~-~ OCFM
J ---
Iamp CFM
I 0 I I UPSTREAM ORIFICE DOWNSTREAM DIITANOE GENTER DIITANCI
FIGURE 6 VARIATION OF HEAT TRANSFER RATE WITH DISllNCE FROM BAFFLE
--
--- --
31
100
100
700
100
_ 100
f 9- 400 z-
100
tOO
100
0 - I 0 I I I UHTRIAM OAtfiCI DOWIIITMAM
+ I tyl6 ORIFICE
v I
~~ ~CFM
I v ~CFMI
v v 7
~~ v ~ iOCFM
- ~~ I-shy1-shy ~ICFM
DIITMCI OINTIR DIITANCI
FIGURE 7 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLE
32
TABLE II
POSITION OF MAXIMUM HEAT TRANSFER
Position of Maximum Orifice Size Heat Transfer
(inches) (inches downstream)
1 364 050
1 216 100
1 316 125
1 516 200
33
to orifice size Figure 8 shows the effect of the orifice
size on the position and value of the maximum heat transfer
at a constant flow rate of 15 cubic feet per minute It
can be seen that the larger the orifice size the further
downstream the point of maximum heat transfer occurs
Also as the orifice size increased the rate of heat
transfer decreased for a given flow rate The broken line
indicates the variation of the point of maximum heat transshy
fer with position and size The position of the point of
maximum heat transfer rate downstream from the orifice was
correlated with orifice size by means of the dimensionless
groups (Lde) and (d1de) where L is the distance downshy
stream from the orifice where the maximum rate of heat
transfer occurs d1 is the outside diameter of the inner
tube and de is the equivalent diameter of the orifice
ie de = d2-dlbull
Figure 9 shows a plot of Ld 6 versus d1d6 for the
four orifice sizes studied The four points on this logshy
log plot are approximately in a straight line and the
equation of this line is
Lde = 0 44 d1de)028 (22)
Although the above relationship represents a correlashy
tion of dimensionless groups it is based upon only one
tube diameter and needs to be substantiated further by
studying other tube diameters and other orifice sizes
34
aoo
400
aoo ~
-~ middot-CLshyJ z
200 -
100
0
ORIFICE CENTER
l~
l
t
I J~
1pound~
I
0 I I~
AT 15 CFM
-
bull ~ 1~6~
~ v~
~
~--~~6
~~~ ___ v v V -_
~ o q
~ I 16
v
~
ogWNSTREANI STANCE
FIGURE 8 EFFECT OF ORIFICE SIZE ON POSITION AND VALUE OF MAXIMUM HEAT TRANSFER
35
50
loshy____ -~
~ ~ -shylltl-shy~ r0
2 10 30
FIGURE 9 CORRELATION OF THE POINT OF MAXIMUM HEAT TRANSFER WITH
ORIFICE SIZE
36
Correlation of Data at the Baffle
The heat transfer data were correlated by obtaining a
relationship between the group (Nu)(Pr)-13 and a
Reynolds number based on twice the clearance (d2 - d1
between the tube and the baffle It was found that the
most satisfactory correlation could be obtained when the
term - d1 was used as the length term in the Reynoldsd2
number
Figure 10 shows the variation of the heat transfer
rate at the center of the orifice e xpressed as a function
of Reynolds number and the orifice size This shows that
for a given Reynolds number the heat transfer at the center
of the orifice is greatest for the smallest orifice size
In order to obtain a general correlation of the data
shown i n F1gure 10 the effect of the dimensionless ratio
d1de was considered This ratio considers all of the
geometric factor s needed to describe the annular orifice
The thiclaless of the orifice plate is also a factor but
was constant i n this i nvestigation
The data for the heat transfer at the baffle center
are shown in Figure 11 in which (Nu)( Pr)-13 is plotted
versus (Re)ebd1 de) 0 55 This data on a log-log plot
lies on a straight line for (Re)eb( dld8 )0 55 greater
than 3 x 104 The equation for cor relating the heat
37
4XI~middot~-r~------~--~~------~
Icf t--to_+--_c-c-________ SYMBOL SIZE
0 1~4
6 ~~
9 ~~ -o ~
(Re)eb
FIGURE 10 RATE OF HEAT TRANSFER AT BAFFLE CENTER
38
500
0
4 0 lcf
~ ~
~ ~iC-
~ ~
~IL 0~ 0 SYMBOL SIZE-
p 0 1364-
r 6 1~16 -~ -
9 1~16 --o 1~16
I I
FIGURE II CORRELATION OF HEAT TRANSFER DATA AT BAFFLE CENTER
39
transfer at the center bullOf the a nnular orifice was found by
the method of least s quares to be
(Nu)( Pr)-1 3 = 0018 ( Re)ebO Bl( dlde)04~ (23)
3 x 104 ltRe)eb(a1de)055 lt 105)
Rate of Heat Transfer at the Point of Maximum Heat Transfer-The heat transfer rate at the point of maximum heat
transfer is plotted in Figure 12 to show the variation with
Reynolds number and the size of the orifice It is shown
gives the h1gh st heat transfer ~ate at its point of maxibull
that for a given Reynolds number the smallest orifice size yen il
mum heat transfer
The data ~or the maximum poi~t could be correlated by
plotting (Nu) Pr)-13 versus (Re)eb(d1de)06 This plot
is shown 1n Figure 13 and the resulting eurve shows that
(Nu(Pr)-13 is not a simple p0wer function of the Reynolds
number as was the case for heat transfer at the baffle
center The reason for this is probably because other
factors such as intensity and scala of turbulence should
be considered At the orifice center the streamlines of
the flowing stream are converging_ and thus the flow is
quite stable Downstream from the orifice is a region of
large eddy currents and probably large scale turbulence
These factors could con ceivably cause the results which
were obtained for the point of maximum heat transfer
40
If)
~middotshy Q_-I z_
10~~~--------r----~~--~--
SYMBOL SIZE
0 13$4
6 1~8
Q 13-18
-o 1~8
7)(104
(Re)eb
FIGURE 12 RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
41
Ia ~
0 I
c ~ ~ c v
~ ~lt w ~
17
~ b
v ~ ( SYMBOL SIZE
-~ 0 f-64 -v ~ 6 t211e
~ Q I~~~
-o - l~rs I I
FIGURE 13 CORRELATION OF HEAT TRANSFER DATA AT THE POINT OF MAXIMUM HEAT TRANSFER
4 2
Effect of Upstream Baffles on Heat Transfer at the Orifice Center
The heat transfer rate at the orifice center using the
single orifice in a test section is a pproximately 13 of the
value that was obtained by Lee (7) using a model heat exshy
changer with orifice baffles Lee investigated the cent r al
baffles of the heat exchanger and thus the coeff icients he
obtained would be affected by the presence of a number of
upstream baffles To determine the effect of upstream
baffles an additional l 516 inch baffle was placed four
inches upstream 1n the test section The resulting data are
shown in Figure 14 where (Nu)(Prmiddot)-13 is plotted versus
(Re) eb for the case of a single baffle 1n the test section
and also the case of an additional baffle placed four inches
upstream Comparison is made with the results obtained by
Lee middot(7) using a four-baffle and a ten-baffle model heat exshy
changer Good a greement is obtained with Lees work and the
results show the marked effect that upstream baffles have on
the downstream heat transfer rate The additional up tream
ba ffle caused sufficient turbulence 1n the test section to
i n crease the heat transfer rate nearly three-fold at the
center of the next baffle
Heat Transfer i n the Test Section with No Orifice
In order to check the accuracy 6f the equipment the
orifice baffle was removed and the heat transfer mea sured
with the probe in the empty test section The data were
43
~~BAFFLES
0 l BAFFLE -shy
ll_9 2 BAFFLES
V 4 BAFFLES-LEE
4 10 BAFFLES- LEE lJf ~
~rv ~~ ~ v flvv ~~
I ~ J ~ L v
0
v
( V
40 3XIo 7XIa
(Re)eb
FIGURE 14 EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER AT BAFFLE CENTER
44
compared with heat transfe r coefficients predicted by the
equations for annuli which are recommended in the litera shy9
ture The two equa~ ions u sed tor comparison were
(hfe)=0 023 (rltGr e (~~ur4 (~r45 (24)
which was presente~ by Wiegant (10)
and ( h ) (cnM~5(M~l o14 o 023 CPG k j Mij - (de GJMb )0 2 ( 2 5)
which was presented by McAdams (8 p 242) The comparshy
i son is s hown in Figure 15 lq (25) gives a value which
is low by about ten percent while Eq (24) g ives values
which are high by as much as twenty -five percent when comshy
pared with the experimental data The se equations are gembull
erally considered to give coefficients with an accuracy of
about twenty percent Therefore the present experimental
data are within the accuracy of these equations Also the
plot indicate s that for a Reynold s number greater than 2 x
104 the slope of the line is the same for the experimental
data as for the equations
Pressure Drop Data
The total pressure drop across the orifice was measured
as a function of the flow rate and the orifice size The
pressure drop was expressed as a d1mens1onleas quantity r)
which ie plCltted ver sus the Reynolds number in Figure 18
The pressure drop function cent correlates for all or1f1oe
45
200
100
s z
10 5XI10 10
0 EXPERIMENTAL
--McADAMS
-WIEGAND L
V
~ ~ ~
P ~ ~
LL~ L
v~
~
v v
v 1 ~ ~ v
v -gt
~
~ ~
~
6Xid
FIGURE 15 HEAT TRANSFER WITH NO BAFFLE
46
0 1~4 -~ a 6 t216
Q t316 lJ J
-0 as a )t
A LEE I -shy SULLIVAN 8
p
10bull
BERGELIN
I _ll I
I ~
i I
~middot
lo II
f fl
J j
~middot
A)101
1q
I Ill
1 I3 X 10ao1
FIGURE 16 ORIFICE PRESSURE DROP FUNCTION VS REYNOLDS NUMBER
47
sizes- The present data extends the range covered by preshy
vious workers and agrees well with their work The preshy
vious work of Lee () for a heat exchanger containing 10
orifice baffles and also the data of Su livan and Bergelin
(9) for pressure drop in a model heat exchanger with a
single baffle is shown 1n Figure 16 long with the present
results~ This figure may be used to predict the preseure
drop from the equivalent Reynolds number of the annular
orifice
The pressure drop between individual points 1n the
vicinity of the orifice and an upstream pressure tap wa s
measured to obtain a pressure drop profile As might be
expected 1n all cases the profiles showed a rapid decrea e
in static pressure immediately upstream from the orifice
There was however little or no recovery of the pressure
loss downstream The 1 364 inch orifice did show a maxishy
mum point in the pressure drop but this maximum occurred at
the orifice center and total recovery was reached about 12
inch downstream
Heat Transfer at the Baffle and Maximum Point as a Function of Pressure Drop
In order to compare the effect of the total pressure
drop on the heat transfer at the baffle and the point of
maximum heat transfer Figure 17 was plotted showing
(Nu)(Pr)-13 as a function of the total pressure drop This
shows that for a given pressure drop the largest orifice
48
1200
1000
~ a -sshyz-
100
60 100 700
AT MAXIMUM POINT I 15116 2 13116 3 1~6 4 1364
AT ORIFICE CENTER
60
1
v
r ~ ~ ~
5
~
8 7
13116
8
~
1364
v
~
e6
1~6
v
~~ v ~ ~ -~ ~
~
~ v
l
~
vamp
I ~ ~
~
v L ~
v
I-
5
k= ~~
~ ~ ~
--I
v ~
FIGURE 17 HEAT TRANSFER AT THE BAFFLE AND MAXIMUM POINT AS A FUNCTION OF
ORIFICE PRESSURE DROP
49
size has the greatest heat transfer coefficient This is
true at both the orifice center and at the point of maxishy
mum heat transfer
Another comparison can be made by plotting the heat
transfer coefficient and the pressure drop versus the orishy
fice size at a constant flow rate Figure 18 shows this
plot This graph shows that at a constant flow rate the
pressure drop as well as the heat transfer coefficient
increases as the size of the orifice is decreased In
choosing an orifice size for maximum efficiency 1t would
be necessary to know the pumping power available as well
as the heat transfer desired
70 I I 700
AT 15 CFM 60 ---
~ aug
50 ---
NV
40 ~
~ ~ ~
~ _
MAXIMUM POINT ---- --- ~
1-----t---~ _
~00Qj ~
~t--- ORIFICE CENTER 10 1100
1---~ n
u0 01 02 03 Q35
a ltl
de inches
FIGURE 18 VARIATION OF HEAT TRANSFER RATE AND PRESSURE DROP WITH ORIFICE SIZE AT A CONSTANT FLOW RATE
cn 0
51
CHAPTER VI II
SUMMARY OF RESULTS
This study revealed several significant facts about
the heat transfer in the vicinity of annular orifices
Probably the most important contribution was the presshy
entation of the heat transfer profiles in the vicinity ot
the annular orifice ~ r s shown that t~ local heat
transfer coeffieient re~ches a maximum at a point downshy
stream from the orifice The distance downstream at which
this maximum oocurs is t1ven by the equation
22
The heat transfer coefficients at the center of the
orifice were correlated and found to follow the equation
(Nu)(Pr)-13 = 00176 (Re)eb08l(d 1de) 0 middot4~ (23)
3 x 104 lt( Re) 9 b( d1d6 )055 ltlo5 )
The heat transfer at the point of maximum heat trans
fer for each orifice size was correlated and presented in
Figure 13 as a plot of (Nu)(Pr)-l3 versus (Re)eb(d1de) 06
No simple po-orer relationship exists between the terms
Intensity and scale of turbulence downstream from the orishy
fice are probably important factors which affect the heat
transfer
The large effect of an upstream orifice on the heat
transfer rate at the second orifice was demonstrated by the
52
study of two 1 516 inch orifices in the test section The
added turbulence at the center of the second orifice was
found to raise the heat transfer rate almost three times
over that obtained for a single baffle
The pressure profiles in the vicinity of the orifice
indicate that nearly all the pressure drop occurs at the
orifice center~ Total pressure drop data were correlated
by a pressure drop function cent as a function of the Reynolds
number and good agreement obtained with the results of other
workers
The pressure drop and heat transfer data were correbull
lated by plotting the heat transfer as a function of the
pressure drop for each orifice size It was shown that for
a given pressure drop the largest orifice size gives the
greatest heat transfer coefficient
As a final presentation it was shown that the pressure
drop and the heat transfer coefficient both i ncrease i n
value at a constant flow rate as the orifice size is de shy
creased This is important in choosing the optimum clearshy
ance for orifice baffles
53
CHAPTER IX
RECOMMENDATIONS
A great deal of work remains to be done in the field of
evaluating shellmiddotside heat transfer coefficients This
study included only one tube size and air was the only f luid
used It is recommended that further studies be conducted
using other fluids and tube sizes It will also be necessary
to study several baffle types
The adde d turbulence due to a s e cond baffle placed upbull
s t ream would suggest that the heat transfer coef ficients at
a certain position i n relation to a baffle would increase as
the flow progressed through the exchanger It is recomshy
mended that an extensive s t udy should be made between baffles
the full length of a model heat exchanger
It is further recommended that the pressure drop study
be continued to include other fluids tube sizes and baffle
arrangements
Effects of turbulence downstream from the baff le should
be studied by i n vestigations with hot-wire anemometer equipshy
ment to determi ne t urbulence scale and i ntensity
54
NOMENCLATURE
Area of heat transfer
Heat capacity of the fluid
Outside diameter of the tube
Orifice diameter
Equivalent diameter of the orifice (d2 - dl)
Inside diameter of the test section
Inside diameter of the tube
Gravitational constant
G Mass velocity
h Local heat transfer coefficient
Coefficient of heat transfer from surface to fluid
i Direct current amperes
k Thermal conductivity of the fluid
L Distance downstream of the point of maximum heat transfer
p Absolute pressure
L P Total pressure drop across the orifice
Q Flow in cubio feet per minute at 1 atmosphere and 680 F
q Heat transferred
Thermal energy conducted into the sensing probe
Thermal energy radiated from the resistance ribbon
Resistivity of the resistance ribbon
s Length of the resistance ribbon
T Temperature oR
55
t Temperature of the resistance ribbon deg F
ta Temperature of the bulk stream oF
tw Wall temperature of the tube OF
U Veloc ity of the fluid
w Width of the resistance ribbon
z Thickness of the resistance ribbon
eeuro Density of the fluid in the test section
Density of the fluid at the flow orificef 0
AL Viscosity of the fluid
E9 Angle measured around the tube
Dimensionl ess groups
(Nu) Nusselt number hd1k
(Pr Prandtl number C~k
(Re)eb Equivalent Reynolds number at the baffle (d2 - d1 )uejt-Lshy
(Re)e Equivalent Reynolds number in the test section ( d 8 - d 1 )U fu
cent Orifice pressure drop function 2(~P ) gc~av(d2 - d1) 2
Al
56
BI BLIOGRAPHY
1 Ambrose Tommy W Local shell-side heat transfer coefshyficients in baffled tubular heat exchanger PhD thesis Corvallis Oregon State College 1957 183 numb leaves
2 Bell K J and o P Bergelin Flow through annular orif ices Transactions of the American Society of Mechanical Engineers 70593-601 1957
3 Colburn Allan P A method of correlating forced con shyvection heat transfer data and a comparison with fluid friction Transactions of the American Institute of Chemical Engineers 24 174-210 1933
4 Dittus F w and L M K Boelter Heat transfer 1n automobile radiators of the tubular type University of California Publications in Engineering 2443-461 1930
5 Gurushankariah M s Local shell-side heat transfer coefficients in the vicinity of baffles in tubular heat exchangers Masters thesis Corvallis Ore gon State Colle ge 1958 97 numb leaves
6 Knudsen James G and Donald L Katz Fluid dynamics and heat transfer New York McGraw-Hill 1958 576 p
7 Lee Kyu Sung Local shell-side heat transfer coeffishycients and pressure drop in a tubular heat exchanger with orifice baffles Masters thesis Corvallis Oregon State College 1959 118 numb leaves
8 McAdams William H Heat transmission 3d ed New York McGra ~-Hill 1954 532 p
9 Sullivan F W and 0 P Bergelin Heat transfer and fluid friction in a shell-andbulltube exchanger with a single baffle Chemica l Engineer ing Progress Symposium Series 52 ( 18) 85-94 1956
10 Wiegand J H Discussion on annular heat transfer coshyef f icients for turbulent flow Transactions of American Institut e of Chemical Eng i n eers 41147-153 1945
AP PENDIX
57
TABLE III
CALCULATED HEAT TRANSFER DATA
Baffle Hole Diameter Run No (inches)
1 - 59 1 364
60 - 102 1 216
103 - 138 1 316
139 - 206 1 516
207 - 212 No orifice
213 - 218 2nd - 1 516
TABLE III
CALCULATED HEAT TRANSFER DATA
Local Heat Transfer Coefficients Run
T0 bull Po s ition CFM hr h2 h3 h4 hs he ~ hav Nuav
1 c 1026 10 59 1476 16 09 1559 1510 1435 1203 1518 8511 2 1290 1369 1738 1878 18 05 1755 1689 1515 1773 9964 3 1416 1636 198 1 2068 1977 1924 1845 1715 1959 11030 4 1627 1991 2301 2382 2268 2194 20 ~98 1929 2249 12664 5 1776 2252 2669 2863 2713 2517 2338 2126 2620 14759 6 l2ttD 1109 2311 3317 3386 3373 3387 3394 3071 3371 18888 7 1258 3089 4583 4866 4683 4701 4643 4194 4695 26301 8 1433 38 8 5 55 83 5791 5495 5430 5436 5008 5547 31192 9 1681 4992 7378 7649 6980 6864 6870 64 28 7148 40180
10 1 D 1102 2371 3332 3511 3356 3342 3427 3102 3394 19012 11 1308 3218 4379 45 24 42 53 4255 4373 3965 43 57 24446 12 14 64 38 58 5146 5142 4839 4787 4903 4597 4963 278 79 13 1706 5218 6664 6269 58 81 5884 6237 5973 61 87 34718 14 15
1 l2D 1115 1275
2131 2661
2955 3638
2972 3720
2941 3675
2913 3576
28 22 34 74
2613 3278
2921 36 17
163 09 20246
16 1498 34 87 4644 4503 4441 4371 4343 4194 4460 25010 17 1695 4449 5743 5324 5222 5154 5157 5015 5320 298 97 18 2D 1049 1715 23 90 2550 2610 2656 2624 2208 2566 14363 19 1241 2117 2964 3145 3218 3221 3203 2759 3150 17757 20 1532 28 67 3936 4100 4188 4201 4167 3676 4118 23224 21 1674 3459 4508 4598 4746 4795 4792 4299 4688 26337 22 lU 1074 253 340 380 3 86 388 377 354 374 2097 23 1287 292 392 433 440 441 429 406 427 2394 24 1508 322 439 492 498 499 487 461 48 3 2713 25 18 07 3 38 464 519 5 24 520 499 463 5 05 28 40
~~ (]I agt
TABLE III Continued
Run No Position CFM h 1 h2 ~3 h4 h5 h6 ~ h
av Nu
av 26 c 1029 1171 1491 1589 15 28 1 4 62 1377 1293 1489 83 44 27 1266 1395 1746 1853 18 02 1685 1556 1453 1728 9704 28 1430 1637 2037 2175 2060 1909 1735 1591 1983 11159 29 1729 1982 24 96 2751 2507 2268 2030 1886 2410 13579 30 12D 1054 2934 4041 4321 4326 4423 4359 3706 4298 24160 31 1294 3385 4 8 26 52 42 5326 5450 5277 4566 52 24 293 50 32 1431 3784 5347 5721 57 bull75 58 44 5700 5084 5677 31870 33 1770 52 75 7 7 33 87 35 9005 9007 8267 7059 85 49 48050 34 lD 1058 3235 4401 4444 3877 3496 3451 3294 3934 21973 35 1263 38 98 5484 5330 4347 3964 3981 3987 4621 25823 36 18 36 6701 89 17 7855 6369 5597 5769 6283 69 01 38718 37 1 12D 1029 2404 31 8 2 3333 3459 3624 3577 3045 3435 19264 38 1315 3182 4033 4162 4310 4496 4502 4015 4301 24142 39 1426 3628 4389 4510 4573 4760 4804 43 8 5 4607 25678 40 1757 4547 5559 5(35 5931 6282 63 70 6060 5975 33471 41 2 11D 1080 2034 28 38 3155 3144 3145 2966 2540 3050 17027 42 1305 2650 3 4 87 3aoz 3595 3751 3595 3153 36 46 20405 43 1434 3167 39 07 4156 4371 4320 4126 3709 4176 23395 44 1804 4096 4 9 66 5691 5714 5586 53 15 48 65 5454 30582 45 12U 1088 409 516 557 564 5 60 535 513 5 46 30 67 46 1318 470 579 6 22 631 6 17 5 97 579 6 09 3422 47 14 13 540 640 676 6 86 681 6 60 6 54 6 69 3754 48 1773 641 740 774 782 7 69 749 746 763 42 87 49 l 11 U 1054 270 356 391 397 393 3 71 346 38 2 2133 50 1240 303 399 446 449 447 4 21 398 432 2420 51 1419 361 476 522 530 528 507 467 493 2760 52 1 1(2U 1032 236 311 342 347 344 325 301 334 18 78 53 1314 270 366 403 407 408 386 351 394 2217
(Tt tO
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ h av Nu av
54 1448 301 408 447 454 452 431 403 438 24 61 55 1782 353 494 548 544 415 529 531 506 2843 56 2U 10 61 220 287 316 320 322 303 268 310 1735 57 1216 249 335 370 377 378 353 307 363 2044 58 1322 263 356 394 398 399 374 327 384 2159 59 1639 310 433 478 481 482 452 393 465 2617
60 1D 10 68 2011 2536 2657 2681 2694 2560 15 62 2625 14938 61 1399 2520 3239 3369 3371 33r82 32 39 1946 3320 18968 62 1669 2781 3655 3820 38 76 3883 3738 2355 3794 21712 63 1959 3524 42 37 4399 4438 4497 4417 3047 4397 25156 64 2295 4426 5288 5396 5372 5240 5410 3369 5341 30680 65 2636 5490 6531 6662 6565 6379 6820 4249 6591 37938 66 3390 7869 9538 9462 9387 8924 10508 62 91 9564 59601 67 1U 1190 352 368 401 413 407 395 293 397 2256 68 1559 397 422 462 475 471 456 331 4 57 2603 69 1904 434 465 5 13 529 528 504 358 508 2901 70 2211 493 526 573 5 92 588 564 4 15 569 3257 71 2289 569 587 6 30 649 6 61 6 49 460 635 36 44 72 2727 637 6 60 7 09 733 751 743 521 719 4140 73 3210 728 755 8 15 8 43 8 62 8 54 616 826 4765 74 2nD 1210 181 2256 2393 2399 2333 2206 1325 2317 13158 75 1420 2340 2752 2899 2913 2850 2728 1701 2828 16121 76 1692 2853 3306 3452 3471 3379 3217 2134 3365 19217 77 1894 3102 3588 3713 3736 3670 3557 2455 3653 20892 78 2301 3682 4259 4433 4467 43 83 4289 2892 4366 250 30 79 2621 4117 4828 5017 5012 5030 5109 3071 4999 28785
m 0
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ hav Nuav
80 3230 5158 6006 62 13 61 18 6134 6695 4094 6233 359 87 8 1 12nD 1155 15 27 1854 2028 2064 20 85 1987 1164 1968 118 31 82 1689 2046 24 8 2 2688 2739 2760 2658 1749 2665 152 73 83 1244 2088 2317 2339 2345 2373 2381 1487 2351 13432 84 2100 3211 3539 34 21 3462 3512 3696 2575 3526 20284 85 2292 3 5 05 3761 3648 36 25 36 79 3957 2933 3734 21517 86 2907 4420 48 22 4679 46 04 4705 5206 3792 48 03 27741 87 33 80 59 35 69 38 7404 77 10 7 8 36 7 0 86 5190 7394 427 44 88 1 12D 1 4 27 2 4 58 28 31 3037 3021 2987 2927 18 57 2 9 61 16913 89 18 75 34 75 3 9 87 4230 4255 4317 4337 2734 4225 24258 90 22 59 4221 4796 5046 5052 51 01 5389 3491 5077 29206 91 2682 4978 5664 5943 5966 6054 6573 408 1 60 40 34795 92 3417 63 16 71 02 7 3 93 7385 75 40 8 6 95 51 45 7623 44017 93 c 1 5 17 1240 1305 1399 1467 1479 1429 9 26 1423 8251 94 20 34 1554 1623 1720 18 21 18 53 18 72 1215 1778 10229 95 2 3 48 1795 1843 198 5 2097 2171 2274 1540 2074 11947 96 2716 2028 2048 22 01 2 3 44 2444 2661 18 90 2340 13505 97 3247 2410 2375 2663 2778 2949 3298 2378 2793 1615 98 11 35 967 1040 1124 1186 1200 1142 728 1138 6496 99 14 06 1135 1220 1318 1384 1403 1 3 61 8 77 1336 7656
100 2311 1 8 54 18 78 1980 20 90 2136 2227 1653 2062 118 31 10 1 2666 2085 2094 2227 2 3 62 2438 2626 1902 2349 13508 102 3392 2635 2582 28 01 3026 3141 3529 2567 3016 17390
103 1 U 1235 349 395 434 436 4 28 411 286 423 2416 104 20 10 434 5 02 559 577 569 5 37 345 552 3177 105 28 14 538 626 685 711 7 21 682 424 6 8 6 3966
Q) j-J
TABIE III Continued
Run No Position CFM h1 h2 h3 h4 h5 hu h7 hav Nuav
106 3492 614 7 1 6 7 84 8 13 8 33 7 85 4 88 7 87 4562 107 4395 7 86 894 964 996 1005 9 64 640 9 65 56 06 108 50 75 9 11 10 22 1081 1112 1125 1085 7 24 1085 63 16 109 G 1344 9 22 1042 1120 1 1 46 1173 1131 7 04 1120 63 87 110 1936 1162 1340 1442 1474 1509 14 7 3 9 09 1441 82 77 111 2846 1631 1797 1902 1966 2027 2079 1342 19 2 3 11108 112 3484 207e 2144 2236 2307 2385 2574 1694 2268 13138 113 4066 24 65 24 42 2535 2648 2757 31 71 2178 2 5 96 15078 114 50 12 3059 2916 30 1 5 3176 3312 4059 2849 3105 180 46 115 1D 1362 2268 26 13 2613 26 35 2605 2503 15 46 2617 14934 116 1958 2993 3580 3580 3586 3539 3 5 02 2144 3571 20492 117 2812 4430 50 32 4913 4 9 86 4991 5196 3088 4981 287 66 118 3432 58 16 62 13 6067 61 18 60 66 6698 4143 61 16 354 16 119 40 22 71 71 7 4 62 7369 7419 7329 82 74 51 8 1 7395 42909 120 5026 105 95 11456 115 81 11574 11548 14010 80 91 11540 671 15 121 2D 1244 18 57 2277 2363 2305 2210 2107 1466 2289 13038 122 1960 2622 3240 3388 33 23 3226 31 40 2)99 3294 18919 123 2817 3762 45 87 4739 46 56 45 14 4 6 47 30 15 4624 26689 124 3491 50 22 5723 58 53 57 44 5542 60 18 3871 57 16 330 73 125 4096 61 29 68 16 69 79 6805 65 90 74 79 4677 67 98 39400 126 5037 82 27 94 60 95 69 93 57 9023 11324 65 05 93 52 542 83 127 12D 1278 14 70 1 6 48 1652 1638 1 6 34 1641 9 73 1 6 43 9369 128 1947 19 63 2155 2149 2151 2131 2190 1347 2147 12342 129 2769 2615 2791 2773 28 52 2716 2954 18 96 2783 1 60 82 130 3439 3208 3265 3239 3593 3133 3624 2515 3308 19174 131 4103 3637 35 88 3577 4077 3459 42 66 3138 3676 21343 132 49 78 45 82 44 60 44 8 1 55 17 43 25 5749 4227 4700 27288
Q) tlgt
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
133 1 12D 1299 2094 2507 2622 2625 2567 2489 1465 2578 14736 134 1973 29 56 3505 3772 3790 3718 3718 2115 3700 21290 135 2788 3941 4727 5069 5099 5 0 07 5231 2984 4976 28781 136 3473 5155 59 81 6308 6339 62 39 68 96 4204 6217 36052 137 4118 6135 71 8 6 7662 7731 76 91 87 16 49 8 5 7568 43985 138 4973 7765 94 75 10396 10861 10694 13646 66 64 10357 602 25
139 1ttn 1253 1242 1493 1460 1442 1431 1424 8 84 1457 83 01 140 2366 1942 2150 1961 1910 1897 19 62 1206 1980 11400 141 3461 3007 2957 2562 2513 2606 3143 18 51 2660 15400 142 4325 3942 3571 3060 2999 3198 4248 2631 3207 18618 143 5677 508 6 4359 39 88 3800 42 29 57 78 36 26 4094 23824 144 67 59 64 55 5330 4988 47 25 5494 2517 48 09 5134 29906 145 84 08 9326 72 26 7726 85 56 9172 12319 7733 8170 47626 146 86 54 9831 7582 818 9 94 90 9869 13116 78 97 8783 512 96 147 7376 7335 58 7 6 5941 5796 68 29 81 65 5954 6111 35662 148 2 11 D 4254 4106 48 02 4994 5038 5042 56 78 3419 4969 28881 149 5708 5487 6253 6466 6524 6527 78 63 45 8 2 64 43 37566 150 69 7 8 7983 9440 9848 98 34 97 32 13249 6701 9714 566 59 151 1254 1434 18 53 1947 1915 1850 1760 1186 1891 10772 152 2713 2696 3175 32 94 3288 3237 3288 20 44 3249 18728 153 87 30 118 07 14733 15758 15504 15305 26297 9617 15325 892 71 154 5811 5278 6543 6861 69 30 69 82 7 8 74 4478 68 29 39531 155 4246 3780 4736 4975 49 66 4936 5162 3113 4903 28301 156 (v 1270 8 15 935 959 966 9 51 9 23 6 35 953 5430 157 2714 1164 1390 1427 1447 1454 1455 9 08 1430 8242 158 4310 1655 18 96 1942 1988 2002 2111 1305 1957 11349
(j) ~
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 fry hav Nuav
159 6012 2208 2400 2450 2513 2548 28 20 18 00 2478 14416 160 7279 2696 2881 2927 2989 3081 3599 2340 2970 17326 161 86 90 3257 3360 3 3 76 34 26 3558 4455 2943 3430 2000 162 12D 4368 2209 2600 2558 2518 2466 2774 1753 2536 14713 163 5833 2730 3092 3028 2974 2913 3501 2287 3002 174 78 164 7643 3320 3681 3630 3651 3530 4623 3181 3623 21116 165 87 39 3920 4303 4300 4708 4178 61 60 3937 4372 25456 166 1268 962 1203 1205 1186 1118 1084 725 1178 6693 167 2678 14 67 1785 1779 1752 1698 1726 10 70 1754 88 49 168 1 12D 12 83 936 1217 1414 1397 1239 1190 7 65 1317 7484 169 2729 2502 2930 2914 2934 2956 2979 17 52 2934 16866 170 4345 3884 4357 4283 4318 4421 4836 28 59 4345 25151 171 6036 5546 5858 5764 5791 6028 7129 4184 5860 34045 172 6578 7167 7769 7907 79 82 8263 10492 5915 7980 46437 173 87 84 10237 112 23 120 26 12727 12968 185 19 85 98 12236 71103 174 1278 1344 1803 18 72 1835 1790 1712 1063 1825 10355 175 2711 2328 2972 2932 2893 28 78 2863 1667 2919 167 51 176 4351 3934 4414 4353 4281 4321 4654 28 63 4342 25088 177 5994 5076 5824 5838 5818 59 29 6914 4205 5852 33885 178 1 11 U 1223 388 432 465 464 449 435 338 453 2585 179 2351 521 602 6 22 675 6 57 619 436 639 3687 180 34 48 6 05 1725 803 8 27 8 11 760 518 792 4593 181 4513 718 850 934 9 68 9 57 8 99 609 9 27 5386 18 2 5714 8 32 981 1060 1102 11 06 1034 6 59 1062 61 82 183 6997 1025 1182 1258 1295 1309 1234 8 18 1261 7 3 44 184 8709 1295 1487 1 5 42 1594 1626 1612 1156 1562 9080
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
185 2 12D 4249 3560 4400 4670 4791 4695 47 81 2931 4639 268 37 186 5737 4926 58 54 61 92 6248 62 38 67 78 4134 6131 35590 187 7432 6390 7726 83 46 85 44 86 34 10371 5658 8313 48310 188 8723 7718 107 88 11933 12099 13046 186 22 79 39 119 67 69505 189 1 4 35 1340 1735 18 57 18 52 17 81 1711 1144 18 06 10256 190 2718 2399 3023 3187 3207 3138 30 53 1931 3139 18025 191 7 5 07 6189 80 11 9200 9427 9703 11364 5720 9085 527 38 192 8544 78 42 10666 125 42 13312 13775 178 20 6976 125 74 729 86 193 1287 1417 16 97 18 7 18 69 18 08 1720 1046 1800 10223 194 27 17 2450 2940 3187 3214 3157 3054 1749 3125 17954 195 42 53 3560 4222 45 90 4679 46 63 4743 2741 4539 26247 196 6068 48 69 57 79 6335 65 8 6 66 04 7172 4338 63 26 366 78 197 7389 58 86 72 8 6 82 23 8584 8936 10658 50 60 8257 4798 6 198 86 88 78 91 100 27 120 56 130 29 14299 190 81 6492 12353 71850 199 5864 4694 5 6 67 61 94 6419 65 48 7192 3950 6207 360 14 200 2 D 4177 38 36 4547 48 09 4775 4628 5006 2715 46 90 261 30 201 5712 5170 62 39 66 38 6599 6604 7518 4167 65 20 378 00 202 73 63 7201 8986 98 43 9733 9914 13353 6219 9619 55810 203 8604 10043 13118 148 41 150 42 158 66 25206 82 5 3 14717 85290 204 12 68 1506 18 41 1971 1966 1868 1799 11 42 1913 10880 205 2659 2571 3127 3276 32 50 3130 3069 18 80 3196 18 350 206 39 80 36 76 4347 4573 45~67 4473 46 34 28 37 4490 25910
o 207 Orifice 11496 10 64 1360 15 39 1 5 80 1 6 15 1496 8 58 15 24 88 83 208 9433 8 95 11 78 13 26 1394 1386 1263 727 1346 78 48 209 7387 746 9 77 1123 1184 1159 1048 6 11 1111 64 74 210 52 36 566 7 66 900 934 909 8 21 499 8 27 48 02
0) CJ1
TABLE III Continued
Run No Position CFM h 1 h2 hs h4 h5 h6 h7 hav Nuav
211 212
3309 1293
414 257
563 3 19
6 68 3 57
6 91 3 37
6 72 351
7 37 337
38 4 2 46
4 40 341
3748 1942
213 214 215 216 217 218
c of 2nd 1 516 1235
1919 2712 3320 4153 4704
1532 2447 35 46 4312 5567 74 29
2 1 87 3312 4225 52 86 6902 8 6 50
2360 3555 4340 56 12 7 0 49 8 9 40
2409 3598 4 8 85 5718 7713 9593
2347 2101 35 33 3453 48 00 49 62 5562 59 86 72~6 7 8 79 93 76 11237
1243 20 64 3054 4 2 8 1 5114 6983
2326 35 00 4638 5545 7225 91 40
132 13 200 27 26672 31968 41711 52811
bull
67
TABLE IV
PRESSURE PROFILE DATA
Baffle Flow Qpening Rate ~p
(Inches) Position (CFM) (Inches 295 S G Fluid)
1 364 l2 11 U 1012 0 254 1248 0197 1493 0 141 1718 0112
c 1000 9 80 1210 1710 1436 28 75 1746 4320 1011 1080 1277 2050 1393 3020 1 6 28 4450
12D 1011 9 75 1236 1520 1450 2510 1603 3450
1 D 1011 975 1256 1700 1480 2690 158 1 4070
1 12D 1010 950 1259 1750 1462 2650 1631 3710
2 11 D 1124 1315 1360 2130 1505 2850 1689 4125
1 216 12U 1294 045 1949 0324 2374 0282 2704 0225 3367 0169
c 1326 265 18 81 5 90 2313 990 2731 1480 3439 2660
12D 1272 2 49 1957 661
68
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Pos ition (CPM) Inches 2 95 S G Fluid)
2559 1275 3033 1940 3639 3025
1 216 1nD 1257 242 16 96 476 2117 8 05 2561 1280 2990 1895 3431 26 bull00
1 316 12U 1309 0 479 2004 0422 28 28 0 352 3526 0281 42 28 0225 5199 0225
c 1308 1 43 1998 272 28 14 5 10 3478 795 4248 1235 5048 1885
l2D 1286 140 2005 3 45 2831 725 3495 1180 4194 1805 5046 2945
1 11D 1322 150 2039 352 2841 735 43 77 1980 5378 3440
1 516 12U 1278 0493 2732 0493 4315 0408 5744 0352 7494 0352 8932 0422
c 1300 0 506 2731 1985 4310 348 6080 6 45
69
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Position (CPM) (Inches 295 SG Fluid)
7607 1090 8830 1585
l2D 1343 0549 2738 225 4566 583 6112 1195 7536 2055 9043 3415
1 516 1uD 1249 0464 2713 224 4155 579 5620 1150 7428 2115 90 70 3405
1 12D 1301 0493 2735 220 4501 616 61 50 1235 7440 2065 8862 3445
2D 1265 0 478 2750 226 4366 594 6578 1270 7678 2240 8945 5280
2 12D 1295 0493 2725 222 4293 600 5807 1120 7568 2200 9070 3615
TABLE V
RATE OF HEAT TR AN SFER Ar THE BAFFL~~ CID-TT ER
Orifice Size
(Inches)
Flow Rate
( CFM)
Re d e G tU
R~) 055 Nuav NuPr-l3
1 364 10 26 12 90
8 075 10015
43400 54 600
85 11 99 64
95 83 112 19
1416 11 140 59 900 110 30 124 20 16 27 12 800 68 900 126 64 142 60 17 29 13 610 73 200 135 79 152 90 17 76 13980 75 200 147 59 166 19
1 216 11 35 14 06
8 600 10 660
27000 33500
6 4 96 76 56
73 14 8 6 12
1517 11500 36100 82 51 9291 20 34 15400 48400 10229 115 18 23 11 17500 55000 118 31 13322 2348 17 800 55900 11947 13452 2666 20 200 63400 13508 15210 27 16 20 600 64700 135 05 152 07 32 47 24600 77200 161 57 18 193 3392 25 700 80700 17390 195 8 1
1 316 1344 19 36
9898 14 260
24800 35 700
63 8 7 8 2 77
71 92 93 20
28 46 20 9 60 52 500 111 08 125 08 34 84 25 660 64200 131 38 147 93 40 66 50 12
29900 36900
74800 92400
150 78 18046
169 78 203 20
~ 0
TABLE V Continued
Orifice Flow Re Size Rate d e G R~rmiddot55 NuPr-13(Inches) (CFM) U Nuav
1 516 12 70 8 847 16800 54 ~0 61 14 2 14 18 900 35800 82 42 92 80 43 10 30 000 56900 11349 127 79 60 12 41900 79400 14416 16232 7279 50700 96100 17326 19509 86 90 60540 115000 20098 22529
TABLE VI
RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
Orifice Size
(Inches)
1 364
1 216
1 316
Flow Rate
(CFM)
1054 1294 1431 1681 1770
1068 1399 1669 1959 2295 2636 3390
1299 1973 2788 34 73 4118 4973
Re deG Mshy
8 300 9870
11260 13200 13 930
8100 10600 12650 14850 17400 19980 25700
9 570 14500 20500 25600 30300 36600
R~r-6 51900 61700 70500 82 500 87 100
28200 36900 44000 51700 60 600 69500 89400
26100 39600 56000 69900 82700 99 900
Nuav
2416 293 5 3187 4018 4805
14938 18968 21712 25156 30680 37938 59601
14736 21290 28781 36052 439 85 60225
Uu Pr-1 3
27204 33050 3589 4524 541 0
16820 21358 24448 28326 34546 427 18 67111
16593 23973 32407 40595 495 1 678 13
TABLE VI Continued
Orifice Flow Re Size Rate deG R~rmiddot6 NuPr-13(Inches) (CFM ) M- Nuav
1 516 1268 88 30 17700 108 8 1225 2689 18700 37400 1835 2066 3980 27700 55700 2591 2917 4177 29100 58 500 2713 3055 5712 39800 80000 378 0 425 6 7362 51300 103000 5581 6284 8 604 59 900 120000 8529 9604
74
TABLE VII
EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER
l 516 Inch Orifice
Center ot 2nd Baffle 4 Downstream
Plow Rate (CFM)
1235 1919 2712 3320 4153 4704
Flow Rate (CFM)
1270 2714 4310 6012 7279 8690
(Re)eb -8600 1321
13400 2003 18900 2687 23100 5197 28900 4171 32800 5281
Center ot Single Battle
-8847 543
18900 824 30000 1135 41900 1442 50700 1733 60540 2001
(Nu)(Pr)-l3
1487 2255 3003 3600 4697 5946
(Nu)(Pr)-13
611 928
1278 1623 1951 2253
75
ABLE VIII
HEAT TRANSFER IN THE TEST SECTION WITHOUT ORIFICE
CFM Ute) 0b h Nu
1293 5-951 3 41 1942
33 09 15251 649 3746
5236 24193 827 4802
7387 34001 1111 6474
9433 43419 1346 7848
11496 52-914 1524 8883
76
TABLE IX
PRESSURE DROP FUNCTION
Orltlee Size Flow Rate incbea ~CFM (Re)eb X 10bull8
1 364 1011 7957 0808 1256 9885 1468 1480 11648 2765 1581 12443 4160 1689 1_3293 4 020
1 216 1257 9530 1327 1696 12858 2663 2117 16049 4615 2561 19415 7581 2990 22668 11560 3431 26011 16440
l 316 1322 9736 1819 2039 15016 4332 2845 20952 9275 3495 25739 15300 4377 32014 26800 5378 39607 50100
1 516 1011 7 957 oaos 1256 9885 1469 1480 11646 2765 1581 12443 4160 1689 13293 4020
77
TABLE X
EXPERIMENTAL DATA
Baffle Hole Diameter Run No
1 - 59
60 - 102
103 - 138
139 - 206
207 - 212
213 - 218
(Inches)
1 364
1 216
1 316
1 516
No Baffle
2nd - 1 516
TABLE X
EXPERIMENTAL DATA
Run Thermocouple Reading s (mv) No Position CFM I tc1 tc2 tc3 tc4 t c 5 tc6 tc7 tcair
1 c 1026 530 2055 1825 1768 1782 1802 1837 1965 1198 2 1290 612 2059 18 65 1809 18 32 1851 1880 1965 1160 3 1416 714 2151 1970 1931 1965 1988 2026 209 5 1130 4 1627 8 21 2235 2084 2 049 2093 2126 2173 2266 1130 5 1776 865 2203 2033 1970 2015 2084 2159 2 264 1121 6 12D 1109 542 1636 1507 1499 1499 1498 1498 1528 1218 7 1258 651 1670 1522 1503 1513 1513 1516 1548 1221 8 1433 750 1625 1480 1467 148 3 1487 1487 1516 1153 9 168 1 8 73 1656 1494 148 1 1511 1517 1517 1543 1159
10 1rtD 1102 485 1545 1450 1437 1446 1447 1442 1466 1220 11 13 08 6 10 1571 1470 1460 1476 1476 1469 1498 1194 12 1464 730 1 623 1509 1508 1528 1 5 32 1524 1548 1173 13 11 06 8 71 1663 1559 158 1 1606 160 6 1 583 1601 1190 14 1 12D 1115 520 1698 1579 1575 1 577 1580 1590 1615 1280 15 1275 6 10 1692 1567 1558 1 561 1570 1580 1601 1234 16 1498 770 1760 1619 1630 1 635 1642 1645 1661 1204 17 1695 912 1775 1635 1670 1689 1686 168 6 1701 1165 18 2D 1049 510 1736 15~2 1567 1558 1 553 1558 1620 1236 19 12 41 610 1655 1517 149 1 148 1 148 1 148 4 1546 1108 20 1 5 32 7 35 1720 1550 1530 1520 1519 1523 158 0 1104 21 16 74 8 8 0 1900 1 727 1714 1696 1691 1692 1753 1169 22 1U 1074 38 5 3 324 2740 2534 2478 2 465 2503 258 0 1210 23 1287 4 35 3510 2 870 2682 2 610 2599 2638 27 1 9 1190 24 1 5 08 470 3 618 2920 2690 2 637 2627 2 664 2747 1177 25 18 07 525 4 088 3235 2962 2905 2910 2988 3130 1169
z ())
TABLE X Continued
Run No Position CFM I tc1 tc 2
Thermocouple Readings te3 tc4 tc5
(mv) tc6 tc7 tcair
26 c 10~29 6 32 2340 2~092 2032 2060 2~097 2152 2~213 1211 27 12 66 679 2270 2 047 1993 2013 2069 2142 2 210 1 182 28 1430 723 2336 2097 2033 2080 2153 2~255 2 356 1 138 29 1729 8 52 2318 2070 1980 2061 2158 2279 2367 1121 30 12D 1054 570 1520 1 4 20 1402 1400 1396 1400 1 443 1159 31 1294 6 69 1599 1469 1444 1439 1433 1 442 1485 1168 32 1430 7 88 1720 1562 1536 1532 1528 1537 158 0 118 5 33 1770 8 81 1641 1488 1450 1~441 1 441 1_466 1518 1 163 34 1D 1058 548 1579 1498 1495 1526 1553 1_557 1 571 1 276 35 1263 640 1609 1509 1515 1570 1599 1598 1 598 1 266 36 18 36 8 47 1538 1452 1483 1553 1602 1 590 1 558 1195 37 1 12D 1029 5 41 1 578 1499 148 4 1473 1461 1465 1-512 1200 38 1315 6 30 159 1 1504 1493 1482 1470 1470 1505 118 5 39 1 4 26 743 1765 168 1666 1660 1645 1642 1678 1270 40 1757 8 54 1744 1648 1634 1620 1598 1 593 - 1612 1223 41 2D 1080 5 30 1734 1604 1570 1 570 1570 1 588 1 640 128 1 42 1305 6 40 1744 1622 1589 1 608 1593 1 609 1 661 1240 43 1434 750 1798 1687 1658 1 636 -1641 1 661 1 711 1_220 44 18 04 8 41 1 764 1666 1607 1605 1614 1 635 1 675 1205 45 12nu 1088 415 2614 2295 2195 2 169 2174 2217 2256 1171 46 1318 477 2805 2477 2371 2342 2364 2 401 2 438 1 163 47 1413 5 28 2930 2 646 2 555 2 526 2532 2570 2 577 1 199 48 1773 550 2740 2518 2450 2431 2448 2 479 2 480 1 170 49 1 11 U 1054 380 3175 2670 2505 2 461 2467 2 534 2 621 1 258 50 1240 420 3268 2738 2 546 2 510 2 508 258 2 2 649 1214 51 1419 451 3364 2B07 2 632 2590 2 590 2 651 2773 1 215 52 1 12U 1032 360 3 165 2 629 2 450 2402 2403 2 473 2 bull568 1 163
--I lt0
TABLE X Continued
Run No Position CFM I tc1 tc2
lhermocoup1e Reading s tc3 tc4 t c 5
(mv) tc6 tc7 tc a ir
5 3 1314 38 9 3178 2592 2411 2367 2361 2432 2555 1140 54 1448 403 3095 2544 238 1 2336 2336 2390 2476 1158 55 178 2 427 3006 2434 2286 2253 255 3 2299 2397 1154 56 2 11U 1061 360 3369 2814 2619 2567 2560 2650 2833 1220 57 1216 360 3044 2512 2338 2290 2288 2374 2566 1150 58 1322 387 3196 2614 2425 2383 2382 2472 2670 1138 59 1639 403 3020 2438 2272 2238 2238 2318 2502 1127
60 1D 1068 612 1552 1424 1400 1395 1396 1426 1745 0945 61 1399 612 1355 1246 1230 1229 1230 1250 1509 0872 62 1669 710 1436 1293 1272 1265 1266 1286 1551 0847 63 1959 900 159 5 1468 1444 14 38 1432 1446 1720 0851 64 2295 730 1169 1105 1098 1099 1108 1100 1298 0781 65 2636 8 80 1202 1129 1121 1126 1 138 1115 1342 0748 66 3390 9 35 1060 o 9s7 0999 1001 1017 0971 1154 0703 67 1nu 1190 370 2225 2188 2104 2080 2120 2209 2 7 15 0990 68 1559 368 2005 1950 1871 18 48 1876 1951 2408 0916 69 1904 368 1870 18 1 4 17 34 1711 1730 18 07 2238 0875 70 22 bull11 471 228 6 2 204 2099 2063 2092 218 $ 2732 0840 71 2289 471 2030 2000 1925 1895 18 96 19 5 2498 0785 72 2727 4 71 1854 18 23 1753 17 23 1716 3758 2241 0743 73 3210 471 1680 1651 158 6 1559 1551 158 1 1950 omiddot7o9 74 2uD 1210 404 1261 1212 1198 1197 1205 1222 139 1 0978 75 14 20 540 1321 1260 1242 1 240 1249 1268 148 7 0918 76 1692 7 18 1467 138 6 1364 1361 1376 1405 1678 0883 77 18 94 903 1708 1 591 1565 1560 1575 1603 1948 0 857 78 2301 903 1530 1432 1407 1402 1415 1432 1738 0815
ro 0
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc117 tcair
79 2621 6 50 1069 1 020 1009 1009 1009 1007 1~189 o739 80 3230 901 1200 1128 1113 1119 1119 1086 1341 0694 81 82
l2D 1155 1689
360 575
1191 1345
1142 1252
1122 1218
1118 1210
1118 1209
1132 1228
1292 1446
0916 0822
83 1244 430 1163 1134 1131 1130 1129 1132 1292 0877 84 2100 645 1175 1135 1147 1 142 1138 1122 1286 0757 85 2292 8 25 1 354 1310 1327 1330 1323 1285 148 6 0728 86 2907 8 23 1180 1138 1151 1158 1149 1107 1268 0687 87 3380 902 1113 1049 1025 1011 1006 1042 1178 0673 88 89
1 12D 1427 1875
480 615
118 2 1140
1140 1095
1124 1077
1125 1075
1129 1072
1137 1072
1290 1243
0880 0790
90 2259 8 41 1296 1231 1207 1206 1203 1182 1419 0757 91 2682 8 80 1231 1170 1149 1147 1142 1112 1350 0731 92 3417 940 1142 1092 1076 1076 1069 1021 1252 0693 93 c 15 17 431 1321 1298 1268 1249 1250 1273 1522 0841 94 2034 505 1285 1263 1235 1209 1205 1206 1464 0759 95 2348 6 10 1395 1379 1334 1302 1286 1268 1536 0732 96 2716 706 1486 1480 1427 1383 1358 1311 1572 0 700 97 3247 7 56 1417 1430 1375 1320 1284 1223 1450 0660 98 1135 400 1425 1388 1352 1329 1330 1 364 1651 0893 99 14 06 440 1379 1341 1304 128 2 1281 1305 1583 0 831
100 2311 680 1602 1593 1553 1514 1502 1480 1 7 27 0 802 101 2666 680 1471 1469 1428 1390 1372 1335 1564 0761 102 3392 798 1491 1 509 1449 1395 1372 1305 1534 0 719
103 1U 1235 410 2469 2295 2173 2165 2226 2361 3120 0 897 104 2010 410 2017 1848 1 737 1706 1747 1865 2582 0753 105 28 14 410 1682 1535 1457 1427 1437 1520 2109 0 660
00 t-
TABLE X Continued
Ru n Thermocouple Rea ding s (mv No Positi on CFM I tc1 tc2 tc3 tc4 tc5 tc6 tc7 tcair
106 3492 440 1649 1499 1420 1391 1390 1470 2042 0620 107 4395 550 18 33 1679 1597 1564 1570 1640 2223 0583 108 5075 588 1779 1642 1580 1550 1552 1 615 2 191 0548 109 c 1344 398 1464 1 399 1364 1353 1350 1380 1689 0 907 110 1936 459 1369 1290 1253 1242 1 237 1259 1574 078 2 111 2846 580 1347 128 5 1251 1232 1220 1215 1 5 23 0 683 112 34 8 4 700 1392 1369 1339 1317 1299 1259 1599 0 636 113 4066 8 13 1449 1458 1427 1391 1363 1270 1595 0 591 114 5012 930 1484 1530 1500 1453 1420 1272 1580 0 580 115 1D 1362 513 1269 1218 1 217 1214 1220 1238 1460 0 893 116 19 58 600 1187 1122 1121 1120 1124 1133 1352 0798 117 2812 705 1052 1008 1015 1010 1011 1001 1218 0691 118 34 32 913 1105 1075 1085 1081 1086 1047 1301 0645 119 4022 980 1038 1021 1026 1023 1029 0983 1211 0 609 120 5026 982 0 8 61 0839 0836 0836 0837 0791 0955 0570 121 2D 1244 475 1320 1246 1233 1240 1255 1275 1434 0925 122 1 9 60 5 50 1160 1088 1074 1079 1089 1100 1260 078 7 123 2817 6 80 1096 1024 1 013 1018 1029 1022 1201 0 700 124 3491 960 1248 1175 1163 1172 1192 1153 1435 0 658 125 4096 989 1141 1089 1078 108 9 1105 1051 1310 0629 126 50 37 989 0983 0933 0929 0 936 0949 0880 1090 0 602 127 128
12D 1278 1947
402 545
1270 1261
1 230 1216
1228 1216
1230 1 215
1235 1223
1242 1219
1483 1514
0 913 0778shy
129 2769 695 1273 1234 1237 1221 1251 1212 1525 0678 130 131 132
34 39 4103 4978
8 40 9 80 9 80
1336 1448 1271
1322 1458 1 288
1328 1 462 1286
1 259 1 356 1157
1353 1492 1311
1261 1329 1138
1 555 160 7 1343
0 629 0 600 0599
(l) l)
TABLE X Continued
Run No Position CFM I tel tc 2
Thermocouple Readings tc3 tc4 tc5
( mv) tc6 tc7 tcair
133 1 l2D 1299 5 16 1 28 1 1212 1196 1195 1205 1221 1478 0869 134 1973 6 15 1163 1098 1073 1071 1079 1083 1343 0751 135 136
27 88 34 73
802 9 -_78
1187 1214
1099 1131
1069 1104
1066 1101
1075 1~110
1l061 1066
1370 1360
0662 0618
137 4118 9 81 1084 1010 0983 0979 0982 o937 1209 0581 138 4973 98 1 0969 0897 0 868 0855 0860 0799 1041 0572
139 1D 1253 409 1371 1293 1298 1301 1309 1321 1578 0928 140 2366 480 1130 1 090 1 121 1130 1137 1132 1390 0744 141 34 61 6 38 1081 1086 1152 1161 1147 1069 1382 0644 142 143 144
4325 5677 6759
7 90 939 998
1110 1115 1034
1161 1208 1139
1253 1268 1180
1265 1302 1215
1228 1230 1123
1080 1056 0970
13$913r12 8
0601 0561 0542
145 84 08 989 0863 0961 0934 0895 0871 0 785 09 9 0530 146 86 54 9 80 0808 0901 0 872 0821 0809 0733 0891 0498 147 7376 9 80 0 927 1032 1027 1 040 0961 0889 1032 0511 148 2D 4254 776 1 050 0 981 0965 0961 0962 0922 1155 0579 149 5708 991 1102 1031 1014 1009 1010 0931 1227 0528 150 69 78 990 0914 0853 0839 0 839 0843 0759 0996 0521 151 1254 490 1 479 1352 1329 1334 1351 1379 1607 0930 152 2713 7 00 1310 1220 1201 1201 1211 1209 1516 0723 153 8730 991 0809 0756 0742 0745 0 748 0663 0874 0543 154 5811 966 1219 1108 108 6 1081 1079 1033 1330 0650 155 42 46 8 02 1248 1136 1114 1114 1118 1103 1376 0 699 156 c 1270 429 1671 1571 1551 1545 1563 1600 1933 0929 157 2714 488 1398 1285 1 267 1258 1262 1275 1628 0729 158 4310 642 1424 1318 1299 1282 1283 1261 1683 0617
co ~
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc7 tc a 1r
159 60 12 780 1461 1388 1370 1349 1343 1279 1700 0 573 160 72 79 8 60 1402 1344 1330 1312 1292 1189 1 566 0 520 161 8690 982 1472 1442 1437 1 422 1392 1224 1602 0 521 162 163
12D 4368 5833
6 30 8 30
1195 1368
1105 1270
1111 1283
1117 1294
1131 1313
1081 1194
1369 1553
0613 0 553
164 76 43 959 1428 1338 1348 1341 1371 1180 1488 0535 165 8739 984 1345 1272 1272 1208 129 3 1059 1361 0550 166 1268 459 1701 1548 1541 1547 1589 1 625 1976 0 973 167 2678 570 1485 1351 1349 1356 138 1 1 385 1795 0760 168 169
1 12D 128 3 2729
448 650
1664 1314
1501 1232
1425 1233
1428 1229
1491 1229
1527 1232
1869 1571
0 962 0767
170 4345 847 1245 1179 1187 1182 1172 1132 1476 0 650 171 6036 9 76 1139 1109 1117 1114 1095 1020 1332 0588 172 6578 9 72 0982 0949 0942 0938 0926 0 8 50 1079 0560 173 87 84 9 72 0880 0854 0 8 36 0822 0818 0 749 0941 0585 174 1278 480 1564 1416 1397 1403 1417 1445 1733 0998 175 2711 590 128 3 1175 4 1178 1182 1187 1195 1493 0796 176 4351 8 90 1331 1259 1266 1275 1272 1235 1592 0 682 177 5994 9 60 1228 1152 1150 1151 1143 1075 1 360 0644 178 lU 1223 408 2282 2140 2052 2052 2106 2188 2626 0 878 179 2351 408 178 1 1623 158 5 1519 1556 1634 2068 0717 180 3448 482 1888 1675 1570 1541 1572 1665 2199 0629 181 4513 563 2026 1797 168 4 1644 1670 1770 2385 0583 182 5714 589 1913 1700 1610 1568 1580 1 682 2382 0551 middot 183 6997 653 1903 1718 1643 1611 1612 1700 2326 0 549 184 8709 6 80 1738 158 3 1543 1510 1498 1519 1 912 0577 185 186
2 12D 4249 5737
660 9 74
1055 1221
0 979 1122
0960 1093
0 952 1088
0959 1090
0 956 1054
1147 1350
0661 0602
187 7432 9 8 1 1065 0981 0951 0942 0 939 0881 1135 0582 CD ~
TABLE X Continued
Run No Position CFM I t o1 to 2
188 87 23 9 83 0944 0 879 189 1435 585 18 26 1630 190 2718 690 1433 1298 191 7507 950 1070 0961 192 85 44 964 0982 0 881 193 1287 600 1806 1668 194 2717 7 80 1579 1444 195 4253 8 81 1371 1260 196 60 68 9 78 1252 1152 197 73 89 975 1100 1000 198 86 88 973 0953 0 871 199 58 64 9 81 1269 1155 200 2D 4 1 77 915 1362 1251 201 5712 975 1213 1111 202 7363 9 78 1036 0 951 203 8 604 973 0932 0861 204 1268 6 95 2015 18 20 205 2659 6 96 1405 1295 206 39 80 7 98 1261 1174
No 207 Orifice 114 96 509 1325 1148 208 94 33 509 1477 1243 209 7487 5 09 1686 1409 210 5236 505 2094 1691 211 3309 428 2188 1 778 212 1293 392 2976 2560
Thermo ooup1e Readin g s (mv) to 3 to4 to
5 to
6 to7 toair
0 851 0847 0 8 29 0759 0987 0592 158 4 1583 1611 1647 1993 0986 1270 1266 1 279 1298 1604 0 789 0916 0908 0900 0 858 1115 0602 08 39 0 823 0 818 0 770 1035 0602 1609 1602 1629 1676 2153 0979 139 1 1385 1400 1 430 1938 0776 1212 1201 1205 1201 1601 0669 1 105 1086 1086 1 052 1371 0621 0952 0936 0923 0870 1195 0582 0 8 20 0 801 078 1 0 729 1044 0569 1108 1090 108 2 1043 1407 0610 1218 1221 1241 1202 1582 0659 1081 1083 1084 1031 1 368 0622 0921 0924 0919 0 841 1111 0 610 08 34 0831 0 821 0 751 1003 0 630 1761 1761 1 809 1861 2399 0966 1271 1271 1295 1311 1650 0797 1150 1150 1161 1149 1440 0703
1083 1057 1053 1109 1566 0~530 1158 1125 1138 1217 1763 0 526 1291 1250 1278 1383 2038 0542 1518 1478 1519 1657 2420 0 589 1596 1557 1601 1737 2441 0688 2370 2344 2409 2561 3 297 0921
()) (11
TABLE X Continued
Run Thermocouple Readings (mv) No Position CFM I tc 1 tc2 tc3 tc4 tc tc tc tc i5 6 7 a r
C of 2nd 213 516 1235 4 63 1 432 1291 1265 1258 1 268 1 308 1550 0 971 214 1919 6 17 1357 1223 1196 1191 1199 1211 1461 0 851 215 27 12 8 35 1401 1259 1278 1220 1230 1218 1511 0 762 216 3320 981 1439 1305 1270 1259 1275 1238 1450 0719 217 41 53 980 1251 1142 1132 1094 1121 1088 1305 0 695 218 404 987 1102 1042 1030 1 bull006 1014 0960 1133 0681
Supplementary Equations
Calculating temperatures from thermocouple readings
t = -026tc)2 + 3512(tc) + 3201 (26)
where t is the temp in deg F and tc is the thermocouple reading in millishyvolts
Calculation of the thermal conductivity of air
k = 00000245ta + 0 0132 (27)
where k is the thermal conductivity in Btuhr rt2 degFft and ta is the air temp 1n OF
I I
bull co m
HEAT TRANSFER AND PRESSURE PROFILRS IN THE VICINITY OF ANNULAR ORIFICES
- CHAPTER I
INTRODUCTION
The most common type of industrial heat transfer
equipment is the shell and tube heat exchanger which
consists of a bundle of tubes contained in a cylindrical
shell Heat is transferred from the hot fluid to the cold
fluid through the tube walls as one fluid flows through
the tubes and the other flows through the shell surroundshy
ing the tubes
Most commercial multitube heat exchangers contain
bafflesmiddot to guide the fluid through the equipment and to
prevent stagnant regions from forming in the shell As a
result the flow pattern in the shell is very complicated
and considerable variation of the local rate of heat transshy
fer occurs because of the various types of flow which exist
in the baffled passage The research described in this
thesis concerns a study of one small portion of the shell
side of a heat exchanger
There are three main types of baffles used in commershy
cial heat exchangers
1middot Orifice baffles extend through the cross section
of the shell and all of the shellbullside flow is
through the annular orifice formed at each point
where the tube passes through the baffle
2
2 Disk and doughnut baffles consist of disks and
doughnuts or annular rings placed alternately
along the length of the tube bundle~ There is
some flow through the annular orifices formed
where the tubes pass through the baffles but a
large portion of the flow is around the baffles
3 Segmental baffles are segments of a circle and
Bre arranged so that the fluid flows back and
forth across the tube bank There is still some
f~ow through the small area where each tube goes
through the baffle
In the case of disk and doughnut and segmental baffles
small annular clearances must be allowed at the point where
the tube goes through the baffle so that the bundle may be
assembled easily Thus in all of the types of exchangers
some shell-side fluid flows through the annular orifice
where the tubes pass through the baffles It has been
shown that this is an area of high rate of heat transfer
but its effect on the overall performance of the heat exshy
changer is not well known Also the prediction of rates
of heat transfer 1n these orifices is not yet possible
The purpose of this research was to make an extensive
study of the heat transfer rates in the vicinity of these
annular orifices and to determine the effect of orifice
size flow rate and upstream conditions The work was
5
performed in a onebulltube single orifice type baffle heat
exchanger and provision was made to measure local rates
of heat transfer in the vicinity of the baffle
4
CHAPTER II
THEORY AND PREVI OUS WORK
In 1701 Newton defined the heat transfer rate qc
from a surface of a solid to a fluid by the equat ion
= ~A(tw - t) (1)q0
where hm is the coefficient of heat transfer from the surshy
face to the fluid excluding any radiation A is the area
of the surface tw is the surface temperature of the wall
and t is the bulk temperature of the fluid The equation
for the point of local surface coefficient h is given by
dqdA = h(tw- t) (2)
The mechan ism and the laws covering heat transfer by
true conduction in solids and by radiation through transshy
parent media are well known However with heat transfer
from a solid to a fluid the situation is far more complex
The mechanism of flow of the fluid to a large extent deshy
termines the rate of heat transfer for a given temperature
difference
In addition the coefficient hm depends on certain
physical properties of the flowing fluid the dimensions
of the apparatus the velocity of the fluid past the surshy
face and frequently the temperature potential AT
It was the purpose of t his research to measure the
local shell -side heat transfer coefficient and correlate
it with the several variables mentioned a bove
5
The heat transfer coefficient for fluids flowing inshy
side tubes is more e a sily measured and correlated due to
the simple geometry of t he tube i nterior Much work has
been done on the tube-side coefficients with one of the
more useful e quations being the Dittus - Boelter equation
( 4 p 450) ~
0 023 (---ctwGJbulla (~np M ( 3 ) M k
with the following cond itions satisfied
(1) Fluid properties evaluated at the arithmetic
mean bulk temperature
(2 Reynolds number gt10000
(3) 0 7 lt Pr lt 100
(4) n = 04 for heating and 0 3 for cooling
(5) Ldw gt60
Colburn (3 p 197) obtained an equation for tubeshy
side heat transfer coefficients in which the Stanton
number is used instead of the Nusselt number
hm ) (~~ 23 _ (dwG) 0 2 ( GC k - 0 bull 023 U (4)
p
Much of the research done on average shell-side heat
transfer coefficients has resulted in empirical correlashy
tions of the form of equations (3) and (4) above Several
investigations have been made for a certain set of phys~al
6
variables but the r esults have ne ver satisf a ctorily been
correlated to appl y for all types of heat exchangers
Some basic 1ork has been done recently however on
the local shell-side coefficients Ambrose (1) studied
the local heat transfer coefficients i n a model heat exshy
changer with segmental baffles This study was fairly
extensive at the baffle center but the data were quite
limited for the space between the baffles Gurushankar1ah
(5) further extended Ambroses work by studying a single
baffle space in detail
The results of these two studies indicated a need for
detailed information 1n the vicinity of the baffle Hence
Lee () investigated a single baffle s pace between two
orifice baffles and obtained considerable information on
the rates of heat transfer in the annular orifices Since
his work was carried out in a multitube mode l heat ex~
changer the determination of the rate of flow through the
individual orifice was difficult because of t he outer
clearances existing in the exchanger For this reason the
present research was undertaken to study the rate of heat
transfer in a single annular orifice through which the flow
could be accurately determined
Bell and Bergelin (2) have studied i n detail the pres shy
sure drop coeff icients for the annular orifices formed beshy
tween a circular disk and a circular tube These results
also appl y to the annular orifioe formed when a rod extends
7
through a circular hole in a plata This study was extenshy
sive in the fact that it considered the baffle thickness as
well as the orifice size but no heat transfer data were
presented
Sullivan and Bergelin (9) studied flow through a
single annular orifice through multiple annular orifices
i n parallel and flow around a single baffle both with and
without leakage through the baffle A generalized expres shy
sion is presented for the pressure drop across one baffle
section of a tubular exchanger with leakage through the
tube holes in the baffle but the effect of leakage area
upon heat transfer is only discussed qualitatively The
pressure drop data is correlated by plotting cent as a funcshy
tion of the Reynolds number where cent equals
d1 )22( ~ P) s c e (d2 -
M-2
8
CHAPTER III
~PERI1ffiNTAL APr ARATUS
The heat transfer test section was essentially a
single tube heat exchanger The inner tube was a l-in
OD aluminum tube with an electrically heated probe midshy
way between the two ends of the tube
Test Section
The shell as constructed from lucite plastic tubing
2 5-in I D and 3-in O D The te t section d a total
lengt h of 54 58 inches I t consisted of two sections
The upstream section was 40 i n ches in length in order to
assure freedom from entrance effects and the downstream
section was 13 12 inches in length To further assure
uniform flow a bundle of short copper tubes was placed a
few inches downstream from the entrance Both of these
sections had 12 i nch flanges on one end so t hat a 18
i nch thick orifice plate could be clamped between them
Heat transfer coefficients were measured in the vicinity of
t h is orifice A cross section of the center of the test
section is shown in Figure 1 and the experimental appara~
tus is shown in Figure 2
Cooled air supplied by a Roots -type blower was used
as the shell-side fluid throughout this study It entered
the test section through a l-in ID 1 12-in OD plasshy
tic pipe at the upstream end of the calming section Tbs
j Jl l 6- 11 BOLTS II I nbull middot~11 I HEATING ELEMENTS
J T ( T
-f-shy - - - f-_- __L
7 777 _y A
IT 1] I
I
FIGURE I CROSS SECTION OF TEST SECTION AND PROBE
10
FIGURE 2 EXPERIMENTAL APP1Ub~fUS
11
air left the test section through nine equally spaced 12
ineh holes placed around the side of the tube at the exit
end
Sensing Probe Assembly
The sensing probe was designed to measure the local
heat transfer coefficients at any point along the tube and
around the tube in the test section The tube was designed
so that it could be easily moved up- and downstream to
measure the heat transfer coefficients at various positions
in relation to the orifice
The sensing tube assembly consisted of the sensing
probe the thermoctmple lead s and selector switch the
power lines and the two aluminum tubes between which the
probe was centered
Imbedded in the sensing probe were seven iron-constanshy
tan thermocouples for measuring the temperatures around the
tube The lead wires from these thermocouples were conshy
nected to a seleotor switch at the downstream end or the
aluminum tube A layer of Saran wrap was placed around the
tube over the t hermocouple and three lengths of Trophet C
resistance ribbon were wrapped around the tube nd conshy
nected in series to the power leads
The heating surface of the probe was formed by these
three one inch wide strips of Trophet C resistance ribbons
The ribbons were 0002 inches thick and had a resistance of
12
0 271 ohms per foot and a thermal conductivity of 763
Btuhr ft 2 degFft They were held in position by four
copper bars placed in four parallel longitudinal slots
These copper bars served as connectors for the electrical
leads A photograph of the sensing probe is shown in
Figura 3 and a drawing of the assembled probe is given in
Figure 4
Power Source
Direct current was used to heat the resistance ribbon
on the sensing probe The current was regulated by a slide
wire resistor The po er source consisted of a Raytheon
Voltage Stabilizer to stabilize the city power source at
115 volts and an automatic selenium rectifier with an alshy
ternating current input of 115 volts at 60 cycles per
second and an output of 12 volts and 35 amperes direct
current
Temperature Measuring
The temperatures around the sensing probe were calcushy
lated from the emf readings of the ironbulloonstantan thermoshy
couples The emf measuring system consisted of the seven
probe thermocouples a separate thermocouple for measuring
the inlet air temperature a thermocouple selector switch
a cold junction and a Leeds and Northrup Type K Potentishy
ometer The potentiometer was placed on a Fischer
13
THERMOCOUPLE JUNCTIONS~ ~------- HOLES FOR THERMOCOUPLE LEADS
~----- SCREWS
~ff+--- CONNECTING BARS
END VIEW
POWER LEADS SOLDERED TO LOWER CONNECTING BAR
iER PLASTIC PIECE
RESISTANCE RIBBONS LOCATION OF THERMOCOUPLES
FIGURE 4 DRAWING OF ASSEMBLED SENSING PROBE
15
Vibradamp support to absorb the vibrations produced by the
air blower
Air Source
Air was used as the shell-side cooling fluid during
the study The air was pumped through the test section by
a Roots type air blower with a rating of 280 ofm at 3 12
psig outlet pressure The hot air leaving the blower was
passed tbxfugh two finned-tube box-type coolers and one
tubular edoler to oool it to approximately room temperature
The air flow rate was measured by passing it through a
flow measuring orifice in the line Two sharpbull edged orishy
ficas were used f or flow measurements The calibration
curves for these orifices were presented by Ambrose (1
p 166)
The pressure taps on each side of the orifice were
connected to two differential manometers containing 0 83
and 2 95 specific gravity fluids respectively The presshy
sure drop through the test section and test orifice was
measured by a pressure tap placed 13 inches upstream and
one placed 6 12 inches downstream from the orifice Two
pressure ga ges were used to measure the pressure at the
inlet to the flow orifice and to indicate the statio pres~
sure at the test section inlet
16
Pressure Probe
A probe was designed to measure the pressure drop
between the pressure tap 13 i nches upstream from the ori shy
fice baff le and any point downstream from the tap The
probe eonsisted of a l~in OD copper tube with six 132
i n ch holes even l y s paced around the tube The upstream
pressure tap and the pressure probe were connected to a
differential manometer so the pressure drop to various
points up- and downstream of the orifice could be measshy
ured
17
CHAPTER IV
EXPERIMENTAL PROGRAM
The experimental program was designed to measure the
heat transfer coefficients and pressure drops in the vicinshy
ity of annular orifices The four orifice sizes studied
were 1 364 1 216 l 316 and 1 516 inches~ The inner
tube used in each case was a 1-in OD alumintim tube
Hence tube to baffle clearances were respectively 3128
232 332 and 532 of an inch
Heat transfer coefficients were measured at poait~ons
1 i nch upstream at the orifice center and at 12 1
1 12 and 2 inches downstream for all orifices In addishy
middottion the heat transfer coefficient at a point 2 12
inches downstream from the 1 516 inch orifice was measured
and at the points 12 l 12 and 2 inches upstream from
the 1 364 inch orifice
The heat transfer coefficients at each point were
measured at five different flow rates for the 1 364 inch
orifice and at six different flow rates for the other orishy
fice sizes The high pressure drop through the small orishy
fice size limited the number of flow rates which could be
studied
The flow rate was calculated from the pressure drop
across the flow orifice This flow was corrected to cubic
feet per minute at 68degF and one atmosphere pressure by
18
using the orifice pressure and the test section pressure
which were measured by pressure gages
It was desired to determine a relationship between the
heat transfer coefficient and the total pressure drop for
each orifice size The pressure drop across each orifice
at various flow rates was measured by means of the presshy
sure probe described in Chapter III It was also desired
to obtain pressure profiles for each orifice size since
these might be similar to the heat transfer profiles The
pressure drop was measured from a point 13 inches upstream
of the orifice to points at 1 and 12 ineh upstream the
orifice center 12 1 1 12 and 2 inches downstream
The experimental program is summarized in Table I
TABLE I
SUla~RY OF EXPER IMENTAL PROGRAM
Position Investigated-Distance from Orifice-Inches
Orifice Range of Flow Rate Size Heat Transfer Pressure Drop CFM at 68degF amp 1 atm
1 364 2U 1 12U 1U 12U c 12U C 12D lD 10 - 18 l2D lD 1 12D 2D 1 12D 2D
1 216 1U c 12D lD 1 l2D 2D 12U c 12D lD 10 - 35
1 316 1U c 12D lD 1 l2D 2D l2U C 12D lD 12 - 50
1 516 1U c x2D lD 1 l2D 1U 12U C 12D 12 - 90 2D 2 1 2D l D 1 l2D 2D 2 12D
20
CHAPTER v
EXPERI MENTAL PROCEDURE
The experimental procedure for measuring the heat
transfer coefficients ~d corresponding flow rates reshy
quired the following procedure
(1) Install the orifice size to be studied in the
test section
(2) Place the heat transfer probe in the position up
or downstream from the orifice where the middot heat
transfer rate is to be studied
(3) Fill the cold junction thermos with cracked ice
(4) Measure the atmospheric pressure
(5 Open bypass line from blower and close line to
test section
(6) Turn on the cooling water for the exchangers used
to cool the air leaving the blower
(7) Start the automatic selen ium rectifier by turning
on the t 1mer bull
(8 ) Connect the voltage stabilizer to the wall outlet
(9) middot Set the slide wire resistor to the maximum re shy
s1atanee I
(10) Start the blower
(11 Open the line to the test section until the de shy
sired flow rate is obtained
(12) Switch on the probe direct current power source
21
(13) Adjust the slide wire resistor to obtain the
desired current
(14) After the thermocouples have reached equilibrium
values record the e m bullf across each of the
seven probe thermocouples and also the entering
air thermocouple
(15) Record the direct current amperage
(16) Record the gage pressure at the flow orifice and
the entrance to the test section
(17) Record the manometer measurement of the pressure
drop across the flow orifice and also the presshy
sure drop through the test section
22
CHAPTER VI
CALCULAT ION OF EXPERIMENTAL DATA
The local heat transfer coefficients were calculated
from the temperatures measured on the probe surface the
air temperature and the current input The results were
calculated by using the Alwae III-E computer
The general expression for calculation of the heat
transfer coefficients was derived by Ambrose (1 p 79)
The equation is derived by making an energy balance around
a small increment of the center resistance heating ribbon
The two ribbons tnstalled adjacent to the center ribbon
reduced the amount of logitudinal conduction and assured
little longitudinal temperature variation in the center
ribbon
A heat balan ce on this small increment of resistance
ribbon yields the following
(the heat conducted in) + (heat generated) = (heat
conducted out) +(Heat convected to the fluid) + (heat
radiated to the surroundings) + (Heat conducted into
the plastic center of the probe)
This gives the equation
kzw dtdS + 12RdS kzws [ t + (~) ds] + hwdS (t-ta )
+ ~Aad wd o middot+ qcAond 1 -~- wdS 5 )
23
Hence solving for h gi~ea
i2R kz d2t Qrad qcond w + -d$2 - ~- A
h = ( 6)t - ta
Since S = re where 9 equals the enclosed angle ~n radians
dS rd9 ( 7)
and
dt - dt (8)dS - rd9
Differentiating with respect to S
d2t (9)rd9dS
from which
(10)
Substitut1ng into the equation for heat transfer coeffishy
cient gives
h = i2R Qcond A (11)
w
The rate of radial heat conduction into the plastic
tube making up the probe was assumed to have negligible
effect on the heat transfer coefficient It was also
assumed that the heat loss by radiation from the ribbon
was negligible since all data were obtained with the ribbon
at a temperature less than 125degF
24
When t he rad iation and conduction terms are neglected
Eq (11) becomes
(12)
The following con stants are known
R = 0 271 ohmsft
w = 100 i n ches
k = 763 Btuhr rt2 degFft
z = 0 002 inches
r = 12 inch
Eq (12) putting 9 in degrees then reduces to
1110 12 + 2404 d 2t d92
( 15)h = ------~--~-------t - ta
Thi s equation was programed for the Alwac III- E comshy
puter and used to calculate the local heat transfer coefshy
ficients from the observed data
The average heat transfer coefficient around the tube
at a given position in the t est section was calculated by
averaging the local coefficients calculated from Eq (13 )
It was found 1n the course of the experimental work
that thermocouple numbers 1 and 7 were indicating higher
temperatures than would be expected This resulted in h1
and ~ being lower than the other local coefficients around
the tube Since the fluid was flowing parallel to the axis
of the probe the circumferential variation i n rate of heat
25
transfer should be small Hence in obtaining the average
coefficient around the tube the values of h1 and h7 were
not used even though they were calculated and are tabulated
1n Table I II in the Appendix
Then
(14
A Nusselt number as calculated from this aver age heat
transfer coefficient using the tube diameter as the characshy
teristic dimension
(15)
The air flow rates through the test section were calshy
culated by measuring the pressure drop across the flow orishy
fice the air temperature the pressure at the flow orifice
and the pressure at the entrance to the test section The
orifice calibration curves (1 p 166 ) were used to obtain
a value of the orifice coefficient f8e where Q equals
the flow in cubic feet per minute at 68deg F and one atmosmiddot
phere pressure and te is the density of air at the exchanger
and e the density of the air at the flow orifice The
den sity of the air can be expressed by
e = 2 703 p (16)T
where T equals the temperature in OR and P equals the absoshy
lUte pressure i n lb1n2 Using the value of e Qfo from
26
the calibration charts as A and Eq (16) solving for Q
gives
( 17
This equation was used to calculate the flow rate for
each flow studied
The Reynolds number used i n the correlation of the
data was the equivalent Reynolds number defined as
Re)eb ~ d2 - dl)Uf ( 18 ) lL
where d1 is the outside diameter of the inner tube and d2
is the orifice diameter U is the flow velocity through the
annular orifice e is the density of the air and U- is t he
viscosity of the air This equation can be transformed t o
(Re) b = 1611 Q (19) e dl + d2
where d1 and d2 are in inches
The pressure drop data were calculated i nto a dimenshy
sionless pressure drop function cent where
d1 )22( ~ P)gc f av(d2 shycent 2 bull (20
M-
For air this equation reduces to
where d2 and d1 are in i nches D P is expressed i n inches of
2 95 specific gravity fluid and P av is expressed as lbft3
27
CHAPTER VII
ANALYSIS OF DATA
In analyzing the heat transfer data an attempt was
made to correlate it 1n terms of the dimensionless groups
(Nusselt number Prandtl number and Reynolds number) which
appear in Eqs (3) and (4) Consequently all of the av~
erage heat transfer coefficients hav were brought into
the form ( Nu)( Pr)~3 bull The Nusselt number was based on the
tube diameter and the thermal conductivity of the air at
the flowing temperature The tube diameter was used in the
Nusselt number because comparison could then be made with
previous experimental work on heat exchangers which have
commonly used the Nusselt number defined as in Eq (15)
From the standpoint of dimensional analysis this is
equivalent to considering the tube diameter as the characshy
teristic length so far as the heat transfer is concerned
The Prandtl number of the air was taken as 0 7 in all
cases
Variation of Heat Transfer Rate with Distance from the Baffle
Considerable variation was observed in the rate of
heat transfer in the vicinity of the baffle In order to
obtain the variation with respect to position the term
(Nu)(Pr)-13 was plotted versus the flow rate Q for each
position and orifice studied Cros s plots were then made
28
at constant flow rates in order to obtain the variation of
(Nu)(Pr) -13 with position The resulting cross plots are
shown 1n Fi gures 5 6 and 7 for the four orifices studshy
ied
About one inch upstream from the orifice the heat
transfer coefficient begins to rise rapidly and continues
to do so until it reaches a maximum some distance downshy
stream After the maximum point the heat transfer coef fi shy
cient decreased slowly The heat transfer rate was found
to reach a maximum at a different position downstream for
each orifice size These figures also show that for a
given orifice size the maximum heat transfer rate occurs
a pproximately at the same point for all flow rates The
position of the maximum point f or each or ifice size is
shown in Table II
The region immediately downstream from the orifice is
one of h i gh turbulence due to the jetting action of the air
flowing through the orifice As the air flows t hrough the
orifice the streamlines continue to converge for some dis shy
tance downstream The point of maximum heat transfer is
probably at the point where the streamlines be gin to diverge
and a boundary layer begins to build up on the tube Tle
decreasing heat transfer coefficient beyond the maximum
point indicated the formation of a boundary layer
Since the position of the maximum point is independent
of flow rate middot it is possible to correlate it with respect
_ ct 11shyz-
100
0 136 ORIFICE
(
I 0
I )
~ 00
~p 0
I 0
--r--- ~
ISCFIII
-_ OCFM
rbull abull
~ middot~ a-1 z-
12fORIFICE
100
200
100
0 0 UPITRAM ORIFICE DISTANCE CENTER
CFM
h I DOWNSTREAM
DISTANCE
FIGURE 5 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLpound
30
too
700
800
100 ~ f gtf
400
z ~
100
100
100
0
13fORIFICE
~ -~ -- ---
)
~
~
-
I ~ ~OCFM
I vI~-~ OCFM
J ---
Iamp CFM
I 0 I I UPSTREAM ORIFICE DOWNSTREAM DIITANOE GENTER DIITANCI
FIGURE 6 VARIATION OF HEAT TRANSFER RATE WITH DISllNCE FROM BAFFLE
--
--- --
31
100
100
700
100
_ 100
f 9- 400 z-
100
tOO
100
0 - I 0 I I I UHTRIAM OAtfiCI DOWIIITMAM
+ I tyl6 ORIFICE
v I
~~ ~CFM
I v ~CFMI
v v 7
~~ v ~ iOCFM
- ~~ I-shy1-shy ~ICFM
DIITMCI OINTIR DIITANCI
FIGURE 7 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLE
32
TABLE II
POSITION OF MAXIMUM HEAT TRANSFER
Position of Maximum Orifice Size Heat Transfer
(inches) (inches downstream)
1 364 050
1 216 100
1 316 125
1 516 200
33
to orifice size Figure 8 shows the effect of the orifice
size on the position and value of the maximum heat transfer
at a constant flow rate of 15 cubic feet per minute It
can be seen that the larger the orifice size the further
downstream the point of maximum heat transfer occurs
Also as the orifice size increased the rate of heat
transfer decreased for a given flow rate The broken line
indicates the variation of the point of maximum heat transshy
fer with position and size The position of the point of
maximum heat transfer rate downstream from the orifice was
correlated with orifice size by means of the dimensionless
groups (Lde) and (d1de) where L is the distance downshy
stream from the orifice where the maximum rate of heat
transfer occurs d1 is the outside diameter of the inner
tube and de is the equivalent diameter of the orifice
ie de = d2-dlbull
Figure 9 shows a plot of Ld 6 versus d1d6 for the
four orifice sizes studied The four points on this logshy
log plot are approximately in a straight line and the
equation of this line is
Lde = 0 44 d1de)028 (22)
Although the above relationship represents a correlashy
tion of dimensionless groups it is based upon only one
tube diameter and needs to be substantiated further by
studying other tube diameters and other orifice sizes
34
aoo
400
aoo ~
-~ middot-CLshyJ z
200 -
100
0
ORIFICE CENTER
l~
l
t
I J~
1pound~
I
0 I I~
AT 15 CFM
-
bull ~ 1~6~
~ v~
~
~--~~6
~~~ ___ v v V -_
~ o q
~ I 16
v
~
ogWNSTREANI STANCE
FIGURE 8 EFFECT OF ORIFICE SIZE ON POSITION AND VALUE OF MAXIMUM HEAT TRANSFER
35
50
loshy____ -~
~ ~ -shylltl-shy~ r0
2 10 30
FIGURE 9 CORRELATION OF THE POINT OF MAXIMUM HEAT TRANSFER WITH
ORIFICE SIZE
36
Correlation of Data at the Baffle
The heat transfer data were correlated by obtaining a
relationship between the group (Nu)(Pr)-13 and a
Reynolds number based on twice the clearance (d2 - d1
between the tube and the baffle It was found that the
most satisfactory correlation could be obtained when the
term - d1 was used as the length term in the Reynoldsd2
number
Figure 10 shows the variation of the heat transfer
rate at the center of the orifice e xpressed as a function
of Reynolds number and the orifice size This shows that
for a given Reynolds number the heat transfer at the center
of the orifice is greatest for the smallest orifice size
In order to obtain a general correlation of the data
shown i n F1gure 10 the effect of the dimensionless ratio
d1de was considered This ratio considers all of the
geometric factor s needed to describe the annular orifice
The thiclaless of the orifice plate is also a factor but
was constant i n this i nvestigation
The data for the heat transfer at the baffle center
are shown in Figure 11 in which (Nu)( Pr)-13 is plotted
versus (Re)ebd1 de) 0 55 This data on a log-log plot
lies on a straight line for (Re)eb( dld8 )0 55 greater
than 3 x 104 The equation for cor relating the heat
37
4XI~middot~-r~------~--~~------~
Icf t--to_+--_c-c-________ SYMBOL SIZE
0 1~4
6 ~~
9 ~~ -o ~
(Re)eb
FIGURE 10 RATE OF HEAT TRANSFER AT BAFFLE CENTER
38
500
0
4 0 lcf
~ ~
~ ~iC-
~ ~
~IL 0~ 0 SYMBOL SIZE-
p 0 1364-
r 6 1~16 -~ -
9 1~16 --o 1~16
I I
FIGURE II CORRELATION OF HEAT TRANSFER DATA AT BAFFLE CENTER
39
transfer at the center bullOf the a nnular orifice was found by
the method of least s quares to be
(Nu)( Pr)-1 3 = 0018 ( Re)ebO Bl( dlde)04~ (23)
3 x 104 ltRe)eb(a1de)055 lt 105)
Rate of Heat Transfer at the Point of Maximum Heat Transfer-The heat transfer rate at the point of maximum heat
transfer is plotted in Figure 12 to show the variation with
Reynolds number and the size of the orifice It is shown
gives the h1gh st heat transfer ~ate at its point of maxibull
that for a given Reynolds number the smallest orifice size yen il
mum heat transfer
The data ~or the maximum poi~t could be correlated by
plotting (Nu) Pr)-13 versus (Re)eb(d1de)06 This plot
is shown 1n Figure 13 and the resulting eurve shows that
(Nu(Pr)-13 is not a simple p0wer function of the Reynolds
number as was the case for heat transfer at the baffle
center The reason for this is probably because other
factors such as intensity and scala of turbulence should
be considered At the orifice center the streamlines of
the flowing stream are converging_ and thus the flow is
quite stable Downstream from the orifice is a region of
large eddy currents and probably large scale turbulence
These factors could con ceivably cause the results which
were obtained for the point of maximum heat transfer
40
If)
~middotshy Q_-I z_
10~~~--------r----~~--~--
SYMBOL SIZE
0 13$4
6 1~8
Q 13-18
-o 1~8
7)(104
(Re)eb
FIGURE 12 RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
41
Ia ~
0 I
c ~ ~ c v
~ ~lt w ~
17
~ b
v ~ ( SYMBOL SIZE
-~ 0 f-64 -v ~ 6 t211e
~ Q I~~~
-o - l~rs I I
FIGURE 13 CORRELATION OF HEAT TRANSFER DATA AT THE POINT OF MAXIMUM HEAT TRANSFER
4 2
Effect of Upstream Baffles on Heat Transfer at the Orifice Center
The heat transfer rate at the orifice center using the
single orifice in a test section is a pproximately 13 of the
value that was obtained by Lee (7) using a model heat exshy
changer with orifice baffles Lee investigated the cent r al
baffles of the heat exchanger and thus the coeff icients he
obtained would be affected by the presence of a number of
upstream baffles To determine the effect of upstream
baffles an additional l 516 inch baffle was placed four
inches upstream 1n the test section The resulting data are
shown in Figure 14 where (Nu)(Prmiddot)-13 is plotted versus
(Re) eb for the case of a single baffle 1n the test section
and also the case of an additional baffle placed four inches
upstream Comparison is made with the results obtained by
Lee middot(7) using a four-baffle and a ten-baffle model heat exshy
changer Good a greement is obtained with Lees work and the
results show the marked effect that upstream baffles have on
the downstream heat transfer rate The additional up tream
ba ffle caused sufficient turbulence 1n the test section to
i n crease the heat transfer rate nearly three-fold at the
center of the next baffle
Heat Transfer i n the Test Section with No Orifice
In order to check the accuracy 6f the equipment the
orifice baffle was removed and the heat transfer mea sured
with the probe in the empty test section The data were
43
~~BAFFLES
0 l BAFFLE -shy
ll_9 2 BAFFLES
V 4 BAFFLES-LEE
4 10 BAFFLES- LEE lJf ~
~rv ~~ ~ v flvv ~~
I ~ J ~ L v
0
v
( V
40 3XIo 7XIa
(Re)eb
FIGURE 14 EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER AT BAFFLE CENTER
44
compared with heat transfe r coefficients predicted by the
equations for annuli which are recommended in the litera shy9
ture The two equa~ ions u sed tor comparison were
(hfe)=0 023 (rltGr e (~~ur4 (~r45 (24)
which was presente~ by Wiegant (10)
and ( h ) (cnM~5(M~l o14 o 023 CPG k j Mij - (de GJMb )0 2 ( 2 5)
which was presented by McAdams (8 p 242) The comparshy
i son is s hown in Figure 15 lq (25) gives a value which
is low by about ten percent while Eq (24) g ives values
which are high by as much as twenty -five percent when comshy
pared with the experimental data The se equations are gembull
erally considered to give coefficients with an accuracy of
about twenty percent Therefore the present experimental
data are within the accuracy of these equations Also the
plot indicate s that for a Reynold s number greater than 2 x
104 the slope of the line is the same for the experimental
data as for the equations
Pressure Drop Data
The total pressure drop across the orifice was measured
as a function of the flow rate and the orifice size The
pressure drop was expressed as a d1mens1onleas quantity r)
which ie plCltted ver sus the Reynolds number in Figure 18
The pressure drop function cent correlates for all or1f1oe
45
200
100
s z
10 5XI10 10
0 EXPERIMENTAL
--McADAMS
-WIEGAND L
V
~ ~ ~
P ~ ~
LL~ L
v~
~
v v
v 1 ~ ~ v
v -gt
~
~ ~
~
6Xid
FIGURE 15 HEAT TRANSFER WITH NO BAFFLE
46
0 1~4 -~ a 6 t216
Q t316 lJ J
-0 as a )t
A LEE I -shy SULLIVAN 8
p
10bull
BERGELIN
I _ll I
I ~
i I
~middot
lo II
f fl
J j
~middot
A)101
1q
I Ill
1 I3 X 10ao1
FIGURE 16 ORIFICE PRESSURE DROP FUNCTION VS REYNOLDS NUMBER
47
sizes- The present data extends the range covered by preshy
vious workers and agrees well with their work The preshy
vious work of Lee () for a heat exchanger containing 10
orifice baffles and also the data of Su livan and Bergelin
(9) for pressure drop in a model heat exchanger with a
single baffle is shown 1n Figure 16 long with the present
results~ This figure may be used to predict the preseure
drop from the equivalent Reynolds number of the annular
orifice
The pressure drop between individual points 1n the
vicinity of the orifice and an upstream pressure tap wa s
measured to obtain a pressure drop profile As might be
expected 1n all cases the profiles showed a rapid decrea e
in static pressure immediately upstream from the orifice
There was however little or no recovery of the pressure
loss downstream The 1 364 inch orifice did show a maxishy
mum point in the pressure drop but this maximum occurred at
the orifice center and total recovery was reached about 12
inch downstream
Heat Transfer at the Baffle and Maximum Point as a Function of Pressure Drop
In order to compare the effect of the total pressure
drop on the heat transfer at the baffle and the point of
maximum heat transfer Figure 17 was plotted showing
(Nu)(Pr)-13 as a function of the total pressure drop This
shows that for a given pressure drop the largest orifice
48
1200
1000
~ a -sshyz-
100
60 100 700
AT MAXIMUM POINT I 15116 2 13116 3 1~6 4 1364
AT ORIFICE CENTER
60
1
v
r ~ ~ ~
5
~
8 7
13116
8
~
1364
v
~
e6
1~6
v
~~ v ~ ~ -~ ~
~
~ v
l
~
vamp
I ~ ~
~
v L ~
v
I-
5
k= ~~
~ ~ ~
--I
v ~
FIGURE 17 HEAT TRANSFER AT THE BAFFLE AND MAXIMUM POINT AS A FUNCTION OF
ORIFICE PRESSURE DROP
49
size has the greatest heat transfer coefficient This is
true at both the orifice center and at the point of maxishy
mum heat transfer
Another comparison can be made by plotting the heat
transfer coefficient and the pressure drop versus the orishy
fice size at a constant flow rate Figure 18 shows this
plot This graph shows that at a constant flow rate the
pressure drop as well as the heat transfer coefficient
increases as the size of the orifice is decreased In
choosing an orifice size for maximum efficiency 1t would
be necessary to know the pumping power available as well
as the heat transfer desired
70 I I 700
AT 15 CFM 60 ---
~ aug
50 ---
NV
40 ~
~ ~ ~
~ _
MAXIMUM POINT ---- --- ~
1-----t---~ _
~00Qj ~
~t--- ORIFICE CENTER 10 1100
1---~ n
u0 01 02 03 Q35
a ltl
de inches
FIGURE 18 VARIATION OF HEAT TRANSFER RATE AND PRESSURE DROP WITH ORIFICE SIZE AT A CONSTANT FLOW RATE
cn 0
51
CHAPTER VI II
SUMMARY OF RESULTS
This study revealed several significant facts about
the heat transfer in the vicinity of annular orifices
Probably the most important contribution was the presshy
entation of the heat transfer profiles in the vicinity ot
the annular orifice ~ r s shown that t~ local heat
transfer coeffieient re~ches a maximum at a point downshy
stream from the orifice The distance downstream at which
this maximum oocurs is t1ven by the equation
22
The heat transfer coefficients at the center of the
orifice were correlated and found to follow the equation
(Nu)(Pr)-13 = 00176 (Re)eb08l(d 1de) 0 middot4~ (23)
3 x 104 lt( Re) 9 b( d1d6 )055 ltlo5 )
The heat transfer at the point of maximum heat trans
fer for each orifice size was correlated and presented in
Figure 13 as a plot of (Nu)(Pr)-l3 versus (Re)eb(d1de) 06
No simple po-orer relationship exists between the terms
Intensity and scale of turbulence downstream from the orishy
fice are probably important factors which affect the heat
transfer
The large effect of an upstream orifice on the heat
transfer rate at the second orifice was demonstrated by the
52
study of two 1 516 inch orifices in the test section The
added turbulence at the center of the second orifice was
found to raise the heat transfer rate almost three times
over that obtained for a single baffle
The pressure profiles in the vicinity of the orifice
indicate that nearly all the pressure drop occurs at the
orifice center~ Total pressure drop data were correlated
by a pressure drop function cent as a function of the Reynolds
number and good agreement obtained with the results of other
workers
The pressure drop and heat transfer data were correbull
lated by plotting the heat transfer as a function of the
pressure drop for each orifice size It was shown that for
a given pressure drop the largest orifice size gives the
greatest heat transfer coefficient
As a final presentation it was shown that the pressure
drop and the heat transfer coefficient both i ncrease i n
value at a constant flow rate as the orifice size is de shy
creased This is important in choosing the optimum clearshy
ance for orifice baffles
53
CHAPTER IX
RECOMMENDATIONS
A great deal of work remains to be done in the field of
evaluating shellmiddotside heat transfer coefficients This
study included only one tube size and air was the only f luid
used It is recommended that further studies be conducted
using other fluids and tube sizes It will also be necessary
to study several baffle types
The adde d turbulence due to a s e cond baffle placed upbull
s t ream would suggest that the heat transfer coef ficients at
a certain position i n relation to a baffle would increase as
the flow progressed through the exchanger It is recomshy
mended that an extensive s t udy should be made between baffles
the full length of a model heat exchanger
It is further recommended that the pressure drop study
be continued to include other fluids tube sizes and baffle
arrangements
Effects of turbulence downstream from the baff le should
be studied by i n vestigations with hot-wire anemometer equipshy
ment to determi ne t urbulence scale and i ntensity
54
NOMENCLATURE
Area of heat transfer
Heat capacity of the fluid
Outside diameter of the tube
Orifice diameter
Equivalent diameter of the orifice (d2 - dl)
Inside diameter of the test section
Inside diameter of the tube
Gravitational constant
G Mass velocity
h Local heat transfer coefficient
Coefficient of heat transfer from surface to fluid
i Direct current amperes
k Thermal conductivity of the fluid
L Distance downstream of the point of maximum heat transfer
p Absolute pressure
L P Total pressure drop across the orifice
Q Flow in cubio feet per minute at 1 atmosphere and 680 F
q Heat transferred
Thermal energy conducted into the sensing probe
Thermal energy radiated from the resistance ribbon
Resistivity of the resistance ribbon
s Length of the resistance ribbon
T Temperature oR
55
t Temperature of the resistance ribbon deg F
ta Temperature of the bulk stream oF
tw Wall temperature of the tube OF
U Veloc ity of the fluid
w Width of the resistance ribbon
z Thickness of the resistance ribbon
eeuro Density of the fluid in the test section
Density of the fluid at the flow orificef 0
AL Viscosity of the fluid
E9 Angle measured around the tube
Dimensionl ess groups
(Nu) Nusselt number hd1k
(Pr Prandtl number C~k
(Re)eb Equivalent Reynolds number at the baffle (d2 - d1 )uejt-Lshy
(Re)e Equivalent Reynolds number in the test section ( d 8 - d 1 )U fu
cent Orifice pressure drop function 2(~P ) gc~av(d2 - d1) 2
Al
56
BI BLIOGRAPHY
1 Ambrose Tommy W Local shell-side heat transfer coefshyficients in baffled tubular heat exchanger PhD thesis Corvallis Oregon State College 1957 183 numb leaves
2 Bell K J and o P Bergelin Flow through annular orif ices Transactions of the American Society of Mechanical Engineers 70593-601 1957
3 Colburn Allan P A method of correlating forced con shyvection heat transfer data and a comparison with fluid friction Transactions of the American Institute of Chemical Engineers 24 174-210 1933
4 Dittus F w and L M K Boelter Heat transfer 1n automobile radiators of the tubular type University of California Publications in Engineering 2443-461 1930
5 Gurushankariah M s Local shell-side heat transfer coefficients in the vicinity of baffles in tubular heat exchangers Masters thesis Corvallis Ore gon State Colle ge 1958 97 numb leaves
6 Knudsen James G and Donald L Katz Fluid dynamics and heat transfer New York McGraw-Hill 1958 576 p
7 Lee Kyu Sung Local shell-side heat transfer coeffishycients and pressure drop in a tubular heat exchanger with orifice baffles Masters thesis Corvallis Oregon State College 1959 118 numb leaves
8 McAdams William H Heat transmission 3d ed New York McGra ~-Hill 1954 532 p
9 Sullivan F W and 0 P Bergelin Heat transfer and fluid friction in a shell-andbulltube exchanger with a single baffle Chemica l Engineer ing Progress Symposium Series 52 ( 18) 85-94 1956
10 Wiegand J H Discussion on annular heat transfer coshyef f icients for turbulent flow Transactions of American Institut e of Chemical Eng i n eers 41147-153 1945
AP PENDIX
57
TABLE III
CALCULATED HEAT TRANSFER DATA
Baffle Hole Diameter Run No (inches)
1 - 59 1 364
60 - 102 1 216
103 - 138 1 316
139 - 206 1 516
207 - 212 No orifice
213 - 218 2nd - 1 516
TABLE III
CALCULATED HEAT TRANSFER DATA
Local Heat Transfer Coefficients Run
T0 bull Po s ition CFM hr h2 h3 h4 hs he ~ hav Nuav
1 c 1026 10 59 1476 16 09 1559 1510 1435 1203 1518 8511 2 1290 1369 1738 1878 18 05 1755 1689 1515 1773 9964 3 1416 1636 198 1 2068 1977 1924 1845 1715 1959 11030 4 1627 1991 2301 2382 2268 2194 20 ~98 1929 2249 12664 5 1776 2252 2669 2863 2713 2517 2338 2126 2620 14759 6 l2ttD 1109 2311 3317 3386 3373 3387 3394 3071 3371 18888 7 1258 3089 4583 4866 4683 4701 4643 4194 4695 26301 8 1433 38 8 5 55 83 5791 5495 5430 5436 5008 5547 31192 9 1681 4992 7378 7649 6980 6864 6870 64 28 7148 40180
10 1 D 1102 2371 3332 3511 3356 3342 3427 3102 3394 19012 11 1308 3218 4379 45 24 42 53 4255 4373 3965 43 57 24446 12 14 64 38 58 5146 5142 4839 4787 4903 4597 4963 278 79 13 1706 5218 6664 6269 58 81 5884 6237 5973 61 87 34718 14 15
1 l2D 1115 1275
2131 2661
2955 3638
2972 3720
2941 3675
2913 3576
28 22 34 74
2613 3278
2921 36 17
163 09 20246
16 1498 34 87 4644 4503 4441 4371 4343 4194 4460 25010 17 1695 4449 5743 5324 5222 5154 5157 5015 5320 298 97 18 2D 1049 1715 23 90 2550 2610 2656 2624 2208 2566 14363 19 1241 2117 2964 3145 3218 3221 3203 2759 3150 17757 20 1532 28 67 3936 4100 4188 4201 4167 3676 4118 23224 21 1674 3459 4508 4598 4746 4795 4792 4299 4688 26337 22 lU 1074 253 340 380 3 86 388 377 354 374 2097 23 1287 292 392 433 440 441 429 406 427 2394 24 1508 322 439 492 498 499 487 461 48 3 2713 25 18 07 3 38 464 519 5 24 520 499 463 5 05 28 40
~~ (]I agt
TABLE III Continued
Run No Position CFM h 1 h2 ~3 h4 h5 h6 ~ h
av Nu
av 26 c 1029 1171 1491 1589 15 28 1 4 62 1377 1293 1489 83 44 27 1266 1395 1746 1853 18 02 1685 1556 1453 1728 9704 28 1430 1637 2037 2175 2060 1909 1735 1591 1983 11159 29 1729 1982 24 96 2751 2507 2268 2030 1886 2410 13579 30 12D 1054 2934 4041 4321 4326 4423 4359 3706 4298 24160 31 1294 3385 4 8 26 52 42 5326 5450 5277 4566 52 24 293 50 32 1431 3784 5347 5721 57 bull75 58 44 5700 5084 5677 31870 33 1770 52 75 7 7 33 87 35 9005 9007 8267 7059 85 49 48050 34 lD 1058 3235 4401 4444 3877 3496 3451 3294 3934 21973 35 1263 38 98 5484 5330 4347 3964 3981 3987 4621 25823 36 18 36 6701 89 17 7855 6369 5597 5769 6283 69 01 38718 37 1 12D 1029 2404 31 8 2 3333 3459 3624 3577 3045 3435 19264 38 1315 3182 4033 4162 4310 4496 4502 4015 4301 24142 39 1426 3628 4389 4510 4573 4760 4804 43 8 5 4607 25678 40 1757 4547 5559 5(35 5931 6282 63 70 6060 5975 33471 41 2 11D 1080 2034 28 38 3155 3144 3145 2966 2540 3050 17027 42 1305 2650 3 4 87 3aoz 3595 3751 3595 3153 36 46 20405 43 1434 3167 39 07 4156 4371 4320 4126 3709 4176 23395 44 1804 4096 4 9 66 5691 5714 5586 53 15 48 65 5454 30582 45 12U 1088 409 516 557 564 5 60 535 513 5 46 30 67 46 1318 470 579 6 22 631 6 17 5 97 579 6 09 3422 47 14 13 540 640 676 6 86 681 6 60 6 54 6 69 3754 48 1773 641 740 774 782 7 69 749 746 763 42 87 49 l 11 U 1054 270 356 391 397 393 3 71 346 38 2 2133 50 1240 303 399 446 449 447 4 21 398 432 2420 51 1419 361 476 522 530 528 507 467 493 2760 52 1 1(2U 1032 236 311 342 347 344 325 301 334 18 78 53 1314 270 366 403 407 408 386 351 394 2217
(Tt tO
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ h av Nu av
54 1448 301 408 447 454 452 431 403 438 24 61 55 1782 353 494 548 544 415 529 531 506 2843 56 2U 10 61 220 287 316 320 322 303 268 310 1735 57 1216 249 335 370 377 378 353 307 363 2044 58 1322 263 356 394 398 399 374 327 384 2159 59 1639 310 433 478 481 482 452 393 465 2617
60 1D 10 68 2011 2536 2657 2681 2694 2560 15 62 2625 14938 61 1399 2520 3239 3369 3371 33r82 32 39 1946 3320 18968 62 1669 2781 3655 3820 38 76 3883 3738 2355 3794 21712 63 1959 3524 42 37 4399 4438 4497 4417 3047 4397 25156 64 2295 4426 5288 5396 5372 5240 5410 3369 5341 30680 65 2636 5490 6531 6662 6565 6379 6820 4249 6591 37938 66 3390 7869 9538 9462 9387 8924 10508 62 91 9564 59601 67 1U 1190 352 368 401 413 407 395 293 397 2256 68 1559 397 422 462 475 471 456 331 4 57 2603 69 1904 434 465 5 13 529 528 504 358 508 2901 70 2211 493 526 573 5 92 588 564 4 15 569 3257 71 2289 569 587 6 30 649 6 61 6 49 460 635 36 44 72 2727 637 6 60 7 09 733 751 743 521 719 4140 73 3210 728 755 8 15 8 43 8 62 8 54 616 826 4765 74 2nD 1210 181 2256 2393 2399 2333 2206 1325 2317 13158 75 1420 2340 2752 2899 2913 2850 2728 1701 2828 16121 76 1692 2853 3306 3452 3471 3379 3217 2134 3365 19217 77 1894 3102 3588 3713 3736 3670 3557 2455 3653 20892 78 2301 3682 4259 4433 4467 43 83 4289 2892 4366 250 30 79 2621 4117 4828 5017 5012 5030 5109 3071 4999 28785
m 0
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ hav Nuav
80 3230 5158 6006 62 13 61 18 6134 6695 4094 6233 359 87 8 1 12nD 1155 15 27 1854 2028 2064 20 85 1987 1164 1968 118 31 82 1689 2046 24 8 2 2688 2739 2760 2658 1749 2665 152 73 83 1244 2088 2317 2339 2345 2373 2381 1487 2351 13432 84 2100 3211 3539 34 21 3462 3512 3696 2575 3526 20284 85 2292 3 5 05 3761 3648 36 25 36 79 3957 2933 3734 21517 86 2907 4420 48 22 4679 46 04 4705 5206 3792 48 03 27741 87 33 80 59 35 69 38 7404 77 10 7 8 36 7 0 86 5190 7394 427 44 88 1 12D 1 4 27 2 4 58 28 31 3037 3021 2987 2927 18 57 2 9 61 16913 89 18 75 34 75 3 9 87 4230 4255 4317 4337 2734 4225 24258 90 22 59 4221 4796 5046 5052 51 01 5389 3491 5077 29206 91 2682 4978 5664 5943 5966 6054 6573 408 1 60 40 34795 92 3417 63 16 71 02 7 3 93 7385 75 40 8 6 95 51 45 7623 44017 93 c 1 5 17 1240 1305 1399 1467 1479 1429 9 26 1423 8251 94 20 34 1554 1623 1720 18 21 18 53 18 72 1215 1778 10229 95 2 3 48 1795 1843 198 5 2097 2171 2274 1540 2074 11947 96 2716 2028 2048 22 01 2 3 44 2444 2661 18 90 2340 13505 97 3247 2410 2375 2663 2778 2949 3298 2378 2793 1615 98 11 35 967 1040 1124 1186 1200 1142 728 1138 6496 99 14 06 1135 1220 1318 1384 1403 1 3 61 8 77 1336 7656
100 2311 1 8 54 18 78 1980 20 90 2136 2227 1653 2062 118 31 10 1 2666 2085 2094 2227 2 3 62 2438 2626 1902 2349 13508 102 3392 2635 2582 28 01 3026 3141 3529 2567 3016 17390
103 1 U 1235 349 395 434 436 4 28 411 286 423 2416 104 20 10 434 5 02 559 577 569 5 37 345 552 3177 105 28 14 538 626 685 711 7 21 682 424 6 8 6 3966
Q) j-J
TABIE III Continued
Run No Position CFM h1 h2 h3 h4 h5 hu h7 hav Nuav
106 3492 614 7 1 6 7 84 8 13 8 33 7 85 4 88 7 87 4562 107 4395 7 86 894 964 996 1005 9 64 640 9 65 56 06 108 50 75 9 11 10 22 1081 1112 1125 1085 7 24 1085 63 16 109 G 1344 9 22 1042 1120 1 1 46 1173 1131 7 04 1120 63 87 110 1936 1162 1340 1442 1474 1509 14 7 3 9 09 1441 82 77 111 2846 1631 1797 1902 1966 2027 2079 1342 19 2 3 11108 112 3484 207e 2144 2236 2307 2385 2574 1694 2268 13138 113 4066 24 65 24 42 2535 2648 2757 31 71 2178 2 5 96 15078 114 50 12 3059 2916 30 1 5 3176 3312 4059 2849 3105 180 46 115 1D 1362 2268 26 13 2613 26 35 2605 2503 15 46 2617 14934 116 1958 2993 3580 3580 3586 3539 3 5 02 2144 3571 20492 117 2812 4430 50 32 4913 4 9 86 4991 5196 3088 4981 287 66 118 3432 58 16 62 13 6067 61 18 60 66 6698 4143 61 16 354 16 119 40 22 71 71 7 4 62 7369 7419 7329 82 74 51 8 1 7395 42909 120 5026 105 95 11456 115 81 11574 11548 14010 80 91 11540 671 15 121 2D 1244 18 57 2277 2363 2305 2210 2107 1466 2289 13038 122 1960 2622 3240 3388 33 23 3226 31 40 2)99 3294 18919 123 2817 3762 45 87 4739 46 56 45 14 4 6 47 30 15 4624 26689 124 3491 50 22 5723 58 53 57 44 5542 60 18 3871 57 16 330 73 125 4096 61 29 68 16 69 79 6805 65 90 74 79 4677 67 98 39400 126 5037 82 27 94 60 95 69 93 57 9023 11324 65 05 93 52 542 83 127 12D 1278 14 70 1 6 48 1652 1638 1 6 34 1641 9 73 1 6 43 9369 128 1947 19 63 2155 2149 2151 2131 2190 1347 2147 12342 129 2769 2615 2791 2773 28 52 2716 2954 18 96 2783 1 60 82 130 3439 3208 3265 3239 3593 3133 3624 2515 3308 19174 131 4103 3637 35 88 3577 4077 3459 42 66 3138 3676 21343 132 49 78 45 82 44 60 44 8 1 55 17 43 25 5749 4227 4700 27288
Q) tlgt
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
133 1 12D 1299 2094 2507 2622 2625 2567 2489 1465 2578 14736 134 1973 29 56 3505 3772 3790 3718 3718 2115 3700 21290 135 2788 3941 4727 5069 5099 5 0 07 5231 2984 4976 28781 136 3473 5155 59 81 6308 6339 62 39 68 96 4204 6217 36052 137 4118 6135 71 8 6 7662 7731 76 91 87 16 49 8 5 7568 43985 138 4973 7765 94 75 10396 10861 10694 13646 66 64 10357 602 25
139 1ttn 1253 1242 1493 1460 1442 1431 1424 8 84 1457 83 01 140 2366 1942 2150 1961 1910 1897 19 62 1206 1980 11400 141 3461 3007 2957 2562 2513 2606 3143 18 51 2660 15400 142 4325 3942 3571 3060 2999 3198 4248 2631 3207 18618 143 5677 508 6 4359 39 88 3800 42 29 57 78 36 26 4094 23824 144 67 59 64 55 5330 4988 47 25 5494 2517 48 09 5134 29906 145 84 08 9326 72 26 7726 85 56 9172 12319 7733 8170 47626 146 86 54 9831 7582 818 9 94 90 9869 13116 78 97 8783 512 96 147 7376 7335 58 7 6 5941 5796 68 29 81 65 5954 6111 35662 148 2 11 D 4254 4106 48 02 4994 5038 5042 56 78 3419 4969 28881 149 5708 5487 6253 6466 6524 6527 78 63 45 8 2 64 43 37566 150 69 7 8 7983 9440 9848 98 34 97 32 13249 6701 9714 566 59 151 1254 1434 18 53 1947 1915 1850 1760 1186 1891 10772 152 2713 2696 3175 32 94 3288 3237 3288 20 44 3249 18728 153 87 30 118 07 14733 15758 15504 15305 26297 9617 15325 892 71 154 5811 5278 6543 6861 69 30 69 82 7 8 74 4478 68 29 39531 155 4246 3780 4736 4975 49 66 4936 5162 3113 4903 28301 156 (v 1270 8 15 935 959 966 9 51 9 23 6 35 953 5430 157 2714 1164 1390 1427 1447 1454 1455 9 08 1430 8242 158 4310 1655 18 96 1942 1988 2002 2111 1305 1957 11349
(j) ~
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 fry hav Nuav
159 6012 2208 2400 2450 2513 2548 28 20 18 00 2478 14416 160 7279 2696 2881 2927 2989 3081 3599 2340 2970 17326 161 86 90 3257 3360 3 3 76 34 26 3558 4455 2943 3430 2000 162 12D 4368 2209 2600 2558 2518 2466 2774 1753 2536 14713 163 5833 2730 3092 3028 2974 2913 3501 2287 3002 174 78 164 7643 3320 3681 3630 3651 3530 4623 3181 3623 21116 165 87 39 3920 4303 4300 4708 4178 61 60 3937 4372 25456 166 1268 962 1203 1205 1186 1118 1084 725 1178 6693 167 2678 14 67 1785 1779 1752 1698 1726 10 70 1754 88 49 168 1 12D 12 83 936 1217 1414 1397 1239 1190 7 65 1317 7484 169 2729 2502 2930 2914 2934 2956 2979 17 52 2934 16866 170 4345 3884 4357 4283 4318 4421 4836 28 59 4345 25151 171 6036 5546 5858 5764 5791 6028 7129 4184 5860 34045 172 6578 7167 7769 7907 79 82 8263 10492 5915 7980 46437 173 87 84 10237 112 23 120 26 12727 12968 185 19 85 98 12236 71103 174 1278 1344 1803 18 72 1835 1790 1712 1063 1825 10355 175 2711 2328 2972 2932 2893 28 78 2863 1667 2919 167 51 176 4351 3934 4414 4353 4281 4321 4654 28 63 4342 25088 177 5994 5076 5824 5838 5818 59 29 6914 4205 5852 33885 178 1 11 U 1223 388 432 465 464 449 435 338 453 2585 179 2351 521 602 6 22 675 6 57 619 436 639 3687 180 34 48 6 05 1725 803 8 27 8 11 760 518 792 4593 181 4513 718 850 934 9 68 9 57 8 99 609 9 27 5386 18 2 5714 8 32 981 1060 1102 11 06 1034 6 59 1062 61 82 183 6997 1025 1182 1258 1295 1309 1234 8 18 1261 7 3 44 184 8709 1295 1487 1 5 42 1594 1626 1612 1156 1562 9080
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
185 2 12D 4249 3560 4400 4670 4791 4695 47 81 2931 4639 268 37 186 5737 4926 58 54 61 92 6248 62 38 67 78 4134 6131 35590 187 7432 6390 7726 83 46 85 44 86 34 10371 5658 8313 48310 188 8723 7718 107 88 11933 12099 13046 186 22 79 39 119 67 69505 189 1 4 35 1340 1735 18 57 18 52 17 81 1711 1144 18 06 10256 190 2718 2399 3023 3187 3207 3138 30 53 1931 3139 18025 191 7 5 07 6189 80 11 9200 9427 9703 11364 5720 9085 527 38 192 8544 78 42 10666 125 42 13312 13775 178 20 6976 125 74 729 86 193 1287 1417 16 97 18 7 18 69 18 08 1720 1046 1800 10223 194 27 17 2450 2940 3187 3214 3157 3054 1749 3125 17954 195 42 53 3560 4222 45 90 4679 46 63 4743 2741 4539 26247 196 6068 48 69 57 79 6335 65 8 6 66 04 7172 4338 63 26 366 78 197 7389 58 86 72 8 6 82 23 8584 8936 10658 50 60 8257 4798 6 198 86 88 78 91 100 27 120 56 130 29 14299 190 81 6492 12353 71850 199 5864 4694 5 6 67 61 94 6419 65 48 7192 3950 6207 360 14 200 2 D 4177 38 36 4547 48 09 4775 4628 5006 2715 46 90 261 30 201 5712 5170 62 39 66 38 6599 6604 7518 4167 65 20 378 00 202 73 63 7201 8986 98 43 9733 9914 13353 6219 9619 55810 203 8604 10043 13118 148 41 150 42 158 66 25206 82 5 3 14717 85290 204 12 68 1506 18 41 1971 1966 1868 1799 11 42 1913 10880 205 2659 2571 3127 3276 32 50 3130 3069 18 80 3196 18 350 206 39 80 36 76 4347 4573 45~67 4473 46 34 28 37 4490 25910
o 207 Orifice 11496 10 64 1360 15 39 1 5 80 1 6 15 1496 8 58 15 24 88 83 208 9433 8 95 11 78 13 26 1394 1386 1263 727 1346 78 48 209 7387 746 9 77 1123 1184 1159 1048 6 11 1111 64 74 210 52 36 566 7 66 900 934 909 8 21 499 8 27 48 02
0) CJ1
TABLE III Continued
Run No Position CFM h 1 h2 hs h4 h5 h6 h7 hav Nuav
211 212
3309 1293
414 257
563 3 19
6 68 3 57
6 91 3 37
6 72 351
7 37 337
38 4 2 46
4 40 341
3748 1942
213 214 215 216 217 218
c of 2nd 1 516 1235
1919 2712 3320 4153 4704
1532 2447 35 46 4312 5567 74 29
2 1 87 3312 4225 52 86 6902 8 6 50
2360 3555 4340 56 12 7 0 49 8 9 40
2409 3598 4 8 85 5718 7713 9593
2347 2101 35 33 3453 48 00 49 62 5562 59 86 72~6 7 8 79 93 76 11237
1243 20 64 3054 4 2 8 1 5114 6983
2326 35 00 4638 5545 7225 91 40
132 13 200 27 26672 31968 41711 52811
bull
67
TABLE IV
PRESSURE PROFILE DATA
Baffle Flow Qpening Rate ~p
(Inches) Position (CFM) (Inches 295 S G Fluid)
1 364 l2 11 U 1012 0 254 1248 0197 1493 0 141 1718 0112
c 1000 9 80 1210 1710 1436 28 75 1746 4320 1011 1080 1277 2050 1393 3020 1 6 28 4450
12D 1011 9 75 1236 1520 1450 2510 1603 3450
1 D 1011 975 1256 1700 1480 2690 158 1 4070
1 12D 1010 950 1259 1750 1462 2650 1631 3710
2 11 D 1124 1315 1360 2130 1505 2850 1689 4125
1 216 12U 1294 045 1949 0324 2374 0282 2704 0225 3367 0169
c 1326 265 18 81 5 90 2313 990 2731 1480 3439 2660
12D 1272 2 49 1957 661
68
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Pos ition (CPM) Inches 2 95 S G Fluid)
2559 1275 3033 1940 3639 3025
1 216 1nD 1257 242 16 96 476 2117 8 05 2561 1280 2990 1895 3431 26 bull00
1 316 12U 1309 0 479 2004 0422 28 28 0 352 3526 0281 42 28 0225 5199 0225
c 1308 1 43 1998 272 28 14 5 10 3478 795 4248 1235 5048 1885
l2D 1286 140 2005 3 45 2831 725 3495 1180 4194 1805 5046 2945
1 11D 1322 150 2039 352 2841 735 43 77 1980 5378 3440
1 516 12U 1278 0493 2732 0493 4315 0408 5744 0352 7494 0352 8932 0422
c 1300 0 506 2731 1985 4310 348 6080 6 45
69
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Position (CPM) (Inches 295 SG Fluid)
7607 1090 8830 1585
l2D 1343 0549 2738 225 4566 583 6112 1195 7536 2055 9043 3415
1 516 1uD 1249 0464 2713 224 4155 579 5620 1150 7428 2115 90 70 3405
1 12D 1301 0493 2735 220 4501 616 61 50 1235 7440 2065 8862 3445
2D 1265 0 478 2750 226 4366 594 6578 1270 7678 2240 8945 5280
2 12D 1295 0493 2725 222 4293 600 5807 1120 7568 2200 9070 3615
TABLE V
RATE OF HEAT TR AN SFER Ar THE BAFFL~~ CID-TT ER
Orifice Size
(Inches)
Flow Rate
( CFM)
Re d e G tU
R~) 055 Nuav NuPr-l3
1 364 10 26 12 90
8 075 10015
43400 54 600
85 11 99 64
95 83 112 19
1416 11 140 59 900 110 30 124 20 16 27 12 800 68 900 126 64 142 60 17 29 13 610 73 200 135 79 152 90 17 76 13980 75 200 147 59 166 19
1 216 11 35 14 06
8 600 10 660
27000 33500
6 4 96 76 56
73 14 8 6 12
1517 11500 36100 82 51 9291 20 34 15400 48400 10229 115 18 23 11 17500 55000 118 31 13322 2348 17 800 55900 11947 13452 2666 20 200 63400 13508 15210 27 16 20 600 64700 135 05 152 07 32 47 24600 77200 161 57 18 193 3392 25 700 80700 17390 195 8 1
1 316 1344 19 36
9898 14 260
24800 35 700
63 8 7 8 2 77
71 92 93 20
28 46 20 9 60 52 500 111 08 125 08 34 84 25 660 64200 131 38 147 93 40 66 50 12
29900 36900
74800 92400
150 78 18046
169 78 203 20
~ 0
TABLE V Continued
Orifice Flow Re Size Rate d e G R~rmiddot55 NuPr-13(Inches) (CFM) U Nuav
1 516 12 70 8 847 16800 54 ~0 61 14 2 14 18 900 35800 82 42 92 80 43 10 30 000 56900 11349 127 79 60 12 41900 79400 14416 16232 7279 50700 96100 17326 19509 86 90 60540 115000 20098 22529
TABLE VI
RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
Orifice Size
(Inches)
1 364
1 216
1 316
Flow Rate
(CFM)
1054 1294 1431 1681 1770
1068 1399 1669 1959 2295 2636 3390
1299 1973 2788 34 73 4118 4973
Re deG Mshy
8 300 9870
11260 13200 13 930
8100 10600 12650 14850 17400 19980 25700
9 570 14500 20500 25600 30300 36600
R~r-6 51900 61700 70500 82 500 87 100
28200 36900 44000 51700 60 600 69500 89400
26100 39600 56000 69900 82700 99 900
Nuav
2416 293 5 3187 4018 4805
14938 18968 21712 25156 30680 37938 59601
14736 21290 28781 36052 439 85 60225
Uu Pr-1 3
27204 33050 3589 4524 541 0
16820 21358 24448 28326 34546 427 18 67111
16593 23973 32407 40595 495 1 678 13
TABLE VI Continued
Orifice Flow Re Size Rate deG R~rmiddot6 NuPr-13(Inches) (CFM ) M- Nuav
1 516 1268 88 30 17700 108 8 1225 2689 18700 37400 1835 2066 3980 27700 55700 2591 2917 4177 29100 58 500 2713 3055 5712 39800 80000 378 0 425 6 7362 51300 103000 5581 6284 8 604 59 900 120000 8529 9604
74
TABLE VII
EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER
l 516 Inch Orifice
Center ot 2nd Baffle 4 Downstream
Plow Rate (CFM)
1235 1919 2712 3320 4153 4704
Flow Rate (CFM)
1270 2714 4310 6012 7279 8690
(Re)eb -8600 1321
13400 2003 18900 2687 23100 5197 28900 4171 32800 5281
Center ot Single Battle
-8847 543
18900 824 30000 1135 41900 1442 50700 1733 60540 2001
(Nu)(Pr)-l3
1487 2255 3003 3600 4697 5946
(Nu)(Pr)-13
611 928
1278 1623 1951 2253
75
ABLE VIII
HEAT TRANSFER IN THE TEST SECTION WITHOUT ORIFICE
CFM Ute) 0b h Nu
1293 5-951 3 41 1942
33 09 15251 649 3746
5236 24193 827 4802
7387 34001 1111 6474
9433 43419 1346 7848
11496 52-914 1524 8883
76
TABLE IX
PRESSURE DROP FUNCTION
Orltlee Size Flow Rate incbea ~CFM (Re)eb X 10bull8
1 364 1011 7957 0808 1256 9885 1468 1480 11648 2765 1581 12443 4160 1689 1_3293 4 020
1 216 1257 9530 1327 1696 12858 2663 2117 16049 4615 2561 19415 7581 2990 22668 11560 3431 26011 16440
l 316 1322 9736 1819 2039 15016 4332 2845 20952 9275 3495 25739 15300 4377 32014 26800 5378 39607 50100
1 516 1011 7 957 oaos 1256 9885 1469 1480 11646 2765 1581 12443 4160 1689 13293 4020
77
TABLE X
EXPERIMENTAL DATA
Baffle Hole Diameter Run No
1 - 59
60 - 102
103 - 138
139 - 206
207 - 212
213 - 218
(Inches)
1 364
1 216
1 316
1 516
No Baffle
2nd - 1 516
TABLE X
EXPERIMENTAL DATA
Run Thermocouple Reading s (mv) No Position CFM I tc1 tc2 tc3 tc4 t c 5 tc6 tc7 tcair
1 c 1026 530 2055 1825 1768 1782 1802 1837 1965 1198 2 1290 612 2059 18 65 1809 18 32 1851 1880 1965 1160 3 1416 714 2151 1970 1931 1965 1988 2026 209 5 1130 4 1627 8 21 2235 2084 2 049 2093 2126 2173 2266 1130 5 1776 865 2203 2033 1970 2015 2084 2159 2 264 1121 6 12D 1109 542 1636 1507 1499 1499 1498 1498 1528 1218 7 1258 651 1670 1522 1503 1513 1513 1516 1548 1221 8 1433 750 1625 1480 1467 148 3 1487 1487 1516 1153 9 168 1 8 73 1656 1494 148 1 1511 1517 1517 1543 1159
10 1rtD 1102 485 1545 1450 1437 1446 1447 1442 1466 1220 11 13 08 6 10 1571 1470 1460 1476 1476 1469 1498 1194 12 1464 730 1 623 1509 1508 1528 1 5 32 1524 1548 1173 13 11 06 8 71 1663 1559 158 1 1606 160 6 1 583 1601 1190 14 1 12D 1115 520 1698 1579 1575 1 577 1580 1590 1615 1280 15 1275 6 10 1692 1567 1558 1 561 1570 1580 1601 1234 16 1498 770 1760 1619 1630 1 635 1642 1645 1661 1204 17 1695 912 1775 1635 1670 1689 1686 168 6 1701 1165 18 2D 1049 510 1736 15~2 1567 1558 1 553 1558 1620 1236 19 12 41 610 1655 1517 149 1 148 1 148 1 148 4 1546 1108 20 1 5 32 7 35 1720 1550 1530 1520 1519 1523 158 0 1104 21 16 74 8 8 0 1900 1 727 1714 1696 1691 1692 1753 1169 22 1U 1074 38 5 3 324 2740 2534 2478 2 465 2503 258 0 1210 23 1287 4 35 3510 2 870 2682 2 610 2599 2638 27 1 9 1190 24 1 5 08 470 3 618 2920 2690 2 637 2627 2 664 2747 1177 25 18 07 525 4 088 3235 2962 2905 2910 2988 3130 1169
z ())
TABLE X Continued
Run No Position CFM I tc1 tc 2
Thermocouple Readings te3 tc4 tc5
(mv) tc6 tc7 tcair
26 c 10~29 6 32 2340 2~092 2032 2060 2~097 2152 2~213 1211 27 12 66 679 2270 2 047 1993 2013 2069 2142 2 210 1 182 28 1430 723 2336 2097 2033 2080 2153 2~255 2 356 1 138 29 1729 8 52 2318 2070 1980 2061 2158 2279 2367 1121 30 12D 1054 570 1520 1 4 20 1402 1400 1396 1400 1 443 1159 31 1294 6 69 1599 1469 1444 1439 1433 1 442 1485 1168 32 1430 7 88 1720 1562 1536 1532 1528 1537 158 0 118 5 33 1770 8 81 1641 1488 1450 1~441 1 441 1_466 1518 1 163 34 1D 1058 548 1579 1498 1495 1526 1553 1_557 1 571 1 276 35 1263 640 1609 1509 1515 1570 1599 1598 1 598 1 266 36 18 36 8 47 1538 1452 1483 1553 1602 1 590 1 558 1195 37 1 12D 1029 5 41 1 578 1499 148 4 1473 1461 1465 1-512 1200 38 1315 6 30 159 1 1504 1493 1482 1470 1470 1505 118 5 39 1 4 26 743 1765 168 1666 1660 1645 1642 1678 1270 40 1757 8 54 1744 1648 1634 1620 1598 1 593 - 1612 1223 41 2D 1080 5 30 1734 1604 1570 1 570 1570 1 588 1 640 128 1 42 1305 6 40 1744 1622 1589 1 608 1593 1 609 1 661 1240 43 1434 750 1798 1687 1658 1 636 -1641 1 661 1 711 1_220 44 18 04 8 41 1 764 1666 1607 1605 1614 1 635 1 675 1205 45 12nu 1088 415 2614 2295 2195 2 169 2174 2217 2256 1171 46 1318 477 2805 2477 2371 2342 2364 2 401 2 438 1 163 47 1413 5 28 2930 2 646 2 555 2 526 2532 2570 2 577 1 199 48 1773 550 2740 2518 2450 2431 2448 2 479 2 480 1 170 49 1 11 U 1054 380 3175 2670 2505 2 461 2467 2 534 2 621 1 258 50 1240 420 3268 2738 2 546 2 510 2 508 258 2 2 649 1214 51 1419 451 3364 2B07 2 632 2590 2 590 2 651 2773 1 215 52 1 12U 1032 360 3 165 2 629 2 450 2402 2403 2 473 2 bull568 1 163
--I lt0
TABLE X Continued
Run No Position CFM I tc1 tc2
lhermocoup1e Reading s tc3 tc4 t c 5
(mv) tc6 tc7 tc a ir
5 3 1314 38 9 3178 2592 2411 2367 2361 2432 2555 1140 54 1448 403 3095 2544 238 1 2336 2336 2390 2476 1158 55 178 2 427 3006 2434 2286 2253 255 3 2299 2397 1154 56 2 11U 1061 360 3369 2814 2619 2567 2560 2650 2833 1220 57 1216 360 3044 2512 2338 2290 2288 2374 2566 1150 58 1322 387 3196 2614 2425 2383 2382 2472 2670 1138 59 1639 403 3020 2438 2272 2238 2238 2318 2502 1127
60 1D 1068 612 1552 1424 1400 1395 1396 1426 1745 0945 61 1399 612 1355 1246 1230 1229 1230 1250 1509 0872 62 1669 710 1436 1293 1272 1265 1266 1286 1551 0847 63 1959 900 159 5 1468 1444 14 38 1432 1446 1720 0851 64 2295 730 1169 1105 1098 1099 1108 1100 1298 0781 65 2636 8 80 1202 1129 1121 1126 1 138 1115 1342 0748 66 3390 9 35 1060 o 9s7 0999 1001 1017 0971 1154 0703 67 1nu 1190 370 2225 2188 2104 2080 2120 2209 2 7 15 0990 68 1559 368 2005 1950 1871 18 48 1876 1951 2408 0916 69 1904 368 1870 18 1 4 17 34 1711 1730 18 07 2238 0875 70 22 bull11 471 228 6 2 204 2099 2063 2092 218 $ 2732 0840 71 2289 471 2030 2000 1925 1895 18 96 19 5 2498 0785 72 2727 4 71 1854 18 23 1753 17 23 1716 3758 2241 0743 73 3210 471 1680 1651 158 6 1559 1551 158 1 1950 omiddot7o9 74 2uD 1210 404 1261 1212 1198 1197 1205 1222 139 1 0978 75 14 20 540 1321 1260 1242 1 240 1249 1268 148 7 0918 76 1692 7 18 1467 138 6 1364 1361 1376 1405 1678 0883 77 18 94 903 1708 1 591 1565 1560 1575 1603 1948 0 857 78 2301 903 1530 1432 1407 1402 1415 1432 1738 0815
ro 0
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc117 tcair
79 2621 6 50 1069 1 020 1009 1009 1009 1007 1~189 o739 80 3230 901 1200 1128 1113 1119 1119 1086 1341 0694 81 82
l2D 1155 1689
360 575
1191 1345
1142 1252
1122 1218
1118 1210
1118 1209
1132 1228
1292 1446
0916 0822
83 1244 430 1163 1134 1131 1130 1129 1132 1292 0877 84 2100 645 1175 1135 1147 1 142 1138 1122 1286 0757 85 2292 8 25 1 354 1310 1327 1330 1323 1285 148 6 0728 86 2907 8 23 1180 1138 1151 1158 1149 1107 1268 0687 87 3380 902 1113 1049 1025 1011 1006 1042 1178 0673 88 89
1 12D 1427 1875
480 615
118 2 1140
1140 1095
1124 1077
1125 1075
1129 1072
1137 1072
1290 1243
0880 0790
90 2259 8 41 1296 1231 1207 1206 1203 1182 1419 0757 91 2682 8 80 1231 1170 1149 1147 1142 1112 1350 0731 92 3417 940 1142 1092 1076 1076 1069 1021 1252 0693 93 c 15 17 431 1321 1298 1268 1249 1250 1273 1522 0841 94 2034 505 1285 1263 1235 1209 1205 1206 1464 0759 95 2348 6 10 1395 1379 1334 1302 1286 1268 1536 0732 96 2716 706 1486 1480 1427 1383 1358 1311 1572 0 700 97 3247 7 56 1417 1430 1375 1320 1284 1223 1450 0660 98 1135 400 1425 1388 1352 1329 1330 1 364 1651 0893 99 14 06 440 1379 1341 1304 128 2 1281 1305 1583 0 831
100 2311 680 1602 1593 1553 1514 1502 1480 1 7 27 0 802 101 2666 680 1471 1469 1428 1390 1372 1335 1564 0761 102 3392 798 1491 1 509 1449 1395 1372 1305 1534 0 719
103 1U 1235 410 2469 2295 2173 2165 2226 2361 3120 0 897 104 2010 410 2017 1848 1 737 1706 1747 1865 2582 0753 105 28 14 410 1682 1535 1457 1427 1437 1520 2109 0 660
00 t-
TABLE X Continued
Ru n Thermocouple Rea ding s (mv No Positi on CFM I tc1 tc2 tc3 tc4 tc5 tc6 tc7 tcair
106 3492 440 1649 1499 1420 1391 1390 1470 2042 0620 107 4395 550 18 33 1679 1597 1564 1570 1640 2223 0583 108 5075 588 1779 1642 1580 1550 1552 1 615 2 191 0548 109 c 1344 398 1464 1 399 1364 1353 1350 1380 1689 0 907 110 1936 459 1369 1290 1253 1242 1 237 1259 1574 078 2 111 2846 580 1347 128 5 1251 1232 1220 1215 1 5 23 0 683 112 34 8 4 700 1392 1369 1339 1317 1299 1259 1599 0 636 113 4066 8 13 1449 1458 1427 1391 1363 1270 1595 0 591 114 5012 930 1484 1530 1500 1453 1420 1272 1580 0 580 115 1D 1362 513 1269 1218 1 217 1214 1220 1238 1460 0 893 116 19 58 600 1187 1122 1121 1120 1124 1133 1352 0798 117 2812 705 1052 1008 1015 1010 1011 1001 1218 0691 118 34 32 913 1105 1075 1085 1081 1086 1047 1301 0645 119 4022 980 1038 1021 1026 1023 1029 0983 1211 0 609 120 5026 982 0 8 61 0839 0836 0836 0837 0791 0955 0570 121 2D 1244 475 1320 1246 1233 1240 1255 1275 1434 0925 122 1 9 60 5 50 1160 1088 1074 1079 1089 1100 1260 078 7 123 2817 6 80 1096 1024 1 013 1018 1029 1022 1201 0 700 124 3491 960 1248 1175 1163 1172 1192 1153 1435 0 658 125 4096 989 1141 1089 1078 108 9 1105 1051 1310 0629 126 50 37 989 0983 0933 0929 0 936 0949 0880 1090 0 602 127 128
12D 1278 1947
402 545
1270 1261
1 230 1216
1228 1216
1230 1 215
1235 1223
1242 1219
1483 1514
0 913 0778shy
129 2769 695 1273 1234 1237 1221 1251 1212 1525 0678 130 131 132
34 39 4103 4978
8 40 9 80 9 80
1336 1448 1271
1322 1458 1 288
1328 1 462 1286
1 259 1 356 1157
1353 1492 1311
1261 1329 1138
1 555 160 7 1343
0 629 0 600 0599
(l) l)
TABLE X Continued
Run No Position CFM I tel tc 2
Thermocouple Readings tc3 tc4 tc5
( mv) tc6 tc7 tcair
133 1 l2D 1299 5 16 1 28 1 1212 1196 1195 1205 1221 1478 0869 134 1973 6 15 1163 1098 1073 1071 1079 1083 1343 0751 135 136
27 88 34 73
802 9 -_78
1187 1214
1099 1131
1069 1104
1066 1101
1075 1~110
1l061 1066
1370 1360
0662 0618
137 4118 9 81 1084 1010 0983 0979 0982 o937 1209 0581 138 4973 98 1 0969 0897 0 868 0855 0860 0799 1041 0572
139 1D 1253 409 1371 1293 1298 1301 1309 1321 1578 0928 140 2366 480 1130 1 090 1 121 1130 1137 1132 1390 0744 141 34 61 6 38 1081 1086 1152 1161 1147 1069 1382 0644 142 143 144
4325 5677 6759
7 90 939 998
1110 1115 1034
1161 1208 1139
1253 1268 1180
1265 1302 1215
1228 1230 1123
1080 1056 0970
13$913r12 8
0601 0561 0542
145 84 08 989 0863 0961 0934 0895 0871 0 785 09 9 0530 146 86 54 9 80 0808 0901 0 872 0821 0809 0733 0891 0498 147 7376 9 80 0 927 1032 1027 1 040 0961 0889 1032 0511 148 2D 4254 776 1 050 0 981 0965 0961 0962 0922 1155 0579 149 5708 991 1102 1031 1014 1009 1010 0931 1227 0528 150 69 78 990 0914 0853 0839 0 839 0843 0759 0996 0521 151 1254 490 1 479 1352 1329 1334 1351 1379 1607 0930 152 2713 7 00 1310 1220 1201 1201 1211 1209 1516 0723 153 8730 991 0809 0756 0742 0745 0 748 0663 0874 0543 154 5811 966 1219 1108 108 6 1081 1079 1033 1330 0650 155 42 46 8 02 1248 1136 1114 1114 1118 1103 1376 0 699 156 c 1270 429 1671 1571 1551 1545 1563 1600 1933 0929 157 2714 488 1398 1285 1 267 1258 1262 1275 1628 0729 158 4310 642 1424 1318 1299 1282 1283 1261 1683 0617
co ~
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc7 tc a 1r
159 60 12 780 1461 1388 1370 1349 1343 1279 1700 0 573 160 72 79 8 60 1402 1344 1330 1312 1292 1189 1 566 0 520 161 8690 982 1472 1442 1437 1 422 1392 1224 1602 0 521 162 163
12D 4368 5833
6 30 8 30
1195 1368
1105 1270
1111 1283
1117 1294
1131 1313
1081 1194
1369 1553
0613 0 553
164 76 43 959 1428 1338 1348 1341 1371 1180 1488 0535 165 8739 984 1345 1272 1272 1208 129 3 1059 1361 0550 166 1268 459 1701 1548 1541 1547 1589 1 625 1976 0 973 167 2678 570 1485 1351 1349 1356 138 1 1 385 1795 0760 168 169
1 12D 128 3 2729
448 650
1664 1314
1501 1232
1425 1233
1428 1229
1491 1229
1527 1232
1869 1571
0 962 0767
170 4345 847 1245 1179 1187 1182 1172 1132 1476 0 650 171 6036 9 76 1139 1109 1117 1114 1095 1020 1332 0588 172 6578 9 72 0982 0949 0942 0938 0926 0 8 50 1079 0560 173 87 84 9 72 0880 0854 0 8 36 0822 0818 0 749 0941 0585 174 1278 480 1564 1416 1397 1403 1417 1445 1733 0998 175 2711 590 128 3 1175 4 1178 1182 1187 1195 1493 0796 176 4351 8 90 1331 1259 1266 1275 1272 1235 1592 0 682 177 5994 9 60 1228 1152 1150 1151 1143 1075 1 360 0644 178 lU 1223 408 2282 2140 2052 2052 2106 2188 2626 0 878 179 2351 408 178 1 1623 158 5 1519 1556 1634 2068 0717 180 3448 482 1888 1675 1570 1541 1572 1665 2199 0629 181 4513 563 2026 1797 168 4 1644 1670 1770 2385 0583 182 5714 589 1913 1700 1610 1568 1580 1 682 2382 0551 middot 183 6997 653 1903 1718 1643 1611 1612 1700 2326 0 549 184 8709 6 80 1738 158 3 1543 1510 1498 1519 1 912 0577 185 186
2 12D 4249 5737
660 9 74
1055 1221
0 979 1122
0960 1093
0 952 1088
0959 1090
0 956 1054
1147 1350
0661 0602
187 7432 9 8 1 1065 0981 0951 0942 0 939 0881 1135 0582 CD ~
TABLE X Continued
Run No Position CFM I t o1 to 2
188 87 23 9 83 0944 0 879 189 1435 585 18 26 1630 190 2718 690 1433 1298 191 7507 950 1070 0961 192 85 44 964 0982 0 881 193 1287 600 1806 1668 194 2717 7 80 1579 1444 195 4253 8 81 1371 1260 196 60 68 9 78 1252 1152 197 73 89 975 1100 1000 198 86 88 973 0953 0 871 199 58 64 9 81 1269 1155 200 2D 4 1 77 915 1362 1251 201 5712 975 1213 1111 202 7363 9 78 1036 0 951 203 8 604 973 0932 0861 204 1268 6 95 2015 18 20 205 2659 6 96 1405 1295 206 39 80 7 98 1261 1174
No 207 Orifice 114 96 509 1325 1148 208 94 33 509 1477 1243 209 7487 5 09 1686 1409 210 5236 505 2094 1691 211 3309 428 2188 1 778 212 1293 392 2976 2560
Thermo ooup1e Readin g s (mv) to 3 to4 to
5 to
6 to7 toair
0 851 0847 0 8 29 0759 0987 0592 158 4 1583 1611 1647 1993 0986 1270 1266 1 279 1298 1604 0 789 0916 0908 0900 0 858 1115 0602 08 39 0 823 0 818 0 770 1035 0602 1609 1602 1629 1676 2153 0979 139 1 1385 1400 1 430 1938 0776 1212 1201 1205 1201 1601 0669 1 105 1086 1086 1 052 1371 0621 0952 0936 0923 0870 1195 0582 0 8 20 0 801 078 1 0 729 1044 0569 1108 1090 108 2 1043 1407 0610 1218 1221 1241 1202 1582 0659 1081 1083 1084 1031 1 368 0622 0921 0924 0919 0 841 1111 0 610 08 34 0831 0 821 0 751 1003 0 630 1761 1761 1 809 1861 2399 0966 1271 1271 1295 1311 1650 0797 1150 1150 1161 1149 1440 0703
1083 1057 1053 1109 1566 0~530 1158 1125 1138 1217 1763 0 526 1291 1250 1278 1383 2038 0542 1518 1478 1519 1657 2420 0 589 1596 1557 1601 1737 2441 0688 2370 2344 2409 2561 3 297 0921
()) (11
TABLE X Continued
Run Thermocouple Readings (mv) No Position CFM I tc 1 tc2 tc3 tc4 tc tc tc tc i5 6 7 a r
C of 2nd 213 516 1235 4 63 1 432 1291 1265 1258 1 268 1 308 1550 0 971 214 1919 6 17 1357 1223 1196 1191 1199 1211 1461 0 851 215 27 12 8 35 1401 1259 1278 1220 1230 1218 1511 0 762 216 3320 981 1439 1305 1270 1259 1275 1238 1450 0719 217 41 53 980 1251 1142 1132 1094 1121 1088 1305 0 695 218 404 987 1102 1042 1030 1 bull006 1014 0960 1133 0681
Supplementary Equations
Calculating temperatures from thermocouple readings
t = -026tc)2 + 3512(tc) + 3201 (26)
where t is the temp in deg F and tc is the thermocouple reading in millishyvolts
Calculation of the thermal conductivity of air
k = 00000245ta + 0 0132 (27)
where k is the thermal conductivity in Btuhr rt2 degFft and ta is the air temp 1n OF
I I
bull co m
2
2 Disk and doughnut baffles consist of disks and
doughnuts or annular rings placed alternately
along the length of the tube bundle~ There is
some flow through the annular orifices formed
where the tubes pass through the baffles but a
large portion of the flow is around the baffles
3 Segmental baffles are segments of a circle and
Bre arranged so that the fluid flows back and
forth across the tube bank There is still some
f~ow through the small area where each tube goes
through the baffle
In the case of disk and doughnut and segmental baffles
small annular clearances must be allowed at the point where
the tube goes through the baffle so that the bundle may be
assembled easily Thus in all of the types of exchangers
some shell-side fluid flows through the annular orifice
where the tubes pass through the baffles It has been
shown that this is an area of high rate of heat transfer
but its effect on the overall performance of the heat exshy
changer is not well known Also the prediction of rates
of heat transfer 1n these orifices is not yet possible
The purpose of this research was to make an extensive
study of the heat transfer rates in the vicinity of these
annular orifices and to determine the effect of orifice
size flow rate and upstream conditions The work was
5
performed in a onebulltube single orifice type baffle heat
exchanger and provision was made to measure local rates
of heat transfer in the vicinity of the baffle
4
CHAPTER II
THEORY AND PREVI OUS WORK
In 1701 Newton defined the heat transfer rate qc
from a surface of a solid to a fluid by the equat ion
= ~A(tw - t) (1)q0
where hm is the coefficient of heat transfer from the surshy
face to the fluid excluding any radiation A is the area
of the surface tw is the surface temperature of the wall
and t is the bulk temperature of the fluid The equation
for the point of local surface coefficient h is given by
dqdA = h(tw- t) (2)
The mechan ism and the laws covering heat transfer by
true conduction in solids and by radiation through transshy
parent media are well known However with heat transfer
from a solid to a fluid the situation is far more complex
The mechanism of flow of the fluid to a large extent deshy
termines the rate of heat transfer for a given temperature
difference
In addition the coefficient hm depends on certain
physical properties of the flowing fluid the dimensions
of the apparatus the velocity of the fluid past the surshy
face and frequently the temperature potential AT
It was the purpose of t his research to measure the
local shell -side heat transfer coefficient and correlate
it with the several variables mentioned a bove
5
The heat transfer coefficient for fluids flowing inshy
side tubes is more e a sily measured and correlated due to
the simple geometry of t he tube i nterior Much work has
been done on the tube-side coefficients with one of the
more useful e quations being the Dittus - Boelter equation
( 4 p 450) ~
0 023 (---ctwGJbulla (~np M ( 3 ) M k
with the following cond itions satisfied
(1) Fluid properties evaluated at the arithmetic
mean bulk temperature
(2 Reynolds number gt10000
(3) 0 7 lt Pr lt 100
(4) n = 04 for heating and 0 3 for cooling
(5) Ldw gt60
Colburn (3 p 197) obtained an equation for tubeshy
side heat transfer coefficients in which the Stanton
number is used instead of the Nusselt number
hm ) (~~ 23 _ (dwG) 0 2 ( GC k - 0 bull 023 U (4)
p
Much of the research done on average shell-side heat
transfer coefficients has resulted in empirical correlashy
tions of the form of equations (3) and (4) above Several
investigations have been made for a certain set of phys~al
6
variables but the r esults have ne ver satisf a ctorily been
correlated to appl y for all types of heat exchangers
Some basic 1ork has been done recently however on
the local shell-side coefficients Ambrose (1) studied
the local heat transfer coefficients i n a model heat exshy
changer with segmental baffles This study was fairly
extensive at the baffle center but the data were quite
limited for the space between the baffles Gurushankar1ah
(5) further extended Ambroses work by studying a single
baffle space in detail
The results of these two studies indicated a need for
detailed information 1n the vicinity of the baffle Hence
Lee () investigated a single baffle s pace between two
orifice baffles and obtained considerable information on
the rates of heat transfer in the annular orifices Since
his work was carried out in a multitube mode l heat ex~
changer the determination of the rate of flow through the
individual orifice was difficult because of t he outer
clearances existing in the exchanger For this reason the
present research was undertaken to study the rate of heat
transfer in a single annular orifice through which the flow
could be accurately determined
Bell and Bergelin (2) have studied i n detail the pres shy
sure drop coeff icients for the annular orifices formed beshy
tween a circular disk and a circular tube These results
also appl y to the annular orifioe formed when a rod extends
7
through a circular hole in a plata This study was extenshy
sive in the fact that it considered the baffle thickness as
well as the orifice size but no heat transfer data were
presented
Sullivan and Bergelin (9) studied flow through a
single annular orifice through multiple annular orifices
i n parallel and flow around a single baffle both with and
without leakage through the baffle A generalized expres shy
sion is presented for the pressure drop across one baffle
section of a tubular exchanger with leakage through the
tube holes in the baffle but the effect of leakage area
upon heat transfer is only discussed qualitatively The
pressure drop data is correlated by plotting cent as a funcshy
tion of the Reynolds number where cent equals
d1 )22( ~ P) s c e (d2 -
M-2
8
CHAPTER III
~PERI1ffiNTAL APr ARATUS
The heat transfer test section was essentially a
single tube heat exchanger The inner tube was a l-in
OD aluminum tube with an electrically heated probe midshy
way between the two ends of the tube
Test Section
The shell as constructed from lucite plastic tubing
2 5-in I D and 3-in O D The te t section d a total
lengt h of 54 58 inches I t consisted of two sections
The upstream section was 40 i n ches in length in order to
assure freedom from entrance effects and the downstream
section was 13 12 inches in length To further assure
uniform flow a bundle of short copper tubes was placed a
few inches downstream from the entrance Both of these
sections had 12 i nch flanges on one end so t hat a 18
i nch thick orifice plate could be clamped between them
Heat transfer coefficients were measured in the vicinity of
t h is orifice A cross section of the center of the test
section is shown in Figure 1 and the experimental appara~
tus is shown in Figure 2
Cooled air supplied by a Roots -type blower was used
as the shell-side fluid throughout this study It entered
the test section through a l-in ID 1 12-in OD plasshy
tic pipe at the upstream end of the calming section Tbs
j Jl l 6- 11 BOLTS II I nbull middot~11 I HEATING ELEMENTS
J T ( T
-f-shy - - - f-_- __L
7 777 _y A
IT 1] I
I
FIGURE I CROSS SECTION OF TEST SECTION AND PROBE
10
FIGURE 2 EXPERIMENTAL APP1Ub~fUS
11
air left the test section through nine equally spaced 12
ineh holes placed around the side of the tube at the exit
end
Sensing Probe Assembly
The sensing probe was designed to measure the local
heat transfer coefficients at any point along the tube and
around the tube in the test section The tube was designed
so that it could be easily moved up- and downstream to
measure the heat transfer coefficients at various positions
in relation to the orifice
The sensing tube assembly consisted of the sensing
probe the thermoctmple lead s and selector switch the
power lines and the two aluminum tubes between which the
probe was centered
Imbedded in the sensing probe were seven iron-constanshy
tan thermocouples for measuring the temperatures around the
tube The lead wires from these thermocouples were conshy
nected to a seleotor switch at the downstream end or the
aluminum tube A layer of Saran wrap was placed around the
tube over the t hermocouple and three lengths of Trophet C
resistance ribbon were wrapped around the tube nd conshy
nected in series to the power leads
The heating surface of the probe was formed by these
three one inch wide strips of Trophet C resistance ribbons
The ribbons were 0002 inches thick and had a resistance of
12
0 271 ohms per foot and a thermal conductivity of 763
Btuhr ft 2 degFft They were held in position by four
copper bars placed in four parallel longitudinal slots
These copper bars served as connectors for the electrical
leads A photograph of the sensing probe is shown in
Figura 3 and a drawing of the assembled probe is given in
Figure 4
Power Source
Direct current was used to heat the resistance ribbon
on the sensing probe The current was regulated by a slide
wire resistor The po er source consisted of a Raytheon
Voltage Stabilizer to stabilize the city power source at
115 volts and an automatic selenium rectifier with an alshy
ternating current input of 115 volts at 60 cycles per
second and an output of 12 volts and 35 amperes direct
current
Temperature Measuring
The temperatures around the sensing probe were calcushy
lated from the emf readings of the ironbulloonstantan thermoshy
couples The emf measuring system consisted of the seven
probe thermocouples a separate thermocouple for measuring
the inlet air temperature a thermocouple selector switch
a cold junction and a Leeds and Northrup Type K Potentishy
ometer The potentiometer was placed on a Fischer
13
THERMOCOUPLE JUNCTIONS~ ~------- HOLES FOR THERMOCOUPLE LEADS
~----- SCREWS
~ff+--- CONNECTING BARS
END VIEW
POWER LEADS SOLDERED TO LOWER CONNECTING BAR
iER PLASTIC PIECE
RESISTANCE RIBBONS LOCATION OF THERMOCOUPLES
FIGURE 4 DRAWING OF ASSEMBLED SENSING PROBE
15
Vibradamp support to absorb the vibrations produced by the
air blower
Air Source
Air was used as the shell-side cooling fluid during
the study The air was pumped through the test section by
a Roots type air blower with a rating of 280 ofm at 3 12
psig outlet pressure The hot air leaving the blower was
passed tbxfugh two finned-tube box-type coolers and one
tubular edoler to oool it to approximately room temperature
The air flow rate was measured by passing it through a
flow measuring orifice in the line Two sharpbull edged orishy
ficas were used f or flow measurements The calibration
curves for these orifices were presented by Ambrose (1
p 166)
The pressure taps on each side of the orifice were
connected to two differential manometers containing 0 83
and 2 95 specific gravity fluids respectively The presshy
sure drop through the test section and test orifice was
measured by a pressure tap placed 13 inches upstream and
one placed 6 12 inches downstream from the orifice Two
pressure ga ges were used to measure the pressure at the
inlet to the flow orifice and to indicate the statio pres~
sure at the test section inlet
16
Pressure Probe
A probe was designed to measure the pressure drop
between the pressure tap 13 i nches upstream from the ori shy
fice baff le and any point downstream from the tap The
probe eonsisted of a l~in OD copper tube with six 132
i n ch holes even l y s paced around the tube The upstream
pressure tap and the pressure probe were connected to a
differential manometer so the pressure drop to various
points up- and downstream of the orifice could be measshy
ured
17
CHAPTER IV
EXPERIMENTAL PROGRAM
The experimental program was designed to measure the
heat transfer coefficients and pressure drops in the vicinshy
ity of annular orifices The four orifice sizes studied
were 1 364 1 216 l 316 and 1 516 inches~ The inner
tube used in each case was a 1-in OD alumintim tube
Hence tube to baffle clearances were respectively 3128
232 332 and 532 of an inch
Heat transfer coefficients were measured at poait~ons
1 i nch upstream at the orifice center and at 12 1
1 12 and 2 inches downstream for all orifices In addishy
middottion the heat transfer coefficient at a point 2 12
inches downstream from the 1 516 inch orifice was measured
and at the points 12 l 12 and 2 inches upstream from
the 1 364 inch orifice
The heat transfer coefficients at each point were
measured at five different flow rates for the 1 364 inch
orifice and at six different flow rates for the other orishy
fice sizes The high pressure drop through the small orishy
fice size limited the number of flow rates which could be
studied
The flow rate was calculated from the pressure drop
across the flow orifice This flow was corrected to cubic
feet per minute at 68degF and one atmosphere pressure by
18
using the orifice pressure and the test section pressure
which were measured by pressure gages
It was desired to determine a relationship between the
heat transfer coefficient and the total pressure drop for
each orifice size The pressure drop across each orifice
at various flow rates was measured by means of the presshy
sure probe described in Chapter III It was also desired
to obtain pressure profiles for each orifice size since
these might be similar to the heat transfer profiles The
pressure drop was measured from a point 13 inches upstream
of the orifice to points at 1 and 12 ineh upstream the
orifice center 12 1 1 12 and 2 inches downstream
The experimental program is summarized in Table I
TABLE I
SUla~RY OF EXPER IMENTAL PROGRAM
Position Investigated-Distance from Orifice-Inches
Orifice Range of Flow Rate Size Heat Transfer Pressure Drop CFM at 68degF amp 1 atm
1 364 2U 1 12U 1U 12U c 12U C 12D lD 10 - 18 l2D lD 1 12D 2D 1 12D 2D
1 216 1U c 12D lD 1 l2D 2D 12U c 12D lD 10 - 35
1 316 1U c 12D lD 1 l2D 2D l2U C 12D lD 12 - 50
1 516 1U c x2D lD 1 l2D 1U 12U C 12D 12 - 90 2D 2 1 2D l D 1 l2D 2D 2 12D
20
CHAPTER v
EXPERI MENTAL PROCEDURE
The experimental procedure for measuring the heat
transfer coefficients ~d corresponding flow rates reshy
quired the following procedure
(1) Install the orifice size to be studied in the
test section
(2) Place the heat transfer probe in the position up
or downstream from the orifice where the middot heat
transfer rate is to be studied
(3) Fill the cold junction thermos with cracked ice
(4) Measure the atmospheric pressure
(5 Open bypass line from blower and close line to
test section
(6) Turn on the cooling water for the exchangers used
to cool the air leaving the blower
(7) Start the automatic selen ium rectifier by turning
on the t 1mer bull
(8 ) Connect the voltage stabilizer to the wall outlet
(9) middot Set the slide wire resistor to the maximum re shy
s1atanee I
(10) Start the blower
(11 Open the line to the test section until the de shy
sired flow rate is obtained
(12) Switch on the probe direct current power source
21
(13) Adjust the slide wire resistor to obtain the
desired current
(14) After the thermocouples have reached equilibrium
values record the e m bullf across each of the
seven probe thermocouples and also the entering
air thermocouple
(15) Record the direct current amperage
(16) Record the gage pressure at the flow orifice and
the entrance to the test section
(17) Record the manometer measurement of the pressure
drop across the flow orifice and also the presshy
sure drop through the test section
22
CHAPTER VI
CALCULAT ION OF EXPERIMENTAL DATA
The local heat transfer coefficients were calculated
from the temperatures measured on the probe surface the
air temperature and the current input The results were
calculated by using the Alwae III-E computer
The general expression for calculation of the heat
transfer coefficients was derived by Ambrose (1 p 79)
The equation is derived by making an energy balance around
a small increment of the center resistance heating ribbon
The two ribbons tnstalled adjacent to the center ribbon
reduced the amount of logitudinal conduction and assured
little longitudinal temperature variation in the center
ribbon
A heat balan ce on this small increment of resistance
ribbon yields the following
(the heat conducted in) + (heat generated) = (heat
conducted out) +(Heat convected to the fluid) + (heat
radiated to the surroundings) + (Heat conducted into
the plastic center of the probe)
This gives the equation
kzw dtdS + 12RdS kzws [ t + (~) ds] + hwdS (t-ta )
+ ~Aad wd o middot+ qcAond 1 -~- wdS 5 )
23
Hence solving for h gi~ea
i2R kz d2t Qrad qcond w + -d$2 - ~- A
h = ( 6)t - ta
Since S = re where 9 equals the enclosed angle ~n radians
dS rd9 ( 7)
and
dt - dt (8)dS - rd9
Differentiating with respect to S
d2t (9)rd9dS
from which
(10)
Substitut1ng into the equation for heat transfer coeffishy
cient gives
h = i2R Qcond A (11)
w
The rate of radial heat conduction into the plastic
tube making up the probe was assumed to have negligible
effect on the heat transfer coefficient It was also
assumed that the heat loss by radiation from the ribbon
was negligible since all data were obtained with the ribbon
at a temperature less than 125degF
24
When t he rad iation and conduction terms are neglected
Eq (11) becomes
(12)
The following con stants are known
R = 0 271 ohmsft
w = 100 i n ches
k = 763 Btuhr rt2 degFft
z = 0 002 inches
r = 12 inch
Eq (12) putting 9 in degrees then reduces to
1110 12 + 2404 d 2t d92
( 15)h = ------~--~-------t - ta
Thi s equation was programed for the Alwac III- E comshy
puter and used to calculate the local heat transfer coefshy
ficients from the observed data
The average heat transfer coefficient around the tube
at a given position in the t est section was calculated by
averaging the local coefficients calculated from Eq (13 )
It was found 1n the course of the experimental work
that thermocouple numbers 1 and 7 were indicating higher
temperatures than would be expected This resulted in h1
and ~ being lower than the other local coefficients around
the tube Since the fluid was flowing parallel to the axis
of the probe the circumferential variation i n rate of heat
25
transfer should be small Hence in obtaining the average
coefficient around the tube the values of h1 and h7 were
not used even though they were calculated and are tabulated
1n Table I II in the Appendix
Then
(14
A Nusselt number as calculated from this aver age heat
transfer coefficient using the tube diameter as the characshy
teristic dimension
(15)
The air flow rates through the test section were calshy
culated by measuring the pressure drop across the flow orishy
fice the air temperature the pressure at the flow orifice
and the pressure at the entrance to the test section The
orifice calibration curves (1 p 166 ) were used to obtain
a value of the orifice coefficient f8e where Q equals
the flow in cubic feet per minute at 68deg F and one atmosmiddot
phere pressure and te is the density of air at the exchanger
and e the density of the air at the flow orifice The
den sity of the air can be expressed by
e = 2 703 p (16)T
where T equals the temperature in OR and P equals the absoshy
lUte pressure i n lb1n2 Using the value of e Qfo from
26
the calibration charts as A and Eq (16) solving for Q
gives
( 17
This equation was used to calculate the flow rate for
each flow studied
The Reynolds number used i n the correlation of the
data was the equivalent Reynolds number defined as
Re)eb ~ d2 - dl)Uf ( 18 ) lL
where d1 is the outside diameter of the inner tube and d2
is the orifice diameter U is the flow velocity through the
annular orifice e is the density of the air and U- is t he
viscosity of the air This equation can be transformed t o
(Re) b = 1611 Q (19) e dl + d2
where d1 and d2 are in inches
The pressure drop data were calculated i nto a dimenshy
sionless pressure drop function cent where
d1 )22( ~ P)gc f av(d2 shycent 2 bull (20
M-
For air this equation reduces to
where d2 and d1 are in i nches D P is expressed i n inches of
2 95 specific gravity fluid and P av is expressed as lbft3
27
CHAPTER VII
ANALYSIS OF DATA
In analyzing the heat transfer data an attempt was
made to correlate it 1n terms of the dimensionless groups
(Nusselt number Prandtl number and Reynolds number) which
appear in Eqs (3) and (4) Consequently all of the av~
erage heat transfer coefficients hav were brought into
the form ( Nu)( Pr)~3 bull The Nusselt number was based on the
tube diameter and the thermal conductivity of the air at
the flowing temperature The tube diameter was used in the
Nusselt number because comparison could then be made with
previous experimental work on heat exchangers which have
commonly used the Nusselt number defined as in Eq (15)
From the standpoint of dimensional analysis this is
equivalent to considering the tube diameter as the characshy
teristic length so far as the heat transfer is concerned
The Prandtl number of the air was taken as 0 7 in all
cases
Variation of Heat Transfer Rate with Distance from the Baffle
Considerable variation was observed in the rate of
heat transfer in the vicinity of the baffle In order to
obtain the variation with respect to position the term
(Nu)(Pr)-13 was plotted versus the flow rate Q for each
position and orifice studied Cros s plots were then made
28
at constant flow rates in order to obtain the variation of
(Nu)(Pr) -13 with position The resulting cross plots are
shown 1n Fi gures 5 6 and 7 for the four orifices studshy
ied
About one inch upstream from the orifice the heat
transfer coefficient begins to rise rapidly and continues
to do so until it reaches a maximum some distance downshy
stream After the maximum point the heat transfer coef fi shy
cient decreased slowly The heat transfer rate was found
to reach a maximum at a different position downstream for
each orifice size These figures also show that for a
given orifice size the maximum heat transfer rate occurs
a pproximately at the same point for all flow rates The
position of the maximum point f or each or ifice size is
shown in Table II
The region immediately downstream from the orifice is
one of h i gh turbulence due to the jetting action of the air
flowing through the orifice As the air flows t hrough the
orifice the streamlines continue to converge for some dis shy
tance downstream The point of maximum heat transfer is
probably at the point where the streamlines be gin to diverge
and a boundary layer begins to build up on the tube Tle
decreasing heat transfer coefficient beyond the maximum
point indicated the formation of a boundary layer
Since the position of the maximum point is independent
of flow rate middot it is possible to correlate it with respect
_ ct 11shyz-
100
0 136 ORIFICE
(
I 0
I )
~ 00
~p 0
I 0
--r--- ~
ISCFIII
-_ OCFM
rbull abull
~ middot~ a-1 z-
12fORIFICE
100
200
100
0 0 UPITRAM ORIFICE DISTANCE CENTER
CFM
h I DOWNSTREAM
DISTANCE
FIGURE 5 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLpound
30
too
700
800
100 ~ f gtf
400
z ~
100
100
100
0
13fORIFICE
~ -~ -- ---
)
~
~
-
I ~ ~OCFM
I vI~-~ OCFM
J ---
Iamp CFM
I 0 I I UPSTREAM ORIFICE DOWNSTREAM DIITANOE GENTER DIITANCI
FIGURE 6 VARIATION OF HEAT TRANSFER RATE WITH DISllNCE FROM BAFFLE
--
--- --
31
100
100
700
100
_ 100
f 9- 400 z-
100
tOO
100
0 - I 0 I I I UHTRIAM OAtfiCI DOWIIITMAM
+ I tyl6 ORIFICE
v I
~~ ~CFM
I v ~CFMI
v v 7
~~ v ~ iOCFM
- ~~ I-shy1-shy ~ICFM
DIITMCI OINTIR DIITANCI
FIGURE 7 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLE
32
TABLE II
POSITION OF MAXIMUM HEAT TRANSFER
Position of Maximum Orifice Size Heat Transfer
(inches) (inches downstream)
1 364 050
1 216 100
1 316 125
1 516 200
33
to orifice size Figure 8 shows the effect of the orifice
size on the position and value of the maximum heat transfer
at a constant flow rate of 15 cubic feet per minute It
can be seen that the larger the orifice size the further
downstream the point of maximum heat transfer occurs
Also as the orifice size increased the rate of heat
transfer decreased for a given flow rate The broken line
indicates the variation of the point of maximum heat transshy
fer with position and size The position of the point of
maximum heat transfer rate downstream from the orifice was
correlated with orifice size by means of the dimensionless
groups (Lde) and (d1de) where L is the distance downshy
stream from the orifice where the maximum rate of heat
transfer occurs d1 is the outside diameter of the inner
tube and de is the equivalent diameter of the orifice
ie de = d2-dlbull
Figure 9 shows a plot of Ld 6 versus d1d6 for the
four orifice sizes studied The four points on this logshy
log plot are approximately in a straight line and the
equation of this line is
Lde = 0 44 d1de)028 (22)
Although the above relationship represents a correlashy
tion of dimensionless groups it is based upon only one
tube diameter and needs to be substantiated further by
studying other tube diameters and other orifice sizes
34
aoo
400
aoo ~
-~ middot-CLshyJ z
200 -
100
0
ORIFICE CENTER
l~
l
t
I J~
1pound~
I
0 I I~
AT 15 CFM
-
bull ~ 1~6~
~ v~
~
~--~~6
~~~ ___ v v V -_
~ o q
~ I 16
v
~
ogWNSTREANI STANCE
FIGURE 8 EFFECT OF ORIFICE SIZE ON POSITION AND VALUE OF MAXIMUM HEAT TRANSFER
35
50
loshy____ -~
~ ~ -shylltl-shy~ r0
2 10 30
FIGURE 9 CORRELATION OF THE POINT OF MAXIMUM HEAT TRANSFER WITH
ORIFICE SIZE
36
Correlation of Data at the Baffle
The heat transfer data were correlated by obtaining a
relationship between the group (Nu)(Pr)-13 and a
Reynolds number based on twice the clearance (d2 - d1
between the tube and the baffle It was found that the
most satisfactory correlation could be obtained when the
term - d1 was used as the length term in the Reynoldsd2
number
Figure 10 shows the variation of the heat transfer
rate at the center of the orifice e xpressed as a function
of Reynolds number and the orifice size This shows that
for a given Reynolds number the heat transfer at the center
of the orifice is greatest for the smallest orifice size
In order to obtain a general correlation of the data
shown i n F1gure 10 the effect of the dimensionless ratio
d1de was considered This ratio considers all of the
geometric factor s needed to describe the annular orifice
The thiclaless of the orifice plate is also a factor but
was constant i n this i nvestigation
The data for the heat transfer at the baffle center
are shown in Figure 11 in which (Nu)( Pr)-13 is plotted
versus (Re)ebd1 de) 0 55 This data on a log-log plot
lies on a straight line for (Re)eb( dld8 )0 55 greater
than 3 x 104 The equation for cor relating the heat
37
4XI~middot~-r~------~--~~------~
Icf t--to_+--_c-c-________ SYMBOL SIZE
0 1~4
6 ~~
9 ~~ -o ~
(Re)eb
FIGURE 10 RATE OF HEAT TRANSFER AT BAFFLE CENTER
38
500
0
4 0 lcf
~ ~
~ ~iC-
~ ~
~IL 0~ 0 SYMBOL SIZE-
p 0 1364-
r 6 1~16 -~ -
9 1~16 --o 1~16
I I
FIGURE II CORRELATION OF HEAT TRANSFER DATA AT BAFFLE CENTER
39
transfer at the center bullOf the a nnular orifice was found by
the method of least s quares to be
(Nu)( Pr)-1 3 = 0018 ( Re)ebO Bl( dlde)04~ (23)
3 x 104 ltRe)eb(a1de)055 lt 105)
Rate of Heat Transfer at the Point of Maximum Heat Transfer-The heat transfer rate at the point of maximum heat
transfer is plotted in Figure 12 to show the variation with
Reynolds number and the size of the orifice It is shown
gives the h1gh st heat transfer ~ate at its point of maxibull
that for a given Reynolds number the smallest orifice size yen il
mum heat transfer
The data ~or the maximum poi~t could be correlated by
plotting (Nu) Pr)-13 versus (Re)eb(d1de)06 This plot
is shown 1n Figure 13 and the resulting eurve shows that
(Nu(Pr)-13 is not a simple p0wer function of the Reynolds
number as was the case for heat transfer at the baffle
center The reason for this is probably because other
factors such as intensity and scala of turbulence should
be considered At the orifice center the streamlines of
the flowing stream are converging_ and thus the flow is
quite stable Downstream from the orifice is a region of
large eddy currents and probably large scale turbulence
These factors could con ceivably cause the results which
were obtained for the point of maximum heat transfer
40
If)
~middotshy Q_-I z_
10~~~--------r----~~--~--
SYMBOL SIZE
0 13$4
6 1~8
Q 13-18
-o 1~8
7)(104
(Re)eb
FIGURE 12 RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
41
Ia ~
0 I
c ~ ~ c v
~ ~lt w ~
17
~ b
v ~ ( SYMBOL SIZE
-~ 0 f-64 -v ~ 6 t211e
~ Q I~~~
-o - l~rs I I
FIGURE 13 CORRELATION OF HEAT TRANSFER DATA AT THE POINT OF MAXIMUM HEAT TRANSFER
4 2
Effect of Upstream Baffles on Heat Transfer at the Orifice Center
The heat transfer rate at the orifice center using the
single orifice in a test section is a pproximately 13 of the
value that was obtained by Lee (7) using a model heat exshy
changer with orifice baffles Lee investigated the cent r al
baffles of the heat exchanger and thus the coeff icients he
obtained would be affected by the presence of a number of
upstream baffles To determine the effect of upstream
baffles an additional l 516 inch baffle was placed four
inches upstream 1n the test section The resulting data are
shown in Figure 14 where (Nu)(Prmiddot)-13 is plotted versus
(Re) eb for the case of a single baffle 1n the test section
and also the case of an additional baffle placed four inches
upstream Comparison is made with the results obtained by
Lee middot(7) using a four-baffle and a ten-baffle model heat exshy
changer Good a greement is obtained with Lees work and the
results show the marked effect that upstream baffles have on
the downstream heat transfer rate The additional up tream
ba ffle caused sufficient turbulence 1n the test section to
i n crease the heat transfer rate nearly three-fold at the
center of the next baffle
Heat Transfer i n the Test Section with No Orifice
In order to check the accuracy 6f the equipment the
orifice baffle was removed and the heat transfer mea sured
with the probe in the empty test section The data were
43
~~BAFFLES
0 l BAFFLE -shy
ll_9 2 BAFFLES
V 4 BAFFLES-LEE
4 10 BAFFLES- LEE lJf ~
~rv ~~ ~ v flvv ~~
I ~ J ~ L v
0
v
( V
40 3XIo 7XIa
(Re)eb
FIGURE 14 EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER AT BAFFLE CENTER
44
compared with heat transfe r coefficients predicted by the
equations for annuli which are recommended in the litera shy9
ture The two equa~ ions u sed tor comparison were
(hfe)=0 023 (rltGr e (~~ur4 (~r45 (24)
which was presente~ by Wiegant (10)
and ( h ) (cnM~5(M~l o14 o 023 CPG k j Mij - (de GJMb )0 2 ( 2 5)
which was presented by McAdams (8 p 242) The comparshy
i son is s hown in Figure 15 lq (25) gives a value which
is low by about ten percent while Eq (24) g ives values
which are high by as much as twenty -five percent when comshy
pared with the experimental data The se equations are gembull
erally considered to give coefficients with an accuracy of
about twenty percent Therefore the present experimental
data are within the accuracy of these equations Also the
plot indicate s that for a Reynold s number greater than 2 x
104 the slope of the line is the same for the experimental
data as for the equations
Pressure Drop Data
The total pressure drop across the orifice was measured
as a function of the flow rate and the orifice size The
pressure drop was expressed as a d1mens1onleas quantity r)
which ie plCltted ver sus the Reynolds number in Figure 18
The pressure drop function cent correlates for all or1f1oe
45
200
100
s z
10 5XI10 10
0 EXPERIMENTAL
--McADAMS
-WIEGAND L
V
~ ~ ~
P ~ ~
LL~ L
v~
~
v v
v 1 ~ ~ v
v -gt
~
~ ~
~
6Xid
FIGURE 15 HEAT TRANSFER WITH NO BAFFLE
46
0 1~4 -~ a 6 t216
Q t316 lJ J
-0 as a )t
A LEE I -shy SULLIVAN 8
p
10bull
BERGELIN
I _ll I
I ~
i I
~middot
lo II
f fl
J j
~middot
A)101
1q
I Ill
1 I3 X 10ao1
FIGURE 16 ORIFICE PRESSURE DROP FUNCTION VS REYNOLDS NUMBER
47
sizes- The present data extends the range covered by preshy
vious workers and agrees well with their work The preshy
vious work of Lee () for a heat exchanger containing 10
orifice baffles and also the data of Su livan and Bergelin
(9) for pressure drop in a model heat exchanger with a
single baffle is shown 1n Figure 16 long with the present
results~ This figure may be used to predict the preseure
drop from the equivalent Reynolds number of the annular
orifice
The pressure drop between individual points 1n the
vicinity of the orifice and an upstream pressure tap wa s
measured to obtain a pressure drop profile As might be
expected 1n all cases the profiles showed a rapid decrea e
in static pressure immediately upstream from the orifice
There was however little or no recovery of the pressure
loss downstream The 1 364 inch orifice did show a maxishy
mum point in the pressure drop but this maximum occurred at
the orifice center and total recovery was reached about 12
inch downstream
Heat Transfer at the Baffle and Maximum Point as a Function of Pressure Drop
In order to compare the effect of the total pressure
drop on the heat transfer at the baffle and the point of
maximum heat transfer Figure 17 was plotted showing
(Nu)(Pr)-13 as a function of the total pressure drop This
shows that for a given pressure drop the largest orifice
48
1200
1000
~ a -sshyz-
100
60 100 700
AT MAXIMUM POINT I 15116 2 13116 3 1~6 4 1364
AT ORIFICE CENTER
60
1
v
r ~ ~ ~
5
~
8 7
13116
8
~
1364
v
~
e6
1~6
v
~~ v ~ ~ -~ ~
~
~ v
l
~
vamp
I ~ ~
~
v L ~
v
I-
5
k= ~~
~ ~ ~
--I
v ~
FIGURE 17 HEAT TRANSFER AT THE BAFFLE AND MAXIMUM POINT AS A FUNCTION OF
ORIFICE PRESSURE DROP
49
size has the greatest heat transfer coefficient This is
true at both the orifice center and at the point of maxishy
mum heat transfer
Another comparison can be made by plotting the heat
transfer coefficient and the pressure drop versus the orishy
fice size at a constant flow rate Figure 18 shows this
plot This graph shows that at a constant flow rate the
pressure drop as well as the heat transfer coefficient
increases as the size of the orifice is decreased In
choosing an orifice size for maximum efficiency 1t would
be necessary to know the pumping power available as well
as the heat transfer desired
70 I I 700
AT 15 CFM 60 ---
~ aug
50 ---
NV
40 ~
~ ~ ~
~ _
MAXIMUM POINT ---- --- ~
1-----t---~ _
~00Qj ~
~t--- ORIFICE CENTER 10 1100
1---~ n
u0 01 02 03 Q35
a ltl
de inches
FIGURE 18 VARIATION OF HEAT TRANSFER RATE AND PRESSURE DROP WITH ORIFICE SIZE AT A CONSTANT FLOW RATE
cn 0
51
CHAPTER VI II
SUMMARY OF RESULTS
This study revealed several significant facts about
the heat transfer in the vicinity of annular orifices
Probably the most important contribution was the presshy
entation of the heat transfer profiles in the vicinity ot
the annular orifice ~ r s shown that t~ local heat
transfer coeffieient re~ches a maximum at a point downshy
stream from the orifice The distance downstream at which
this maximum oocurs is t1ven by the equation
22
The heat transfer coefficients at the center of the
orifice were correlated and found to follow the equation
(Nu)(Pr)-13 = 00176 (Re)eb08l(d 1de) 0 middot4~ (23)
3 x 104 lt( Re) 9 b( d1d6 )055 ltlo5 )
The heat transfer at the point of maximum heat trans
fer for each orifice size was correlated and presented in
Figure 13 as a plot of (Nu)(Pr)-l3 versus (Re)eb(d1de) 06
No simple po-orer relationship exists between the terms
Intensity and scale of turbulence downstream from the orishy
fice are probably important factors which affect the heat
transfer
The large effect of an upstream orifice on the heat
transfer rate at the second orifice was demonstrated by the
52
study of two 1 516 inch orifices in the test section The
added turbulence at the center of the second orifice was
found to raise the heat transfer rate almost three times
over that obtained for a single baffle
The pressure profiles in the vicinity of the orifice
indicate that nearly all the pressure drop occurs at the
orifice center~ Total pressure drop data were correlated
by a pressure drop function cent as a function of the Reynolds
number and good agreement obtained with the results of other
workers
The pressure drop and heat transfer data were correbull
lated by plotting the heat transfer as a function of the
pressure drop for each orifice size It was shown that for
a given pressure drop the largest orifice size gives the
greatest heat transfer coefficient
As a final presentation it was shown that the pressure
drop and the heat transfer coefficient both i ncrease i n
value at a constant flow rate as the orifice size is de shy
creased This is important in choosing the optimum clearshy
ance for orifice baffles
53
CHAPTER IX
RECOMMENDATIONS
A great deal of work remains to be done in the field of
evaluating shellmiddotside heat transfer coefficients This
study included only one tube size and air was the only f luid
used It is recommended that further studies be conducted
using other fluids and tube sizes It will also be necessary
to study several baffle types
The adde d turbulence due to a s e cond baffle placed upbull
s t ream would suggest that the heat transfer coef ficients at
a certain position i n relation to a baffle would increase as
the flow progressed through the exchanger It is recomshy
mended that an extensive s t udy should be made between baffles
the full length of a model heat exchanger
It is further recommended that the pressure drop study
be continued to include other fluids tube sizes and baffle
arrangements
Effects of turbulence downstream from the baff le should
be studied by i n vestigations with hot-wire anemometer equipshy
ment to determi ne t urbulence scale and i ntensity
54
NOMENCLATURE
Area of heat transfer
Heat capacity of the fluid
Outside diameter of the tube
Orifice diameter
Equivalent diameter of the orifice (d2 - dl)
Inside diameter of the test section
Inside diameter of the tube
Gravitational constant
G Mass velocity
h Local heat transfer coefficient
Coefficient of heat transfer from surface to fluid
i Direct current amperes
k Thermal conductivity of the fluid
L Distance downstream of the point of maximum heat transfer
p Absolute pressure
L P Total pressure drop across the orifice
Q Flow in cubio feet per minute at 1 atmosphere and 680 F
q Heat transferred
Thermal energy conducted into the sensing probe
Thermal energy radiated from the resistance ribbon
Resistivity of the resistance ribbon
s Length of the resistance ribbon
T Temperature oR
55
t Temperature of the resistance ribbon deg F
ta Temperature of the bulk stream oF
tw Wall temperature of the tube OF
U Veloc ity of the fluid
w Width of the resistance ribbon
z Thickness of the resistance ribbon
eeuro Density of the fluid in the test section
Density of the fluid at the flow orificef 0
AL Viscosity of the fluid
E9 Angle measured around the tube
Dimensionl ess groups
(Nu) Nusselt number hd1k
(Pr Prandtl number C~k
(Re)eb Equivalent Reynolds number at the baffle (d2 - d1 )uejt-Lshy
(Re)e Equivalent Reynolds number in the test section ( d 8 - d 1 )U fu
cent Orifice pressure drop function 2(~P ) gc~av(d2 - d1) 2
Al
56
BI BLIOGRAPHY
1 Ambrose Tommy W Local shell-side heat transfer coefshyficients in baffled tubular heat exchanger PhD thesis Corvallis Oregon State College 1957 183 numb leaves
2 Bell K J and o P Bergelin Flow through annular orif ices Transactions of the American Society of Mechanical Engineers 70593-601 1957
3 Colburn Allan P A method of correlating forced con shyvection heat transfer data and a comparison with fluid friction Transactions of the American Institute of Chemical Engineers 24 174-210 1933
4 Dittus F w and L M K Boelter Heat transfer 1n automobile radiators of the tubular type University of California Publications in Engineering 2443-461 1930
5 Gurushankariah M s Local shell-side heat transfer coefficients in the vicinity of baffles in tubular heat exchangers Masters thesis Corvallis Ore gon State Colle ge 1958 97 numb leaves
6 Knudsen James G and Donald L Katz Fluid dynamics and heat transfer New York McGraw-Hill 1958 576 p
7 Lee Kyu Sung Local shell-side heat transfer coeffishycients and pressure drop in a tubular heat exchanger with orifice baffles Masters thesis Corvallis Oregon State College 1959 118 numb leaves
8 McAdams William H Heat transmission 3d ed New York McGra ~-Hill 1954 532 p
9 Sullivan F W and 0 P Bergelin Heat transfer and fluid friction in a shell-andbulltube exchanger with a single baffle Chemica l Engineer ing Progress Symposium Series 52 ( 18) 85-94 1956
10 Wiegand J H Discussion on annular heat transfer coshyef f icients for turbulent flow Transactions of American Institut e of Chemical Eng i n eers 41147-153 1945
AP PENDIX
57
TABLE III
CALCULATED HEAT TRANSFER DATA
Baffle Hole Diameter Run No (inches)
1 - 59 1 364
60 - 102 1 216
103 - 138 1 316
139 - 206 1 516
207 - 212 No orifice
213 - 218 2nd - 1 516
TABLE III
CALCULATED HEAT TRANSFER DATA
Local Heat Transfer Coefficients Run
T0 bull Po s ition CFM hr h2 h3 h4 hs he ~ hav Nuav
1 c 1026 10 59 1476 16 09 1559 1510 1435 1203 1518 8511 2 1290 1369 1738 1878 18 05 1755 1689 1515 1773 9964 3 1416 1636 198 1 2068 1977 1924 1845 1715 1959 11030 4 1627 1991 2301 2382 2268 2194 20 ~98 1929 2249 12664 5 1776 2252 2669 2863 2713 2517 2338 2126 2620 14759 6 l2ttD 1109 2311 3317 3386 3373 3387 3394 3071 3371 18888 7 1258 3089 4583 4866 4683 4701 4643 4194 4695 26301 8 1433 38 8 5 55 83 5791 5495 5430 5436 5008 5547 31192 9 1681 4992 7378 7649 6980 6864 6870 64 28 7148 40180
10 1 D 1102 2371 3332 3511 3356 3342 3427 3102 3394 19012 11 1308 3218 4379 45 24 42 53 4255 4373 3965 43 57 24446 12 14 64 38 58 5146 5142 4839 4787 4903 4597 4963 278 79 13 1706 5218 6664 6269 58 81 5884 6237 5973 61 87 34718 14 15
1 l2D 1115 1275
2131 2661
2955 3638
2972 3720
2941 3675
2913 3576
28 22 34 74
2613 3278
2921 36 17
163 09 20246
16 1498 34 87 4644 4503 4441 4371 4343 4194 4460 25010 17 1695 4449 5743 5324 5222 5154 5157 5015 5320 298 97 18 2D 1049 1715 23 90 2550 2610 2656 2624 2208 2566 14363 19 1241 2117 2964 3145 3218 3221 3203 2759 3150 17757 20 1532 28 67 3936 4100 4188 4201 4167 3676 4118 23224 21 1674 3459 4508 4598 4746 4795 4792 4299 4688 26337 22 lU 1074 253 340 380 3 86 388 377 354 374 2097 23 1287 292 392 433 440 441 429 406 427 2394 24 1508 322 439 492 498 499 487 461 48 3 2713 25 18 07 3 38 464 519 5 24 520 499 463 5 05 28 40
~~ (]I agt
TABLE III Continued
Run No Position CFM h 1 h2 ~3 h4 h5 h6 ~ h
av Nu
av 26 c 1029 1171 1491 1589 15 28 1 4 62 1377 1293 1489 83 44 27 1266 1395 1746 1853 18 02 1685 1556 1453 1728 9704 28 1430 1637 2037 2175 2060 1909 1735 1591 1983 11159 29 1729 1982 24 96 2751 2507 2268 2030 1886 2410 13579 30 12D 1054 2934 4041 4321 4326 4423 4359 3706 4298 24160 31 1294 3385 4 8 26 52 42 5326 5450 5277 4566 52 24 293 50 32 1431 3784 5347 5721 57 bull75 58 44 5700 5084 5677 31870 33 1770 52 75 7 7 33 87 35 9005 9007 8267 7059 85 49 48050 34 lD 1058 3235 4401 4444 3877 3496 3451 3294 3934 21973 35 1263 38 98 5484 5330 4347 3964 3981 3987 4621 25823 36 18 36 6701 89 17 7855 6369 5597 5769 6283 69 01 38718 37 1 12D 1029 2404 31 8 2 3333 3459 3624 3577 3045 3435 19264 38 1315 3182 4033 4162 4310 4496 4502 4015 4301 24142 39 1426 3628 4389 4510 4573 4760 4804 43 8 5 4607 25678 40 1757 4547 5559 5(35 5931 6282 63 70 6060 5975 33471 41 2 11D 1080 2034 28 38 3155 3144 3145 2966 2540 3050 17027 42 1305 2650 3 4 87 3aoz 3595 3751 3595 3153 36 46 20405 43 1434 3167 39 07 4156 4371 4320 4126 3709 4176 23395 44 1804 4096 4 9 66 5691 5714 5586 53 15 48 65 5454 30582 45 12U 1088 409 516 557 564 5 60 535 513 5 46 30 67 46 1318 470 579 6 22 631 6 17 5 97 579 6 09 3422 47 14 13 540 640 676 6 86 681 6 60 6 54 6 69 3754 48 1773 641 740 774 782 7 69 749 746 763 42 87 49 l 11 U 1054 270 356 391 397 393 3 71 346 38 2 2133 50 1240 303 399 446 449 447 4 21 398 432 2420 51 1419 361 476 522 530 528 507 467 493 2760 52 1 1(2U 1032 236 311 342 347 344 325 301 334 18 78 53 1314 270 366 403 407 408 386 351 394 2217
(Tt tO
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ h av Nu av
54 1448 301 408 447 454 452 431 403 438 24 61 55 1782 353 494 548 544 415 529 531 506 2843 56 2U 10 61 220 287 316 320 322 303 268 310 1735 57 1216 249 335 370 377 378 353 307 363 2044 58 1322 263 356 394 398 399 374 327 384 2159 59 1639 310 433 478 481 482 452 393 465 2617
60 1D 10 68 2011 2536 2657 2681 2694 2560 15 62 2625 14938 61 1399 2520 3239 3369 3371 33r82 32 39 1946 3320 18968 62 1669 2781 3655 3820 38 76 3883 3738 2355 3794 21712 63 1959 3524 42 37 4399 4438 4497 4417 3047 4397 25156 64 2295 4426 5288 5396 5372 5240 5410 3369 5341 30680 65 2636 5490 6531 6662 6565 6379 6820 4249 6591 37938 66 3390 7869 9538 9462 9387 8924 10508 62 91 9564 59601 67 1U 1190 352 368 401 413 407 395 293 397 2256 68 1559 397 422 462 475 471 456 331 4 57 2603 69 1904 434 465 5 13 529 528 504 358 508 2901 70 2211 493 526 573 5 92 588 564 4 15 569 3257 71 2289 569 587 6 30 649 6 61 6 49 460 635 36 44 72 2727 637 6 60 7 09 733 751 743 521 719 4140 73 3210 728 755 8 15 8 43 8 62 8 54 616 826 4765 74 2nD 1210 181 2256 2393 2399 2333 2206 1325 2317 13158 75 1420 2340 2752 2899 2913 2850 2728 1701 2828 16121 76 1692 2853 3306 3452 3471 3379 3217 2134 3365 19217 77 1894 3102 3588 3713 3736 3670 3557 2455 3653 20892 78 2301 3682 4259 4433 4467 43 83 4289 2892 4366 250 30 79 2621 4117 4828 5017 5012 5030 5109 3071 4999 28785
m 0
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ hav Nuav
80 3230 5158 6006 62 13 61 18 6134 6695 4094 6233 359 87 8 1 12nD 1155 15 27 1854 2028 2064 20 85 1987 1164 1968 118 31 82 1689 2046 24 8 2 2688 2739 2760 2658 1749 2665 152 73 83 1244 2088 2317 2339 2345 2373 2381 1487 2351 13432 84 2100 3211 3539 34 21 3462 3512 3696 2575 3526 20284 85 2292 3 5 05 3761 3648 36 25 36 79 3957 2933 3734 21517 86 2907 4420 48 22 4679 46 04 4705 5206 3792 48 03 27741 87 33 80 59 35 69 38 7404 77 10 7 8 36 7 0 86 5190 7394 427 44 88 1 12D 1 4 27 2 4 58 28 31 3037 3021 2987 2927 18 57 2 9 61 16913 89 18 75 34 75 3 9 87 4230 4255 4317 4337 2734 4225 24258 90 22 59 4221 4796 5046 5052 51 01 5389 3491 5077 29206 91 2682 4978 5664 5943 5966 6054 6573 408 1 60 40 34795 92 3417 63 16 71 02 7 3 93 7385 75 40 8 6 95 51 45 7623 44017 93 c 1 5 17 1240 1305 1399 1467 1479 1429 9 26 1423 8251 94 20 34 1554 1623 1720 18 21 18 53 18 72 1215 1778 10229 95 2 3 48 1795 1843 198 5 2097 2171 2274 1540 2074 11947 96 2716 2028 2048 22 01 2 3 44 2444 2661 18 90 2340 13505 97 3247 2410 2375 2663 2778 2949 3298 2378 2793 1615 98 11 35 967 1040 1124 1186 1200 1142 728 1138 6496 99 14 06 1135 1220 1318 1384 1403 1 3 61 8 77 1336 7656
100 2311 1 8 54 18 78 1980 20 90 2136 2227 1653 2062 118 31 10 1 2666 2085 2094 2227 2 3 62 2438 2626 1902 2349 13508 102 3392 2635 2582 28 01 3026 3141 3529 2567 3016 17390
103 1 U 1235 349 395 434 436 4 28 411 286 423 2416 104 20 10 434 5 02 559 577 569 5 37 345 552 3177 105 28 14 538 626 685 711 7 21 682 424 6 8 6 3966
Q) j-J
TABIE III Continued
Run No Position CFM h1 h2 h3 h4 h5 hu h7 hav Nuav
106 3492 614 7 1 6 7 84 8 13 8 33 7 85 4 88 7 87 4562 107 4395 7 86 894 964 996 1005 9 64 640 9 65 56 06 108 50 75 9 11 10 22 1081 1112 1125 1085 7 24 1085 63 16 109 G 1344 9 22 1042 1120 1 1 46 1173 1131 7 04 1120 63 87 110 1936 1162 1340 1442 1474 1509 14 7 3 9 09 1441 82 77 111 2846 1631 1797 1902 1966 2027 2079 1342 19 2 3 11108 112 3484 207e 2144 2236 2307 2385 2574 1694 2268 13138 113 4066 24 65 24 42 2535 2648 2757 31 71 2178 2 5 96 15078 114 50 12 3059 2916 30 1 5 3176 3312 4059 2849 3105 180 46 115 1D 1362 2268 26 13 2613 26 35 2605 2503 15 46 2617 14934 116 1958 2993 3580 3580 3586 3539 3 5 02 2144 3571 20492 117 2812 4430 50 32 4913 4 9 86 4991 5196 3088 4981 287 66 118 3432 58 16 62 13 6067 61 18 60 66 6698 4143 61 16 354 16 119 40 22 71 71 7 4 62 7369 7419 7329 82 74 51 8 1 7395 42909 120 5026 105 95 11456 115 81 11574 11548 14010 80 91 11540 671 15 121 2D 1244 18 57 2277 2363 2305 2210 2107 1466 2289 13038 122 1960 2622 3240 3388 33 23 3226 31 40 2)99 3294 18919 123 2817 3762 45 87 4739 46 56 45 14 4 6 47 30 15 4624 26689 124 3491 50 22 5723 58 53 57 44 5542 60 18 3871 57 16 330 73 125 4096 61 29 68 16 69 79 6805 65 90 74 79 4677 67 98 39400 126 5037 82 27 94 60 95 69 93 57 9023 11324 65 05 93 52 542 83 127 12D 1278 14 70 1 6 48 1652 1638 1 6 34 1641 9 73 1 6 43 9369 128 1947 19 63 2155 2149 2151 2131 2190 1347 2147 12342 129 2769 2615 2791 2773 28 52 2716 2954 18 96 2783 1 60 82 130 3439 3208 3265 3239 3593 3133 3624 2515 3308 19174 131 4103 3637 35 88 3577 4077 3459 42 66 3138 3676 21343 132 49 78 45 82 44 60 44 8 1 55 17 43 25 5749 4227 4700 27288
Q) tlgt
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
133 1 12D 1299 2094 2507 2622 2625 2567 2489 1465 2578 14736 134 1973 29 56 3505 3772 3790 3718 3718 2115 3700 21290 135 2788 3941 4727 5069 5099 5 0 07 5231 2984 4976 28781 136 3473 5155 59 81 6308 6339 62 39 68 96 4204 6217 36052 137 4118 6135 71 8 6 7662 7731 76 91 87 16 49 8 5 7568 43985 138 4973 7765 94 75 10396 10861 10694 13646 66 64 10357 602 25
139 1ttn 1253 1242 1493 1460 1442 1431 1424 8 84 1457 83 01 140 2366 1942 2150 1961 1910 1897 19 62 1206 1980 11400 141 3461 3007 2957 2562 2513 2606 3143 18 51 2660 15400 142 4325 3942 3571 3060 2999 3198 4248 2631 3207 18618 143 5677 508 6 4359 39 88 3800 42 29 57 78 36 26 4094 23824 144 67 59 64 55 5330 4988 47 25 5494 2517 48 09 5134 29906 145 84 08 9326 72 26 7726 85 56 9172 12319 7733 8170 47626 146 86 54 9831 7582 818 9 94 90 9869 13116 78 97 8783 512 96 147 7376 7335 58 7 6 5941 5796 68 29 81 65 5954 6111 35662 148 2 11 D 4254 4106 48 02 4994 5038 5042 56 78 3419 4969 28881 149 5708 5487 6253 6466 6524 6527 78 63 45 8 2 64 43 37566 150 69 7 8 7983 9440 9848 98 34 97 32 13249 6701 9714 566 59 151 1254 1434 18 53 1947 1915 1850 1760 1186 1891 10772 152 2713 2696 3175 32 94 3288 3237 3288 20 44 3249 18728 153 87 30 118 07 14733 15758 15504 15305 26297 9617 15325 892 71 154 5811 5278 6543 6861 69 30 69 82 7 8 74 4478 68 29 39531 155 4246 3780 4736 4975 49 66 4936 5162 3113 4903 28301 156 (v 1270 8 15 935 959 966 9 51 9 23 6 35 953 5430 157 2714 1164 1390 1427 1447 1454 1455 9 08 1430 8242 158 4310 1655 18 96 1942 1988 2002 2111 1305 1957 11349
(j) ~
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 fry hav Nuav
159 6012 2208 2400 2450 2513 2548 28 20 18 00 2478 14416 160 7279 2696 2881 2927 2989 3081 3599 2340 2970 17326 161 86 90 3257 3360 3 3 76 34 26 3558 4455 2943 3430 2000 162 12D 4368 2209 2600 2558 2518 2466 2774 1753 2536 14713 163 5833 2730 3092 3028 2974 2913 3501 2287 3002 174 78 164 7643 3320 3681 3630 3651 3530 4623 3181 3623 21116 165 87 39 3920 4303 4300 4708 4178 61 60 3937 4372 25456 166 1268 962 1203 1205 1186 1118 1084 725 1178 6693 167 2678 14 67 1785 1779 1752 1698 1726 10 70 1754 88 49 168 1 12D 12 83 936 1217 1414 1397 1239 1190 7 65 1317 7484 169 2729 2502 2930 2914 2934 2956 2979 17 52 2934 16866 170 4345 3884 4357 4283 4318 4421 4836 28 59 4345 25151 171 6036 5546 5858 5764 5791 6028 7129 4184 5860 34045 172 6578 7167 7769 7907 79 82 8263 10492 5915 7980 46437 173 87 84 10237 112 23 120 26 12727 12968 185 19 85 98 12236 71103 174 1278 1344 1803 18 72 1835 1790 1712 1063 1825 10355 175 2711 2328 2972 2932 2893 28 78 2863 1667 2919 167 51 176 4351 3934 4414 4353 4281 4321 4654 28 63 4342 25088 177 5994 5076 5824 5838 5818 59 29 6914 4205 5852 33885 178 1 11 U 1223 388 432 465 464 449 435 338 453 2585 179 2351 521 602 6 22 675 6 57 619 436 639 3687 180 34 48 6 05 1725 803 8 27 8 11 760 518 792 4593 181 4513 718 850 934 9 68 9 57 8 99 609 9 27 5386 18 2 5714 8 32 981 1060 1102 11 06 1034 6 59 1062 61 82 183 6997 1025 1182 1258 1295 1309 1234 8 18 1261 7 3 44 184 8709 1295 1487 1 5 42 1594 1626 1612 1156 1562 9080
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
185 2 12D 4249 3560 4400 4670 4791 4695 47 81 2931 4639 268 37 186 5737 4926 58 54 61 92 6248 62 38 67 78 4134 6131 35590 187 7432 6390 7726 83 46 85 44 86 34 10371 5658 8313 48310 188 8723 7718 107 88 11933 12099 13046 186 22 79 39 119 67 69505 189 1 4 35 1340 1735 18 57 18 52 17 81 1711 1144 18 06 10256 190 2718 2399 3023 3187 3207 3138 30 53 1931 3139 18025 191 7 5 07 6189 80 11 9200 9427 9703 11364 5720 9085 527 38 192 8544 78 42 10666 125 42 13312 13775 178 20 6976 125 74 729 86 193 1287 1417 16 97 18 7 18 69 18 08 1720 1046 1800 10223 194 27 17 2450 2940 3187 3214 3157 3054 1749 3125 17954 195 42 53 3560 4222 45 90 4679 46 63 4743 2741 4539 26247 196 6068 48 69 57 79 6335 65 8 6 66 04 7172 4338 63 26 366 78 197 7389 58 86 72 8 6 82 23 8584 8936 10658 50 60 8257 4798 6 198 86 88 78 91 100 27 120 56 130 29 14299 190 81 6492 12353 71850 199 5864 4694 5 6 67 61 94 6419 65 48 7192 3950 6207 360 14 200 2 D 4177 38 36 4547 48 09 4775 4628 5006 2715 46 90 261 30 201 5712 5170 62 39 66 38 6599 6604 7518 4167 65 20 378 00 202 73 63 7201 8986 98 43 9733 9914 13353 6219 9619 55810 203 8604 10043 13118 148 41 150 42 158 66 25206 82 5 3 14717 85290 204 12 68 1506 18 41 1971 1966 1868 1799 11 42 1913 10880 205 2659 2571 3127 3276 32 50 3130 3069 18 80 3196 18 350 206 39 80 36 76 4347 4573 45~67 4473 46 34 28 37 4490 25910
o 207 Orifice 11496 10 64 1360 15 39 1 5 80 1 6 15 1496 8 58 15 24 88 83 208 9433 8 95 11 78 13 26 1394 1386 1263 727 1346 78 48 209 7387 746 9 77 1123 1184 1159 1048 6 11 1111 64 74 210 52 36 566 7 66 900 934 909 8 21 499 8 27 48 02
0) CJ1
TABLE III Continued
Run No Position CFM h 1 h2 hs h4 h5 h6 h7 hav Nuav
211 212
3309 1293
414 257
563 3 19
6 68 3 57
6 91 3 37
6 72 351
7 37 337
38 4 2 46
4 40 341
3748 1942
213 214 215 216 217 218
c of 2nd 1 516 1235
1919 2712 3320 4153 4704
1532 2447 35 46 4312 5567 74 29
2 1 87 3312 4225 52 86 6902 8 6 50
2360 3555 4340 56 12 7 0 49 8 9 40
2409 3598 4 8 85 5718 7713 9593
2347 2101 35 33 3453 48 00 49 62 5562 59 86 72~6 7 8 79 93 76 11237
1243 20 64 3054 4 2 8 1 5114 6983
2326 35 00 4638 5545 7225 91 40
132 13 200 27 26672 31968 41711 52811
bull
67
TABLE IV
PRESSURE PROFILE DATA
Baffle Flow Qpening Rate ~p
(Inches) Position (CFM) (Inches 295 S G Fluid)
1 364 l2 11 U 1012 0 254 1248 0197 1493 0 141 1718 0112
c 1000 9 80 1210 1710 1436 28 75 1746 4320 1011 1080 1277 2050 1393 3020 1 6 28 4450
12D 1011 9 75 1236 1520 1450 2510 1603 3450
1 D 1011 975 1256 1700 1480 2690 158 1 4070
1 12D 1010 950 1259 1750 1462 2650 1631 3710
2 11 D 1124 1315 1360 2130 1505 2850 1689 4125
1 216 12U 1294 045 1949 0324 2374 0282 2704 0225 3367 0169
c 1326 265 18 81 5 90 2313 990 2731 1480 3439 2660
12D 1272 2 49 1957 661
68
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Pos ition (CPM) Inches 2 95 S G Fluid)
2559 1275 3033 1940 3639 3025
1 216 1nD 1257 242 16 96 476 2117 8 05 2561 1280 2990 1895 3431 26 bull00
1 316 12U 1309 0 479 2004 0422 28 28 0 352 3526 0281 42 28 0225 5199 0225
c 1308 1 43 1998 272 28 14 5 10 3478 795 4248 1235 5048 1885
l2D 1286 140 2005 3 45 2831 725 3495 1180 4194 1805 5046 2945
1 11D 1322 150 2039 352 2841 735 43 77 1980 5378 3440
1 516 12U 1278 0493 2732 0493 4315 0408 5744 0352 7494 0352 8932 0422
c 1300 0 506 2731 1985 4310 348 6080 6 45
69
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Position (CPM) (Inches 295 SG Fluid)
7607 1090 8830 1585
l2D 1343 0549 2738 225 4566 583 6112 1195 7536 2055 9043 3415
1 516 1uD 1249 0464 2713 224 4155 579 5620 1150 7428 2115 90 70 3405
1 12D 1301 0493 2735 220 4501 616 61 50 1235 7440 2065 8862 3445
2D 1265 0 478 2750 226 4366 594 6578 1270 7678 2240 8945 5280
2 12D 1295 0493 2725 222 4293 600 5807 1120 7568 2200 9070 3615
TABLE V
RATE OF HEAT TR AN SFER Ar THE BAFFL~~ CID-TT ER
Orifice Size
(Inches)
Flow Rate
( CFM)
Re d e G tU
R~) 055 Nuav NuPr-l3
1 364 10 26 12 90
8 075 10015
43400 54 600
85 11 99 64
95 83 112 19
1416 11 140 59 900 110 30 124 20 16 27 12 800 68 900 126 64 142 60 17 29 13 610 73 200 135 79 152 90 17 76 13980 75 200 147 59 166 19
1 216 11 35 14 06
8 600 10 660
27000 33500
6 4 96 76 56
73 14 8 6 12
1517 11500 36100 82 51 9291 20 34 15400 48400 10229 115 18 23 11 17500 55000 118 31 13322 2348 17 800 55900 11947 13452 2666 20 200 63400 13508 15210 27 16 20 600 64700 135 05 152 07 32 47 24600 77200 161 57 18 193 3392 25 700 80700 17390 195 8 1
1 316 1344 19 36
9898 14 260
24800 35 700
63 8 7 8 2 77
71 92 93 20
28 46 20 9 60 52 500 111 08 125 08 34 84 25 660 64200 131 38 147 93 40 66 50 12
29900 36900
74800 92400
150 78 18046
169 78 203 20
~ 0
TABLE V Continued
Orifice Flow Re Size Rate d e G R~rmiddot55 NuPr-13(Inches) (CFM) U Nuav
1 516 12 70 8 847 16800 54 ~0 61 14 2 14 18 900 35800 82 42 92 80 43 10 30 000 56900 11349 127 79 60 12 41900 79400 14416 16232 7279 50700 96100 17326 19509 86 90 60540 115000 20098 22529
TABLE VI
RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
Orifice Size
(Inches)
1 364
1 216
1 316
Flow Rate
(CFM)
1054 1294 1431 1681 1770
1068 1399 1669 1959 2295 2636 3390
1299 1973 2788 34 73 4118 4973
Re deG Mshy
8 300 9870
11260 13200 13 930
8100 10600 12650 14850 17400 19980 25700
9 570 14500 20500 25600 30300 36600
R~r-6 51900 61700 70500 82 500 87 100
28200 36900 44000 51700 60 600 69500 89400
26100 39600 56000 69900 82700 99 900
Nuav
2416 293 5 3187 4018 4805
14938 18968 21712 25156 30680 37938 59601
14736 21290 28781 36052 439 85 60225
Uu Pr-1 3
27204 33050 3589 4524 541 0
16820 21358 24448 28326 34546 427 18 67111
16593 23973 32407 40595 495 1 678 13
TABLE VI Continued
Orifice Flow Re Size Rate deG R~rmiddot6 NuPr-13(Inches) (CFM ) M- Nuav
1 516 1268 88 30 17700 108 8 1225 2689 18700 37400 1835 2066 3980 27700 55700 2591 2917 4177 29100 58 500 2713 3055 5712 39800 80000 378 0 425 6 7362 51300 103000 5581 6284 8 604 59 900 120000 8529 9604
74
TABLE VII
EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER
l 516 Inch Orifice
Center ot 2nd Baffle 4 Downstream
Plow Rate (CFM)
1235 1919 2712 3320 4153 4704
Flow Rate (CFM)
1270 2714 4310 6012 7279 8690
(Re)eb -8600 1321
13400 2003 18900 2687 23100 5197 28900 4171 32800 5281
Center ot Single Battle
-8847 543
18900 824 30000 1135 41900 1442 50700 1733 60540 2001
(Nu)(Pr)-l3
1487 2255 3003 3600 4697 5946
(Nu)(Pr)-13
611 928
1278 1623 1951 2253
75
ABLE VIII
HEAT TRANSFER IN THE TEST SECTION WITHOUT ORIFICE
CFM Ute) 0b h Nu
1293 5-951 3 41 1942
33 09 15251 649 3746
5236 24193 827 4802
7387 34001 1111 6474
9433 43419 1346 7848
11496 52-914 1524 8883
76
TABLE IX
PRESSURE DROP FUNCTION
Orltlee Size Flow Rate incbea ~CFM (Re)eb X 10bull8
1 364 1011 7957 0808 1256 9885 1468 1480 11648 2765 1581 12443 4160 1689 1_3293 4 020
1 216 1257 9530 1327 1696 12858 2663 2117 16049 4615 2561 19415 7581 2990 22668 11560 3431 26011 16440
l 316 1322 9736 1819 2039 15016 4332 2845 20952 9275 3495 25739 15300 4377 32014 26800 5378 39607 50100
1 516 1011 7 957 oaos 1256 9885 1469 1480 11646 2765 1581 12443 4160 1689 13293 4020
77
TABLE X
EXPERIMENTAL DATA
Baffle Hole Diameter Run No
1 - 59
60 - 102
103 - 138
139 - 206
207 - 212
213 - 218
(Inches)
1 364
1 216
1 316
1 516
No Baffle
2nd - 1 516
TABLE X
EXPERIMENTAL DATA
Run Thermocouple Reading s (mv) No Position CFM I tc1 tc2 tc3 tc4 t c 5 tc6 tc7 tcair
1 c 1026 530 2055 1825 1768 1782 1802 1837 1965 1198 2 1290 612 2059 18 65 1809 18 32 1851 1880 1965 1160 3 1416 714 2151 1970 1931 1965 1988 2026 209 5 1130 4 1627 8 21 2235 2084 2 049 2093 2126 2173 2266 1130 5 1776 865 2203 2033 1970 2015 2084 2159 2 264 1121 6 12D 1109 542 1636 1507 1499 1499 1498 1498 1528 1218 7 1258 651 1670 1522 1503 1513 1513 1516 1548 1221 8 1433 750 1625 1480 1467 148 3 1487 1487 1516 1153 9 168 1 8 73 1656 1494 148 1 1511 1517 1517 1543 1159
10 1rtD 1102 485 1545 1450 1437 1446 1447 1442 1466 1220 11 13 08 6 10 1571 1470 1460 1476 1476 1469 1498 1194 12 1464 730 1 623 1509 1508 1528 1 5 32 1524 1548 1173 13 11 06 8 71 1663 1559 158 1 1606 160 6 1 583 1601 1190 14 1 12D 1115 520 1698 1579 1575 1 577 1580 1590 1615 1280 15 1275 6 10 1692 1567 1558 1 561 1570 1580 1601 1234 16 1498 770 1760 1619 1630 1 635 1642 1645 1661 1204 17 1695 912 1775 1635 1670 1689 1686 168 6 1701 1165 18 2D 1049 510 1736 15~2 1567 1558 1 553 1558 1620 1236 19 12 41 610 1655 1517 149 1 148 1 148 1 148 4 1546 1108 20 1 5 32 7 35 1720 1550 1530 1520 1519 1523 158 0 1104 21 16 74 8 8 0 1900 1 727 1714 1696 1691 1692 1753 1169 22 1U 1074 38 5 3 324 2740 2534 2478 2 465 2503 258 0 1210 23 1287 4 35 3510 2 870 2682 2 610 2599 2638 27 1 9 1190 24 1 5 08 470 3 618 2920 2690 2 637 2627 2 664 2747 1177 25 18 07 525 4 088 3235 2962 2905 2910 2988 3130 1169
z ())
TABLE X Continued
Run No Position CFM I tc1 tc 2
Thermocouple Readings te3 tc4 tc5
(mv) tc6 tc7 tcair
26 c 10~29 6 32 2340 2~092 2032 2060 2~097 2152 2~213 1211 27 12 66 679 2270 2 047 1993 2013 2069 2142 2 210 1 182 28 1430 723 2336 2097 2033 2080 2153 2~255 2 356 1 138 29 1729 8 52 2318 2070 1980 2061 2158 2279 2367 1121 30 12D 1054 570 1520 1 4 20 1402 1400 1396 1400 1 443 1159 31 1294 6 69 1599 1469 1444 1439 1433 1 442 1485 1168 32 1430 7 88 1720 1562 1536 1532 1528 1537 158 0 118 5 33 1770 8 81 1641 1488 1450 1~441 1 441 1_466 1518 1 163 34 1D 1058 548 1579 1498 1495 1526 1553 1_557 1 571 1 276 35 1263 640 1609 1509 1515 1570 1599 1598 1 598 1 266 36 18 36 8 47 1538 1452 1483 1553 1602 1 590 1 558 1195 37 1 12D 1029 5 41 1 578 1499 148 4 1473 1461 1465 1-512 1200 38 1315 6 30 159 1 1504 1493 1482 1470 1470 1505 118 5 39 1 4 26 743 1765 168 1666 1660 1645 1642 1678 1270 40 1757 8 54 1744 1648 1634 1620 1598 1 593 - 1612 1223 41 2D 1080 5 30 1734 1604 1570 1 570 1570 1 588 1 640 128 1 42 1305 6 40 1744 1622 1589 1 608 1593 1 609 1 661 1240 43 1434 750 1798 1687 1658 1 636 -1641 1 661 1 711 1_220 44 18 04 8 41 1 764 1666 1607 1605 1614 1 635 1 675 1205 45 12nu 1088 415 2614 2295 2195 2 169 2174 2217 2256 1171 46 1318 477 2805 2477 2371 2342 2364 2 401 2 438 1 163 47 1413 5 28 2930 2 646 2 555 2 526 2532 2570 2 577 1 199 48 1773 550 2740 2518 2450 2431 2448 2 479 2 480 1 170 49 1 11 U 1054 380 3175 2670 2505 2 461 2467 2 534 2 621 1 258 50 1240 420 3268 2738 2 546 2 510 2 508 258 2 2 649 1214 51 1419 451 3364 2B07 2 632 2590 2 590 2 651 2773 1 215 52 1 12U 1032 360 3 165 2 629 2 450 2402 2403 2 473 2 bull568 1 163
--I lt0
TABLE X Continued
Run No Position CFM I tc1 tc2
lhermocoup1e Reading s tc3 tc4 t c 5
(mv) tc6 tc7 tc a ir
5 3 1314 38 9 3178 2592 2411 2367 2361 2432 2555 1140 54 1448 403 3095 2544 238 1 2336 2336 2390 2476 1158 55 178 2 427 3006 2434 2286 2253 255 3 2299 2397 1154 56 2 11U 1061 360 3369 2814 2619 2567 2560 2650 2833 1220 57 1216 360 3044 2512 2338 2290 2288 2374 2566 1150 58 1322 387 3196 2614 2425 2383 2382 2472 2670 1138 59 1639 403 3020 2438 2272 2238 2238 2318 2502 1127
60 1D 1068 612 1552 1424 1400 1395 1396 1426 1745 0945 61 1399 612 1355 1246 1230 1229 1230 1250 1509 0872 62 1669 710 1436 1293 1272 1265 1266 1286 1551 0847 63 1959 900 159 5 1468 1444 14 38 1432 1446 1720 0851 64 2295 730 1169 1105 1098 1099 1108 1100 1298 0781 65 2636 8 80 1202 1129 1121 1126 1 138 1115 1342 0748 66 3390 9 35 1060 o 9s7 0999 1001 1017 0971 1154 0703 67 1nu 1190 370 2225 2188 2104 2080 2120 2209 2 7 15 0990 68 1559 368 2005 1950 1871 18 48 1876 1951 2408 0916 69 1904 368 1870 18 1 4 17 34 1711 1730 18 07 2238 0875 70 22 bull11 471 228 6 2 204 2099 2063 2092 218 $ 2732 0840 71 2289 471 2030 2000 1925 1895 18 96 19 5 2498 0785 72 2727 4 71 1854 18 23 1753 17 23 1716 3758 2241 0743 73 3210 471 1680 1651 158 6 1559 1551 158 1 1950 omiddot7o9 74 2uD 1210 404 1261 1212 1198 1197 1205 1222 139 1 0978 75 14 20 540 1321 1260 1242 1 240 1249 1268 148 7 0918 76 1692 7 18 1467 138 6 1364 1361 1376 1405 1678 0883 77 18 94 903 1708 1 591 1565 1560 1575 1603 1948 0 857 78 2301 903 1530 1432 1407 1402 1415 1432 1738 0815
ro 0
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc117 tcair
79 2621 6 50 1069 1 020 1009 1009 1009 1007 1~189 o739 80 3230 901 1200 1128 1113 1119 1119 1086 1341 0694 81 82
l2D 1155 1689
360 575
1191 1345
1142 1252
1122 1218
1118 1210
1118 1209
1132 1228
1292 1446
0916 0822
83 1244 430 1163 1134 1131 1130 1129 1132 1292 0877 84 2100 645 1175 1135 1147 1 142 1138 1122 1286 0757 85 2292 8 25 1 354 1310 1327 1330 1323 1285 148 6 0728 86 2907 8 23 1180 1138 1151 1158 1149 1107 1268 0687 87 3380 902 1113 1049 1025 1011 1006 1042 1178 0673 88 89
1 12D 1427 1875
480 615
118 2 1140
1140 1095
1124 1077
1125 1075
1129 1072
1137 1072
1290 1243
0880 0790
90 2259 8 41 1296 1231 1207 1206 1203 1182 1419 0757 91 2682 8 80 1231 1170 1149 1147 1142 1112 1350 0731 92 3417 940 1142 1092 1076 1076 1069 1021 1252 0693 93 c 15 17 431 1321 1298 1268 1249 1250 1273 1522 0841 94 2034 505 1285 1263 1235 1209 1205 1206 1464 0759 95 2348 6 10 1395 1379 1334 1302 1286 1268 1536 0732 96 2716 706 1486 1480 1427 1383 1358 1311 1572 0 700 97 3247 7 56 1417 1430 1375 1320 1284 1223 1450 0660 98 1135 400 1425 1388 1352 1329 1330 1 364 1651 0893 99 14 06 440 1379 1341 1304 128 2 1281 1305 1583 0 831
100 2311 680 1602 1593 1553 1514 1502 1480 1 7 27 0 802 101 2666 680 1471 1469 1428 1390 1372 1335 1564 0761 102 3392 798 1491 1 509 1449 1395 1372 1305 1534 0 719
103 1U 1235 410 2469 2295 2173 2165 2226 2361 3120 0 897 104 2010 410 2017 1848 1 737 1706 1747 1865 2582 0753 105 28 14 410 1682 1535 1457 1427 1437 1520 2109 0 660
00 t-
TABLE X Continued
Ru n Thermocouple Rea ding s (mv No Positi on CFM I tc1 tc2 tc3 tc4 tc5 tc6 tc7 tcair
106 3492 440 1649 1499 1420 1391 1390 1470 2042 0620 107 4395 550 18 33 1679 1597 1564 1570 1640 2223 0583 108 5075 588 1779 1642 1580 1550 1552 1 615 2 191 0548 109 c 1344 398 1464 1 399 1364 1353 1350 1380 1689 0 907 110 1936 459 1369 1290 1253 1242 1 237 1259 1574 078 2 111 2846 580 1347 128 5 1251 1232 1220 1215 1 5 23 0 683 112 34 8 4 700 1392 1369 1339 1317 1299 1259 1599 0 636 113 4066 8 13 1449 1458 1427 1391 1363 1270 1595 0 591 114 5012 930 1484 1530 1500 1453 1420 1272 1580 0 580 115 1D 1362 513 1269 1218 1 217 1214 1220 1238 1460 0 893 116 19 58 600 1187 1122 1121 1120 1124 1133 1352 0798 117 2812 705 1052 1008 1015 1010 1011 1001 1218 0691 118 34 32 913 1105 1075 1085 1081 1086 1047 1301 0645 119 4022 980 1038 1021 1026 1023 1029 0983 1211 0 609 120 5026 982 0 8 61 0839 0836 0836 0837 0791 0955 0570 121 2D 1244 475 1320 1246 1233 1240 1255 1275 1434 0925 122 1 9 60 5 50 1160 1088 1074 1079 1089 1100 1260 078 7 123 2817 6 80 1096 1024 1 013 1018 1029 1022 1201 0 700 124 3491 960 1248 1175 1163 1172 1192 1153 1435 0 658 125 4096 989 1141 1089 1078 108 9 1105 1051 1310 0629 126 50 37 989 0983 0933 0929 0 936 0949 0880 1090 0 602 127 128
12D 1278 1947
402 545
1270 1261
1 230 1216
1228 1216
1230 1 215
1235 1223
1242 1219
1483 1514
0 913 0778shy
129 2769 695 1273 1234 1237 1221 1251 1212 1525 0678 130 131 132
34 39 4103 4978
8 40 9 80 9 80
1336 1448 1271
1322 1458 1 288
1328 1 462 1286
1 259 1 356 1157
1353 1492 1311
1261 1329 1138
1 555 160 7 1343
0 629 0 600 0599
(l) l)
TABLE X Continued
Run No Position CFM I tel tc 2
Thermocouple Readings tc3 tc4 tc5
( mv) tc6 tc7 tcair
133 1 l2D 1299 5 16 1 28 1 1212 1196 1195 1205 1221 1478 0869 134 1973 6 15 1163 1098 1073 1071 1079 1083 1343 0751 135 136
27 88 34 73
802 9 -_78
1187 1214
1099 1131
1069 1104
1066 1101
1075 1~110
1l061 1066
1370 1360
0662 0618
137 4118 9 81 1084 1010 0983 0979 0982 o937 1209 0581 138 4973 98 1 0969 0897 0 868 0855 0860 0799 1041 0572
139 1D 1253 409 1371 1293 1298 1301 1309 1321 1578 0928 140 2366 480 1130 1 090 1 121 1130 1137 1132 1390 0744 141 34 61 6 38 1081 1086 1152 1161 1147 1069 1382 0644 142 143 144
4325 5677 6759
7 90 939 998
1110 1115 1034
1161 1208 1139
1253 1268 1180
1265 1302 1215
1228 1230 1123
1080 1056 0970
13$913r12 8
0601 0561 0542
145 84 08 989 0863 0961 0934 0895 0871 0 785 09 9 0530 146 86 54 9 80 0808 0901 0 872 0821 0809 0733 0891 0498 147 7376 9 80 0 927 1032 1027 1 040 0961 0889 1032 0511 148 2D 4254 776 1 050 0 981 0965 0961 0962 0922 1155 0579 149 5708 991 1102 1031 1014 1009 1010 0931 1227 0528 150 69 78 990 0914 0853 0839 0 839 0843 0759 0996 0521 151 1254 490 1 479 1352 1329 1334 1351 1379 1607 0930 152 2713 7 00 1310 1220 1201 1201 1211 1209 1516 0723 153 8730 991 0809 0756 0742 0745 0 748 0663 0874 0543 154 5811 966 1219 1108 108 6 1081 1079 1033 1330 0650 155 42 46 8 02 1248 1136 1114 1114 1118 1103 1376 0 699 156 c 1270 429 1671 1571 1551 1545 1563 1600 1933 0929 157 2714 488 1398 1285 1 267 1258 1262 1275 1628 0729 158 4310 642 1424 1318 1299 1282 1283 1261 1683 0617
co ~
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc7 tc a 1r
159 60 12 780 1461 1388 1370 1349 1343 1279 1700 0 573 160 72 79 8 60 1402 1344 1330 1312 1292 1189 1 566 0 520 161 8690 982 1472 1442 1437 1 422 1392 1224 1602 0 521 162 163
12D 4368 5833
6 30 8 30
1195 1368
1105 1270
1111 1283
1117 1294
1131 1313
1081 1194
1369 1553
0613 0 553
164 76 43 959 1428 1338 1348 1341 1371 1180 1488 0535 165 8739 984 1345 1272 1272 1208 129 3 1059 1361 0550 166 1268 459 1701 1548 1541 1547 1589 1 625 1976 0 973 167 2678 570 1485 1351 1349 1356 138 1 1 385 1795 0760 168 169
1 12D 128 3 2729
448 650
1664 1314
1501 1232
1425 1233
1428 1229
1491 1229
1527 1232
1869 1571
0 962 0767
170 4345 847 1245 1179 1187 1182 1172 1132 1476 0 650 171 6036 9 76 1139 1109 1117 1114 1095 1020 1332 0588 172 6578 9 72 0982 0949 0942 0938 0926 0 8 50 1079 0560 173 87 84 9 72 0880 0854 0 8 36 0822 0818 0 749 0941 0585 174 1278 480 1564 1416 1397 1403 1417 1445 1733 0998 175 2711 590 128 3 1175 4 1178 1182 1187 1195 1493 0796 176 4351 8 90 1331 1259 1266 1275 1272 1235 1592 0 682 177 5994 9 60 1228 1152 1150 1151 1143 1075 1 360 0644 178 lU 1223 408 2282 2140 2052 2052 2106 2188 2626 0 878 179 2351 408 178 1 1623 158 5 1519 1556 1634 2068 0717 180 3448 482 1888 1675 1570 1541 1572 1665 2199 0629 181 4513 563 2026 1797 168 4 1644 1670 1770 2385 0583 182 5714 589 1913 1700 1610 1568 1580 1 682 2382 0551 middot 183 6997 653 1903 1718 1643 1611 1612 1700 2326 0 549 184 8709 6 80 1738 158 3 1543 1510 1498 1519 1 912 0577 185 186
2 12D 4249 5737
660 9 74
1055 1221
0 979 1122
0960 1093
0 952 1088
0959 1090
0 956 1054
1147 1350
0661 0602
187 7432 9 8 1 1065 0981 0951 0942 0 939 0881 1135 0582 CD ~
TABLE X Continued
Run No Position CFM I t o1 to 2
188 87 23 9 83 0944 0 879 189 1435 585 18 26 1630 190 2718 690 1433 1298 191 7507 950 1070 0961 192 85 44 964 0982 0 881 193 1287 600 1806 1668 194 2717 7 80 1579 1444 195 4253 8 81 1371 1260 196 60 68 9 78 1252 1152 197 73 89 975 1100 1000 198 86 88 973 0953 0 871 199 58 64 9 81 1269 1155 200 2D 4 1 77 915 1362 1251 201 5712 975 1213 1111 202 7363 9 78 1036 0 951 203 8 604 973 0932 0861 204 1268 6 95 2015 18 20 205 2659 6 96 1405 1295 206 39 80 7 98 1261 1174
No 207 Orifice 114 96 509 1325 1148 208 94 33 509 1477 1243 209 7487 5 09 1686 1409 210 5236 505 2094 1691 211 3309 428 2188 1 778 212 1293 392 2976 2560
Thermo ooup1e Readin g s (mv) to 3 to4 to
5 to
6 to7 toair
0 851 0847 0 8 29 0759 0987 0592 158 4 1583 1611 1647 1993 0986 1270 1266 1 279 1298 1604 0 789 0916 0908 0900 0 858 1115 0602 08 39 0 823 0 818 0 770 1035 0602 1609 1602 1629 1676 2153 0979 139 1 1385 1400 1 430 1938 0776 1212 1201 1205 1201 1601 0669 1 105 1086 1086 1 052 1371 0621 0952 0936 0923 0870 1195 0582 0 8 20 0 801 078 1 0 729 1044 0569 1108 1090 108 2 1043 1407 0610 1218 1221 1241 1202 1582 0659 1081 1083 1084 1031 1 368 0622 0921 0924 0919 0 841 1111 0 610 08 34 0831 0 821 0 751 1003 0 630 1761 1761 1 809 1861 2399 0966 1271 1271 1295 1311 1650 0797 1150 1150 1161 1149 1440 0703
1083 1057 1053 1109 1566 0~530 1158 1125 1138 1217 1763 0 526 1291 1250 1278 1383 2038 0542 1518 1478 1519 1657 2420 0 589 1596 1557 1601 1737 2441 0688 2370 2344 2409 2561 3 297 0921
()) (11
TABLE X Continued
Run Thermocouple Readings (mv) No Position CFM I tc 1 tc2 tc3 tc4 tc tc tc tc i5 6 7 a r
C of 2nd 213 516 1235 4 63 1 432 1291 1265 1258 1 268 1 308 1550 0 971 214 1919 6 17 1357 1223 1196 1191 1199 1211 1461 0 851 215 27 12 8 35 1401 1259 1278 1220 1230 1218 1511 0 762 216 3320 981 1439 1305 1270 1259 1275 1238 1450 0719 217 41 53 980 1251 1142 1132 1094 1121 1088 1305 0 695 218 404 987 1102 1042 1030 1 bull006 1014 0960 1133 0681
Supplementary Equations
Calculating temperatures from thermocouple readings
t = -026tc)2 + 3512(tc) + 3201 (26)
where t is the temp in deg F and tc is the thermocouple reading in millishyvolts
Calculation of the thermal conductivity of air
k = 00000245ta + 0 0132 (27)
where k is the thermal conductivity in Btuhr rt2 degFft and ta is the air temp 1n OF
I I
bull co m
5
performed in a onebulltube single orifice type baffle heat
exchanger and provision was made to measure local rates
of heat transfer in the vicinity of the baffle
4
CHAPTER II
THEORY AND PREVI OUS WORK
In 1701 Newton defined the heat transfer rate qc
from a surface of a solid to a fluid by the equat ion
= ~A(tw - t) (1)q0
where hm is the coefficient of heat transfer from the surshy
face to the fluid excluding any radiation A is the area
of the surface tw is the surface temperature of the wall
and t is the bulk temperature of the fluid The equation
for the point of local surface coefficient h is given by
dqdA = h(tw- t) (2)
The mechan ism and the laws covering heat transfer by
true conduction in solids and by radiation through transshy
parent media are well known However with heat transfer
from a solid to a fluid the situation is far more complex
The mechanism of flow of the fluid to a large extent deshy
termines the rate of heat transfer for a given temperature
difference
In addition the coefficient hm depends on certain
physical properties of the flowing fluid the dimensions
of the apparatus the velocity of the fluid past the surshy
face and frequently the temperature potential AT
It was the purpose of t his research to measure the
local shell -side heat transfer coefficient and correlate
it with the several variables mentioned a bove
5
The heat transfer coefficient for fluids flowing inshy
side tubes is more e a sily measured and correlated due to
the simple geometry of t he tube i nterior Much work has
been done on the tube-side coefficients with one of the
more useful e quations being the Dittus - Boelter equation
( 4 p 450) ~
0 023 (---ctwGJbulla (~np M ( 3 ) M k
with the following cond itions satisfied
(1) Fluid properties evaluated at the arithmetic
mean bulk temperature
(2 Reynolds number gt10000
(3) 0 7 lt Pr lt 100
(4) n = 04 for heating and 0 3 for cooling
(5) Ldw gt60
Colburn (3 p 197) obtained an equation for tubeshy
side heat transfer coefficients in which the Stanton
number is used instead of the Nusselt number
hm ) (~~ 23 _ (dwG) 0 2 ( GC k - 0 bull 023 U (4)
p
Much of the research done on average shell-side heat
transfer coefficients has resulted in empirical correlashy
tions of the form of equations (3) and (4) above Several
investigations have been made for a certain set of phys~al
6
variables but the r esults have ne ver satisf a ctorily been
correlated to appl y for all types of heat exchangers
Some basic 1ork has been done recently however on
the local shell-side coefficients Ambrose (1) studied
the local heat transfer coefficients i n a model heat exshy
changer with segmental baffles This study was fairly
extensive at the baffle center but the data were quite
limited for the space between the baffles Gurushankar1ah
(5) further extended Ambroses work by studying a single
baffle space in detail
The results of these two studies indicated a need for
detailed information 1n the vicinity of the baffle Hence
Lee () investigated a single baffle s pace between two
orifice baffles and obtained considerable information on
the rates of heat transfer in the annular orifices Since
his work was carried out in a multitube mode l heat ex~
changer the determination of the rate of flow through the
individual orifice was difficult because of t he outer
clearances existing in the exchanger For this reason the
present research was undertaken to study the rate of heat
transfer in a single annular orifice through which the flow
could be accurately determined
Bell and Bergelin (2) have studied i n detail the pres shy
sure drop coeff icients for the annular orifices formed beshy
tween a circular disk and a circular tube These results
also appl y to the annular orifioe formed when a rod extends
7
through a circular hole in a plata This study was extenshy
sive in the fact that it considered the baffle thickness as
well as the orifice size but no heat transfer data were
presented
Sullivan and Bergelin (9) studied flow through a
single annular orifice through multiple annular orifices
i n parallel and flow around a single baffle both with and
without leakage through the baffle A generalized expres shy
sion is presented for the pressure drop across one baffle
section of a tubular exchanger with leakage through the
tube holes in the baffle but the effect of leakage area
upon heat transfer is only discussed qualitatively The
pressure drop data is correlated by plotting cent as a funcshy
tion of the Reynolds number where cent equals
d1 )22( ~ P) s c e (d2 -
M-2
8
CHAPTER III
~PERI1ffiNTAL APr ARATUS
The heat transfer test section was essentially a
single tube heat exchanger The inner tube was a l-in
OD aluminum tube with an electrically heated probe midshy
way between the two ends of the tube
Test Section
The shell as constructed from lucite plastic tubing
2 5-in I D and 3-in O D The te t section d a total
lengt h of 54 58 inches I t consisted of two sections
The upstream section was 40 i n ches in length in order to
assure freedom from entrance effects and the downstream
section was 13 12 inches in length To further assure
uniform flow a bundle of short copper tubes was placed a
few inches downstream from the entrance Both of these
sections had 12 i nch flanges on one end so t hat a 18
i nch thick orifice plate could be clamped between them
Heat transfer coefficients were measured in the vicinity of
t h is orifice A cross section of the center of the test
section is shown in Figure 1 and the experimental appara~
tus is shown in Figure 2
Cooled air supplied by a Roots -type blower was used
as the shell-side fluid throughout this study It entered
the test section through a l-in ID 1 12-in OD plasshy
tic pipe at the upstream end of the calming section Tbs
j Jl l 6- 11 BOLTS II I nbull middot~11 I HEATING ELEMENTS
J T ( T
-f-shy - - - f-_- __L
7 777 _y A
IT 1] I
I
FIGURE I CROSS SECTION OF TEST SECTION AND PROBE
10
FIGURE 2 EXPERIMENTAL APP1Ub~fUS
11
air left the test section through nine equally spaced 12
ineh holes placed around the side of the tube at the exit
end
Sensing Probe Assembly
The sensing probe was designed to measure the local
heat transfer coefficients at any point along the tube and
around the tube in the test section The tube was designed
so that it could be easily moved up- and downstream to
measure the heat transfer coefficients at various positions
in relation to the orifice
The sensing tube assembly consisted of the sensing
probe the thermoctmple lead s and selector switch the
power lines and the two aluminum tubes between which the
probe was centered
Imbedded in the sensing probe were seven iron-constanshy
tan thermocouples for measuring the temperatures around the
tube The lead wires from these thermocouples were conshy
nected to a seleotor switch at the downstream end or the
aluminum tube A layer of Saran wrap was placed around the
tube over the t hermocouple and three lengths of Trophet C
resistance ribbon were wrapped around the tube nd conshy
nected in series to the power leads
The heating surface of the probe was formed by these
three one inch wide strips of Trophet C resistance ribbons
The ribbons were 0002 inches thick and had a resistance of
12
0 271 ohms per foot and a thermal conductivity of 763
Btuhr ft 2 degFft They were held in position by four
copper bars placed in four parallel longitudinal slots
These copper bars served as connectors for the electrical
leads A photograph of the sensing probe is shown in
Figura 3 and a drawing of the assembled probe is given in
Figure 4
Power Source
Direct current was used to heat the resistance ribbon
on the sensing probe The current was regulated by a slide
wire resistor The po er source consisted of a Raytheon
Voltage Stabilizer to stabilize the city power source at
115 volts and an automatic selenium rectifier with an alshy
ternating current input of 115 volts at 60 cycles per
second and an output of 12 volts and 35 amperes direct
current
Temperature Measuring
The temperatures around the sensing probe were calcushy
lated from the emf readings of the ironbulloonstantan thermoshy
couples The emf measuring system consisted of the seven
probe thermocouples a separate thermocouple for measuring
the inlet air temperature a thermocouple selector switch
a cold junction and a Leeds and Northrup Type K Potentishy
ometer The potentiometer was placed on a Fischer
13
THERMOCOUPLE JUNCTIONS~ ~------- HOLES FOR THERMOCOUPLE LEADS
~----- SCREWS
~ff+--- CONNECTING BARS
END VIEW
POWER LEADS SOLDERED TO LOWER CONNECTING BAR
iER PLASTIC PIECE
RESISTANCE RIBBONS LOCATION OF THERMOCOUPLES
FIGURE 4 DRAWING OF ASSEMBLED SENSING PROBE
15
Vibradamp support to absorb the vibrations produced by the
air blower
Air Source
Air was used as the shell-side cooling fluid during
the study The air was pumped through the test section by
a Roots type air blower with a rating of 280 ofm at 3 12
psig outlet pressure The hot air leaving the blower was
passed tbxfugh two finned-tube box-type coolers and one
tubular edoler to oool it to approximately room temperature
The air flow rate was measured by passing it through a
flow measuring orifice in the line Two sharpbull edged orishy
ficas were used f or flow measurements The calibration
curves for these orifices were presented by Ambrose (1
p 166)
The pressure taps on each side of the orifice were
connected to two differential manometers containing 0 83
and 2 95 specific gravity fluids respectively The presshy
sure drop through the test section and test orifice was
measured by a pressure tap placed 13 inches upstream and
one placed 6 12 inches downstream from the orifice Two
pressure ga ges were used to measure the pressure at the
inlet to the flow orifice and to indicate the statio pres~
sure at the test section inlet
16
Pressure Probe
A probe was designed to measure the pressure drop
between the pressure tap 13 i nches upstream from the ori shy
fice baff le and any point downstream from the tap The
probe eonsisted of a l~in OD copper tube with six 132
i n ch holes even l y s paced around the tube The upstream
pressure tap and the pressure probe were connected to a
differential manometer so the pressure drop to various
points up- and downstream of the orifice could be measshy
ured
17
CHAPTER IV
EXPERIMENTAL PROGRAM
The experimental program was designed to measure the
heat transfer coefficients and pressure drops in the vicinshy
ity of annular orifices The four orifice sizes studied
were 1 364 1 216 l 316 and 1 516 inches~ The inner
tube used in each case was a 1-in OD alumintim tube
Hence tube to baffle clearances were respectively 3128
232 332 and 532 of an inch
Heat transfer coefficients were measured at poait~ons
1 i nch upstream at the orifice center and at 12 1
1 12 and 2 inches downstream for all orifices In addishy
middottion the heat transfer coefficient at a point 2 12
inches downstream from the 1 516 inch orifice was measured
and at the points 12 l 12 and 2 inches upstream from
the 1 364 inch orifice
The heat transfer coefficients at each point were
measured at five different flow rates for the 1 364 inch
orifice and at six different flow rates for the other orishy
fice sizes The high pressure drop through the small orishy
fice size limited the number of flow rates which could be
studied
The flow rate was calculated from the pressure drop
across the flow orifice This flow was corrected to cubic
feet per minute at 68degF and one atmosphere pressure by
18
using the orifice pressure and the test section pressure
which were measured by pressure gages
It was desired to determine a relationship between the
heat transfer coefficient and the total pressure drop for
each orifice size The pressure drop across each orifice
at various flow rates was measured by means of the presshy
sure probe described in Chapter III It was also desired
to obtain pressure profiles for each orifice size since
these might be similar to the heat transfer profiles The
pressure drop was measured from a point 13 inches upstream
of the orifice to points at 1 and 12 ineh upstream the
orifice center 12 1 1 12 and 2 inches downstream
The experimental program is summarized in Table I
TABLE I
SUla~RY OF EXPER IMENTAL PROGRAM
Position Investigated-Distance from Orifice-Inches
Orifice Range of Flow Rate Size Heat Transfer Pressure Drop CFM at 68degF amp 1 atm
1 364 2U 1 12U 1U 12U c 12U C 12D lD 10 - 18 l2D lD 1 12D 2D 1 12D 2D
1 216 1U c 12D lD 1 l2D 2D 12U c 12D lD 10 - 35
1 316 1U c 12D lD 1 l2D 2D l2U C 12D lD 12 - 50
1 516 1U c x2D lD 1 l2D 1U 12U C 12D 12 - 90 2D 2 1 2D l D 1 l2D 2D 2 12D
20
CHAPTER v
EXPERI MENTAL PROCEDURE
The experimental procedure for measuring the heat
transfer coefficients ~d corresponding flow rates reshy
quired the following procedure
(1) Install the orifice size to be studied in the
test section
(2) Place the heat transfer probe in the position up
or downstream from the orifice where the middot heat
transfer rate is to be studied
(3) Fill the cold junction thermos with cracked ice
(4) Measure the atmospheric pressure
(5 Open bypass line from blower and close line to
test section
(6) Turn on the cooling water for the exchangers used
to cool the air leaving the blower
(7) Start the automatic selen ium rectifier by turning
on the t 1mer bull
(8 ) Connect the voltage stabilizer to the wall outlet
(9) middot Set the slide wire resistor to the maximum re shy
s1atanee I
(10) Start the blower
(11 Open the line to the test section until the de shy
sired flow rate is obtained
(12) Switch on the probe direct current power source
21
(13) Adjust the slide wire resistor to obtain the
desired current
(14) After the thermocouples have reached equilibrium
values record the e m bullf across each of the
seven probe thermocouples and also the entering
air thermocouple
(15) Record the direct current amperage
(16) Record the gage pressure at the flow orifice and
the entrance to the test section
(17) Record the manometer measurement of the pressure
drop across the flow orifice and also the presshy
sure drop through the test section
22
CHAPTER VI
CALCULAT ION OF EXPERIMENTAL DATA
The local heat transfer coefficients were calculated
from the temperatures measured on the probe surface the
air temperature and the current input The results were
calculated by using the Alwae III-E computer
The general expression for calculation of the heat
transfer coefficients was derived by Ambrose (1 p 79)
The equation is derived by making an energy balance around
a small increment of the center resistance heating ribbon
The two ribbons tnstalled adjacent to the center ribbon
reduced the amount of logitudinal conduction and assured
little longitudinal temperature variation in the center
ribbon
A heat balan ce on this small increment of resistance
ribbon yields the following
(the heat conducted in) + (heat generated) = (heat
conducted out) +(Heat convected to the fluid) + (heat
radiated to the surroundings) + (Heat conducted into
the plastic center of the probe)
This gives the equation
kzw dtdS + 12RdS kzws [ t + (~) ds] + hwdS (t-ta )
+ ~Aad wd o middot+ qcAond 1 -~- wdS 5 )
23
Hence solving for h gi~ea
i2R kz d2t Qrad qcond w + -d$2 - ~- A
h = ( 6)t - ta
Since S = re where 9 equals the enclosed angle ~n radians
dS rd9 ( 7)
and
dt - dt (8)dS - rd9
Differentiating with respect to S
d2t (9)rd9dS
from which
(10)
Substitut1ng into the equation for heat transfer coeffishy
cient gives
h = i2R Qcond A (11)
w
The rate of radial heat conduction into the plastic
tube making up the probe was assumed to have negligible
effect on the heat transfer coefficient It was also
assumed that the heat loss by radiation from the ribbon
was negligible since all data were obtained with the ribbon
at a temperature less than 125degF
24
When t he rad iation and conduction terms are neglected
Eq (11) becomes
(12)
The following con stants are known
R = 0 271 ohmsft
w = 100 i n ches
k = 763 Btuhr rt2 degFft
z = 0 002 inches
r = 12 inch
Eq (12) putting 9 in degrees then reduces to
1110 12 + 2404 d 2t d92
( 15)h = ------~--~-------t - ta
Thi s equation was programed for the Alwac III- E comshy
puter and used to calculate the local heat transfer coefshy
ficients from the observed data
The average heat transfer coefficient around the tube
at a given position in the t est section was calculated by
averaging the local coefficients calculated from Eq (13 )
It was found 1n the course of the experimental work
that thermocouple numbers 1 and 7 were indicating higher
temperatures than would be expected This resulted in h1
and ~ being lower than the other local coefficients around
the tube Since the fluid was flowing parallel to the axis
of the probe the circumferential variation i n rate of heat
25
transfer should be small Hence in obtaining the average
coefficient around the tube the values of h1 and h7 were
not used even though they were calculated and are tabulated
1n Table I II in the Appendix
Then
(14
A Nusselt number as calculated from this aver age heat
transfer coefficient using the tube diameter as the characshy
teristic dimension
(15)
The air flow rates through the test section were calshy
culated by measuring the pressure drop across the flow orishy
fice the air temperature the pressure at the flow orifice
and the pressure at the entrance to the test section The
orifice calibration curves (1 p 166 ) were used to obtain
a value of the orifice coefficient f8e where Q equals
the flow in cubic feet per minute at 68deg F and one atmosmiddot
phere pressure and te is the density of air at the exchanger
and e the density of the air at the flow orifice The
den sity of the air can be expressed by
e = 2 703 p (16)T
where T equals the temperature in OR and P equals the absoshy
lUte pressure i n lb1n2 Using the value of e Qfo from
26
the calibration charts as A and Eq (16) solving for Q
gives
( 17
This equation was used to calculate the flow rate for
each flow studied
The Reynolds number used i n the correlation of the
data was the equivalent Reynolds number defined as
Re)eb ~ d2 - dl)Uf ( 18 ) lL
where d1 is the outside diameter of the inner tube and d2
is the orifice diameter U is the flow velocity through the
annular orifice e is the density of the air and U- is t he
viscosity of the air This equation can be transformed t o
(Re) b = 1611 Q (19) e dl + d2
where d1 and d2 are in inches
The pressure drop data were calculated i nto a dimenshy
sionless pressure drop function cent where
d1 )22( ~ P)gc f av(d2 shycent 2 bull (20
M-
For air this equation reduces to
where d2 and d1 are in i nches D P is expressed i n inches of
2 95 specific gravity fluid and P av is expressed as lbft3
27
CHAPTER VII
ANALYSIS OF DATA
In analyzing the heat transfer data an attempt was
made to correlate it 1n terms of the dimensionless groups
(Nusselt number Prandtl number and Reynolds number) which
appear in Eqs (3) and (4) Consequently all of the av~
erage heat transfer coefficients hav were brought into
the form ( Nu)( Pr)~3 bull The Nusselt number was based on the
tube diameter and the thermal conductivity of the air at
the flowing temperature The tube diameter was used in the
Nusselt number because comparison could then be made with
previous experimental work on heat exchangers which have
commonly used the Nusselt number defined as in Eq (15)
From the standpoint of dimensional analysis this is
equivalent to considering the tube diameter as the characshy
teristic length so far as the heat transfer is concerned
The Prandtl number of the air was taken as 0 7 in all
cases
Variation of Heat Transfer Rate with Distance from the Baffle
Considerable variation was observed in the rate of
heat transfer in the vicinity of the baffle In order to
obtain the variation with respect to position the term
(Nu)(Pr)-13 was plotted versus the flow rate Q for each
position and orifice studied Cros s plots were then made
28
at constant flow rates in order to obtain the variation of
(Nu)(Pr) -13 with position The resulting cross plots are
shown 1n Fi gures 5 6 and 7 for the four orifices studshy
ied
About one inch upstream from the orifice the heat
transfer coefficient begins to rise rapidly and continues
to do so until it reaches a maximum some distance downshy
stream After the maximum point the heat transfer coef fi shy
cient decreased slowly The heat transfer rate was found
to reach a maximum at a different position downstream for
each orifice size These figures also show that for a
given orifice size the maximum heat transfer rate occurs
a pproximately at the same point for all flow rates The
position of the maximum point f or each or ifice size is
shown in Table II
The region immediately downstream from the orifice is
one of h i gh turbulence due to the jetting action of the air
flowing through the orifice As the air flows t hrough the
orifice the streamlines continue to converge for some dis shy
tance downstream The point of maximum heat transfer is
probably at the point where the streamlines be gin to diverge
and a boundary layer begins to build up on the tube Tle
decreasing heat transfer coefficient beyond the maximum
point indicated the formation of a boundary layer
Since the position of the maximum point is independent
of flow rate middot it is possible to correlate it with respect
_ ct 11shyz-
100
0 136 ORIFICE
(
I 0
I )
~ 00
~p 0
I 0
--r--- ~
ISCFIII
-_ OCFM
rbull abull
~ middot~ a-1 z-
12fORIFICE
100
200
100
0 0 UPITRAM ORIFICE DISTANCE CENTER
CFM
h I DOWNSTREAM
DISTANCE
FIGURE 5 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLpound
30
too
700
800
100 ~ f gtf
400
z ~
100
100
100
0
13fORIFICE
~ -~ -- ---
)
~
~
-
I ~ ~OCFM
I vI~-~ OCFM
J ---
Iamp CFM
I 0 I I UPSTREAM ORIFICE DOWNSTREAM DIITANOE GENTER DIITANCI
FIGURE 6 VARIATION OF HEAT TRANSFER RATE WITH DISllNCE FROM BAFFLE
--
--- --
31
100
100
700
100
_ 100
f 9- 400 z-
100
tOO
100
0 - I 0 I I I UHTRIAM OAtfiCI DOWIIITMAM
+ I tyl6 ORIFICE
v I
~~ ~CFM
I v ~CFMI
v v 7
~~ v ~ iOCFM
- ~~ I-shy1-shy ~ICFM
DIITMCI OINTIR DIITANCI
FIGURE 7 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLE
32
TABLE II
POSITION OF MAXIMUM HEAT TRANSFER
Position of Maximum Orifice Size Heat Transfer
(inches) (inches downstream)
1 364 050
1 216 100
1 316 125
1 516 200
33
to orifice size Figure 8 shows the effect of the orifice
size on the position and value of the maximum heat transfer
at a constant flow rate of 15 cubic feet per minute It
can be seen that the larger the orifice size the further
downstream the point of maximum heat transfer occurs
Also as the orifice size increased the rate of heat
transfer decreased for a given flow rate The broken line
indicates the variation of the point of maximum heat transshy
fer with position and size The position of the point of
maximum heat transfer rate downstream from the orifice was
correlated with orifice size by means of the dimensionless
groups (Lde) and (d1de) where L is the distance downshy
stream from the orifice where the maximum rate of heat
transfer occurs d1 is the outside diameter of the inner
tube and de is the equivalent diameter of the orifice
ie de = d2-dlbull
Figure 9 shows a plot of Ld 6 versus d1d6 for the
four orifice sizes studied The four points on this logshy
log plot are approximately in a straight line and the
equation of this line is
Lde = 0 44 d1de)028 (22)
Although the above relationship represents a correlashy
tion of dimensionless groups it is based upon only one
tube diameter and needs to be substantiated further by
studying other tube diameters and other orifice sizes
34
aoo
400
aoo ~
-~ middot-CLshyJ z
200 -
100
0
ORIFICE CENTER
l~
l
t
I J~
1pound~
I
0 I I~
AT 15 CFM
-
bull ~ 1~6~
~ v~
~
~--~~6
~~~ ___ v v V -_
~ o q
~ I 16
v
~
ogWNSTREANI STANCE
FIGURE 8 EFFECT OF ORIFICE SIZE ON POSITION AND VALUE OF MAXIMUM HEAT TRANSFER
35
50
loshy____ -~
~ ~ -shylltl-shy~ r0
2 10 30
FIGURE 9 CORRELATION OF THE POINT OF MAXIMUM HEAT TRANSFER WITH
ORIFICE SIZE
36
Correlation of Data at the Baffle
The heat transfer data were correlated by obtaining a
relationship between the group (Nu)(Pr)-13 and a
Reynolds number based on twice the clearance (d2 - d1
between the tube and the baffle It was found that the
most satisfactory correlation could be obtained when the
term - d1 was used as the length term in the Reynoldsd2
number
Figure 10 shows the variation of the heat transfer
rate at the center of the orifice e xpressed as a function
of Reynolds number and the orifice size This shows that
for a given Reynolds number the heat transfer at the center
of the orifice is greatest for the smallest orifice size
In order to obtain a general correlation of the data
shown i n F1gure 10 the effect of the dimensionless ratio
d1de was considered This ratio considers all of the
geometric factor s needed to describe the annular orifice
The thiclaless of the orifice plate is also a factor but
was constant i n this i nvestigation
The data for the heat transfer at the baffle center
are shown in Figure 11 in which (Nu)( Pr)-13 is plotted
versus (Re)ebd1 de) 0 55 This data on a log-log plot
lies on a straight line for (Re)eb( dld8 )0 55 greater
than 3 x 104 The equation for cor relating the heat
37
4XI~middot~-r~------~--~~------~
Icf t--to_+--_c-c-________ SYMBOL SIZE
0 1~4
6 ~~
9 ~~ -o ~
(Re)eb
FIGURE 10 RATE OF HEAT TRANSFER AT BAFFLE CENTER
38
500
0
4 0 lcf
~ ~
~ ~iC-
~ ~
~IL 0~ 0 SYMBOL SIZE-
p 0 1364-
r 6 1~16 -~ -
9 1~16 --o 1~16
I I
FIGURE II CORRELATION OF HEAT TRANSFER DATA AT BAFFLE CENTER
39
transfer at the center bullOf the a nnular orifice was found by
the method of least s quares to be
(Nu)( Pr)-1 3 = 0018 ( Re)ebO Bl( dlde)04~ (23)
3 x 104 ltRe)eb(a1de)055 lt 105)
Rate of Heat Transfer at the Point of Maximum Heat Transfer-The heat transfer rate at the point of maximum heat
transfer is plotted in Figure 12 to show the variation with
Reynolds number and the size of the orifice It is shown
gives the h1gh st heat transfer ~ate at its point of maxibull
that for a given Reynolds number the smallest orifice size yen il
mum heat transfer
The data ~or the maximum poi~t could be correlated by
plotting (Nu) Pr)-13 versus (Re)eb(d1de)06 This plot
is shown 1n Figure 13 and the resulting eurve shows that
(Nu(Pr)-13 is not a simple p0wer function of the Reynolds
number as was the case for heat transfer at the baffle
center The reason for this is probably because other
factors such as intensity and scala of turbulence should
be considered At the orifice center the streamlines of
the flowing stream are converging_ and thus the flow is
quite stable Downstream from the orifice is a region of
large eddy currents and probably large scale turbulence
These factors could con ceivably cause the results which
were obtained for the point of maximum heat transfer
40
If)
~middotshy Q_-I z_
10~~~--------r----~~--~--
SYMBOL SIZE
0 13$4
6 1~8
Q 13-18
-o 1~8
7)(104
(Re)eb
FIGURE 12 RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
41
Ia ~
0 I
c ~ ~ c v
~ ~lt w ~
17
~ b
v ~ ( SYMBOL SIZE
-~ 0 f-64 -v ~ 6 t211e
~ Q I~~~
-o - l~rs I I
FIGURE 13 CORRELATION OF HEAT TRANSFER DATA AT THE POINT OF MAXIMUM HEAT TRANSFER
4 2
Effect of Upstream Baffles on Heat Transfer at the Orifice Center
The heat transfer rate at the orifice center using the
single orifice in a test section is a pproximately 13 of the
value that was obtained by Lee (7) using a model heat exshy
changer with orifice baffles Lee investigated the cent r al
baffles of the heat exchanger and thus the coeff icients he
obtained would be affected by the presence of a number of
upstream baffles To determine the effect of upstream
baffles an additional l 516 inch baffle was placed four
inches upstream 1n the test section The resulting data are
shown in Figure 14 where (Nu)(Prmiddot)-13 is plotted versus
(Re) eb for the case of a single baffle 1n the test section
and also the case of an additional baffle placed four inches
upstream Comparison is made with the results obtained by
Lee middot(7) using a four-baffle and a ten-baffle model heat exshy
changer Good a greement is obtained with Lees work and the
results show the marked effect that upstream baffles have on
the downstream heat transfer rate The additional up tream
ba ffle caused sufficient turbulence 1n the test section to
i n crease the heat transfer rate nearly three-fold at the
center of the next baffle
Heat Transfer i n the Test Section with No Orifice
In order to check the accuracy 6f the equipment the
orifice baffle was removed and the heat transfer mea sured
with the probe in the empty test section The data were
43
~~BAFFLES
0 l BAFFLE -shy
ll_9 2 BAFFLES
V 4 BAFFLES-LEE
4 10 BAFFLES- LEE lJf ~
~rv ~~ ~ v flvv ~~
I ~ J ~ L v
0
v
( V
40 3XIo 7XIa
(Re)eb
FIGURE 14 EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER AT BAFFLE CENTER
44
compared with heat transfe r coefficients predicted by the
equations for annuli which are recommended in the litera shy9
ture The two equa~ ions u sed tor comparison were
(hfe)=0 023 (rltGr e (~~ur4 (~r45 (24)
which was presente~ by Wiegant (10)
and ( h ) (cnM~5(M~l o14 o 023 CPG k j Mij - (de GJMb )0 2 ( 2 5)
which was presented by McAdams (8 p 242) The comparshy
i son is s hown in Figure 15 lq (25) gives a value which
is low by about ten percent while Eq (24) g ives values
which are high by as much as twenty -five percent when comshy
pared with the experimental data The se equations are gembull
erally considered to give coefficients with an accuracy of
about twenty percent Therefore the present experimental
data are within the accuracy of these equations Also the
plot indicate s that for a Reynold s number greater than 2 x
104 the slope of the line is the same for the experimental
data as for the equations
Pressure Drop Data
The total pressure drop across the orifice was measured
as a function of the flow rate and the orifice size The
pressure drop was expressed as a d1mens1onleas quantity r)
which ie plCltted ver sus the Reynolds number in Figure 18
The pressure drop function cent correlates for all or1f1oe
45
200
100
s z
10 5XI10 10
0 EXPERIMENTAL
--McADAMS
-WIEGAND L
V
~ ~ ~
P ~ ~
LL~ L
v~
~
v v
v 1 ~ ~ v
v -gt
~
~ ~
~
6Xid
FIGURE 15 HEAT TRANSFER WITH NO BAFFLE
46
0 1~4 -~ a 6 t216
Q t316 lJ J
-0 as a )t
A LEE I -shy SULLIVAN 8
p
10bull
BERGELIN
I _ll I
I ~
i I
~middot
lo II
f fl
J j
~middot
A)101
1q
I Ill
1 I3 X 10ao1
FIGURE 16 ORIFICE PRESSURE DROP FUNCTION VS REYNOLDS NUMBER
47
sizes- The present data extends the range covered by preshy
vious workers and agrees well with their work The preshy
vious work of Lee () for a heat exchanger containing 10
orifice baffles and also the data of Su livan and Bergelin
(9) for pressure drop in a model heat exchanger with a
single baffle is shown 1n Figure 16 long with the present
results~ This figure may be used to predict the preseure
drop from the equivalent Reynolds number of the annular
orifice
The pressure drop between individual points 1n the
vicinity of the orifice and an upstream pressure tap wa s
measured to obtain a pressure drop profile As might be
expected 1n all cases the profiles showed a rapid decrea e
in static pressure immediately upstream from the orifice
There was however little or no recovery of the pressure
loss downstream The 1 364 inch orifice did show a maxishy
mum point in the pressure drop but this maximum occurred at
the orifice center and total recovery was reached about 12
inch downstream
Heat Transfer at the Baffle and Maximum Point as a Function of Pressure Drop
In order to compare the effect of the total pressure
drop on the heat transfer at the baffle and the point of
maximum heat transfer Figure 17 was plotted showing
(Nu)(Pr)-13 as a function of the total pressure drop This
shows that for a given pressure drop the largest orifice
48
1200
1000
~ a -sshyz-
100
60 100 700
AT MAXIMUM POINT I 15116 2 13116 3 1~6 4 1364
AT ORIFICE CENTER
60
1
v
r ~ ~ ~
5
~
8 7
13116
8
~
1364
v
~
e6
1~6
v
~~ v ~ ~ -~ ~
~
~ v
l
~
vamp
I ~ ~
~
v L ~
v
I-
5
k= ~~
~ ~ ~
--I
v ~
FIGURE 17 HEAT TRANSFER AT THE BAFFLE AND MAXIMUM POINT AS A FUNCTION OF
ORIFICE PRESSURE DROP
49
size has the greatest heat transfer coefficient This is
true at both the orifice center and at the point of maxishy
mum heat transfer
Another comparison can be made by plotting the heat
transfer coefficient and the pressure drop versus the orishy
fice size at a constant flow rate Figure 18 shows this
plot This graph shows that at a constant flow rate the
pressure drop as well as the heat transfer coefficient
increases as the size of the orifice is decreased In
choosing an orifice size for maximum efficiency 1t would
be necessary to know the pumping power available as well
as the heat transfer desired
70 I I 700
AT 15 CFM 60 ---
~ aug
50 ---
NV
40 ~
~ ~ ~
~ _
MAXIMUM POINT ---- --- ~
1-----t---~ _
~00Qj ~
~t--- ORIFICE CENTER 10 1100
1---~ n
u0 01 02 03 Q35
a ltl
de inches
FIGURE 18 VARIATION OF HEAT TRANSFER RATE AND PRESSURE DROP WITH ORIFICE SIZE AT A CONSTANT FLOW RATE
cn 0
51
CHAPTER VI II
SUMMARY OF RESULTS
This study revealed several significant facts about
the heat transfer in the vicinity of annular orifices
Probably the most important contribution was the presshy
entation of the heat transfer profiles in the vicinity ot
the annular orifice ~ r s shown that t~ local heat
transfer coeffieient re~ches a maximum at a point downshy
stream from the orifice The distance downstream at which
this maximum oocurs is t1ven by the equation
22
The heat transfer coefficients at the center of the
orifice were correlated and found to follow the equation
(Nu)(Pr)-13 = 00176 (Re)eb08l(d 1de) 0 middot4~ (23)
3 x 104 lt( Re) 9 b( d1d6 )055 ltlo5 )
The heat transfer at the point of maximum heat trans
fer for each orifice size was correlated and presented in
Figure 13 as a plot of (Nu)(Pr)-l3 versus (Re)eb(d1de) 06
No simple po-orer relationship exists between the terms
Intensity and scale of turbulence downstream from the orishy
fice are probably important factors which affect the heat
transfer
The large effect of an upstream orifice on the heat
transfer rate at the second orifice was demonstrated by the
52
study of two 1 516 inch orifices in the test section The
added turbulence at the center of the second orifice was
found to raise the heat transfer rate almost three times
over that obtained for a single baffle
The pressure profiles in the vicinity of the orifice
indicate that nearly all the pressure drop occurs at the
orifice center~ Total pressure drop data were correlated
by a pressure drop function cent as a function of the Reynolds
number and good agreement obtained with the results of other
workers
The pressure drop and heat transfer data were correbull
lated by plotting the heat transfer as a function of the
pressure drop for each orifice size It was shown that for
a given pressure drop the largest orifice size gives the
greatest heat transfer coefficient
As a final presentation it was shown that the pressure
drop and the heat transfer coefficient both i ncrease i n
value at a constant flow rate as the orifice size is de shy
creased This is important in choosing the optimum clearshy
ance for orifice baffles
53
CHAPTER IX
RECOMMENDATIONS
A great deal of work remains to be done in the field of
evaluating shellmiddotside heat transfer coefficients This
study included only one tube size and air was the only f luid
used It is recommended that further studies be conducted
using other fluids and tube sizes It will also be necessary
to study several baffle types
The adde d turbulence due to a s e cond baffle placed upbull
s t ream would suggest that the heat transfer coef ficients at
a certain position i n relation to a baffle would increase as
the flow progressed through the exchanger It is recomshy
mended that an extensive s t udy should be made between baffles
the full length of a model heat exchanger
It is further recommended that the pressure drop study
be continued to include other fluids tube sizes and baffle
arrangements
Effects of turbulence downstream from the baff le should
be studied by i n vestigations with hot-wire anemometer equipshy
ment to determi ne t urbulence scale and i ntensity
54
NOMENCLATURE
Area of heat transfer
Heat capacity of the fluid
Outside diameter of the tube
Orifice diameter
Equivalent diameter of the orifice (d2 - dl)
Inside diameter of the test section
Inside diameter of the tube
Gravitational constant
G Mass velocity
h Local heat transfer coefficient
Coefficient of heat transfer from surface to fluid
i Direct current amperes
k Thermal conductivity of the fluid
L Distance downstream of the point of maximum heat transfer
p Absolute pressure
L P Total pressure drop across the orifice
Q Flow in cubio feet per minute at 1 atmosphere and 680 F
q Heat transferred
Thermal energy conducted into the sensing probe
Thermal energy radiated from the resistance ribbon
Resistivity of the resistance ribbon
s Length of the resistance ribbon
T Temperature oR
55
t Temperature of the resistance ribbon deg F
ta Temperature of the bulk stream oF
tw Wall temperature of the tube OF
U Veloc ity of the fluid
w Width of the resistance ribbon
z Thickness of the resistance ribbon
eeuro Density of the fluid in the test section
Density of the fluid at the flow orificef 0
AL Viscosity of the fluid
E9 Angle measured around the tube
Dimensionl ess groups
(Nu) Nusselt number hd1k
(Pr Prandtl number C~k
(Re)eb Equivalent Reynolds number at the baffle (d2 - d1 )uejt-Lshy
(Re)e Equivalent Reynolds number in the test section ( d 8 - d 1 )U fu
cent Orifice pressure drop function 2(~P ) gc~av(d2 - d1) 2
Al
56
BI BLIOGRAPHY
1 Ambrose Tommy W Local shell-side heat transfer coefshyficients in baffled tubular heat exchanger PhD thesis Corvallis Oregon State College 1957 183 numb leaves
2 Bell K J and o P Bergelin Flow through annular orif ices Transactions of the American Society of Mechanical Engineers 70593-601 1957
3 Colburn Allan P A method of correlating forced con shyvection heat transfer data and a comparison with fluid friction Transactions of the American Institute of Chemical Engineers 24 174-210 1933
4 Dittus F w and L M K Boelter Heat transfer 1n automobile radiators of the tubular type University of California Publications in Engineering 2443-461 1930
5 Gurushankariah M s Local shell-side heat transfer coefficients in the vicinity of baffles in tubular heat exchangers Masters thesis Corvallis Ore gon State Colle ge 1958 97 numb leaves
6 Knudsen James G and Donald L Katz Fluid dynamics and heat transfer New York McGraw-Hill 1958 576 p
7 Lee Kyu Sung Local shell-side heat transfer coeffishycients and pressure drop in a tubular heat exchanger with orifice baffles Masters thesis Corvallis Oregon State College 1959 118 numb leaves
8 McAdams William H Heat transmission 3d ed New York McGra ~-Hill 1954 532 p
9 Sullivan F W and 0 P Bergelin Heat transfer and fluid friction in a shell-andbulltube exchanger with a single baffle Chemica l Engineer ing Progress Symposium Series 52 ( 18) 85-94 1956
10 Wiegand J H Discussion on annular heat transfer coshyef f icients for turbulent flow Transactions of American Institut e of Chemical Eng i n eers 41147-153 1945
AP PENDIX
57
TABLE III
CALCULATED HEAT TRANSFER DATA
Baffle Hole Diameter Run No (inches)
1 - 59 1 364
60 - 102 1 216
103 - 138 1 316
139 - 206 1 516
207 - 212 No orifice
213 - 218 2nd - 1 516
TABLE III
CALCULATED HEAT TRANSFER DATA
Local Heat Transfer Coefficients Run
T0 bull Po s ition CFM hr h2 h3 h4 hs he ~ hav Nuav
1 c 1026 10 59 1476 16 09 1559 1510 1435 1203 1518 8511 2 1290 1369 1738 1878 18 05 1755 1689 1515 1773 9964 3 1416 1636 198 1 2068 1977 1924 1845 1715 1959 11030 4 1627 1991 2301 2382 2268 2194 20 ~98 1929 2249 12664 5 1776 2252 2669 2863 2713 2517 2338 2126 2620 14759 6 l2ttD 1109 2311 3317 3386 3373 3387 3394 3071 3371 18888 7 1258 3089 4583 4866 4683 4701 4643 4194 4695 26301 8 1433 38 8 5 55 83 5791 5495 5430 5436 5008 5547 31192 9 1681 4992 7378 7649 6980 6864 6870 64 28 7148 40180
10 1 D 1102 2371 3332 3511 3356 3342 3427 3102 3394 19012 11 1308 3218 4379 45 24 42 53 4255 4373 3965 43 57 24446 12 14 64 38 58 5146 5142 4839 4787 4903 4597 4963 278 79 13 1706 5218 6664 6269 58 81 5884 6237 5973 61 87 34718 14 15
1 l2D 1115 1275
2131 2661
2955 3638
2972 3720
2941 3675
2913 3576
28 22 34 74
2613 3278
2921 36 17
163 09 20246
16 1498 34 87 4644 4503 4441 4371 4343 4194 4460 25010 17 1695 4449 5743 5324 5222 5154 5157 5015 5320 298 97 18 2D 1049 1715 23 90 2550 2610 2656 2624 2208 2566 14363 19 1241 2117 2964 3145 3218 3221 3203 2759 3150 17757 20 1532 28 67 3936 4100 4188 4201 4167 3676 4118 23224 21 1674 3459 4508 4598 4746 4795 4792 4299 4688 26337 22 lU 1074 253 340 380 3 86 388 377 354 374 2097 23 1287 292 392 433 440 441 429 406 427 2394 24 1508 322 439 492 498 499 487 461 48 3 2713 25 18 07 3 38 464 519 5 24 520 499 463 5 05 28 40
~~ (]I agt
TABLE III Continued
Run No Position CFM h 1 h2 ~3 h4 h5 h6 ~ h
av Nu
av 26 c 1029 1171 1491 1589 15 28 1 4 62 1377 1293 1489 83 44 27 1266 1395 1746 1853 18 02 1685 1556 1453 1728 9704 28 1430 1637 2037 2175 2060 1909 1735 1591 1983 11159 29 1729 1982 24 96 2751 2507 2268 2030 1886 2410 13579 30 12D 1054 2934 4041 4321 4326 4423 4359 3706 4298 24160 31 1294 3385 4 8 26 52 42 5326 5450 5277 4566 52 24 293 50 32 1431 3784 5347 5721 57 bull75 58 44 5700 5084 5677 31870 33 1770 52 75 7 7 33 87 35 9005 9007 8267 7059 85 49 48050 34 lD 1058 3235 4401 4444 3877 3496 3451 3294 3934 21973 35 1263 38 98 5484 5330 4347 3964 3981 3987 4621 25823 36 18 36 6701 89 17 7855 6369 5597 5769 6283 69 01 38718 37 1 12D 1029 2404 31 8 2 3333 3459 3624 3577 3045 3435 19264 38 1315 3182 4033 4162 4310 4496 4502 4015 4301 24142 39 1426 3628 4389 4510 4573 4760 4804 43 8 5 4607 25678 40 1757 4547 5559 5(35 5931 6282 63 70 6060 5975 33471 41 2 11D 1080 2034 28 38 3155 3144 3145 2966 2540 3050 17027 42 1305 2650 3 4 87 3aoz 3595 3751 3595 3153 36 46 20405 43 1434 3167 39 07 4156 4371 4320 4126 3709 4176 23395 44 1804 4096 4 9 66 5691 5714 5586 53 15 48 65 5454 30582 45 12U 1088 409 516 557 564 5 60 535 513 5 46 30 67 46 1318 470 579 6 22 631 6 17 5 97 579 6 09 3422 47 14 13 540 640 676 6 86 681 6 60 6 54 6 69 3754 48 1773 641 740 774 782 7 69 749 746 763 42 87 49 l 11 U 1054 270 356 391 397 393 3 71 346 38 2 2133 50 1240 303 399 446 449 447 4 21 398 432 2420 51 1419 361 476 522 530 528 507 467 493 2760 52 1 1(2U 1032 236 311 342 347 344 325 301 334 18 78 53 1314 270 366 403 407 408 386 351 394 2217
(Tt tO
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ h av Nu av
54 1448 301 408 447 454 452 431 403 438 24 61 55 1782 353 494 548 544 415 529 531 506 2843 56 2U 10 61 220 287 316 320 322 303 268 310 1735 57 1216 249 335 370 377 378 353 307 363 2044 58 1322 263 356 394 398 399 374 327 384 2159 59 1639 310 433 478 481 482 452 393 465 2617
60 1D 10 68 2011 2536 2657 2681 2694 2560 15 62 2625 14938 61 1399 2520 3239 3369 3371 33r82 32 39 1946 3320 18968 62 1669 2781 3655 3820 38 76 3883 3738 2355 3794 21712 63 1959 3524 42 37 4399 4438 4497 4417 3047 4397 25156 64 2295 4426 5288 5396 5372 5240 5410 3369 5341 30680 65 2636 5490 6531 6662 6565 6379 6820 4249 6591 37938 66 3390 7869 9538 9462 9387 8924 10508 62 91 9564 59601 67 1U 1190 352 368 401 413 407 395 293 397 2256 68 1559 397 422 462 475 471 456 331 4 57 2603 69 1904 434 465 5 13 529 528 504 358 508 2901 70 2211 493 526 573 5 92 588 564 4 15 569 3257 71 2289 569 587 6 30 649 6 61 6 49 460 635 36 44 72 2727 637 6 60 7 09 733 751 743 521 719 4140 73 3210 728 755 8 15 8 43 8 62 8 54 616 826 4765 74 2nD 1210 181 2256 2393 2399 2333 2206 1325 2317 13158 75 1420 2340 2752 2899 2913 2850 2728 1701 2828 16121 76 1692 2853 3306 3452 3471 3379 3217 2134 3365 19217 77 1894 3102 3588 3713 3736 3670 3557 2455 3653 20892 78 2301 3682 4259 4433 4467 43 83 4289 2892 4366 250 30 79 2621 4117 4828 5017 5012 5030 5109 3071 4999 28785
m 0
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ hav Nuav
80 3230 5158 6006 62 13 61 18 6134 6695 4094 6233 359 87 8 1 12nD 1155 15 27 1854 2028 2064 20 85 1987 1164 1968 118 31 82 1689 2046 24 8 2 2688 2739 2760 2658 1749 2665 152 73 83 1244 2088 2317 2339 2345 2373 2381 1487 2351 13432 84 2100 3211 3539 34 21 3462 3512 3696 2575 3526 20284 85 2292 3 5 05 3761 3648 36 25 36 79 3957 2933 3734 21517 86 2907 4420 48 22 4679 46 04 4705 5206 3792 48 03 27741 87 33 80 59 35 69 38 7404 77 10 7 8 36 7 0 86 5190 7394 427 44 88 1 12D 1 4 27 2 4 58 28 31 3037 3021 2987 2927 18 57 2 9 61 16913 89 18 75 34 75 3 9 87 4230 4255 4317 4337 2734 4225 24258 90 22 59 4221 4796 5046 5052 51 01 5389 3491 5077 29206 91 2682 4978 5664 5943 5966 6054 6573 408 1 60 40 34795 92 3417 63 16 71 02 7 3 93 7385 75 40 8 6 95 51 45 7623 44017 93 c 1 5 17 1240 1305 1399 1467 1479 1429 9 26 1423 8251 94 20 34 1554 1623 1720 18 21 18 53 18 72 1215 1778 10229 95 2 3 48 1795 1843 198 5 2097 2171 2274 1540 2074 11947 96 2716 2028 2048 22 01 2 3 44 2444 2661 18 90 2340 13505 97 3247 2410 2375 2663 2778 2949 3298 2378 2793 1615 98 11 35 967 1040 1124 1186 1200 1142 728 1138 6496 99 14 06 1135 1220 1318 1384 1403 1 3 61 8 77 1336 7656
100 2311 1 8 54 18 78 1980 20 90 2136 2227 1653 2062 118 31 10 1 2666 2085 2094 2227 2 3 62 2438 2626 1902 2349 13508 102 3392 2635 2582 28 01 3026 3141 3529 2567 3016 17390
103 1 U 1235 349 395 434 436 4 28 411 286 423 2416 104 20 10 434 5 02 559 577 569 5 37 345 552 3177 105 28 14 538 626 685 711 7 21 682 424 6 8 6 3966
Q) j-J
TABIE III Continued
Run No Position CFM h1 h2 h3 h4 h5 hu h7 hav Nuav
106 3492 614 7 1 6 7 84 8 13 8 33 7 85 4 88 7 87 4562 107 4395 7 86 894 964 996 1005 9 64 640 9 65 56 06 108 50 75 9 11 10 22 1081 1112 1125 1085 7 24 1085 63 16 109 G 1344 9 22 1042 1120 1 1 46 1173 1131 7 04 1120 63 87 110 1936 1162 1340 1442 1474 1509 14 7 3 9 09 1441 82 77 111 2846 1631 1797 1902 1966 2027 2079 1342 19 2 3 11108 112 3484 207e 2144 2236 2307 2385 2574 1694 2268 13138 113 4066 24 65 24 42 2535 2648 2757 31 71 2178 2 5 96 15078 114 50 12 3059 2916 30 1 5 3176 3312 4059 2849 3105 180 46 115 1D 1362 2268 26 13 2613 26 35 2605 2503 15 46 2617 14934 116 1958 2993 3580 3580 3586 3539 3 5 02 2144 3571 20492 117 2812 4430 50 32 4913 4 9 86 4991 5196 3088 4981 287 66 118 3432 58 16 62 13 6067 61 18 60 66 6698 4143 61 16 354 16 119 40 22 71 71 7 4 62 7369 7419 7329 82 74 51 8 1 7395 42909 120 5026 105 95 11456 115 81 11574 11548 14010 80 91 11540 671 15 121 2D 1244 18 57 2277 2363 2305 2210 2107 1466 2289 13038 122 1960 2622 3240 3388 33 23 3226 31 40 2)99 3294 18919 123 2817 3762 45 87 4739 46 56 45 14 4 6 47 30 15 4624 26689 124 3491 50 22 5723 58 53 57 44 5542 60 18 3871 57 16 330 73 125 4096 61 29 68 16 69 79 6805 65 90 74 79 4677 67 98 39400 126 5037 82 27 94 60 95 69 93 57 9023 11324 65 05 93 52 542 83 127 12D 1278 14 70 1 6 48 1652 1638 1 6 34 1641 9 73 1 6 43 9369 128 1947 19 63 2155 2149 2151 2131 2190 1347 2147 12342 129 2769 2615 2791 2773 28 52 2716 2954 18 96 2783 1 60 82 130 3439 3208 3265 3239 3593 3133 3624 2515 3308 19174 131 4103 3637 35 88 3577 4077 3459 42 66 3138 3676 21343 132 49 78 45 82 44 60 44 8 1 55 17 43 25 5749 4227 4700 27288
Q) tlgt
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
133 1 12D 1299 2094 2507 2622 2625 2567 2489 1465 2578 14736 134 1973 29 56 3505 3772 3790 3718 3718 2115 3700 21290 135 2788 3941 4727 5069 5099 5 0 07 5231 2984 4976 28781 136 3473 5155 59 81 6308 6339 62 39 68 96 4204 6217 36052 137 4118 6135 71 8 6 7662 7731 76 91 87 16 49 8 5 7568 43985 138 4973 7765 94 75 10396 10861 10694 13646 66 64 10357 602 25
139 1ttn 1253 1242 1493 1460 1442 1431 1424 8 84 1457 83 01 140 2366 1942 2150 1961 1910 1897 19 62 1206 1980 11400 141 3461 3007 2957 2562 2513 2606 3143 18 51 2660 15400 142 4325 3942 3571 3060 2999 3198 4248 2631 3207 18618 143 5677 508 6 4359 39 88 3800 42 29 57 78 36 26 4094 23824 144 67 59 64 55 5330 4988 47 25 5494 2517 48 09 5134 29906 145 84 08 9326 72 26 7726 85 56 9172 12319 7733 8170 47626 146 86 54 9831 7582 818 9 94 90 9869 13116 78 97 8783 512 96 147 7376 7335 58 7 6 5941 5796 68 29 81 65 5954 6111 35662 148 2 11 D 4254 4106 48 02 4994 5038 5042 56 78 3419 4969 28881 149 5708 5487 6253 6466 6524 6527 78 63 45 8 2 64 43 37566 150 69 7 8 7983 9440 9848 98 34 97 32 13249 6701 9714 566 59 151 1254 1434 18 53 1947 1915 1850 1760 1186 1891 10772 152 2713 2696 3175 32 94 3288 3237 3288 20 44 3249 18728 153 87 30 118 07 14733 15758 15504 15305 26297 9617 15325 892 71 154 5811 5278 6543 6861 69 30 69 82 7 8 74 4478 68 29 39531 155 4246 3780 4736 4975 49 66 4936 5162 3113 4903 28301 156 (v 1270 8 15 935 959 966 9 51 9 23 6 35 953 5430 157 2714 1164 1390 1427 1447 1454 1455 9 08 1430 8242 158 4310 1655 18 96 1942 1988 2002 2111 1305 1957 11349
(j) ~
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 fry hav Nuav
159 6012 2208 2400 2450 2513 2548 28 20 18 00 2478 14416 160 7279 2696 2881 2927 2989 3081 3599 2340 2970 17326 161 86 90 3257 3360 3 3 76 34 26 3558 4455 2943 3430 2000 162 12D 4368 2209 2600 2558 2518 2466 2774 1753 2536 14713 163 5833 2730 3092 3028 2974 2913 3501 2287 3002 174 78 164 7643 3320 3681 3630 3651 3530 4623 3181 3623 21116 165 87 39 3920 4303 4300 4708 4178 61 60 3937 4372 25456 166 1268 962 1203 1205 1186 1118 1084 725 1178 6693 167 2678 14 67 1785 1779 1752 1698 1726 10 70 1754 88 49 168 1 12D 12 83 936 1217 1414 1397 1239 1190 7 65 1317 7484 169 2729 2502 2930 2914 2934 2956 2979 17 52 2934 16866 170 4345 3884 4357 4283 4318 4421 4836 28 59 4345 25151 171 6036 5546 5858 5764 5791 6028 7129 4184 5860 34045 172 6578 7167 7769 7907 79 82 8263 10492 5915 7980 46437 173 87 84 10237 112 23 120 26 12727 12968 185 19 85 98 12236 71103 174 1278 1344 1803 18 72 1835 1790 1712 1063 1825 10355 175 2711 2328 2972 2932 2893 28 78 2863 1667 2919 167 51 176 4351 3934 4414 4353 4281 4321 4654 28 63 4342 25088 177 5994 5076 5824 5838 5818 59 29 6914 4205 5852 33885 178 1 11 U 1223 388 432 465 464 449 435 338 453 2585 179 2351 521 602 6 22 675 6 57 619 436 639 3687 180 34 48 6 05 1725 803 8 27 8 11 760 518 792 4593 181 4513 718 850 934 9 68 9 57 8 99 609 9 27 5386 18 2 5714 8 32 981 1060 1102 11 06 1034 6 59 1062 61 82 183 6997 1025 1182 1258 1295 1309 1234 8 18 1261 7 3 44 184 8709 1295 1487 1 5 42 1594 1626 1612 1156 1562 9080
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
185 2 12D 4249 3560 4400 4670 4791 4695 47 81 2931 4639 268 37 186 5737 4926 58 54 61 92 6248 62 38 67 78 4134 6131 35590 187 7432 6390 7726 83 46 85 44 86 34 10371 5658 8313 48310 188 8723 7718 107 88 11933 12099 13046 186 22 79 39 119 67 69505 189 1 4 35 1340 1735 18 57 18 52 17 81 1711 1144 18 06 10256 190 2718 2399 3023 3187 3207 3138 30 53 1931 3139 18025 191 7 5 07 6189 80 11 9200 9427 9703 11364 5720 9085 527 38 192 8544 78 42 10666 125 42 13312 13775 178 20 6976 125 74 729 86 193 1287 1417 16 97 18 7 18 69 18 08 1720 1046 1800 10223 194 27 17 2450 2940 3187 3214 3157 3054 1749 3125 17954 195 42 53 3560 4222 45 90 4679 46 63 4743 2741 4539 26247 196 6068 48 69 57 79 6335 65 8 6 66 04 7172 4338 63 26 366 78 197 7389 58 86 72 8 6 82 23 8584 8936 10658 50 60 8257 4798 6 198 86 88 78 91 100 27 120 56 130 29 14299 190 81 6492 12353 71850 199 5864 4694 5 6 67 61 94 6419 65 48 7192 3950 6207 360 14 200 2 D 4177 38 36 4547 48 09 4775 4628 5006 2715 46 90 261 30 201 5712 5170 62 39 66 38 6599 6604 7518 4167 65 20 378 00 202 73 63 7201 8986 98 43 9733 9914 13353 6219 9619 55810 203 8604 10043 13118 148 41 150 42 158 66 25206 82 5 3 14717 85290 204 12 68 1506 18 41 1971 1966 1868 1799 11 42 1913 10880 205 2659 2571 3127 3276 32 50 3130 3069 18 80 3196 18 350 206 39 80 36 76 4347 4573 45~67 4473 46 34 28 37 4490 25910
o 207 Orifice 11496 10 64 1360 15 39 1 5 80 1 6 15 1496 8 58 15 24 88 83 208 9433 8 95 11 78 13 26 1394 1386 1263 727 1346 78 48 209 7387 746 9 77 1123 1184 1159 1048 6 11 1111 64 74 210 52 36 566 7 66 900 934 909 8 21 499 8 27 48 02
0) CJ1
TABLE III Continued
Run No Position CFM h 1 h2 hs h4 h5 h6 h7 hav Nuav
211 212
3309 1293
414 257
563 3 19
6 68 3 57
6 91 3 37
6 72 351
7 37 337
38 4 2 46
4 40 341
3748 1942
213 214 215 216 217 218
c of 2nd 1 516 1235
1919 2712 3320 4153 4704
1532 2447 35 46 4312 5567 74 29
2 1 87 3312 4225 52 86 6902 8 6 50
2360 3555 4340 56 12 7 0 49 8 9 40
2409 3598 4 8 85 5718 7713 9593
2347 2101 35 33 3453 48 00 49 62 5562 59 86 72~6 7 8 79 93 76 11237
1243 20 64 3054 4 2 8 1 5114 6983
2326 35 00 4638 5545 7225 91 40
132 13 200 27 26672 31968 41711 52811
bull
67
TABLE IV
PRESSURE PROFILE DATA
Baffle Flow Qpening Rate ~p
(Inches) Position (CFM) (Inches 295 S G Fluid)
1 364 l2 11 U 1012 0 254 1248 0197 1493 0 141 1718 0112
c 1000 9 80 1210 1710 1436 28 75 1746 4320 1011 1080 1277 2050 1393 3020 1 6 28 4450
12D 1011 9 75 1236 1520 1450 2510 1603 3450
1 D 1011 975 1256 1700 1480 2690 158 1 4070
1 12D 1010 950 1259 1750 1462 2650 1631 3710
2 11 D 1124 1315 1360 2130 1505 2850 1689 4125
1 216 12U 1294 045 1949 0324 2374 0282 2704 0225 3367 0169
c 1326 265 18 81 5 90 2313 990 2731 1480 3439 2660
12D 1272 2 49 1957 661
68
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Pos ition (CPM) Inches 2 95 S G Fluid)
2559 1275 3033 1940 3639 3025
1 216 1nD 1257 242 16 96 476 2117 8 05 2561 1280 2990 1895 3431 26 bull00
1 316 12U 1309 0 479 2004 0422 28 28 0 352 3526 0281 42 28 0225 5199 0225
c 1308 1 43 1998 272 28 14 5 10 3478 795 4248 1235 5048 1885
l2D 1286 140 2005 3 45 2831 725 3495 1180 4194 1805 5046 2945
1 11D 1322 150 2039 352 2841 735 43 77 1980 5378 3440
1 516 12U 1278 0493 2732 0493 4315 0408 5744 0352 7494 0352 8932 0422
c 1300 0 506 2731 1985 4310 348 6080 6 45
69
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Position (CPM) (Inches 295 SG Fluid)
7607 1090 8830 1585
l2D 1343 0549 2738 225 4566 583 6112 1195 7536 2055 9043 3415
1 516 1uD 1249 0464 2713 224 4155 579 5620 1150 7428 2115 90 70 3405
1 12D 1301 0493 2735 220 4501 616 61 50 1235 7440 2065 8862 3445
2D 1265 0 478 2750 226 4366 594 6578 1270 7678 2240 8945 5280
2 12D 1295 0493 2725 222 4293 600 5807 1120 7568 2200 9070 3615
TABLE V
RATE OF HEAT TR AN SFER Ar THE BAFFL~~ CID-TT ER
Orifice Size
(Inches)
Flow Rate
( CFM)
Re d e G tU
R~) 055 Nuav NuPr-l3
1 364 10 26 12 90
8 075 10015
43400 54 600
85 11 99 64
95 83 112 19
1416 11 140 59 900 110 30 124 20 16 27 12 800 68 900 126 64 142 60 17 29 13 610 73 200 135 79 152 90 17 76 13980 75 200 147 59 166 19
1 216 11 35 14 06
8 600 10 660
27000 33500
6 4 96 76 56
73 14 8 6 12
1517 11500 36100 82 51 9291 20 34 15400 48400 10229 115 18 23 11 17500 55000 118 31 13322 2348 17 800 55900 11947 13452 2666 20 200 63400 13508 15210 27 16 20 600 64700 135 05 152 07 32 47 24600 77200 161 57 18 193 3392 25 700 80700 17390 195 8 1
1 316 1344 19 36
9898 14 260
24800 35 700
63 8 7 8 2 77
71 92 93 20
28 46 20 9 60 52 500 111 08 125 08 34 84 25 660 64200 131 38 147 93 40 66 50 12
29900 36900
74800 92400
150 78 18046
169 78 203 20
~ 0
TABLE V Continued
Orifice Flow Re Size Rate d e G R~rmiddot55 NuPr-13(Inches) (CFM) U Nuav
1 516 12 70 8 847 16800 54 ~0 61 14 2 14 18 900 35800 82 42 92 80 43 10 30 000 56900 11349 127 79 60 12 41900 79400 14416 16232 7279 50700 96100 17326 19509 86 90 60540 115000 20098 22529
TABLE VI
RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
Orifice Size
(Inches)
1 364
1 216
1 316
Flow Rate
(CFM)
1054 1294 1431 1681 1770
1068 1399 1669 1959 2295 2636 3390
1299 1973 2788 34 73 4118 4973
Re deG Mshy
8 300 9870
11260 13200 13 930
8100 10600 12650 14850 17400 19980 25700
9 570 14500 20500 25600 30300 36600
R~r-6 51900 61700 70500 82 500 87 100
28200 36900 44000 51700 60 600 69500 89400
26100 39600 56000 69900 82700 99 900
Nuav
2416 293 5 3187 4018 4805
14938 18968 21712 25156 30680 37938 59601
14736 21290 28781 36052 439 85 60225
Uu Pr-1 3
27204 33050 3589 4524 541 0
16820 21358 24448 28326 34546 427 18 67111
16593 23973 32407 40595 495 1 678 13
TABLE VI Continued
Orifice Flow Re Size Rate deG R~rmiddot6 NuPr-13(Inches) (CFM ) M- Nuav
1 516 1268 88 30 17700 108 8 1225 2689 18700 37400 1835 2066 3980 27700 55700 2591 2917 4177 29100 58 500 2713 3055 5712 39800 80000 378 0 425 6 7362 51300 103000 5581 6284 8 604 59 900 120000 8529 9604
74
TABLE VII
EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER
l 516 Inch Orifice
Center ot 2nd Baffle 4 Downstream
Plow Rate (CFM)
1235 1919 2712 3320 4153 4704
Flow Rate (CFM)
1270 2714 4310 6012 7279 8690
(Re)eb -8600 1321
13400 2003 18900 2687 23100 5197 28900 4171 32800 5281
Center ot Single Battle
-8847 543
18900 824 30000 1135 41900 1442 50700 1733 60540 2001
(Nu)(Pr)-l3
1487 2255 3003 3600 4697 5946
(Nu)(Pr)-13
611 928
1278 1623 1951 2253
75
ABLE VIII
HEAT TRANSFER IN THE TEST SECTION WITHOUT ORIFICE
CFM Ute) 0b h Nu
1293 5-951 3 41 1942
33 09 15251 649 3746
5236 24193 827 4802
7387 34001 1111 6474
9433 43419 1346 7848
11496 52-914 1524 8883
76
TABLE IX
PRESSURE DROP FUNCTION
Orltlee Size Flow Rate incbea ~CFM (Re)eb X 10bull8
1 364 1011 7957 0808 1256 9885 1468 1480 11648 2765 1581 12443 4160 1689 1_3293 4 020
1 216 1257 9530 1327 1696 12858 2663 2117 16049 4615 2561 19415 7581 2990 22668 11560 3431 26011 16440
l 316 1322 9736 1819 2039 15016 4332 2845 20952 9275 3495 25739 15300 4377 32014 26800 5378 39607 50100
1 516 1011 7 957 oaos 1256 9885 1469 1480 11646 2765 1581 12443 4160 1689 13293 4020
77
TABLE X
EXPERIMENTAL DATA
Baffle Hole Diameter Run No
1 - 59
60 - 102
103 - 138
139 - 206
207 - 212
213 - 218
(Inches)
1 364
1 216
1 316
1 516
No Baffle
2nd - 1 516
TABLE X
EXPERIMENTAL DATA
Run Thermocouple Reading s (mv) No Position CFM I tc1 tc2 tc3 tc4 t c 5 tc6 tc7 tcair
1 c 1026 530 2055 1825 1768 1782 1802 1837 1965 1198 2 1290 612 2059 18 65 1809 18 32 1851 1880 1965 1160 3 1416 714 2151 1970 1931 1965 1988 2026 209 5 1130 4 1627 8 21 2235 2084 2 049 2093 2126 2173 2266 1130 5 1776 865 2203 2033 1970 2015 2084 2159 2 264 1121 6 12D 1109 542 1636 1507 1499 1499 1498 1498 1528 1218 7 1258 651 1670 1522 1503 1513 1513 1516 1548 1221 8 1433 750 1625 1480 1467 148 3 1487 1487 1516 1153 9 168 1 8 73 1656 1494 148 1 1511 1517 1517 1543 1159
10 1rtD 1102 485 1545 1450 1437 1446 1447 1442 1466 1220 11 13 08 6 10 1571 1470 1460 1476 1476 1469 1498 1194 12 1464 730 1 623 1509 1508 1528 1 5 32 1524 1548 1173 13 11 06 8 71 1663 1559 158 1 1606 160 6 1 583 1601 1190 14 1 12D 1115 520 1698 1579 1575 1 577 1580 1590 1615 1280 15 1275 6 10 1692 1567 1558 1 561 1570 1580 1601 1234 16 1498 770 1760 1619 1630 1 635 1642 1645 1661 1204 17 1695 912 1775 1635 1670 1689 1686 168 6 1701 1165 18 2D 1049 510 1736 15~2 1567 1558 1 553 1558 1620 1236 19 12 41 610 1655 1517 149 1 148 1 148 1 148 4 1546 1108 20 1 5 32 7 35 1720 1550 1530 1520 1519 1523 158 0 1104 21 16 74 8 8 0 1900 1 727 1714 1696 1691 1692 1753 1169 22 1U 1074 38 5 3 324 2740 2534 2478 2 465 2503 258 0 1210 23 1287 4 35 3510 2 870 2682 2 610 2599 2638 27 1 9 1190 24 1 5 08 470 3 618 2920 2690 2 637 2627 2 664 2747 1177 25 18 07 525 4 088 3235 2962 2905 2910 2988 3130 1169
z ())
TABLE X Continued
Run No Position CFM I tc1 tc 2
Thermocouple Readings te3 tc4 tc5
(mv) tc6 tc7 tcair
26 c 10~29 6 32 2340 2~092 2032 2060 2~097 2152 2~213 1211 27 12 66 679 2270 2 047 1993 2013 2069 2142 2 210 1 182 28 1430 723 2336 2097 2033 2080 2153 2~255 2 356 1 138 29 1729 8 52 2318 2070 1980 2061 2158 2279 2367 1121 30 12D 1054 570 1520 1 4 20 1402 1400 1396 1400 1 443 1159 31 1294 6 69 1599 1469 1444 1439 1433 1 442 1485 1168 32 1430 7 88 1720 1562 1536 1532 1528 1537 158 0 118 5 33 1770 8 81 1641 1488 1450 1~441 1 441 1_466 1518 1 163 34 1D 1058 548 1579 1498 1495 1526 1553 1_557 1 571 1 276 35 1263 640 1609 1509 1515 1570 1599 1598 1 598 1 266 36 18 36 8 47 1538 1452 1483 1553 1602 1 590 1 558 1195 37 1 12D 1029 5 41 1 578 1499 148 4 1473 1461 1465 1-512 1200 38 1315 6 30 159 1 1504 1493 1482 1470 1470 1505 118 5 39 1 4 26 743 1765 168 1666 1660 1645 1642 1678 1270 40 1757 8 54 1744 1648 1634 1620 1598 1 593 - 1612 1223 41 2D 1080 5 30 1734 1604 1570 1 570 1570 1 588 1 640 128 1 42 1305 6 40 1744 1622 1589 1 608 1593 1 609 1 661 1240 43 1434 750 1798 1687 1658 1 636 -1641 1 661 1 711 1_220 44 18 04 8 41 1 764 1666 1607 1605 1614 1 635 1 675 1205 45 12nu 1088 415 2614 2295 2195 2 169 2174 2217 2256 1171 46 1318 477 2805 2477 2371 2342 2364 2 401 2 438 1 163 47 1413 5 28 2930 2 646 2 555 2 526 2532 2570 2 577 1 199 48 1773 550 2740 2518 2450 2431 2448 2 479 2 480 1 170 49 1 11 U 1054 380 3175 2670 2505 2 461 2467 2 534 2 621 1 258 50 1240 420 3268 2738 2 546 2 510 2 508 258 2 2 649 1214 51 1419 451 3364 2B07 2 632 2590 2 590 2 651 2773 1 215 52 1 12U 1032 360 3 165 2 629 2 450 2402 2403 2 473 2 bull568 1 163
--I lt0
TABLE X Continued
Run No Position CFM I tc1 tc2
lhermocoup1e Reading s tc3 tc4 t c 5
(mv) tc6 tc7 tc a ir
5 3 1314 38 9 3178 2592 2411 2367 2361 2432 2555 1140 54 1448 403 3095 2544 238 1 2336 2336 2390 2476 1158 55 178 2 427 3006 2434 2286 2253 255 3 2299 2397 1154 56 2 11U 1061 360 3369 2814 2619 2567 2560 2650 2833 1220 57 1216 360 3044 2512 2338 2290 2288 2374 2566 1150 58 1322 387 3196 2614 2425 2383 2382 2472 2670 1138 59 1639 403 3020 2438 2272 2238 2238 2318 2502 1127
60 1D 1068 612 1552 1424 1400 1395 1396 1426 1745 0945 61 1399 612 1355 1246 1230 1229 1230 1250 1509 0872 62 1669 710 1436 1293 1272 1265 1266 1286 1551 0847 63 1959 900 159 5 1468 1444 14 38 1432 1446 1720 0851 64 2295 730 1169 1105 1098 1099 1108 1100 1298 0781 65 2636 8 80 1202 1129 1121 1126 1 138 1115 1342 0748 66 3390 9 35 1060 o 9s7 0999 1001 1017 0971 1154 0703 67 1nu 1190 370 2225 2188 2104 2080 2120 2209 2 7 15 0990 68 1559 368 2005 1950 1871 18 48 1876 1951 2408 0916 69 1904 368 1870 18 1 4 17 34 1711 1730 18 07 2238 0875 70 22 bull11 471 228 6 2 204 2099 2063 2092 218 $ 2732 0840 71 2289 471 2030 2000 1925 1895 18 96 19 5 2498 0785 72 2727 4 71 1854 18 23 1753 17 23 1716 3758 2241 0743 73 3210 471 1680 1651 158 6 1559 1551 158 1 1950 omiddot7o9 74 2uD 1210 404 1261 1212 1198 1197 1205 1222 139 1 0978 75 14 20 540 1321 1260 1242 1 240 1249 1268 148 7 0918 76 1692 7 18 1467 138 6 1364 1361 1376 1405 1678 0883 77 18 94 903 1708 1 591 1565 1560 1575 1603 1948 0 857 78 2301 903 1530 1432 1407 1402 1415 1432 1738 0815
ro 0
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc117 tcair
79 2621 6 50 1069 1 020 1009 1009 1009 1007 1~189 o739 80 3230 901 1200 1128 1113 1119 1119 1086 1341 0694 81 82
l2D 1155 1689
360 575
1191 1345
1142 1252
1122 1218
1118 1210
1118 1209
1132 1228
1292 1446
0916 0822
83 1244 430 1163 1134 1131 1130 1129 1132 1292 0877 84 2100 645 1175 1135 1147 1 142 1138 1122 1286 0757 85 2292 8 25 1 354 1310 1327 1330 1323 1285 148 6 0728 86 2907 8 23 1180 1138 1151 1158 1149 1107 1268 0687 87 3380 902 1113 1049 1025 1011 1006 1042 1178 0673 88 89
1 12D 1427 1875
480 615
118 2 1140
1140 1095
1124 1077
1125 1075
1129 1072
1137 1072
1290 1243
0880 0790
90 2259 8 41 1296 1231 1207 1206 1203 1182 1419 0757 91 2682 8 80 1231 1170 1149 1147 1142 1112 1350 0731 92 3417 940 1142 1092 1076 1076 1069 1021 1252 0693 93 c 15 17 431 1321 1298 1268 1249 1250 1273 1522 0841 94 2034 505 1285 1263 1235 1209 1205 1206 1464 0759 95 2348 6 10 1395 1379 1334 1302 1286 1268 1536 0732 96 2716 706 1486 1480 1427 1383 1358 1311 1572 0 700 97 3247 7 56 1417 1430 1375 1320 1284 1223 1450 0660 98 1135 400 1425 1388 1352 1329 1330 1 364 1651 0893 99 14 06 440 1379 1341 1304 128 2 1281 1305 1583 0 831
100 2311 680 1602 1593 1553 1514 1502 1480 1 7 27 0 802 101 2666 680 1471 1469 1428 1390 1372 1335 1564 0761 102 3392 798 1491 1 509 1449 1395 1372 1305 1534 0 719
103 1U 1235 410 2469 2295 2173 2165 2226 2361 3120 0 897 104 2010 410 2017 1848 1 737 1706 1747 1865 2582 0753 105 28 14 410 1682 1535 1457 1427 1437 1520 2109 0 660
00 t-
TABLE X Continued
Ru n Thermocouple Rea ding s (mv No Positi on CFM I tc1 tc2 tc3 tc4 tc5 tc6 tc7 tcair
106 3492 440 1649 1499 1420 1391 1390 1470 2042 0620 107 4395 550 18 33 1679 1597 1564 1570 1640 2223 0583 108 5075 588 1779 1642 1580 1550 1552 1 615 2 191 0548 109 c 1344 398 1464 1 399 1364 1353 1350 1380 1689 0 907 110 1936 459 1369 1290 1253 1242 1 237 1259 1574 078 2 111 2846 580 1347 128 5 1251 1232 1220 1215 1 5 23 0 683 112 34 8 4 700 1392 1369 1339 1317 1299 1259 1599 0 636 113 4066 8 13 1449 1458 1427 1391 1363 1270 1595 0 591 114 5012 930 1484 1530 1500 1453 1420 1272 1580 0 580 115 1D 1362 513 1269 1218 1 217 1214 1220 1238 1460 0 893 116 19 58 600 1187 1122 1121 1120 1124 1133 1352 0798 117 2812 705 1052 1008 1015 1010 1011 1001 1218 0691 118 34 32 913 1105 1075 1085 1081 1086 1047 1301 0645 119 4022 980 1038 1021 1026 1023 1029 0983 1211 0 609 120 5026 982 0 8 61 0839 0836 0836 0837 0791 0955 0570 121 2D 1244 475 1320 1246 1233 1240 1255 1275 1434 0925 122 1 9 60 5 50 1160 1088 1074 1079 1089 1100 1260 078 7 123 2817 6 80 1096 1024 1 013 1018 1029 1022 1201 0 700 124 3491 960 1248 1175 1163 1172 1192 1153 1435 0 658 125 4096 989 1141 1089 1078 108 9 1105 1051 1310 0629 126 50 37 989 0983 0933 0929 0 936 0949 0880 1090 0 602 127 128
12D 1278 1947
402 545
1270 1261
1 230 1216
1228 1216
1230 1 215
1235 1223
1242 1219
1483 1514
0 913 0778shy
129 2769 695 1273 1234 1237 1221 1251 1212 1525 0678 130 131 132
34 39 4103 4978
8 40 9 80 9 80
1336 1448 1271
1322 1458 1 288
1328 1 462 1286
1 259 1 356 1157
1353 1492 1311
1261 1329 1138
1 555 160 7 1343
0 629 0 600 0599
(l) l)
TABLE X Continued
Run No Position CFM I tel tc 2
Thermocouple Readings tc3 tc4 tc5
( mv) tc6 tc7 tcair
133 1 l2D 1299 5 16 1 28 1 1212 1196 1195 1205 1221 1478 0869 134 1973 6 15 1163 1098 1073 1071 1079 1083 1343 0751 135 136
27 88 34 73
802 9 -_78
1187 1214
1099 1131
1069 1104
1066 1101
1075 1~110
1l061 1066
1370 1360
0662 0618
137 4118 9 81 1084 1010 0983 0979 0982 o937 1209 0581 138 4973 98 1 0969 0897 0 868 0855 0860 0799 1041 0572
139 1D 1253 409 1371 1293 1298 1301 1309 1321 1578 0928 140 2366 480 1130 1 090 1 121 1130 1137 1132 1390 0744 141 34 61 6 38 1081 1086 1152 1161 1147 1069 1382 0644 142 143 144
4325 5677 6759
7 90 939 998
1110 1115 1034
1161 1208 1139
1253 1268 1180
1265 1302 1215
1228 1230 1123
1080 1056 0970
13$913r12 8
0601 0561 0542
145 84 08 989 0863 0961 0934 0895 0871 0 785 09 9 0530 146 86 54 9 80 0808 0901 0 872 0821 0809 0733 0891 0498 147 7376 9 80 0 927 1032 1027 1 040 0961 0889 1032 0511 148 2D 4254 776 1 050 0 981 0965 0961 0962 0922 1155 0579 149 5708 991 1102 1031 1014 1009 1010 0931 1227 0528 150 69 78 990 0914 0853 0839 0 839 0843 0759 0996 0521 151 1254 490 1 479 1352 1329 1334 1351 1379 1607 0930 152 2713 7 00 1310 1220 1201 1201 1211 1209 1516 0723 153 8730 991 0809 0756 0742 0745 0 748 0663 0874 0543 154 5811 966 1219 1108 108 6 1081 1079 1033 1330 0650 155 42 46 8 02 1248 1136 1114 1114 1118 1103 1376 0 699 156 c 1270 429 1671 1571 1551 1545 1563 1600 1933 0929 157 2714 488 1398 1285 1 267 1258 1262 1275 1628 0729 158 4310 642 1424 1318 1299 1282 1283 1261 1683 0617
co ~
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc7 tc a 1r
159 60 12 780 1461 1388 1370 1349 1343 1279 1700 0 573 160 72 79 8 60 1402 1344 1330 1312 1292 1189 1 566 0 520 161 8690 982 1472 1442 1437 1 422 1392 1224 1602 0 521 162 163
12D 4368 5833
6 30 8 30
1195 1368
1105 1270
1111 1283
1117 1294
1131 1313
1081 1194
1369 1553
0613 0 553
164 76 43 959 1428 1338 1348 1341 1371 1180 1488 0535 165 8739 984 1345 1272 1272 1208 129 3 1059 1361 0550 166 1268 459 1701 1548 1541 1547 1589 1 625 1976 0 973 167 2678 570 1485 1351 1349 1356 138 1 1 385 1795 0760 168 169
1 12D 128 3 2729
448 650
1664 1314
1501 1232
1425 1233
1428 1229
1491 1229
1527 1232
1869 1571
0 962 0767
170 4345 847 1245 1179 1187 1182 1172 1132 1476 0 650 171 6036 9 76 1139 1109 1117 1114 1095 1020 1332 0588 172 6578 9 72 0982 0949 0942 0938 0926 0 8 50 1079 0560 173 87 84 9 72 0880 0854 0 8 36 0822 0818 0 749 0941 0585 174 1278 480 1564 1416 1397 1403 1417 1445 1733 0998 175 2711 590 128 3 1175 4 1178 1182 1187 1195 1493 0796 176 4351 8 90 1331 1259 1266 1275 1272 1235 1592 0 682 177 5994 9 60 1228 1152 1150 1151 1143 1075 1 360 0644 178 lU 1223 408 2282 2140 2052 2052 2106 2188 2626 0 878 179 2351 408 178 1 1623 158 5 1519 1556 1634 2068 0717 180 3448 482 1888 1675 1570 1541 1572 1665 2199 0629 181 4513 563 2026 1797 168 4 1644 1670 1770 2385 0583 182 5714 589 1913 1700 1610 1568 1580 1 682 2382 0551 middot 183 6997 653 1903 1718 1643 1611 1612 1700 2326 0 549 184 8709 6 80 1738 158 3 1543 1510 1498 1519 1 912 0577 185 186
2 12D 4249 5737
660 9 74
1055 1221
0 979 1122
0960 1093
0 952 1088
0959 1090
0 956 1054
1147 1350
0661 0602
187 7432 9 8 1 1065 0981 0951 0942 0 939 0881 1135 0582 CD ~
TABLE X Continued
Run No Position CFM I t o1 to 2
188 87 23 9 83 0944 0 879 189 1435 585 18 26 1630 190 2718 690 1433 1298 191 7507 950 1070 0961 192 85 44 964 0982 0 881 193 1287 600 1806 1668 194 2717 7 80 1579 1444 195 4253 8 81 1371 1260 196 60 68 9 78 1252 1152 197 73 89 975 1100 1000 198 86 88 973 0953 0 871 199 58 64 9 81 1269 1155 200 2D 4 1 77 915 1362 1251 201 5712 975 1213 1111 202 7363 9 78 1036 0 951 203 8 604 973 0932 0861 204 1268 6 95 2015 18 20 205 2659 6 96 1405 1295 206 39 80 7 98 1261 1174
No 207 Orifice 114 96 509 1325 1148 208 94 33 509 1477 1243 209 7487 5 09 1686 1409 210 5236 505 2094 1691 211 3309 428 2188 1 778 212 1293 392 2976 2560
Thermo ooup1e Readin g s (mv) to 3 to4 to
5 to
6 to7 toair
0 851 0847 0 8 29 0759 0987 0592 158 4 1583 1611 1647 1993 0986 1270 1266 1 279 1298 1604 0 789 0916 0908 0900 0 858 1115 0602 08 39 0 823 0 818 0 770 1035 0602 1609 1602 1629 1676 2153 0979 139 1 1385 1400 1 430 1938 0776 1212 1201 1205 1201 1601 0669 1 105 1086 1086 1 052 1371 0621 0952 0936 0923 0870 1195 0582 0 8 20 0 801 078 1 0 729 1044 0569 1108 1090 108 2 1043 1407 0610 1218 1221 1241 1202 1582 0659 1081 1083 1084 1031 1 368 0622 0921 0924 0919 0 841 1111 0 610 08 34 0831 0 821 0 751 1003 0 630 1761 1761 1 809 1861 2399 0966 1271 1271 1295 1311 1650 0797 1150 1150 1161 1149 1440 0703
1083 1057 1053 1109 1566 0~530 1158 1125 1138 1217 1763 0 526 1291 1250 1278 1383 2038 0542 1518 1478 1519 1657 2420 0 589 1596 1557 1601 1737 2441 0688 2370 2344 2409 2561 3 297 0921
()) (11
TABLE X Continued
Run Thermocouple Readings (mv) No Position CFM I tc 1 tc2 tc3 tc4 tc tc tc tc i5 6 7 a r
C of 2nd 213 516 1235 4 63 1 432 1291 1265 1258 1 268 1 308 1550 0 971 214 1919 6 17 1357 1223 1196 1191 1199 1211 1461 0 851 215 27 12 8 35 1401 1259 1278 1220 1230 1218 1511 0 762 216 3320 981 1439 1305 1270 1259 1275 1238 1450 0719 217 41 53 980 1251 1142 1132 1094 1121 1088 1305 0 695 218 404 987 1102 1042 1030 1 bull006 1014 0960 1133 0681
Supplementary Equations
Calculating temperatures from thermocouple readings
t = -026tc)2 + 3512(tc) + 3201 (26)
where t is the temp in deg F and tc is the thermocouple reading in millishyvolts
Calculation of the thermal conductivity of air
k = 00000245ta + 0 0132 (27)
where k is the thermal conductivity in Btuhr rt2 degFft and ta is the air temp 1n OF
I I
bull co m
4
CHAPTER II
THEORY AND PREVI OUS WORK
In 1701 Newton defined the heat transfer rate qc
from a surface of a solid to a fluid by the equat ion
= ~A(tw - t) (1)q0
where hm is the coefficient of heat transfer from the surshy
face to the fluid excluding any radiation A is the area
of the surface tw is the surface temperature of the wall
and t is the bulk temperature of the fluid The equation
for the point of local surface coefficient h is given by
dqdA = h(tw- t) (2)
The mechan ism and the laws covering heat transfer by
true conduction in solids and by radiation through transshy
parent media are well known However with heat transfer
from a solid to a fluid the situation is far more complex
The mechanism of flow of the fluid to a large extent deshy
termines the rate of heat transfer for a given temperature
difference
In addition the coefficient hm depends on certain
physical properties of the flowing fluid the dimensions
of the apparatus the velocity of the fluid past the surshy
face and frequently the temperature potential AT
It was the purpose of t his research to measure the
local shell -side heat transfer coefficient and correlate
it with the several variables mentioned a bove
5
The heat transfer coefficient for fluids flowing inshy
side tubes is more e a sily measured and correlated due to
the simple geometry of t he tube i nterior Much work has
been done on the tube-side coefficients with one of the
more useful e quations being the Dittus - Boelter equation
( 4 p 450) ~
0 023 (---ctwGJbulla (~np M ( 3 ) M k
with the following cond itions satisfied
(1) Fluid properties evaluated at the arithmetic
mean bulk temperature
(2 Reynolds number gt10000
(3) 0 7 lt Pr lt 100
(4) n = 04 for heating and 0 3 for cooling
(5) Ldw gt60
Colburn (3 p 197) obtained an equation for tubeshy
side heat transfer coefficients in which the Stanton
number is used instead of the Nusselt number
hm ) (~~ 23 _ (dwG) 0 2 ( GC k - 0 bull 023 U (4)
p
Much of the research done on average shell-side heat
transfer coefficients has resulted in empirical correlashy
tions of the form of equations (3) and (4) above Several
investigations have been made for a certain set of phys~al
6
variables but the r esults have ne ver satisf a ctorily been
correlated to appl y for all types of heat exchangers
Some basic 1ork has been done recently however on
the local shell-side coefficients Ambrose (1) studied
the local heat transfer coefficients i n a model heat exshy
changer with segmental baffles This study was fairly
extensive at the baffle center but the data were quite
limited for the space between the baffles Gurushankar1ah
(5) further extended Ambroses work by studying a single
baffle space in detail
The results of these two studies indicated a need for
detailed information 1n the vicinity of the baffle Hence
Lee () investigated a single baffle s pace between two
orifice baffles and obtained considerable information on
the rates of heat transfer in the annular orifices Since
his work was carried out in a multitube mode l heat ex~
changer the determination of the rate of flow through the
individual orifice was difficult because of t he outer
clearances existing in the exchanger For this reason the
present research was undertaken to study the rate of heat
transfer in a single annular orifice through which the flow
could be accurately determined
Bell and Bergelin (2) have studied i n detail the pres shy
sure drop coeff icients for the annular orifices formed beshy
tween a circular disk and a circular tube These results
also appl y to the annular orifioe formed when a rod extends
7
through a circular hole in a plata This study was extenshy
sive in the fact that it considered the baffle thickness as
well as the orifice size but no heat transfer data were
presented
Sullivan and Bergelin (9) studied flow through a
single annular orifice through multiple annular orifices
i n parallel and flow around a single baffle both with and
without leakage through the baffle A generalized expres shy
sion is presented for the pressure drop across one baffle
section of a tubular exchanger with leakage through the
tube holes in the baffle but the effect of leakage area
upon heat transfer is only discussed qualitatively The
pressure drop data is correlated by plotting cent as a funcshy
tion of the Reynolds number where cent equals
d1 )22( ~ P) s c e (d2 -
M-2
8
CHAPTER III
~PERI1ffiNTAL APr ARATUS
The heat transfer test section was essentially a
single tube heat exchanger The inner tube was a l-in
OD aluminum tube with an electrically heated probe midshy
way between the two ends of the tube
Test Section
The shell as constructed from lucite plastic tubing
2 5-in I D and 3-in O D The te t section d a total
lengt h of 54 58 inches I t consisted of two sections
The upstream section was 40 i n ches in length in order to
assure freedom from entrance effects and the downstream
section was 13 12 inches in length To further assure
uniform flow a bundle of short copper tubes was placed a
few inches downstream from the entrance Both of these
sections had 12 i nch flanges on one end so t hat a 18
i nch thick orifice plate could be clamped between them
Heat transfer coefficients were measured in the vicinity of
t h is orifice A cross section of the center of the test
section is shown in Figure 1 and the experimental appara~
tus is shown in Figure 2
Cooled air supplied by a Roots -type blower was used
as the shell-side fluid throughout this study It entered
the test section through a l-in ID 1 12-in OD plasshy
tic pipe at the upstream end of the calming section Tbs
j Jl l 6- 11 BOLTS II I nbull middot~11 I HEATING ELEMENTS
J T ( T
-f-shy - - - f-_- __L
7 777 _y A
IT 1] I
I
FIGURE I CROSS SECTION OF TEST SECTION AND PROBE
10
FIGURE 2 EXPERIMENTAL APP1Ub~fUS
11
air left the test section through nine equally spaced 12
ineh holes placed around the side of the tube at the exit
end
Sensing Probe Assembly
The sensing probe was designed to measure the local
heat transfer coefficients at any point along the tube and
around the tube in the test section The tube was designed
so that it could be easily moved up- and downstream to
measure the heat transfer coefficients at various positions
in relation to the orifice
The sensing tube assembly consisted of the sensing
probe the thermoctmple lead s and selector switch the
power lines and the two aluminum tubes between which the
probe was centered
Imbedded in the sensing probe were seven iron-constanshy
tan thermocouples for measuring the temperatures around the
tube The lead wires from these thermocouples were conshy
nected to a seleotor switch at the downstream end or the
aluminum tube A layer of Saran wrap was placed around the
tube over the t hermocouple and three lengths of Trophet C
resistance ribbon were wrapped around the tube nd conshy
nected in series to the power leads
The heating surface of the probe was formed by these
three one inch wide strips of Trophet C resistance ribbons
The ribbons were 0002 inches thick and had a resistance of
12
0 271 ohms per foot and a thermal conductivity of 763
Btuhr ft 2 degFft They were held in position by four
copper bars placed in four parallel longitudinal slots
These copper bars served as connectors for the electrical
leads A photograph of the sensing probe is shown in
Figura 3 and a drawing of the assembled probe is given in
Figure 4
Power Source
Direct current was used to heat the resistance ribbon
on the sensing probe The current was regulated by a slide
wire resistor The po er source consisted of a Raytheon
Voltage Stabilizer to stabilize the city power source at
115 volts and an automatic selenium rectifier with an alshy
ternating current input of 115 volts at 60 cycles per
second and an output of 12 volts and 35 amperes direct
current
Temperature Measuring
The temperatures around the sensing probe were calcushy
lated from the emf readings of the ironbulloonstantan thermoshy
couples The emf measuring system consisted of the seven
probe thermocouples a separate thermocouple for measuring
the inlet air temperature a thermocouple selector switch
a cold junction and a Leeds and Northrup Type K Potentishy
ometer The potentiometer was placed on a Fischer
13
THERMOCOUPLE JUNCTIONS~ ~------- HOLES FOR THERMOCOUPLE LEADS
~----- SCREWS
~ff+--- CONNECTING BARS
END VIEW
POWER LEADS SOLDERED TO LOWER CONNECTING BAR
iER PLASTIC PIECE
RESISTANCE RIBBONS LOCATION OF THERMOCOUPLES
FIGURE 4 DRAWING OF ASSEMBLED SENSING PROBE
15
Vibradamp support to absorb the vibrations produced by the
air blower
Air Source
Air was used as the shell-side cooling fluid during
the study The air was pumped through the test section by
a Roots type air blower with a rating of 280 ofm at 3 12
psig outlet pressure The hot air leaving the blower was
passed tbxfugh two finned-tube box-type coolers and one
tubular edoler to oool it to approximately room temperature
The air flow rate was measured by passing it through a
flow measuring orifice in the line Two sharpbull edged orishy
ficas were used f or flow measurements The calibration
curves for these orifices were presented by Ambrose (1
p 166)
The pressure taps on each side of the orifice were
connected to two differential manometers containing 0 83
and 2 95 specific gravity fluids respectively The presshy
sure drop through the test section and test orifice was
measured by a pressure tap placed 13 inches upstream and
one placed 6 12 inches downstream from the orifice Two
pressure ga ges were used to measure the pressure at the
inlet to the flow orifice and to indicate the statio pres~
sure at the test section inlet
16
Pressure Probe
A probe was designed to measure the pressure drop
between the pressure tap 13 i nches upstream from the ori shy
fice baff le and any point downstream from the tap The
probe eonsisted of a l~in OD copper tube with six 132
i n ch holes even l y s paced around the tube The upstream
pressure tap and the pressure probe were connected to a
differential manometer so the pressure drop to various
points up- and downstream of the orifice could be measshy
ured
17
CHAPTER IV
EXPERIMENTAL PROGRAM
The experimental program was designed to measure the
heat transfer coefficients and pressure drops in the vicinshy
ity of annular orifices The four orifice sizes studied
were 1 364 1 216 l 316 and 1 516 inches~ The inner
tube used in each case was a 1-in OD alumintim tube
Hence tube to baffle clearances were respectively 3128
232 332 and 532 of an inch
Heat transfer coefficients were measured at poait~ons
1 i nch upstream at the orifice center and at 12 1
1 12 and 2 inches downstream for all orifices In addishy
middottion the heat transfer coefficient at a point 2 12
inches downstream from the 1 516 inch orifice was measured
and at the points 12 l 12 and 2 inches upstream from
the 1 364 inch orifice
The heat transfer coefficients at each point were
measured at five different flow rates for the 1 364 inch
orifice and at six different flow rates for the other orishy
fice sizes The high pressure drop through the small orishy
fice size limited the number of flow rates which could be
studied
The flow rate was calculated from the pressure drop
across the flow orifice This flow was corrected to cubic
feet per minute at 68degF and one atmosphere pressure by
18
using the orifice pressure and the test section pressure
which were measured by pressure gages
It was desired to determine a relationship between the
heat transfer coefficient and the total pressure drop for
each orifice size The pressure drop across each orifice
at various flow rates was measured by means of the presshy
sure probe described in Chapter III It was also desired
to obtain pressure profiles for each orifice size since
these might be similar to the heat transfer profiles The
pressure drop was measured from a point 13 inches upstream
of the orifice to points at 1 and 12 ineh upstream the
orifice center 12 1 1 12 and 2 inches downstream
The experimental program is summarized in Table I
TABLE I
SUla~RY OF EXPER IMENTAL PROGRAM
Position Investigated-Distance from Orifice-Inches
Orifice Range of Flow Rate Size Heat Transfer Pressure Drop CFM at 68degF amp 1 atm
1 364 2U 1 12U 1U 12U c 12U C 12D lD 10 - 18 l2D lD 1 12D 2D 1 12D 2D
1 216 1U c 12D lD 1 l2D 2D 12U c 12D lD 10 - 35
1 316 1U c 12D lD 1 l2D 2D l2U C 12D lD 12 - 50
1 516 1U c x2D lD 1 l2D 1U 12U C 12D 12 - 90 2D 2 1 2D l D 1 l2D 2D 2 12D
20
CHAPTER v
EXPERI MENTAL PROCEDURE
The experimental procedure for measuring the heat
transfer coefficients ~d corresponding flow rates reshy
quired the following procedure
(1) Install the orifice size to be studied in the
test section
(2) Place the heat transfer probe in the position up
or downstream from the orifice where the middot heat
transfer rate is to be studied
(3) Fill the cold junction thermos with cracked ice
(4) Measure the atmospheric pressure
(5 Open bypass line from blower and close line to
test section
(6) Turn on the cooling water for the exchangers used
to cool the air leaving the blower
(7) Start the automatic selen ium rectifier by turning
on the t 1mer bull
(8 ) Connect the voltage stabilizer to the wall outlet
(9) middot Set the slide wire resistor to the maximum re shy
s1atanee I
(10) Start the blower
(11 Open the line to the test section until the de shy
sired flow rate is obtained
(12) Switch on the probe direct current power source
21
(13) Adjust the slide wire resistor to obtain the
desired current
(14) After the thermocouples have reached equilibrium
values record the e m bullf across each of the
seven probe thermocouples and also the entering
air thermocouple
(15) Record the direct current amperage
(16) Record the gage pressure at the flow orifice and
the entrance to the test section
(17) Record the manometer measurement of the pressure
drop across the flow orifice and also the presshy
sure drop through the test section
22
CHAPTER VI
CALCULAT ION OF EXPERIMENTAL DATA
The local heat transfer coefficients were calculated
from the temperatures measured on the probe surface the
air temperature and the current input The results were
calculated by using the Alwae III-E computer
The general expression for calculation of the heat
transfer coefficients was derived by Ambrose (1 p 79)
The equation is derived by making an energy balance around
a small increment of the center resistance heating ribbon
The two ribbons tnstalled adjacent to the center ribbon
reduced the amount of logitudinal conduction and assured
little longitudinal temperature variation in the center
ribbon
A heat balan ce on this small increment of resistance
ribbon yields the following
(the heat conducted in) + (heat generated) = (heat
conducted out) +(Heat convected to the fluid) + (heat
radiated to the surroundings) + (Heat conducted into
the plastic center of the probe)
This gives the equation
kzw dtdS + 12RdS kzws [ t + (~) ds] + hwdS (t-ta )
+ ~Aad wd o middot+ qcAond 1 -~- wdS 5 )
23
Hence solving for h gi~ea
i2R kz d2t Qrad qcond w + -d$2 - ~- A
h = ( 6)t - ta
Since S = re where 9 equals the enclosed angle ~n radians
dS rd9 ( 7)
and
dt - dt (8)dS - rd9
Differentiating with respect to S
d2t (9)rd9dS
from which
(10)
Substitut1ng into the equation for heat transfer coeffishy
cient gives
h = i2R Qcond A (11)
w
The rate of radial heat conduction into the plastic
tube making up the probe was assumed to have negligible
effect on the heat transfer coefficient It was also
assumed that the heat loss by radiation from the ribbon
was negligible since all data were obtained with the ribbon
at a temperature less than 125degF
24
When t he rad iation and conduction terms are neglected
Eq (11) becomes
(12)
The following con stants are known
R = 0 271 ohmsft
w = 100 i n ches
k = 763 Btuhr rt2 degFft
z = 0 002 inches
r = 12 inch
Eq (12) putting 9 in degrees then reduces to
1110 12 + 2404 d 2t d92
( 15)h = ------~--~-------t - ta
Thi s equation was programed for the Alwac III- E comshy
puter and used to calculate the local heat transfer coefshy
ficients from the observed data
The average heat transfer coefficient around the tube
at a given position in the t est section was calculated by
averaging the local coefficients calculated from Eq (13 )
It was found 1n the course of the experimental work
that thermocouple numbers 1 and 7 were indicating higher
temperatures than would be expected This resulted in h1
and ~ being lower than the other local coefficients around
the tube Since the fluid was flowing parallel to the axis
of the probe the circumferential variation i n rate of heat
25
transfer should be small Hence in obtaining the average
coefficient around the tube the values of h1 and h7 were
not used even though they were calculated and are tabulated
1n Table I II in the Appendix
Then
(14
A Nusselt number as calculated from this aver age heat
transfer coefficient using the tube diameter as the characshy
teristic dimension
(15)
The air flow rates through the test section were calshy
culated by measuring the pressure drop across the flow orishy
fice the air temperature the pressure at the flow orifice
and the pressure at the entrance to the test section The
orifice calibration curves (1 p 166 ) were used to obtain
a value of the orifice coefficient f8e where Q equals
the flow in cubic feet per minute at 68deg F and one atmosmiddot
phere pressure and te is the density of air at the exchanger
and e the density of the air at the flow orifice The
den sity of the air can be expressed by
e = 2 703 p (16)T
where T equals the temperature in OR and P equals the absoshy
lUte pressure i n lb1n2 Using the value of e Qfo from
26
the calibration charts as A and Eq (16) solving for Q
gives
( 17
This equation was used to calculate the flow rate for
each flow studied
The Reynolds number used i n the correlation of the
data was the equivalent Reynolds number defined as
Re)eb ~ d2 - dl)Uf ( 18 ) lL
where d1 is the outside diameter of the inner tube and d2
is the orifice diameter U is the flow velocity through the
annular orifice e is the density of the air and U- is t he
viscosity of the air This equation can be transformed t o
(Re) b = 1611 Q (19) e dl + d2
where d1 and d2 are in inches
The pressure drop data were calculated i nto a dimenshy
sionless pressure drop function cent where
d1 )22( ~ P)gc f av(d2 shycent 2 bull (20
M-
For air this equation reduces to
where d2 and d1 are in i nches D P is expressed i n inches of
2 95 specific gravity fluid and P av is expressed as lbft3
27
CHAPTER VII
ANALYSIS OF DATA
In analyzing the heat transfer data an attempt was
made to correlate it 1n terms of the dimensionless groups
(Nusselt number Prandtl number and Reynolds number) which
appear in Eqs (3) and (4) Consequently all of the av~
erage heat transfer coefficients hav were brought into
the form ( Nu)( Pr)~3 bull The Nusselt number was based on the
tube diameter and the thermal conductivity of the air at
the flowing temperature The tube diameter was used in the
Nusselt number because comparison could then be made with
previous experimental work on heat exchangers which have
commonly used the Nusselt number defined as in Eq (15)
From the standpoint of dimensional analysis this is
equivalent to considering the tube diameter as the characshy
teristic length so far as the heat transfer is concerned
The Prandtl number of the air was taken as 0 7 in all
cases
Variation of Heat Transfer Rate with Distance from the Baffle
Considerable variation was observed in the rate of
heat transfer in the vicinity of the baffle In order to
obtain the variation with respect to position the term
(Nu)(Pr)-13 was plotted versus the flow rate Q for each
position and orifice studied Cros s plots were then made
28
at constant flow rates in order to obtain the variation of
(Nu)(Pr) -13 with position The resulting cross plots are
shown 1n Fi gures 5 6 and 7 for the four orifices studshy
ied
About one inch upstream from the orifice the heat
transfer coefficient begins to rise rapidly and continues
to do so until it reaches a maximum some distance downshy
stream After the maximum point the heat transfer coef fi shy
cient decreased slowly The heat transfer rate was found
to reach a maximum at a different position downstream for
each orifice size These figures also show that for a
given orifice size the maximum heat transfer rate occurs
a pproximately at the same point for all flow rates The
position of the maximum point f or each or ifice size is
shown in Table II
The region immediately downstream from the orifice is
one of h i gh turbulence due to the jetting action of the air
flowing through the orifice As the air flows t hrough the
orifice the streamlines continue to converge for some dis shy
tance downstream The point of maximum heat transfer is
probably at the point where the streamlines be gin to diverge
and a boundary layer begins to build up on the tube Tle
decreasing heat transfer coefficient beyond the maximum
point indicated the formation of a boundary layer
Since the position of the maximum point is independent
of flow rate middot it is possible to correlate it with respect
_ ct 11shyz-
100
0 136 ORIFICE
(
I 0
I )
~ 00
~p 0
I 0
--r--- ~
ISCFIII
-_ OCFM
rbull abull
~ middot~ a-1 z-
12fORIFICE
100
200
100
0 0 UPITRAM ORIFICE DISTANCE CENTER
CFM
h I DOWNSTREAM
DISTANCE
FIGURE 5 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLpound
30
too
700
800
100 ~ f gtf
400
z ~
100
100
100
0
13fORIFICE
~ -~ -- ---
)
~
~
-
I ~ ~OCFM
I vI~-~ OCFM
J ---
Iamp CFM
I 0 I I UPSTREAM ORIFICE DOWNSTREAM DIITANOE GENTER DIITANCI
FIGURE 6 VARIATION OF HEAT TRANSFER RATE WITH DISllNCE FROM BAFFLE
--
--- --
31
100
100
700
100
_ 100
f 9- 400 z-
100
tOO
100
0 - I 0 I I I UHTRIAM OAtfiCI DOWIIITMAM
+ I tyl6 ORIFICE
v I
~~ ~CFM
I v ~CFMI
v v 7
~~ v ~ iOCFM
- ~~ I-shy1-shy ~ICFM
DIITMCI OINTIR DIITANCI
FIGURE 7 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLE
32
TABLE II
POSITION OF MAXIMUM HEAT TRANSFER
Position of Maximum Orifice Size Heat Transfer
(inches) (inches downstream)
1 364 050
1 216 100
1 316 125
1 516 200
33
to orifice size Figure 8 shows the effect of the orifice
size on the position and value of the maximum heat transfer
at a constant flow rate of 15 cubic feet per minute It
can be seen that the larger the orifice size the further
downstream the point of maximum heat transfer occurs
Also as the orifice size increased the rate of heat
transfer decreased for a given flow rate The broken line
indicates the variation of the point of maximum heat transshy
fer with position and size The position of the point of
maximum heat transfer rate downstream from the orifice was
correlated with orifice size by means of the dimensionless
groups (Lde) and (d1de) where L is the distance downshy
stream from the orifice where the maximum rate of heat
transfer occurs d1 is the outside diameter of the inner
tube and de is the equivalent diameter of the orifice
ie de = d2-dlbull
Figure 9 shows a plot of Ld 6 versus d1d6 for the
four orifice sizes studied The four points on this logshy
log plot are approximately in a straight line and the
equation of this line is
Lde = 0 44 d1de)028 (22)
Although the above relationship represents a correlashy
tion of dimensionless groups it is based upon only one
tube diameter and needs to be substantiated further by
studying other tube diameters and other orifice sizes
34
aoo
400
aoo ~
-~ middot-CLshyJ z
200 -
100
0
ORIFICE CENTER
l~
l
t
I J~
1pound~
I
0 I I~
AT 15 CFM
-
bull ~ 1~6~
~ v~
~
~--~~6
~~~ ___ v v V -_
~ o q
~ I 16
v
~
ogWNSTREANI STANCE
FIGURE 8 EFFECT OF ORIFICE SIZE ON POSITION AND VALUE OF MAXIMUM HEAT TRANSFER
35
50
loshy____ -~
~ ~ -shylltl-shy~ r0
2 10 30
FIGURE 9 CORRELATION OF THE POINT OF MAXIMUM HEAT TRANSFER WITH
ORIFICE SIZE
36
Correlation of Data at the Baffle
The heat transfer data were correlated by obtaining a
relationship between the group (Nu)(Pr)-13 and a
Reynolds number based on twice the clearance (d2 - d1
between the tube and the baffle It was found that the
most satisfactory correlation could be obtained when the
term - d1 was used as the length term in the Reynoldsd2
number
Figure 10 shows the variation of the heat transfer
rate at the center of the orifice e xpressed as a function
of Reynolds number and the orifice size This shows that
for a given Reynolds number the heat transfer at the center
of the orifice is greatest for the smallest orifice size
In order to obtain a general correlation of the data
shown i n F1gure 10 the effect of the dimensionless ratio
d1de was considered This ratio considers all of the
geometric factor s needed to describe the annular orifice
The thiclaless of the orifice plate is also a factor but
was constant i n this i nvestigation
The data for the heat transfer at the baffle center
are shown in Figure 11 in which (Nu)( Pr)-13 is plotted
versus (Re)ebd1 de) 0 55 This data on a log-log plot
lies on a straight line for (Re)eb( dld8 )0 55 greater
than 3 x 104 The equation for cor relating the heat
37
4XI~middot~-r~------~--~~------~
Icf t--to_+--_c-c-________ SYMBOL SIZE
0 1~4
6 ~~
9 ~~ -o ~
(Re)eb
FIGURE 10 RATE OF HEAT TRANSFER AT BAFFLE CENTER
38
500
0
4 0 lcf
~ ~
~ ~iC-
~ ~
~IL 0~ 0 SYMBOL SIZE-
p 0 1364-
r 6 1~16 -~ -
9 1~16 --o 1~16
I I
FIGURE II CORRELATION OF HEAT TRANSFER DATA AT BAFFLE CENTER
39
transfer at the center bullOf the a nnular orifice was found by
the method of least s quares to be
(Nu)( Pr)-1 3 = 0018 ( Re)ebO Bl( dlde)04~ (23)
3 x 104 ltRe)eb(a1de)055 lt 105)
Rate of Heat Transfer at the Point of Maximum Heat Transfer-The heat transfer rate at the point of maximum heat
transfer is plotted in Figure 12 to show the variation with
Reynolds number and the size of the orifice It is shown
gives the h1gh st heat transfer ~ate at its point of maxibull
that for a given Reynolds number the smallest orifice size yen il
mum heat transfer
The data ~or the maximum poi~t could be correlated by
plotting (Nu) Pr)-13 versus (Re)eb(d1de)06 This plot
is shown 1n Figure 13 and the resulting eurve shows that
(Nu(Pr)-13 is not a simple p0wer function of the Reynolds
number as was the case for heat transfer at the baffle
center The reason for this is probably because other
factors such as intensity and scala of turbulence should
be considered At the orifice center the streamlines of
the flowing stream are converging_ and thus the flow is
quite stable Downstream from the orifice is a region of
large eddy currents and probably large scale turbulence
These factors could con ceivably cause the results which
were obtained for the point of maximum heat transfer
40
If)
~middotshy Q_-I z_
10~~~--------r----~~--~--
SYMBOL SIZE
0 13$4
6 1~8
Q 13-18
-o 1~8
7)(104
(Re)eb
FIGURE 12 RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
41
Ia ~
0 I
c ~ ~ c v
~ ~lt w ~
17
~ b
v ~ ( SYMBOL SIZE
-~ 0 f-64 -v ~ 6 t211e
~ Q I~~~
-o - l~rs I I
FIGURE 13 CORRELATION OF HEAT TRANSFER DATA AT THE POINT OF MAXIMUM HEAT TRANSFER
4 2
Effect of Upstream Baffles on Heat Transfer at the Orifice Center
The heat transfer rate at the orifice center using the
single orifice in a test section is a pproximately 13 of the
value that was obtained by Lee (7) using a model heat exshy
changer with orifice baffles Lee investigated the cent r al
baffles of the heat exchanger and thus the coeff icients he
obtained would be affected by the presence of a number of
upstream baffles To determine the effect of upstream
baffles an additional l 516 inch baffle was placed four
inches upstream 1n the test section The resulting data are
shown in Figure 14 where (Nu)(Prmiddot)-13 is plotted versus
(Re) eb for the case of a single baffle 1n the test section
and also the case of an additional baffle placed four inches
upstream Comparison is made with the results obtained by
Lee middot(7) using a four-baffle and a ten-baffle model heat exshy
changer Good a greement is obtained with Lees work and the
results show the marked effect that upstream baffles have on
the downstream heat transfer rate The additional up tream
ba ffle caused sufficient turbulence 1n the test section to
i n crease the heat transfer rate nearly three-fold at the
center of the next baffle
Heat Transfer i n the Test Section with No Orifice
In order to check the accuracy 6f the equipment the
orifice baffle was removed and the heat transfer mea sured
with the probe in the empty test section The data were
43
~~BAFFLES
0 l BAFFLE -shy
ll_9 2 BAFFLES
V 4 BAFFLES-LEE
4 10 BAFFLES- LEE lJf ~
~rv ~~ ~ v flvv ~~
I ~ J ~ L v
0
v
( V
40 3XIo 7XIa
(Re)eb
FIGURE 14 EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER AT BAFFLE CENTER
44
compared with heat transfe r coefficients predicted by the
equations for annuli which are recommended in the litera shy9
ture The two equa~ ions u sed tor comparison were
(hfe)=0 023 (rltGr e (~~ur4 (~r45 (24)
which was presente~ by Wiegant (10)
and ( h ) (cnM~5(M~l o14 o 023 CPG k j Mij - (de GJMb )0 2 ( 2 5)
which was presented by McAdams (8 p 242) The comparshy
i son is s hown in Figure 15 lq (25) gives a value which
is low by about ten percent while Eq (24) g ives values
which are high by as much as twenty -five percent when comshy
pared with the experimental data The se equations are gembull
erally considered to give coefficients with an accuracy of
about twenty percent Therefore the present experimental
data are within the accuracy of these equations Also the
plot indicate s that for a Reynold s number greater than 2 x
104 the slope of the line is the same for the experimental
data as for the equations
Pressure Drop Data
The total pressure drop across the orifice was measured
as a function of the flow rate and the orifice size The
pressure drop was expressed as a d1mens1onleas quantity r)
which ie plCltted ver sus the Reynolds number in Figure 18
The pressure drop function cent correlates for all or1f1oe
45
200
100
s z
10 5XI10 10
0 EXPERIMENTAL
--McADAMS
-WIEGAND L
V
~ ~ ~
P ~ ~
LL~ L
v~
~
v v
v 1 ~ ~ v
v -gt
~
~ ~
~
6Xid
FIGURE 15 HEAT TRANSFER WITH NO BAFFLE
46
0 1~4 -~ a 6 t216
Q t316 lJ J
-0 as a )t
A LEE I -shy SULLIVAN 8
p
10bull
BERGELIN
I _ll I
I ~
i I
~middot
lo II
f fl
J j
~middot
A)101
1q
I Ill
1 I3 X 10ao1
FIGURE 16 ORIFICE PRESSURE DROP FUNCTION VS REYNOLDS NUMBER
47
sizes- The present data extends the range covered by preshy
vious workers and agrees well with their work The preshy
vious work of Lee () for a heat exchanger containing 10
orifice baffles and also the data of Su livan and Bergelin
(9) for pressure drop in a model heat exchanger with a
single baffle is shown 1n Figure 16 long with the present
results~ This figure may be used to predict the preseure
drop from the equivalent Reynolds number of the annular
orifice
The pressure drop between individual points 1n the
vicinity of the orifice and an upstream pressure tap wa s
measured to obtain a pressure drop profile As might be
expected 1n all cases the profiles showed a rapid decrea e
in static pressure immediately upstream from the orifice
There was however little or no recovery of the pressure
loss downstream The 1 364 inch orifice did show a maxishy
mum point in the pressure drop but this maximum occurred at
the orifice center and total recovery was reached about 12
inch downstream
Heat Transfer at the Baffle and Maximum Point as a Function of Pressure Drop
In order to compare the effect of the total pressure
drop on the heat transfer at the baffle and the point of
maximum heat transfer Figure 17 was plotted showing
(Nu)(Pr)-13 as a function of the total pressure drop This
shows that for a given pressure drop the largest orifice
48
1200
1000
~ a -sshyz-
100
60 100 700
AT MAXIMUM POINT I 15116 2 13116 3 1~6 4 1364
AT ORIFICE CENTER
60
1
v
r ~ ~ ~
5
~
8 7
13116
8
~
1364
v
~
e6
1~6
v
~~ v ~ ~ -~ ~
~
~ v
l
~
vamp
I ~ ~
~
v L ~
v
I-
5
k= ~~
~ ~ ~
--I
v ~
FIGURE 17 HEAT TRANSFER AT THE BAFFLE AND MAXIMUM POINT AS A FUNCTION OF
ORIFICE PRESSURE DROP
49
size has the greatest heat transfer coefficient This is
true at both the orifice center and at the point of maxishy
mum heat transfer
Another comparison can be made by plotting the heat
transfer coefficient and the pressure drop versus the orishy
fice size at a constant flow rate Figure 18 shows this
plot This graph shows that at a constant flow rate the
pressure drop as well as the heat transfer coefficient
increases as the size of the orifice is decreased In
choosing an orifice size for maximum efficiency 1t would
be necessary to know the pumping power available as well
as the heat transfer desired
70 I I 700
AT 15 CFM 60 ---
~ aug
50 ---
NV
40 ~
~ ~ ~
~ _
MAXIMUM POINT ---- --- ~
1-----t---~ _
~00Qj ~
~t--- ORIFICE CENTER 10 1100
1---~ n
u0 01 02 03 Q35
a ltl
de inches
FIGURE 18 VARIATION OF HEAT TRANSFER RATE AND PRESSURE DROP WITH ORIFICE SIZE AT A CONSTANT FLOW RATE
cn 0
51
CHAPTER VI II
SUMMARY OF RESULTS
This study revealed several significant facts about
the heat transfer in the vicinity of annular orifices
Probably the most important contribution was the presshy
entation of the heat transfer profiles in the vicinity ot
the annular orifice ~ r s shown that t~ local heat
transfer coeffieient re~ches a maximum at a point downshy
stream from the orifice The distance downstream at which
this maximum oocurs is t1ven by the equation
22
The heat transfer coefficients at the center of the
orifice were correlated and found to follow the equation
(Nu)(Pr)-13 = 00176 (Re)eb08l(d 1de) 0 middot4~ (23)
3 x 104 lt( Re) 9 b( d1d6 )055 ltlo5 )
The heat transfer at the point of maximum heat trans
fer for each orifice size was correlated and presented in
Figure 13 as a plot of (Nu)(Pr)-l3 versus (Re)eb(d1de) 06
No simple po-orer relationship exists between the terms
Intensity and scale of turbulence downstream from the orishy
fice are probably important factors which affect the heat
transfer
The large effect of an upstream orifice on the heat
transfer rate at the second orifice was demonstrated by the
52
study of two 1 516 inch orifices in the test section The
added turbulence at the center of the second orifice was
found to raise the heat transfer rate almost three times
over that obtained for a single baffle
The pressure profiles in the vicinity of the orifice
indicate that nearly all the pressure drop occurs at the
orifice center~ Total pressure drop data were correlated
by a pressure drop function cent as a function of the Reynolds
number and good agreement obtained with the results of other
workers
The pressure drop and heat transfer data were correbull
lated by plotting the heat transfer as a function of the
pressure drop for each orifice size It was shown that for
a given pressure drop the largest orifice size gives the
greatest heat transfer coefficient
As a final presentation it was shown that the pressure
drop and the heat transfer coefficient both i ncrease i n
value at a constant flow rate as the orifice size is de shy
creased This is important in choosing the optimum clearshy
ance for orifice baffles
53
CHAPTER IX
RECOMMENDATIONS
A great deal of work remains to be done in the field of
evaluating shellmiddotside heat transfer coefficients This
study included only one tube size and air was the only f luid
used It is recommended that further studies be conducted
using other fluids and tube sizes It will also be necessary
to study several baffle types
The adde d turbulence due to a s e cond baffle placed upbull
s t ream would suggest that the heat transfer coef ficients at
a certain position i n relation to a baffle would increase as
the flow progressed through the exchanger It is recomshy
mended that an extensive s t udy should be made between baffles
the full length of a model heat exchanger
It is further recommended that the pressure drop study
be continued to include other fluids tube sizes and baffle
arrangements
Effects of turbulence downstream from the baff le should
be studied by i n vestigations with hot-wire anemometer equipshy
ment to determi ne t urbulence scale and i ntensity
54
NOMENCLATURE
Area of heat transfer
Heat capacity of the fluid
Outside diameter of the tube
Orifice diameter
Equivalent diameter of the orifice (d2 - dl)
Inside diameter of the test section
Inside diameter of the tube
Gravitational constant
G Mass velocity
h Local heat transfer coefficient
Coefficient of heat transfer from surface to fluid
i Direct current amperes
k Thermal conductivity of the fluid
L Distance downstream of the point of maximum heat transfer
p Absolute pressure
L P Total pressure drop across the orifice
Q Flow in cubio feet per minute at 1 atmosphere and 680 F
q Heat transferred
Thermal energy conducted into the sensing probe
Thermal energy radiated from the resistance ribbon
Resistivity of the resistance ribbon
s Length of the resistance ribbon
T Temperature oR
55
t Temperature of the resistance ribbon deg F
ta Temperature of the bulk stream oF
tw Wall temperature of the tube OF
U Veloc ity of the fluid
w Width of the resistance ribbon
z Thickness of the resistance ribbon
eeuro Density of the fluid in the test section
Density of the fluid at the flow orificef 0
AL Viscosity of the fluid
E9 Angle measured around the tube
Dimensionl ess groups
(Nu) Nusselt number hd1k
(Pr Prandtl number C~k
(Re)eb Equivalent Reynolds number at the baffle (d2 - d1 )uejt-Lshy
(Re)e Equivalent Reynolds number in the test section ( d 8 - d 1 )U fu
cent Orifice pressure drop function 2(~P ) gc~av(d2 - d1) 2
Al
56
BI BLIOGRAPHY
1 Ambrose Tommy W Local shell-side heat transfer coefshyficients in baffled tubular heat exchanger PhD thesis Corvallis Oregon State College 1957 183 numb leaves
2 Bell K J and o P Bergelin Flow through annular orif ices Transactions of the American Society of Mechanical Engineers 70593-601 1957
3 Colburn Allan P A method of correlating forced con shyvection heat transfer data and a comparison with fluid friction Transactions of the American Institute of Chemical Engineers 24 174-210 1933
4 Dittus F w and L M K Boelter Heat transfer 1n automobile radiators of the tubular type University of California Publications in Engineering 2443-461 1930
5 Gurushankariah M s Local shell-side heat transfer coefficients in the vicinity of baffles in tubular heat exchangers Masters thesis Corvallis Ore gon State Colle ge 1958 97 numb leaves
6 Knudsen James G and Donald L Katz Fluid dynamics and heat transfer New York McGraw-Hill 1958 576 p
7 Lee Kyu Sung Local shell-side heat transfer coeffishycients and pressure drop in a tubular heat exchanger with orifice baffles Masters thesis Corvallis Oregon State College 1959 118 numb leaves
8 McAdams William H Heat transmission 3d ed New York McGra ~-Hill 1954 532 p
9 Sullivan F W and 0 P Bergelin Heat transfer and fluid friction in a shell-andbulltube exchanger with a single baffle Chemica l Engineer ing Progress Symposium Series 52 ( 18) 85-94 1956
10 Wiegand J H Discussion on annular heat transfer coshyef f icients for turbulent flow Transactions of American Institut e of Chemical Eng i n eers 41147-153 1945
AP PENDIX
57
TABLE III
CALCULATED HEAT TRANSFER DATA
Baffle Hole Diameter Run No (inches)
1 - 59 1 364
60 - 102 1 216
103 - 138 1 316
139 - 206 1 516
207 - 212 No orifice
213 - 218 2nd - 1 516
TABLE III
CALCULATED HEAT TRANSFER DATA
Local Heat Transfer Coefficients Run
T0 bull Po s ition CFM hr h2 h3 h4 hs he ~ hav Nuav
1 c 1026 10 59 1476 16 09 1559 1510 1435 1203 1518 8511 2 1290 1369 1738 1878 18 05 1755 1689 1515 1773 9964 3 1416 1636 198 1 2068 1977 1924 1845 1715 1959 11030 4 1627 1991 2301 2382 2268 2194 20 ~98 1929 2249 12664 5 1776 2252 2669 2863 2713 2517 2338 2126 2620 14759 6 l2ttD 1109 2311 3317 3386 3373 3387 3394 3071 3371 18888 7 1258 3089 4583 4866 4683 4701 4643 4194 4695 26301 8 1433 38 8 5 55 83 5791 5495 5430 5436 5008 5547 31192 9 1681 4992 7378 7649 6980 6864 6870 64 28 7148 40180
10 1 D 1102 2371 3332 3511 3356 3342 3427 3102 3394 19012 11 1308 3218 4379 45 24 42 53 4255 4373 3965 43 57 24446 12 14 64 38 58 5146 5142 4839 4787 4903 4597 4963 278 79 13 1706 5218 6664 6269 58 81 5884 6237 5973 61 87 34718 14 15
1 l2D 1115 1275
2131 2661
2955 3638
2972 3720
2941 3675
2913 3576
28 22 34 74
2613 3278
2921 36 17
163 09 20246
16 1498 34 87 4644 4503 4441 4371 4343 4194 4460 25010 17 1695 4449 5743 5324 5222 5154 5157 5015 5320 298 97 18 2D 1049 1715 23 90 2550 2610 2656 2624 2208 2566 14363 19 1241 2117 2964 3145 3218 3221 3203 2759 3150 17757 20 1532 28 67 3936 4100 4188 4201 4167 3676 4118 23224 21 1674 3459 4508 4598 4746 4795 4792 4299 4688 26337 22 lU 1074 253 340 380 3 86 388 377 354 374 2097 23 1287 292 392 433 440 441 429 406 427 2394 24 1508 322 439 492 498 499 487 461 48 3 2713 25 18 07 3 38 464 519 5 24 520 499 463 5 05 28 40
~~ (]I agt
TABLE III Continued
Run No Position CFM h 1 h2 ~3 h4 h5 h6 ~ h
av Nu
av 26 c 1029 1171 1491 1589 15 28 1 4 62 1377 1293 1489 83 44 27 1266 1395 1746 1853 18 02 1685 1556 1453 1728 9704 28 1430 1637 2037 2175 2060 1909 1735 1591 1983 11159 29 1729 1982 24 96 2751 2507 2268 2030 1886 2410 13579 30 12D 1054 2934 4041 4321 4326 4423 4359 3706 4298 24160 31 1294 3385 4 8 26 52 42 5326 5450 5277 4566 52 24 293 50 32 1431 3784 5347 5721 57 bull75 58 44 5700 5084 5677 31870 33 1770 52 75 7 7 33 87 35 9005 9007 8267 7059 85 49 48050 34 lD 1058 3235 4401 4444 3877 3496 3451 3294 3934 21973 35 1263 38 98 5484 5330 4347 3964 3981 3987 4621 25823 36 18 36 6701 89 17 7855 6369 5597 5769 6283 69 01 38718 37 1 12D 1029 2404 31 8 2 3333 3459 3624 3577 3045 3435 19264 38 1315 3182 4033 4162 4310 4496 4502 4015 4301 24142 39 1426 3628 4389 4510 4573 4760 4804 43 8 5 4607 25678 40 1757 4547 5559 5(35 5931 6282 63 70 6060 5975 33471 41 2 11D 1080 2034 28 38 3155 3144 3145 2966 2540 3050 17027 42 1305 2650 3 4 87 3aoz 3595 3751 3595 3153 36 46 20405 43 1434 3167 39 07 4156 4371 4320 4126 3709 4176 23395 44 1804 4096 4 9 66 5691 5714 5586 53 15 48 65 5454 30582 45 12U 1088 409 516 557 564 5 60 535 513 5 46 30 67 46 1318 470 579 6 22 631 6 17 5 97 579 6 09 3422 47 14 13 540 640 676 6 86 681 6 60 6 54 6 69 3754 48 1773 641 740 774 782 7 69 749 746 763 42 87 49 l 11 U 1054 270 356 391 397 393 3 71 346 38 2 2133 50 1240 303 399 446 449 447 4 21 398 432 2420 51 1419 361 476 522 530 528 507 467 493 2760 52 1 1(2U 1032 236 311 342 347 344 325 301 334 18 78 53 1314 270 366 403 407 408 386 351 394 2217
(Tt tO
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ h av Nu av
54 1448 301 408 447 454 452 431 403 438 24 61 55 1782 353 494 548 544 415 529 531 506 2843 56 2U 10 61 220 287 316 320 322 303 268 310 1735 57 1216 249 335 370 377 378 353 307 363 2044 58 1322 263 356 394 398 399 374 327 384 2159 59 1639 310 433 478 481 482 452 393 465 2617
60 1D 10 68 2011 2536 2657 2681 2694 2560 15 62 2625 14938 61 1399 2520 3239 3369 3371 33r82 32 39 1946 3320 18968 62 1669 2781 3655 3820 38 76 3883 3738 2355 3794 21712 63 1959 3524 42 37 4399 4438 4497 4417 3047 4397 25156 64 2295 4426 5288 5396 5372 5240 5410 3369 5341 30680 65 2636 5490 6531 6662 6565 6379 6820 4249 6591 37938 66 3390 7869 9538 9462 9387 8924 10508 62 91 9564 59601 67 1U 1190 352 368 401 413 407 395 293 397 2256 68 1559 397 422 462 475 471 456 331 4 57 2603 69 1904 434 465 5 13 529 528 504 358 508 2901 70 2211 493 526 573 5 92 588 564 4 15 569 3257 71 2289 569 587 6 30 649 6 61 6 49 460 635 36 44 72 2727 637 6 60 7 09 733 751 743 521 719 4140 73 3210 728 755 8 15 8 43 8 62 8 54 616 826 4765 74 2nD 1210 181 2256 2393 2399 2333 2206 1325 2317 13158 75 1420 2340 2752 2899 2913 2850 2728 1701 2828 16121 76 1692 2853 3306 3452 3471 3379 3217 2134 3365 19217 77 1894 3102 3588 3713 3736 3670 3557 2455 3653 20892 78 2301 3682 4259 4433 4467 43 83 4289 2892 4366 250 30 79 2621 4117 4828 5017 5012 5030 5109 3071 4999 28785
m 0
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ hav Nuav
80 3230 5158 6006 62 13 61 18 6134 6695 4094 6233 359 87 8 1 12nD 1155 15 27 1854 2028 2064 20 85 1987 1164 1968 118 31 82 1689 2046 24 8 2 2688 2739 2760 2658 1749 2665 152 73 83 1244 2088 2317 2339 2345 2373 2381 1487 2351 13432 84 2100 3211 3539 34 21 3462 3512 3696 2575 3526 20284 85 2292 3 5 05 3761 3648 36 25 36 79 3957 2933 3734 21517 86 2907 4420 48 22 4679 46 04 4705 5206 3792 48 03 27741 87 33 80 59 35 69 38 7404 77 10 7 8 36 7 0 86 5190 7394 427 44 88 1 12D 1 4 27 2 4 58 28 31 3037 3021 2987 2927 18 57 2 9 61 16913 89 18 75 34 75 3 9 87 4230 4255 4317 4337 2734 4225 24258 90 22 59 4221 4796 5046 5052 51 01 5389 3491 5077 29206 91 2682 4978 5664 5943 5966 6054 6573 408 1 60 40 34795 92 3417 63 16 71 02 7 3 93 7385 75 40 8 6 95 51 45 7623 44017 93 c 1 5 17 1240 1305 1399 1467 1479 1429 9 26 1423 8251 94 20 34 1554 1623 1720 18 21 18 53 18 72 1215 1778 10229 95 2 3 48 1795 1843 198 5 2097 2171 2274 1540 2074 11947 96 2716 2028 2048 22 01 2 3 44 2444 2661 18 90 2340 13505 97 3247 2410 2375 2663 2778 2949 3298 2378 2793 1615 98 11 35 967 1040 1124 1186 1200 1142 728 1138 6496 99 14 06 1135 1220 1318 1384 1403 1 3 61 8 77 1336 7656
100 2311 1 8 54 18 78 1980 20 90 2136 2227 1653 2062 118 31 10 1 2666 2085 2094 2227 2 3 62 2438 2626 1902 2349 13508 102 3392 2635 2582 28 01 3026 3141 3529 2567 3016 17390
103 1 U 1235 349 395 434 436 4 28 411 286 423 2416 104 20 10 434 5 02 559 577 569 5 37 345 552 3177 105 28 14 538 626 685 711 7 21 682 424 6 8 6 3966
Q) j-J
TABIE III Continued
Run No Position CFM h1 h2 h3 h4 h5 hu h7 hav Nuav
106 3492 614 7 1 6 7 84 8 13 8 33 7 85 4 88 7 87 4562 107 4395 7 86 894 964 996 1005 9 64 640 9 65 56 06 108 50 75 9 11 10 22 1081 1112 1125 1085 7 24 1085 63 16 109 G 1344 9 22 1042 1120 1 1 46 1173 1131 7 04 1120 63 87 110 1936 1162 1340 1442 1474 1509 14 7 3 9 09 1441 82 77 111 2846 1631 1797 1902 1966 2027 2079 1342 19 2 3 11108 112 3484 207e 2144 2236 2307 2385 2574 1694 2268 13138 113 4066 24 65 24 42 2535 2648 2757 31 71 2178 2 5 96 15078 114 50 12 3059 2916 30 1 5 3176 3312 4059 2849 3105 180 46 115 1D 1362 2268 26 13 2613 26 35 2605 2503 15 46 2617 14934 116 1958 2993 3580 3580 3586 3539 3 5 02 2144 3571 20492 117 2812 4430 50 32 4913 4 9 86 4991 5196 3088 4981 287 66 118 3432 58 16 62 13 6067 61 18 60 66 6698 4143 61 16 354 16 119 40 22 71 71 7 4 62 7369 7419 7329 82 74 51 8 1 7395 42909 120 5026 105 95 11456 115 81 11574 11548 14010 80 91 11540 671 15 121 2D 1244 18 57 2277 2363 2305 2210 2107 1466 2289 13038 122 1960 2622 3240 3388 33 23 3226 31 40 2)99 3294 18919 123 2817 3762 45 87 4739 46 56 45 14 4 6 47 30 15 4624 26689 124 3491 50 22 5723 58 53 57 44 5542 60 18 3871 57 16 330 73 125 4096 61 29 68 16 69 79 6805 65 90 74 79 4677 67 98 39400 126 5037 82 27 94 60 95 69 93 57 9023 11324 65 05 93 52 542 83 127 12D 1278 14 70 1 6 48 1652 1638 1 6 34 1641 9 73 1 6 43 9369 128 1947 19 63 2155 2149 2151 2131 2190 1347 2147 12342 129 2769 2615 2791 2773 28 52 2716 2954 18 96 2783 1 60 82 130 3439 3208 3265 3239 3593 3133 3624 2515 3308 19174 131 4103 3637 35 88 3577 4077 3459 42 66 3138 3676 21343 132 49 78 45 82 44 60 44 8 1 55 17 43 25 5749 4227 4700 27288
Q) tlgt
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
133 1 12D 1299 2094 2507 2622 2625 2567 2489 1465 2578 14736 134 1973 29 56 3505 3772 3790 3718 3718 2115 3700 21290 135 2788 3941 4727 5069 5099 5 0 07 5231 2984 4976 28781 136 3473 5155 59 81 6308 6339 62 39 68 96 4204 6217 36052 137 4118 6135 71 8 6 7662 7731 76 91 87 16 49 8 5 7568 43985 138 4973 7765 94 75 10396 10861 10694 13646 66 64 10357 602 25
139 1ttn 1253 1242 1493 1460 1442 1431 1424 8 84 1457 83 01 140 2366 1942 2150 1961 1910 1897 19 62 1206 1980 11400 141 3461 3007 2957 2562 2513 2606 3143 18 51 2660 15400 142 4325 3942 3571 3060 2999 3198 4248 2631 3207 18618 143 5677 508 6 4359 39 88 3800 42 29 57 78 36 26 4094 23824 144 67 59 64 55 5330 4988 47 25 5494 2517 48 09 5134 29906 145 84 08 9326 72 26 7726 85 56 9172 12319 7733 8170 47626 146 86 54 9831 7582 818 9 94 90 9869 13116 78 97 8783 512 96 147 7376 7335 58 7 6 5941 5796 68 29 81 65 5954 6111 35662 148 2 11 D 4254 4106 48 02 4994 5038 5042 56 78 3419 4969 28881 149 5708 5487 6253 6466 6524 6527 78 63 45 8 2 64 43 37566 150 69 7 8 7983 9440 9848 98 34 97 32 13249 6701 9714 566 59 151 1254 1434 18 53 1947 1915 1850 1760 1186 1891 10772 152 2713 2696 3175 32 94 3288 3237 3288 20 44 3249 18728 153 87 30 118 07 14733 15758 15504 15305 26297 9617 15325 892 71 154 5811 5278 6543 6861 69 30 69 82 7 8 74 4478 68 29 39531 155 4246 3780 4736 4975 49 66 4936 5162 3113 4903 28301 156 (v 1270 8 15 935 959 966 9 51 9 23 6 35 953 5430 157 2714 1164 1390 1427 1447 1454 1455 9 08 1430 8242 158 4310 1655 18 96 1942 1988 2002 2111 1305 1957 11349
(j) ~
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 fry hav Nuav
159 6012 2208 2400 2450 2513 2548 28 20 18 00 2478 14416 160 7279 2696 2881 2927 2989 3081 3599 2340 2970 17326 161 86 90 3257 3360 3 3 76 34 26 3558 4455 2943 3430 2000 162 12D 4368 2209 2600 2558 2518 2466 2774 1753 2536 14713 163 5833 2730 3092 3028 2974 2913 3501 2287 3002 174 78 164 7643 3320 3681 3630 3651 3530 4623 3181 3623 21116 165 87 39 3920 4303 4300 4708 4178 61 60 3937 4372 25456 166 1268 962 1203 1205 1186 1118 1084 725 1178 6693 167 2678 14 67 1785 1779 1752 1698 1726 10 70 1754 88 49 168 1 12D 12 83 936 1217 1414 1397 1239 1190 7 65 1317 7484 169 2729 2502 2930 2914 2934 2956 2979 17 52 2934 16866 170 4345 3884 4357 4283 4318 4421 4836 28 59 4345 25151 171 6036 5546 5858 5764 5791 6028 7129 4184 5860 34045 172 6578 7167 7769 7907 79 82 8263 10492 5915 7980 46437 173 87 84 10237 112 23 120 26 12727 12968 185 19 85 98 12236 71103 174 1278 1344 1803 18 72 1835 1790 1712 1063 1825 10355 175 2711 2328 2972 2932 2893 28 78 2863 1667 2919 167 51 176 4351 3934 4414 4353 4281 4321 4654 28 63 4342 25088 177 5994 5076 5824 5838 5818 59 29 6914 4205 5852 33885 178 1 11 U 1223 388 432 465 464 449 435 338 453 2585 179 2351 521 602 6 22 675 6 57 619 436 639 3687 180 34 48 6 05 1725 803 8 27 8 11 760 518 792 4593 181 4513 718 850 934 9 68 9 57 8 99 609 9 27 5386 18 2 5714 8 32 981 1060 1102 11 06 1034 6 59 1062 61 82 183 6997 1025 1182 1258 1295 1309 1234 8 18 1261 7 3 44 184 8709 1295 1487 1 5 42 1594 1626 1612 1156 1562 9080
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
185 2 12D 4249 3560 4400 4670 4791 4695 47 81 2931 4639 268 37 186 5737 4926 58 54 61 92 6248 62 38 67 78 4134 6131 35590 187 7432 6390 7726 83 46 85 44 86 34 10371 5658 8313 48310 188 8723 7718 107 88 11933 12099 13046 186 22 79 39 119 67 69505 189 1 4 35 1340 1735 18 57 18 52 17 81 1711 1144 18 06 10256 190 2718 2399 3023 3187 3207 3138 30 53 1931 3139 18025 191 7 5 07 6189 80 11 9200 9427 9703 11364 5720 9085 527 38 192 8544 78 42 10666 125 42 13312 13775 178 20 6976 125 74 729 86 193 1287 1417 16 97 18 7 18 69 18 08 1720 1046 1800 10223 194 27 17 2450 2940 3187 3214 3157 3054 1749 3125 17954 195 42 53 3560 4222 45 90 4679 46 63 4743 2741 4539 26247 196 6068 48 69 57 79 6335 65 8 6 66 04 7172 4338 63 26 366 78 197 7389 58 86 72 8 6 82 23 8584 8936 10658 50 60 8257 4798 6 198 86 88 78 91 100 27 120 56 130 29 14299 190 81 6492 12353 71850 199 5864 4694 5 6 67 61 94 6419 65 48 7192 3950 6207 360 14 200 2 D 4177 38 36 4547 48 09 4775 4628 5006 2715 46 90 261 30 201 5712 5170 62 39 66 38 6599 6604 7518 4167 65 20 378 00 202 73 63 7201 8986 98 43 9733 9914 13353 6219 9619 55810 203 8604 10043 13118 148 41 150 42 158 66 25206 82 5 3 14717 85290 204 12 68 1506 18 41 1971 1966 1868 1799 11 42 1913 10880 205 2659 2571 3127 3276 32 50 3130 3069 18 80 3196 18 350 206 39 80 36 76 4347 4573 45~67 4473 46 34 28 37 4490 25910
o 207 Orifice 11496 10 64 1360 15 39 1 5 80 1 6 15 1496 8 58 15 24 88 83 208 9433 8 95 11 78 13 26 1394 1386 1263 727 1346 78 48 209 7387 746 9 77 1123 1184 1159 1048 6 11 1111 64 74 210 52 36 566 7 66 900 934 909 8 21 499 8 27 48 02
0) CJ1
TABLE III Continued
Run No Position CFM h 1 h2 hs h4 h5 h6 h7 hav Nuav
211 212
3309 1293
414 257
563 3 19
6 68 3 57
6 91 3 37
6 72 351
7 37 337
38 4 2 46
4 40 341
3748 1942
213 214 215 216 217 218
c of 2nd 1 516 1235
1919 2712 3320 4153 4704
1532 2447 35 46 4312 5567 74 29
2 1 87 3312 4225 52 86 6902 8 6 50
2360 3555 4340 56 12 7 0 49 8 9 40
2409 3598 4 8 85 5718 7713 9593
2347 2101 35 33 3453 48 00 49 62 5562 59 86 72~6 7 8 79 93 76 11237
1243 20 64 3054 4 2 8 1 5114 6983
2326 35 00 4638 5545 7225 91 40
132 13 200 27 26672 31968 41711 52811
bull
67
TABLE IV
PRESSURE PROFILE DATA
Baffle Flow Qpening Rate ~p
(Inches) Position (CFM) (Inches 295 S G Fluid)
1 364 l2 11 U 1012 0 254 1248 0197 1493 0 141 1718 0112
c 1000 9 80 1210 1710 1436 28 75 1746 4320 1011 1080 1277 2050 1393 3020 1 6 28 4450
12D 1011 9 75 1236 1520 1450 2510 1603 3450
1 D 1011 975 1256 1700 1480 2690 158 1 4070
1 12D 1010 950 1259 1750 1462 2650 1631 3710
2 11 D 1124 1315 1360 2130 1505 2850 1689 4125
1 216 12U 1294 045 1949 0324 2374 0282 2704 0225 3367 0169
c 1326 265 18 81 5 90 2313 990 2731 1480 3439 2660
12D 1272 2 49 1957 661
68
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Pos ition (CPM) Inches 2 95 S G Fluid)
2559 1275 3033 1940 3639 3025
1 216 1nD 1257 242 16 96 476 2117 8 05 2561 1280 2990 1895 3431 26 bull00
1 316 12U 1309 0 479 2004 0422 28 28 0 352 3526 0281 42 28 0225 5199 0225
c 1308 1 43 1998 272 28 14 5 10 3478 795 4248 1235 5048 1885
l2D 1286 140 2005 3 45 2831 725 3495 1180 4194 1805 5046 2945
1 11D 1322 150 2039 352 2841 735 43 77 1980 5378 3440
1 516 12U 1278 0493 2732 0493 4315 0408 5744 0352 7494 0352 8932 0422
c 1300 0 506 2731 1985 4310 348 6080 6 45
69
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Position (CPM) (Inches 295 SG Fluid)
7607 1090 8830 1585
l2D 1343 0549 2738 225 4566 583 6112 1195 7536 2055 9043 3415
1 516 1uD 1249 0464 2713 224 4155 579 5620 1150 7428 2115 90 70 3405
1 12D 1301 0493 2735 220 4501 616 61 50 1235 7440 2065 8862 3445
2D 1265 0 478 2750 226 4366 594 6578 1270 7678 2240 8945 5280
2 12D 1295 0493 2725 222 4293 600 5807 1120 7568 2200 9070 3615
TABLE V
RATE OF HEAT TR AN SFER Ar THE BAFFL~~ CID-TT ER
Orifice Size
(Inches)
Flow Rate
( CFM)
Re d e G tU
R~) 055 Nuav NuPr-l3
1 364 10 26 12 90
8 075 10015
43400 54 600
85 11 99 64
95 83 112 19
1416 11 140 59 900 110 30 124 20 16 27 12 800 68 900 126 64 142 60 17 29 13 610 73 200 135 79 152 90 17 76 13980 75 200 147 59 166 19
1 216 11 35 14 06
8 600 10 660
27000 33500
6 4 96 76 56
73 14 8 6 12
1517 11500 36100 82 51 9291 20 34 15400 48400 10229 115 18 23 11 17500 55000 118 31 13322 2348 17 800 55900 11947 13452 2666 20 200 63400 13508 15210 27 16 20 600 64700 135 05 152 07 32 47 24600 77200 161 57 18 193 3392 25 700 80700 17390 195 8 1
1 316 1344 19 36
9898 14 260
24800 35 700
63 8 7 8 2 77
71 92 93 20
28 46 20 9 60 52 500 111 08 125 08 34 84 25 660 64200 131 38 147 93 40 66 50 12
29900 36900
74800 92400
150 78 18046
169 78 203 20
~ 0
TABLE V Continued
Orifice Flow Re Size Rate d e G R~rmiddot55 NuPr-13(Inches) (CFM) U Nuav
1 516 12 70 8 847 16800 54 ~0 61 14 2 14 18 900 35800 82 42 92 80 43 10 30 000 56900 11349 127 79 60 12 41900 79400 14416 16232 7279 50700 96100 17326 19509 86 90 60540 115000 20098 22529
TABLE VI
RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
Orifice Size
(Inches)
1 364
1 216
1 316
Flow Rate
(CFM)
1054 1294 1431 1681 1770
1068 1399 1669 1959 2295 2636 3390
1299 1973 2788 34 73 4118 4973
Re deG Mshy
8 300 9870
11260 13200 13 930
8100 10600 12650 14850 17400 19980 25700
9 570 14500 20500 25600 30300 36600
R~r-6 51900 61700 70500 82 500 87 100
28200 36900 44000 51700 60 600 69500 89400
26100 39600 56000 69900 82700 99 900
Nuav
2416 293 5 3187 4018 4805
14938 18968 21712 25156 30680 37938 59601
14736 21290 28781 36052 439 85 60225
Uu Pr-1 3
27204 33050 3589 4524 541 0
16820 21358 24448 28326 34546 427 18 67111
16593 23973 32407 40595 495 1 678 13
TABLE VI Continued
Orifice Flow Re Size Rate deG R~rmiddot6 NuPr-13(Inches) (CFM ) M- Nuav
1 516 1268 88 30 17700 108 8 1225 2689 18700 37400 1835 2066 3980 27700 55700 2591 2917 4177 29100 58 500 2713 3055 5712 39800 80000 378 0 425 6 7362 51300 103000 5581 6284 8 604 59 900 120000 8529 9604
74
TABLE VII
EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER
l 516 Inch Orifice
Center ot 2nd Baffle 4 Downstream
Plow Rate (CFM)
1235 1919 2712 3320 4153 4704
Flow Rate (CFM)
1270 2714 4310 6012 7279 8690
(Re)eb -8600 1321
13400 2003 18900 2687 23100 5197 28900 4171 32800 5281
Center ot Single Battle
-8847 543
18900 824 30000 1135 41900 1442 50700 1733 60540 2001
(Nu)(Pr)-l3
1487 2255 3003 3600 4697 5946
(Nu)(Pr)-13
611 928
1278 1623 1951 2253
75
ABLE VIII
HEAT TRANSFER IN THE TEST SECTION WITHOUT ORIFICE
CFM Ute) 0b h Nu
1293 5-951 3 41 1942
33 09 15251 649 3746
5236 24193 827 4802
7387 34001 1111 6474
9433 43419 1346 7848
11496 52-914 1524 8883
76
TABLE IX
PRESSURE DROP FUNCTION
Orltlee Size Flow Rate incbea ~CFM (Re)eb X 10bull8
1 364 1011 7957 0808 1256 9885 1468 1480 11648 2765 1581 12443 4160 1689 1_3293 4 020
1 216 1257 9530 1327 1696 12858 2663 2117 16049 4615 2561 19415 7581 2990 22668 11560 3431 26011 16440
l 316 1322 9736 1819 2039 15016 4332 2845 20952 9275 3495 25739 15300 4377 32014 26800 5378 39607 50100
1 516 1011 7 957 oaos 1256 9885 1469 1480 11646 2765 1581 12443 4160 1689 13293 4020
77
TABLE X
EXPERIMENTAL DATA
Baffle Hole Diameter Run No
1 - 59
60 - 102
103 - 138
139 - 206
207 - 212
213 - 218
(Inches)
1 364
1 216
1 316
1 516
No Baffle
2nd - 1 516
TABLE X
EXPERIMENTAL DATA
Run Thermocouple Reading s (mv) No Position CFM I tc1 tc2 tc3 tc4 t c 5 tc6 tc7 tcair
1 c 1026 530 2055 1825 1768 1782 1802 1837 1965 1198 2 1290 612 2059 18 65 1809 18 32 1851 1880 1965 1160 3 1416 714 2151 1970 1931 1965 1988 2026 209 5 1130 4 1627 8 21 2235 2084 2 049 2093 2126 2173 2266 1130 5 1776 865 2203 2033 1970 2015 2084 2159 2 264 1121 6 12D 1109 542 1636 1507 1499 1499 1498 1498 1528 1218 7 1258 651 1670 1522 1503 1513 1513 1516 1548 1221 8 1433 750 1625 1480 1467 148 3 1487 1487 1516 1153 9 168 1 8 73 1656 1494 148 1 1511 1517 1517 1543 1159
10 1rtD 1102 485 1545 1450 1437 1446 1447 1442 1466 1220 11 13 08 6 10 1571 1470 1460 1476 1476 1469 1498 1194 12 1464 730 1 623 1509 1508 1528 1 5 32 1524 1548 1173 13 11 06 8 71 1663 1559 158 1 1606 160 6 1 583 1601 1190 14 1 12D 1115 520 1698 1579 1575 1 577 1580 1590 1615 1280 15 1275 6 10 1692 1567 1558 1 561 1570 1580 1601 1234 16 1498 770 1760 1619 1630 1 635 1642 1645 1661 1204 17 1695 912 1775 1635 1670 1689 1686 168 6 1701 1165 18 2D 1049 510 1736 15~2 1567 1558 1 553 1558 1620 1236 19 12 41 610 1655 1517 149 1 148 1 148 1 148 4 1546 1108 20 1 5 32 7 35 1720 1550 1530 1520 1519 1523 158 0 1104 21 16 74 8 8 0 1900 1 727 1714 1696 1691 1692 1753 1169 22 1U 1074 38 5 3 324 2740 2534 2478 2 465 2503 258 0 1210 23 1287 4 35 3510 2 870 2682 2 610 2599 2638 27 1 9 1190 24 1 5 08 470 3 618 2920 2690 2 637 2627 2 664 2747 1177 25 18 07 525 4 088 3235 2962 2905 2910 2988 3130 1169
z ())
TABLE X Continued
Run No Position CFM I tc1 tc 2
Thermocouple Readings te3 tc4 tc5
(mv) tc6 tc7 tcair
26 c 10~29 6 32 2340 2~092 2032 2060 2~097 2152 2~213 1211 27 12 66 679 2270 2 047 1993 2013 2069 2142 2 210 1 182 28 1430 723 2336 2097 2033 2080 2153 2~255 2 356 1 138 29 1729 8 52 2318 2070 1980 2061 2158 2279 2367 1121 30 12D 1054 570 1520 1 4 20 1402 1400 1396 1400 1 443 1159 31 1294 6 69 1599 1469 1444 1439 1433 1 442 1485 1168 32 1430 7 88 1720 1562 1536 1532 1528 1537 158 0 118 5 33 1770 8 81 1641 1488 1450 1~441 1 441 1_466 1518 1 163 34 1D 1058 548 1579 1498 1495 1526 1553 1_557 1 571 1 276 35 1263 640 1609 1509 1515 1570 1599 1598 1 598 1 266 36 18 36 8 47 1538 1452 1483 1553 1602 1 590 1 558 1195 37 1 12D 1029 5 41 1 578 1499 148 4 1473 1461 1465 1-512 1200 38 1315 6 30 159 1 1504 1493 1482 1470 1470 1505 118 5 39 1 4 26 743 1765 168 1666 1660 1645 1642 1678 1270 40 1757 8 54 1744 1648 1634 1620 1598 1 593 - 1612 1223 41 2D 1080 5 30 1734 1604 1570 1 570 1570 1 588 1 640 128 1 42 1305 6 40 1744 1622 1589 1 608 1593 1 609 1 661 1240 43 1434 750 1798 1687 1658 1 636 -1641 1 661 1 711 1_220 44 18 04 8 41 1 764 1666 1607 1605 1614 1 635 1 675 1205 45 12nu 1088 415 2614 2295 2195 2 169 2174 2217 2256 1171 46 1318 477 2805 2477 2371 2342 2364 2 401 2 438 1 163 47 1413 5 28 2930 2 646 2 555 2 526 2532 2570 2 577 1 199 48 1773 550 2740 2518 2450 2431 2448 2 479 2 480 1 170 49 1 11 U 1054 380 3175 2670 2505 2 461 2467 2 534 2 621 1 258 50 1240 420 3268 2738 2 546 2 510 2 508 258 2 2 649 1214 51 1419 451 3364 2B07 2 632 2590 2 590 2 651 2773 1 215 52 1 12U 1032 360 3 165 2 629 2 450 2402 2403 2 473 2 bull568 1 163
--I lt0
TABLE X Continued
Run No Position CFM I tc1 tc2
lhermocoup1e Reading s tc3 tc4 t c 5
(mv) tc6 tc7 tc a ir
5 3 1314 38 9 3178 2592 2411 2367 2361 2432 2555 1140 54 1448 403 3095 2544 238 1 2336 2336 2390 2476 1158 55 178 2 427 3006 2434 2286 2253 255 3 2299 2397 1154 56 2 11U 1061 360 3369 2814 2619 2567 2560 2650 2833 1220 57 1216 360 3044 2512 2338 2290 2288 2374 2566 1150 58 1322 387 3196 2614 2425 2383 2382 2472 2670 1138 59 1639 403 3020 2438 2272 2238 2238 2318 2502 1127
60 1D 1068 612 1552 1424 1400 1395 1396 1426 1745 0945 61 1399 612 1355 1246 1230 1229 1230 1250 1509 0872 62 1669 710 1436 1293 1272 1265 1266 1286 1551 0847 63 1959 900 159 5 1468 1444 14 38 1432 1446 1720 0851 64 2295 730 1169 1105 1098 1099 1108 1100 1298 0781 65 2636 8 80 1202 1129 1121 1126 1 138 1115 1342 0748 66 3390 9 35 1060 o 9s7 0999 1001 1017 0971 1154 0703 67 1nu 1190 370 2225 2188 2104 2080 2120 2209 2 7 15 0990 68 1559 368 2005 1950 1871 18 48 1876 1951 2408 0916 69 1904 368 1870 18 1 4 17 34 1711 1730 18 07 2238 0875 70 22 bull11 471 228 6 2 204 2099 2063 2092 218 $ 2732 0840 71 2289 471 2030 2000 1925 1895 18 96 19 5 2498 0785 72 2727 4 71 1854 18 23 1753 17 23 1716 3758 2241 0743 73 3210 471 1680 1651 158 6 1559 1551 158 1 1950 omiddot7o9 74 2uD 1210 404 1261 1212 1198 1197 1205 1222 139 1 0978 75 14 20 540 1321 1260 1242 1 240 1249 1268 148 7 0918 76 1692 7 18 1467 138 6 1364 1361 1376 1405 1678 0883 77 18 94 903 1708 1 591 1565 1560 1575 1603 1948 0 857 78 2301 903 1530 1432 1407 1402 1415 1432 1738 0815
ro 0
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc117 tcair
79 2621 6 50 1069 1 020 1009 1009 1009 1007 1~189 o739 80 3230 901 1200 1128 1113 1119 1119 1086 1341 0694 81 82
l2D 1155 1689
360 575
1191 1345
1142 1252
1122 1218
1118 1210
1118 1209
1132 1228
1292 1446
0916 0822
83 1244 430 1163 1134 1131 1130 1129 1132 1292 0877 84 2100 645 1175 1135 1147 1 142 1138 1122 1286 0757 85 2292 8 25 1 354 1310 1327 1330 1323 1285 148 6 0728 86 2907 8 23 1180 1138 1151 1158 1149 1107 1268 0687 87 3380 902 1113 1049 1025 1011 1006 1042 1178 0673 88 89
1 12D 1427 1875
480 615
118 2 1140
1140 1095
1124 1077
1125 1075
1129 1072
1137 1072
1290 1243
0880 0790
90 2259 8 41 1296 1231 1207 1206 1203 1182 1419 0757 91 2682 8 80 1231 1170 1149 1147 1142 1112 1350 0731 92 3417 940 1142 1092 1076 1076 1069 1021 1252 0693 93 c 15 17 431 1321 1298 1268 1249 1250 1273 1522 0841 94 2034 505 1285 1263 1235 1209 1205 1206 1464 0759 95 2348 6 10 1395 1379 1334 1302 1286 1268 1536 0732 96 2716 706 1486 1480 1427 1383 1358 1311 1572 0 700 97 3247 7 56 1417 1430 1375 1320 1284 1223 1450 0660 98 1135 400 1425 1388 1352 1329 1330 1 364 1651 0893 99 14 06 440 1379 1341 1304 128 2 1281 1305 1583 0 831
100 2311 680 1602 1593 1553 1514 1502 1480 1 7 27 0 802 101 2666 680 1471 1469 1428 1390 1372 1335 1564 0761 102 3392 798 1491 1 509 1449 1395 1372 1305 1534 0 719
103 1U 1235 410 2469 2295 2173 2165 2226 2361 3120 0 897 104 2010 410 2017 1848 1 737 1706 1747 1865 2582 0753 105 28 14 410 1682 1535 1457 1427 1437 1520 2109 0 660
00 t-
TABLE X Continued
Ru n Thermocouple Rea ding s (mv No Positi on CFM I tc1 tc2 tc3 tc4 tc5 tc6 tc7 tcair
106 3492 440 1649 1499 1420 1391 1390 1470 2042 0620 107 4395 550 18 33 1679 1597 1564 1570 1640 2223 0583 108 5075 588 1779 1642 1580 1550 1552 1 615 2 191 0548 109 c 1344 398 1464 1 399 1364 1353 1350 1380 1689 0 907 110 1936 459 1369 1290 1253 1242 1 237 1259 1574 078 2 111 2846 580 1347 128 5 1251 1232 1220 1215 1 5 23 0 683 112 34 8 4 700 1392 1369 1339 1317 1299 1259 1599 0 636 113 4066 8 13 1449 1458 1427 1391 1363 1270 1595 0 591 114 5012 930 1484 1530 1500 1453 1420 1272 1580 0 580 115 1D 1362 513 1269 1218 1 217 1214 1220 1238 1460 0 893 116 19 58 600 1187 1122 1121 1120 1124 1133 1352 0798 117 2812 705 1052 1008 1015 1010 1011 1001 1218 0691 118 34 32 913 1105 1075 1085 1081 1086 1047 1301 0645 119 4022 980 1038 1021 1026 1023 1029 0983 1211 0 609 120 5026 982 0 8 61 0839 0836 0836 0837 0791 0955 0570 121 2D 1244 475 1320 1246 1233 1240 1255 1275 1434 0925 122 1 9 60 5 50 1160 1088 1074 1079 1089 1100 1260 078 7 123 2817 6 80 1096 1024 1 013 1018 1029 1022 1201 0 700 124 3491 960 1248 1175 1163 1172 1192 1153 1435 0 658 125 4096 989 1141 1089 1078 108 9 1105 1051 1310 0629 126 50 37 989 0983 0933 0929 0 936 0949 0880 1090 0 602 127 128
12D 1278 1947
402 545
1270 1261
1 230 1216
1228 1216
1230 1 215
1235 1223
1242 1219
1483 1514
0 913 0778shy
129 2769 695 1273 1234 1237 1221 1251 1212 1525 0678 130 131 132
34 39 4103 4978
8 40 9 80 9 80
1336 1448 1271
1322 1458 1 288
1328 1 462 1286
1 259 1 356 1157
1353 1492 1311
1261 1329 1138
1 555 160 7 1343
0 629 0 600 0599
(l) l)
TABLE X Continued
Run No Position CFM I tel tc 2
Thermocouple Readings tc3 tc4 tc5
( mv) tc6 tc7 tcair
133 1 l2D 1299 5 16 1 28 1 1212 1196 1195 1205 1221 1478 0869 134 1973 6 15 1163 1098 1073 1071 1079 1083 1343 0751 135 136
27 88 34 73
802 9 -_78
1187 1214
1099 1131
1069 1104
1066 1101
1075 1~110
1l061 1066
1370 1360
0662 0618
137 4118 9 81 1084 1010 0983 0979 0982 o937 1209 0581 138 4973 98 1 0969 0897 0 868 0855 0860 0799 1041 0572
139 1D 1253 409 1371 1293 1298 1301 1309 1321 1578 0928 140 2366 480 1130 1 090 1 121 1130 1137 1132 1390 0744 141 34 61 6 38 1081 1086 1152 1161 1147 1069 1382 0644 142 143 144
4325 5677 6759
7 90 939 998
1110 1115 1034
1161 1208 1139
1253 1268 1180
1265 1302 1215
1228 1230 1123
1080 1056 0970
13$913r12 8
0601 0561 0542
145 84 08 989 0863 0961 0934 0895 0871 0 785 09 9 0530 146 86 54 9 80 0808 0901 0 872 0821 0809 0733 0891 0498 147 7376 9 80 0 927 1032 1027 1 040 0961 0889 1032 0511 148 2D 4254 776 1 050 0 981 0965 0961 0962 0922 1155 0579 149 5708 991 1102 1031 1014 1009 1010 0931 1227 0528 150 69 78 990 0914 0853 0839 0 839 0843 0759 0996 0521 151 1254 490 1 479 1352 1329 1334 1351 1379 1607 0930 152 2713 7 00 1310 1220 1201 1201 1211 1209 1516 0723 153 8730 991 0809 0756 0742 0745 0 748 0663 0874 0543 154 5811 966 1219 1108 108 6 1081 1079 1033 1330 0650 155 42 46 8 02 1248 1136 1114 1114 1118 1103 1376 0 699 156 c 1270 429 1671 1571 1551 1545 1563 1600 1933 0929 157 2714 488 1398 1285 1 267 1258 1262 1275 1628 0729 158 4310 642 1424 1318 1299 1282 1283 1261 1683 0617
co ~
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc7 tc a 1r
159 60 12 780 1461 1388 1370 1349 1343 1279 1700 0 573 160 72 79 8 60 1402 1344 1330 1312 1292 1189 1 566 0 520 161 8690 982 1472 1442 1437 1 422 1392 1224 1602 0 521 162 163
12D 4368 5833
6 30 8 30
1195 1368
1105 1270
1111 1283
1117 1294
1131 1313
1081 1194
1369 1553
0613 0 553
164 76 43 959 1428 1338 1348 1341 1371 1180 1488 0535 165 8739 984 1345 1272 1272 1208 129 3 1059 1361 0550 166 1268 459 1701 1548 1541 1547 1589 1 625 1976 0 973 167 2678 570 1485 1351 1349 1356 138 1 1 385 1795 0760 168 169
1 12D 128 3 2729
448 650
1664 1314
1501 1232
1425 1233
1428 1229
1491 1229
1527 1232
1869 1571
0 962 0767
170 4345 847 1245 1179 1187 1182 1172 1132 1476 0 650 171 6036 9 76 1139 1109 1117 1114 1095 1020 1332 0588 172 6578 9 72 0982 0949 0942 0938 0926 0 8 50 1079 0560 173 87 84 9 72 0880 0854 0 8 36 0822 0818 0 749 0941 0585 174 1278 480 1564 1416 1397 1403 1417 1445 1733 0998 175 2711 590 128 3 1175 4 1178 1182 1187 1195 1493 0796 176 4351 8 90 1331 1259 1266 1275 1272 1235 1592 0 682 177 5994 9 60 1228 1152 1150 1151 1143 1075 1 360 0644 178 lU 1223 408 2282 2140 2052 2052 2106 2188 2626 0 878 179 2351 408 178 1 1623 158 5 1519 1556 1634 2068 0717 180 3448 482 1888 1675 1570 1541 1572 1665 2199 0629 181 4513 563 2026 1797 168 4 1644 1670 1770 2385 0583 182 5714 589 1913 1700 1610 1568 1580 1 682 2382 0551 middot 183 6997 653 1903 1718 1643 1611 1612 1700 2326 0 549 184 8709 6 80 1738 158 3 1543 1510 1498 1519 1 912 0577 185 186
2 12D 4249 5737
660 9 74
1055 1221
0 979 1122
0960 1093
0 952 1088
0959 1090
0 956 1054
1147 1350
0661 0602
187 7432 9 8 1 1065 0981 0951 0942 0 939 0881 1135 0582 CD ~
TABLE X Continued
Run No Position CFM I t o1 to 2
188 87 23 9 83 0944 0 879 189 1435 585 18 26 1630 190 2718 690 1433 1298 191 7507 950 1070 0961 192 85 44 964 0982 0 881 193 1287 600 1806 1668 194 2717 7 80 1579 1444 195 4253 8 81 1371 1260 196 60 68 9 78 1252 1152 197 73 89 975 1100 1000 198 86 88 973 0953 0 871 199 58 64 9 81 1269 1155 200 2D 4 1 77 915 1362 1251 201 5712 975 1213 1111 202 7363 9 78 1036 0 951 203 8 604 973 0932 0861 204 1268 6 95 2015 18 20 205 2659 6 96 1405 1295 206 39 80 7 98 1261 1174
No 207 Orifice 114 96 509 1325 1148 208 94 33 509 1477 1243 209 7487 5 09 1686 1409 210 5236 505 2094 1691 211 3309 428 2188 1 778 212 1293 392 2976 2560
Thermo ooup1e Readin g s (mv) to 3 to4 to
5 to
6 to7 toair
0 851 0847 0 8 29 0759 0987 0592 158 4 1583 1611 1647 1993 0986 1270 1266 1 279 1298 1604 0 789 0916 0908 0900 0 858 1115 0602 08 39 0 823 0 818 0 770 1035 0602 1609 1602 1629 1676 2153 0979 139 1 1385 1400 1 430 1938 0776 1212 1201 1205 1201 1601 0669 1 105 1086 1086 1 052 1371 0621 0952 0936 0923 0870 1195 0582 0 8 20 0 801 078 1 0 729 1044 0569 1108 1090 108 2 1043 1407 0610 1218 1221 1241 1202 1582 0659 1081 1083 1084 1031 1 368 0622 0921 0924 0919 0 841 1111 0 610 08 34 0831 0 821 0 751 1003 0 630 1761 1761 1 809 1861 2399 0966 1271 1271 1295 1311 1650 0797 1150 1150 1161 1149 1440 0703
1083 1057 1053 1109 1566 0~530 1158 1125 1138 1217 1763 0 526 1291 1250 1278 1383 2038 0542 1518 1478 1519 1657 2420 0 589 1596 1557 1601 1737 2441 0688 2370 2344 2409 2561 3 297 0921
()) (11
TABLE X Continued
Run Thermocouple Readings (mv) No Position CFM I tc 1 tc2 tc3 tc4 tc tc tc tc i5 6 7 a r
C of 2nd 213 516 1235 4 63 1 432 1291 1265 1258 1 268 1 308 1550 0 971 214 1919 6 17 1357 1223 1196 1191 1199 1211 1461 0 851 215 27 12 8 35 1401 1259 1278 1220 1230 1218 1511 0 762 216 3320 981 1439 1305 1270 1259 1275 1238 1450 0719 217 41 53 980 1251 1142 1132 1094 1121 1088 1305 0 695 218 404 987 1102 1042 1030 1 bull006 1014 0960 1133 0681
Supplementary Equations
Calculating temperatures from thermocouple readings
t = -026tc)2 + 3512(tc) + 3201 (26)
where t is the temp in deg F and tc is the thermocouple reading in millishyvolts
Calculation of the thermal conductivity of air
k = 00000245ta + 0 0132 (27)
where k is the thermal conductivity in Btuhr rt2 degFft and ta is the air temp 1n OF
I I
bull co m
5
The heat transfer coefficient for fluids flowing inshy
side tubes is more e a sily measured and correlated due to
the simple geometry of t he tube i nterior Much work has
been done on the tube-side coefficients with one of the
more useful e quations being the Dittus - Boelter equation
( 4 p 450) ~
0 023 (---ctwGJbulla (~np M ( 3 ) M k
with the following cond itions satisfied
(1) Fluid properties evaluated at the arithmetic
mean bulk temperature
(2 Reynolds number gt10000
(3) 0 7 lt Pr lt 100
(4) n = 04 for heating and 0 3 for cooling
(5) Ldw gt60
Colburn (3 p 197) obtained an equation for tubeshy
side heat transfer coefficients in which the Stanton
number is used instead of the Nusselt number
hm ) (~~ 23 _ (dwG) 0 2 ( GC k - 0 bull 023 U (4)
p
Much of the research done on average shell-side heat
transfer coefficients has resulted in empirical correlashy
tions of the form of equations (3) and (4) above Several
investigations have been made for a certain set of phys~al
6
variables but the r esults have ne ver satisf a ctorily been
correlated to appl y for all types of heat exchangers
Some basic 1ork has been done recently however on
the local shell-side coefficients Ambrose (1) studied
the local heat transfer coefficients i n a model heat exshy
changer with segmental baffles This study was fairly
extensive at the baffle center but the data were quite
limited for the space between the baffles Gurushankar1ah
(5) further extended Ambroses work by studying a single
baffle space in detail
The results of these two studies indicated a need for
detailed information 1n the vicinity of the baffle Hence
Lee () investigated a single baffle s pace between two
orifice baffles and obtained considerable information on
the rates of heat transfer in the annular orifices Since
his work was carried out in a multitube mode l heat ex~
changer the determination of the rate of flow through the
individual orifice was difficult because of t he outer
clearances existing in the exchanger For this reason the
present research was undertaken to study the rate of heat
transfer in a single annular orifice through which the flow
could be accurately determined
Bell and Bergelin (2) have studied i n detail the pres shy
sure drop coeff icients for the annular orifices formed beshy
tween a circular disk and a circular tube These results
also appl y to the annular orifioe formed when a rod extends
7
through a circular hole in a plata This study was extenshy
sive in the fact that it considered the baffle thickness as
well as the orifice size but no heat transfer data were
presented
Sullivan and Bergelin (9) studied flow through a
single annular orifice through multiple annular orifices
i n parallel and flow around a single baffle both with and
without leakage through the baffle A generalized expres shy
sion is presented for the pressure drop across one baffle
section of a tubular exchanger with leakage through the
tube holes in the baffle but the effect of leakage area
upon heat transfer is only discussed qualitatively The
pressure drop data is correlated by plotting cent as a funcshy
tion of the Reynolds number where cent equals
d1 )22( ~ P) s c e (d2 -
M-2
8
CHAPTER III
~PERI1ffiNTAL APr ARATUS
The heat transfer test section was essentially a
single tube heat exchanger The inner tube was a l-in
OD aluminum tube with an electrically heated probe midshy
way between the two ends of the tube
Test Section
The shell as constructed from lucite plastic tubing
2 5-in I D and 3-in O D The te t section d a total
lengt h of 54 58 inches I t consisted of two sections
The upstream section was 40 i n ches in length in order to
assure freedom from entrance effects and the downstream
section was 13 12 inches in length To further assure
uniform flow a bundle of short copper tubes was placed a
few inches downstream from the entrance Both of these
sections had 12 i nch flanges on one end so t hat a 18
i nch thick orifice plate could be clamped between them
Heat transfer coefficients were measured in the vicinity of
t h is orifice A cross section of the center of the test
section is shown in Figure 1 and the experimental appara~
tus is shown in Figure 2
Cooled air supplied by a Roots -type blower was used
as the shell-side fluid throughout this study It entered
the test section through a l-in ID 1 12-in OD plasshy
tic pipe at the upstream end of the calming section Tbs
j Jl l 6- 11 BOLTS II I nbull middot~11 I HEATING ELEMENTS
J T ( T
-f-shy - - - f-_- __L
7 777 _y A
IT 1] I
I
FIGURE I CROSS SECTION OF TEST SECTION AND PROBE
10
FIGURE 2 EXPERIMENTAL APP1Ub~fUS
11
air left the test section through nine equally spaced 12
ineh holes placed around the side of the tube at the exit
end
Sensing Probe Assembly
The sensing probe was designed to measure the local
heat transfer coefficients at any point along the tube and
around the tube in the test section The tube was designed
so that it could be easily moved up- and downstream to
measure the heat transfer coefficients at various positions
in relation to the orifice
The sensing tube assembly consisted of the sensing
probe the thermoctmple lead s and selector switch the
power lines and the two aluminum tubes between which the
probe was centered
Imbedded in the sensing probe were seven iron-constanshy
tan thermocouples for measuring the temperatures around the
tube The lead wires from these thermocouples were conshy
nected to a seleotor switch at the downstream end or the
aluminum tube A layer of Saran wrap was placed around the
tube over the t hermocouple and three lengths of Trophet C
resistance ribbon were wrapped around the tube nd conshy
nected in series to the power leads
The heating surface of the probe was formed by these
three one inch wide strips of Trophet C resistance ribbons
The ribbons were 0002 inches thick and had a resistance of
12
0 271 ohms per foot and a thermal conductivity of 763
Btuhr ft 2 degFft They were held in position by four
copper bars placed in four parallel longitudinal slots
These copper bars served as connectors for the electrical
leads A photograph of the sensing probe is shown in
Figura 3 and a drawing of the assembled probe is given in
Figure 4
Power Source
Direct current was used to heat the resistance ribbon
on the sensing probe The current was regulated by a slide
wire resistor The po er source consisted of a Raytheon
Voltage Stabilizer to stabilize the city power source at
115 volts and an automatic selenium rectifier with an alshy
ternating current input of 115 volts at 60 cycles per
second and an output of 12 volts and 35 amperes direct
current
Temperature Measuring
The temperatures around the sensing probe were calcushy
lated from the emf readings of the ironbulloonstantan thermoshy
couples The emf measuring system consisted of the seven
probe thermocouples a separate thermocouple for measuring
the inlet air temperature a thermocouple selector switch
a cold junction and a Leeds and Northrup Type K Potentishy
ometer The potentiometer was placed on a Fischer
13
THERMOCOUPLE JUNCTIONS~ ~------- HOLES FOR THERMOCOUPLE LEADS
~----- SCREWS
~ff+--- CONNECTING BARS
END VIEW
POWER LEADS SOLDERED TO LOWER CONNECTING BAR
iER PLASTIC PIECE
RESISTANCE RIBBONS LOCATION OF THERMOCOUPLES
FIGURE 4 DRAWING OF ASSEMBLED SENSING PROBE
15
Vibradamp support to absorb the vibrations produced by the
air blower
Air Source
Air was used as the shell-side cooling fluid during
the study The air was pumped through the test section by
a Roots type air blower with a rating of 280 ofm at 3 12
psig outlet pressure The hot air leaving the blower was
passed tbxfugh two finned-tube box-type coolers and one
tubular edoler to oool it to approximately room temperature
The air flow rate was measured by passing it through a
flow measuring orifice in the line Two sharpbull edged orishy
ficas were used f or flow measurements The calibration
curves for these orifices were presented by Ambrose (1
p 166)
The pressure taps on each side of the orifice were
connected to two differential manometers containing 0 83
and 2 95 specific gravity fluids respectively The presshy
sure drop through the test section and test orifice was
measured by a pressure tap placed 13 inches upstream and
one placed 6 12 inches downstream from the orifice Two
pressure ga ges were used to measure the pressure at the
inlet to the flow orifice and to indicate the statio pres~
sure at the test section inlet
16
Pressure Probe
A probe was designed to measure the pressure drop
between the pressure tap 13 i nches upstream from the ori shy
fice baff le and any point downstream from the tap The
probe eonsisted of a l~in OD copper tube with six 132
i n ch holes even l y s paced around the tube The upstream
pressure tap and the pressure probe were connected to a
differential manometer so the pressure drop to various
points up- and downstream of the orifice could be measshy
ured
17
CHAPTER IV
EXPERIMENTAL PROGRAM
The experimental program was designed to measure the
heat transfer coefficients and pressure drops in the vicinshy
ity of annular orifices The four orifice sizes studied
were 1 364 1 216 l 316 and 1 516 inches~ The inner
tube used in each case was a 1-in OD alumintim tube
Hence tube to baffle clearances were respectively 3128
232 332 and 532 of an inch
Heat transfer coefficients were measured at poait~ons
1 i nch upstream at the orifice center and at 12 1
1 12 and 2 inches downstream for all orifices In addishy
middottion the heat transfer coefficient at a point 2 12
inches downstream from the 1 516 inch orifice was measured
and at the points 12 l 12 and 2 inches upstream from
the 1 364 inch orifice
The heat transfer coefficients at each point were
measured at five different flow rates for the 1 364 inch
orifice and at six different flow rates for the other orishy
fice sizes The high pressure drop through the small orishy
fice size limited the number of flow rates which could be
studied
The flow rate was calculated from the pressure drop
across the flow orifice This flow was corrected to cubic
feet per minute at 68degF and one atmosphere pressure by
18
using the orifice pressure and the test section pressure
which were measured by pressure gages
It was desired to determine a relationship between the
heat transfer coefficient and the total pressure drop for
each orifice size The pressure drop across each orifice
at various flow rates was measured by means of the presshy
sure probe described in Chapter III It was also desired
to obtain pressure profiles for each orifice size since
these might be similar to the heat transfer profiles The
pressure drop was measured from a point 13 inches upstream
of the orifice to points at 1 and 12 ineh upstream the
orifice center 12 1 1 12 and 2 inches downstream
The experimental program is summarized in Table I
TABLE I
SUla~RY OF EXPER IMENTAL PROGRAM
Position Investigated-Distance from Orifice-Inches
Orifice Range of Flow Rate Size Heat Transfer Pressure Drop CFM at 68degF amp 1 atm
1 364 2U 1 12U 1U 12U c 12U C 12D lD 10 - 18 l2D lD 1 12D 2D 1 12D 2D
1 216 1U c 12D lD 1 l2D 2D 12U c 12D lD 10 - 35
1 316 1U c 12D lD 1 l2D 2D l2U C 12D lD 12 - 50
1 516 1U c x2D lD 1 l2D 1U 12U C 12D 12 - 90 2D 2 1 2D l D 1 l2D 2D 2 12D
20
CHAPTER v
EXPERI MENTAL PROCEDURE
The experimental procedure for measuring the heat
transfer coefficients ~d corresponding flow rates reshy
quired the following procedure
(1) Install the orifice size to be studied in the
test section
(2) Place the heat transfer probe in the position up
or downstream from the orifice where the middot heat
transfer rate is to be studied
(3) Fill the cold junction thermos with cracked ice
(4) Measure the atmospheric pressure
(5 Open bypass line from blower and close line to
test section
(6) Turn on the cooling water for the exchangers used
to cool the air leaving the blower
(7) Start the automatic selen ium rectifier by turning
on the t 1mer bull
(8 ) Connect the voltage stabilizer to the wall outlet
(9) middot Set the slide wire resistor to the maximum re shy
s1atanee I
(10) Start the blower
(11 Open the line to the test section until the de shy
sired flow rate is obtained
(12) Switch on the probe direct current power source
21
(13) Adjust the slide wire resistor to obtain the
desired current
(14) After the thermocouples have reached equilibrium
values record the e m bullf across each of the
seven probe thermocouples and also the entering
air thermocouple
(15) Record the direct current amperage
(16) Record the gage pressure at the flow orifice and
the entrance to the test section
(17) Record the manometer measurement of the pressure
drop across the flow orifice and also the presshy
sure drop through the test section
22
CHAPTER VI
CALCULAT ION OF EXPERIMENTAL DATA
The local heat transfer coefficients were calculated
from the temperatures measured on the probe surface the
air temperature and the current input The results were
calculated by using the Alwae III-E computer
The general expression for calculation of the heat
transfer coefficients was derived by Ambrose (1 p 79)
The equation is derived by making an energy balance around
a small increment of the center resistance heating ribbon
The two ribbons tnstalled adjacent to the center ribbon
reduced the amount of logitudinal conduction and assured
little longitudinal temperature variation in the center
ribbon
A heat balan ce on this small increment of resistance
ribbon yields the following
(the heat conducted in) + (heat generated) = (heat
conducted out) +(Heat convected to the fluid) + (heat
radiated to the surroundings) + (Heat conducted into
the plastic center of the probe)
This gives the equation
kzw dtdS + 12RdS kzws [ t + (~) ds] + hwdS (t-ta )
+ ~Aad wd o middot+ qcAond 1 -~- wdS 5 )
23
Hence solving for h gi~ea
i2R kz d2t Qrad qcond w + -d$2 - ~- A
h = ( 6)t - ta
Since S = re where 9 equals the enclosed angle ~n radians
dS rd9 ( 7)
and
dt - dt (8)dS - rd9
Differentiating with respect to S
d2t (9)rd9dS
from which
(10)
Substitut1ng into the equation for heat transfer coeffishy
cient gives
h = i2R Qcond A (11)
w
The rate of radial heat conduction into the plastic
tube making up the probe was assumed to have negligible
effect on the heat transfer coefficient It was also
assumed that the heat loss by radiation from the ribbon
was negligible since all data were obtained with the ribbon
at a temperature less than 125degF
24
When t he rad iation and conduction terms are neglected
Eq (11) becomes
(12)
The following con stants are known
R = 0 271 ohmsft
w = 100 i n ches
k = 763 Btuhr rt2 degFft
z = 0 002 inches
r = 12 inch
Eq (12) putting 9 in degrees then reduces to
1110 12 + 2404 d 2t d92
( 15)h = ------~--~-------t - ta
Thi s equation was programed for the Alwac III- E comshy
puter and used to calculate the local heat transfer coefshy
ficients from the observed data
The average heat transfer coefficient around the tube
at a given position in the t est section was calculated by
averaging the local coefficients calculated from Eq (13 )
It was found 1n the course of the experimental work
that thermocouple numbers 1 and 7 were indicating higher
temperatures than would be expected This resulted in h1
and ~ being lower than the other local coefficients around
the tube Since the fluid was flowing parallel to the axis
of the probe the circumferential variation i n rate of heat
25
transfer should be small Hence in obtaining the average
coefficient around the tube the values of h1 and h7 were
not used even though they were calculated and are tabulated
1n Table I II in the Appendix
Then
(14
A Nusselt number as calculated from this aver age heat
transfer coefficient using the tube diameter as the characshy
teristic dimension
(15)
The air flow rates through the test section were calshy
culated by measuring the pressure drop across the flow orishy
fice the air temperature the pressure at the flow orifice
and the pressure at the entrance to the test section The
orifice calibration curves (1 p 166 ) were used to obtain
a value of the orifice coefficient f8e where Q equals
the flow in cubic feet per minute at 68deg F and one atmosmiddot
phere pressure and te is the density of air at the exchanger
and e the density of the air at the flow orifice The
den sity of the air can be expressed by
e = 2 703 p (16)T
where T equals the temperature in OR and P equals the absoshy
lUte pressure i n lb1n2 Using the value of e Qfo from
26
the calibration charts as A and Eq (16) solving for Q
gives
( 17
This equation was used to calculate the flow rate for
each flow studied
The Reynolds number used i n the correlation of the
data was the equivalent Reynolds number defined as
Re)eb ~ d2 - dl)Uf ( 18 ) lL
where d1 is the outside diameter of the inner tube and d2
is the orifice diameter U is the flow velocity through the
annular orifice e is the density of the air and U- is t he
viscosity of the air This equation can be transformed t o
(Re) b = 1611 Q (19) e dl + d2
where d1 and d2 are in inches
The pressure drop data were calculated i nto a dimenshy
sionless pressure drop function cent where
d1 )22( ~ P)gc f av(d2 shycent 2 bull (20
M-
For air this equation reduces to
where d2 and d1 are in i nches D P is expressed i n inches of
2 95 specific gravity fluid and P av is expressed as lbft3
27
CHAPTER VII
ANALYSIS OF DATA
In analyzing the heat transfer data an attempt was
made to correlate it 1n terms of the dimensionless groups
(Nusselt number Prandtl number and Reynolds number) which
appear in Eqs (3) and (4) Consequently all of the av~
erage heat transfer coefficients hav were brought into
the form ( Nu)( Pr)~3 bull The Nusselt number was based on the
tube diameter and the thermal conductivity of the air at
the flowing temperature The tube diameter was used in the
Nusselt number because comparison could then be made with
previous experimental work on heat exchangers which have
commonly used the Nusselt number defined as in Eq (15)
From the standpoint of dimensional analysis this is
equivalent to considering the tube diameter as the characshy
teristic length so far as the heat transfer is concerned
The Prandtl number of the air was taken as 0 7 in all
cases
Variation of Heat Transfer Rate with Distance from the Baffle
Considerable variation was observed in the rate of
heat transfer in the vicinity of the baffle In order to
obtain the variation with respect to position the term
(Nu)(Pr)-13 was plotted versus the flow rate Q for each
position and orifice studied Cros s plots were then made
28
at constant flow rates in order to obtain the variation of
(Nu)(Pr) -13 with position The resulting cross plots are
shown 1n Fi gures 5 6 and 7 for the four orifices studshy
ied
About one inch upstream from the orifice the heat
transfer coefficient begins to rise rapidly and continues
to do so until it reaches a maximum some distance downshy
stream After the maximum point the heat transfer coef fi shy
cient decreased slowly The heat transfer rate was found
to reach a maximum at a different position downstream for
each orifice size These figures also show that for a
given orifice size the maximum heat transfer rate occurs
a pproximately at the same point for all flow rates The
position of the maximum point f or each or ifice size is
shown in Table II
The region immediately downstream from the orifice is
one of h i gh turbulence due to the jetting action of the air
flowing through the orifice As the air flows t hrough the
orifice the streamlines continue to converge for some dis shy
tance downstream The point of maximum heat transfer is
probably at the point where the streamlines be gin to diverge
and a boundary layer begins to build up on the tube Tle
decreasing heat transfer coefficient beyond the maximum
point indicated the formation of a boundary layer
Since the position of the maximum point is independent
of flow rate middot it is possible to correlate it with respect
_ ct 11shyz-
100
0 136 ORIFICE
(
I 0
I )
~ 00
~p 0
I 0
--r--- ~
ISCFIII
-_ OCFM
rbull abull
~ middot~ a-1 z-
12fORIFICE
100
200
100
0 0 UPITRAM ORIFICE DISTANCE CENTER
CFM
h I DOWNSTREAM
DISTANCE
FIGURE 5 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLpound
30
too
700
800
100 ~ f gtf
400
z ~
100
100
100
0
13fORIFICE
~ -~ -- ---
)
~
~
-
I ~ ~OCFM
I vI~-~ OCFM
J ---
Iamp CFM
I 0 I I UPSTREAM ORIFICE DOWNSTREAM DIITANOE GENTER DIITANCI
FIGURE 6 VARIATION OF HEAT TRANSFER RATE WITH DISllNCE FROM BAFFLE
--
--- --
31
100
100
700
100
_ 100
f 9- 400 z-
100
tOO
100
0 - I 0 I I I UHTRIAM OAtfiCI DOWIIITMAM
+ I tyl6 ORIFICE
v I
~~ ~CFM
I v ~CFMI
v v 7
~~ v ~ iOCFM
- ~~ I-shy1-shy ~ICFM
DIITMCI OINTIR DIITANCI
FIGURE 7 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLE
32
TABLE II
POSITION OF MAXIMUM HEAT TRANSFER
Position of Maximum Orifice Size Heat Transfer
(inches) (inches downstream)
1 364 050
1 216 100
1 316 125
1 516 200
33
to orifice size Figure 8 shows the effect of the orifice
size on the position and value of the maximum heat transfer
at a constant flow rate of 15 cubic feet per minute It
can be seen that the larger the orifice size the further
downstream the point of maximum heat transfer occurs
Also as the orifice size increased the rate of heat
transfer decreased for a given flow rate The broken line
indicates the variation of the point of maximum heat transshy
fer with position and size The position of the point of
maximum heat transfer rate downstream from the orifice was
correlated with orifice size by means of the dimensionless
groups (Lde) and (d1de) where L is the distance downshy
stream from the orifice where the maximum rate of heat
transfer occurs d1 is the outside diameter of the inner
tube and de is the equivalent diameter of the orifice
ie de = d2-dlbull
Figure 9 shows a plot of Ld 6 versus d1d6 for the
four orifice sizes studied The four points on this logshy
log plot are approximately in a straight line and the
equation of this line is
Lde = 0 44 d1de)028 (22)
Although the above relationship represents a correlashy
tion of dimensionless groups it is based upon only one
tube diameter and needs to be substantiated further by
studying other tube diameters and other orifice sizes
34
aoo
400
aoo ~
-~ middot-CLshyJ z
200 -
100
0
ORIFICE CENTER
l~
l
t
I J~
1pound~
I
0 I I~
AT 15 CFM
-
bull ~ 1~6~
~ v~
~
~--~~6
~~~ ___ v v V -_
~ o q
~ I 16
v
~
ogWNSTREANI STANCE
FIGURE 8 EFFECT OF ORIFICE SIZE ON POSITION AND VALUE OF MAXIMUM HEAT TRANSFER
35
50
loshy____ -~
~ ~ -shylltl-shy~ r0
2 10 30
FIGURE 9 CORRELATION OF THE POINT OF MAXIMUM HEAT TRANSFER WITH
ORIFICE SIZE
36
Correlation of Data at the Baffle
The heat transfer data were correlated by obtaining a
relationship between the group (Nu)(Pr)-13 and a
Reynolds number based on twice the clearance (d2 - d1
between the tube and the baffle It was found that the
most satisfactory correlation could be obtained when the
term - d1 was used as the length term in the Reynoldsd2
number
Figure 10 shows the variation of the heat transfer
rate at the center of the orifice e xpressed as a function
of Reynolds number and the orifice size This shows that
for a given Reynolds number the heat transfer at the center
of the orifice is greatest for the smallest orifice size
In order to obtain a general correlation of the data
shown i n F1gure 10 the effect of the dimensionless ratio
d1de was considered This ratio considers all of the
geometric factor s needed to describe the annular orifice
The thiclaless of the orifice plate is also a factor but
was constant i n this i nvestigation
The data for the heat transfer at the baffle center
are shown in Figure 11 in which (Nu)( Pr)-13 is plotted
versus (Re)ebd1 de) 0 55 This data on a log-log plot
lies on a straight line for (Re)eb( dld8 )0 55 greater
than 3 x 104 The equation for cor relating the heat
37
4XI~middot~-r~------~--~~------~
Icf t--to_+--_c-c-________ SYMBOL SIZE
0 1~4
6 ~~
9 ~~ -o ~
(Re)eb
FIGURE 10 RATE OF HEAT TRANSFER AT BAFFLE CENTER
38
500
0
4 0 lcf
~ ~
~ ~iC-
~ ~
~IL 0~ 0 SYMBOL SIZE-
p 0 1364-
r 6 1~16 -~ -
9 1~16 --o 1~16
I I
FIGURE II CORRELATION OF HEAT TRANSFER DATA AT BAFFLE CENTER
39
transfer at the center bullOf the a nnular orifice was found by
the method of least s quares to be
(Nu)( Pr)-1 3 = 0018 ( Re)ebO Bl( dlde)04~ (23)
3 x 104 ltRe)eb(a1de)055 lt 105)
Rate of Heat Transfer at the Point of Maximum Heat Transfer-The heat transfer rate at the point of maximum heat
transfer is plotted in Figure 12 to show the variation with
Reynolds number and the size of the orifice It is shown
gives the h1gh st heat transfer ~ate at its point of maxibull
that for a given Reynolds number the smallest orifice size yen il
mum heat transfer
The data ~or the maximum poi~t could be correlated by
plotting (Nu) Pr)-13 versus (Re)eb(d1de)06 This plot
is shown 1n Figure 13 and the resulting eurve shows that
(Nu(Pr)-13 is not a simple p0wer function of the Reynolds
number as was the case for heat transfer at the baffle
center The reason for this is probably because other
factors such as intensity and scala of turbulence should
be considered At the orifice center the streamlines of
the flowing stream are converging_ and thus the flow is
quite stable Downstream from the orifice is a region of
large eddy currents and probably large scale turbulence
These factors could con ceivably cause the results which
were obtained for the point of maximum heat transfer
40
If)
~middotshy Q_-I z_
10~~~--------r----~~--~--
SYMBOL SIZE
0 13$4
6 1~8
Q 13-18
-o 1~8
7)(104
(Re)eb
FIGURE 12 RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
41
Ia ~
0 I
c ~ ~ c v
~ ~lt w ~
17
~ b
v ~ ( SYMBOL SIZE
-~ 0 f-64 -v ~ 6 t211e
~ Q I~~~
-o - l~rs I I
FIGURE 13 CORRELATION OF HEAT TRANSFER DATA AT THE POINT OF MAXIMUM HEAT TRANSFER
4 2
Effect of Upstream Baffles on Heat Transfer at the Orifice Center
The heat transfer rate at the orifice center using the
single orifice in a test section is a pproximately 13 of the
value that was obtained by Lee (7) using a model heat exshy
changer with orifice baffles Lee investigated the cent r al
baffles of the heat exchanger and thus the coeff icients he
obtained would be affected by the presence of a number of
upstream baffles To determine the effect of upstream
baffles an additional l 516 inch baffle was placed four
inches upstream 1n the test section The resulting data are
shown in Figure 14 where (Nu)(Prmiddot)-13 is plotted versus
(Re) eb for the case of a single baffle 1n the test section
and also the case of an additional baffle placed four inches
upstream Comparison is made with the results obtained by
Lee middot(7) using a four-baffle and a ten-baffle model heat exshy
changer Good a greement is obtained with Lees work and the
results show the marked effect that upstream baffles have on
the downstream heat transfer rate The additional up tream
ba ffle caused sufficient turbulence 1n the test section to
i n crease the heat transfer rate nearly three-fold at the
center of the next baffle
Heat Transfer i n the Test Section with No Orifice
In order to check the accuracy 6f the equipment the
orifice baffle was removed and the heat transfer mea sured
with the probe in the empty test section The data were
43
~~BAFFLES
0 l BAFFLE -shy
ll_9 2 BAFFLES
V 4 BAFFLES-LEE
4 10 BAFFLES- LEE lJf ~
~rv ~~ ~ v flvv ~~
I ~ J ~ L v
0
v
( V
40 3XIo 7XIa
(Re)eb
FIGURE 14 EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER AT BAFFLE CENTER
44
compared with heat transfe r coefficients predicted by the
equations for annuli which are recommended in the litera shy9
ture The two equa~ ions u sed tor comparison were
(hfe)=0 023 (rltGr e (~~ur4 (~r45 (24)
which was presente~ by Wiegant (10)
and ( h ) (cnM~5(M~l o14 o 023 CPG k j Mij - (de GJMb )0 2 ( 2 5)
which was presented by McAdams (8 p 242) The comparshy
i son is s hown in Figure 15 lq (25) gives a value which
is low by about ten percent while Eq (24) g ives values
which are high by as much as twenty -five percent when comshy
pared with the experimental data The se equations are gembull
erally considered to give coefficients with an accuracy of
about twenty percent Therefore the present experimental
data are within the accuracy of these equations Also the
plot indicate s that for a Reynold s number greater than 2 x
104 the slope of the line is the same for the experimental
data as for the equations
Pressure Drop Data
The total pressure drop across the orifice was measured
as a function of the flow rate and the orifice size The
pressure drop was expressed as a d1mens1onleas quantity r)
which ie plCltted ver sus the Reynolds number in Figure 18
The pressure drop function cent correlates for all or1f1oe
45
200
100
s z
10 5XI10 10
0 EXPERIMENTAL
--McADAMS
-WIEGAND L
V
~ ~ ~
P ~ ~
LL~ L
v~
~
v v
v 1 ~ ~ v
v -gt
~
~ ~
~
6Xid
FIGURE 15 HEAT TRANSFER WITH NO BAFFLE
46
0 1~4 -~ a 6 t216
Q t316 lJ J
-0 as a )t
A LEE I -shy SULLIVAN 8
p
10bull
BERGELIN
I _ll I
I ~
i I
~middot
lo II
f fl
J j
~middot
A)101
1q
I Ill
1 I3 X 10ao1
FIGURE 16 ORIFICE PRESSURE DROP FUNCTION VS REYNOLDS NUMBER
47
sizes- The present data extends the range covered by preshy
vious workers and agrees well with their work The preshy
vious work of Lee () for a heat exchanger containing 10
orifice baffles and also the data of Su livan and Bergelin
(9) for pressure drop in a model heat exchanger with a
single baffle is shown 1n Figure 16 long with the present
results~ This figure may be used to predict the preseure
drop from the equivalent Reynolds number of the annular
orifice
The pressure drop between individual points 1n the
vicinity of the orifice and an upstream pressure tap wa s
measured to obtain a pressure drop profile As might be
expected 1n all cases the profiles showed a rapid decrea e
in static pressure immediately upstream from the orifice
There was however little or no recovery of the pressure
loss downstream The 1 364 inch orifice did show a maxishy
mum point in the pressure drop but this maximum occurred at
the orifice center and total recovery was reached about 12
inch downstream
Heat Transfer at the Baffle and Maximum Point as a Function of Pressure Drop
In order to compare the effect of the total pressure
drop on the heat transfer at the baffle and the point of
maximum heat transfer Figure 17 was plotted showing
(Nu)(Pr)-13 as a function of the total pressure drop This
shows that for a given pressure drop the largest orifice
48
1200
1000
~ a -sshyz-
100
60 100 700
AT MAXIMUM POINT I 15116 2 13116 3 1~6 4 1364
AT ORIFICE CENTER
60
1
v
r ~ ~ ~
5
~
8 7
13116
8
~
1364
v
~
e6
1~6
v
~~ v ~ ~ -~ ~
~
~ v
l
~
vamp
I ~ ~
~
v L ~
v
I-
5
k= ~~
~ ~ ~
--I
v ~
FIGURE 17 HEAT TRANSFER AT THE BAFFLE AND MAXIMUM POINT AS A FUNCTION OF
ORIFICE PRESSURE DROP
49
size has the greatest heat transfer coefficient This is
true at both the orifice center and at the point of maxishy
mum heat transfer
Another comparison can be made by plotting the heat
transfer coefficient and the pressure drop versus the orishy
fice size at a constant flow rate Figure 18 shows this
plot This graph shows that at a constant flow rate the
pressure drop as well as the heat transfer coefficient
increases as the size of the orifice is decreased In
choosing an orifice size for maximum efficiency 1t would
be necessary to know the pumping power available as well
as the heat transfer desired
70 I I 700
AT 15 CFM 60 ---
~ aug
50 ---
NV
40 ~
~ ~ ~
~ _
MAXIMUM POINT ---- --- ~
1-----t---~ _
~00Qj ~
~t--- ORIFICE CENTER 10 1100
1---~ n
u0 01 02 03 Q35
a ltl
de inches
FIGURE 18 VARIATION OF HEAT TRANSFER RATE AND PRESSURE DROP WITH ORIFICE SIZE AT A CONSTANT FLOW RATE
cn 0
51
CHAPTER VI II
SUMMARY OF RESULTS
This study revealed several significant facts about
the heat transfer in the vicinity of annular orifices
Probably the most important contribution was the presshy
entation of the heat transfer profiles in the vicinity ot
the annular orifice ~ r s shown that t~ local heat
transfer coeffieient re~ches a maximum at a point downshy
stream from the orifice The distance downstream at which
this maximum oocurs is t1ven by the equation
22
The heat transfer coefficients at the center of the
orifice were correlated and found to follow the equation
(Nu)(Pr)-13 = 00176 (Re)eb08l(d 1de) 0 middot4~ (23)
3 x 104 lt( Re) 9 b( d1d6 )055 ltlo5 )
The heat transfer at the point of maximum heat trans
fer for each orifice size was correlated and presented in
Figure 13 as a plot of (Nu)(Pr)-l3 versus (Re)eb(d1de) 06
No simple po-orer relationship exists between the terms
Intensity and scale of turbulence downstream from the orishy
fice are probably important factors which affect the heat
transfer
The large effect of an upstream orifice on the heat
transfer rate at the second orifice was demonstrated by the
52
study of two 1 516 inch orifices in the test section The
added turbulence at the center of the second orifice was
found to raise the heat transfer rate almost three times
over that obtained for a single baffle
The pressure profiles in the vicinity of the orifice
indicate that nearly all the pressure drop occurs at the
orifice center~ Total pressure drop data were correlated
by a pressure drop function cent as a function of the Reynolds
number and good agreement obtained with the results of other
workers
The pressure drop and heat transfer data were correbull
lated by plotting the heat transfer as a function of the
pressure drop for each orifice size It was shown that for
a given pressure drop the largest orifice size gives the
greatest heat transfer coefficient
As a final presentation it was shown that the pressure
drop and the heat transfer coefficient both i ncrease i n
value at a constant flow rate as the orifice size is de shy
creased This is important in choosing the optimum clearshy
ance for orifice baffles
53
CHAPTER IX
RECOMMENDATIONS
A great deal of work remains to be done in the field of
evaluating shellmiddotside heat transfer coefficients This
study included only one tube size and air was the only f luid
used It is recommended that further studies be conducted
using other fluids and tube sizes It will also be necessary
to study several baffle types
The adde d turbulence due to a s e cond baffle placed upbull
s t ream would suggest that the heat transfer coef ficients at
a certain position i n relation to a baffle would increase as
the flow progressed through the exchanger It is recomshy
mended that an extensive s t udy should be made between baffles
the full length of a model heat exchanger
It is further recommended that the pressure drop study
be continued to include other fluids tube sizes and baffle
arrangements
Effects of turbulence downstream from the baff le should
be studied by i n vestigations with hot-wire anemometer equipshy
ment to determi ne t urbulence scale and i ntensity
54
NOMENCLATURE
Area of heat transfer
Heat capacity of the fluid
Outside diameter of the tube
Orifice diameter
Equivalent diameter of the orifice (d2 - dl)
Inside diameter of the test section
Inside diameter of the tube
Gravitational constant
G Mass velocity
h Local heat transfer coefficient
Coefficient of heat transfer from surface to fluid
i Direct current amperes
k Thermal conductivity of the fluid
L Distance downstream of the point of maximum heat transfer
p Absolute pressure
L P Total pressure drop across the orifice
Q Flow in cubio feet per minute at 1 atmosphere and 680 F
q Heat transferred
Thermal energy conducted into the sensing probe
Thermal energy radiated from the resistance ribbon
Resistivity of the resistance ribbon
s Length of the resistance ribbon
T Temperature oR
55
t Temperature of the resistance ribbon deg F
ta Temperature of the bulk stream oF
tw Wall temperature of the tube OF
U Veloc ity of the fluid
w Width of the resistance ribbon
z Thickness of the resistance ribbon
eeuro Density of the fluid in the test section
Density of the fluid at the flow orificef 0
AL Viscosity of the fluid
E9 Angle measured around the tube
Dimensionl ess groups
(Nu) Nusselt number hd1k
(Pr Prandtl number C~k
(Re)eb Equivalent Reynolds number at the baffle (d2 - d1 )uejt-Lshy
(Re)e Equivalent Reynolds number in the test section ( d 8 - d 1 )U fu
cent Orifice pressure drop function 2(~P ) gc~av(d2 - d1) 2
Al
56
BI BLIOGRAPHY
1 Ambrose Tommy W Local shell-side heat transfer coefshyficients in baffled tubular heat exchanger PhD thesis Corvallis Oregon State College 1957 183 numb leaves
2 Bell K J and o P Bergelin Flow through annular orif ices Transactions of the American Society of Mechanical Engineers 70593-601 1957
3 Colburn Allan P A method of correlating forced con shyvection heat transfer data and a comparison with fluid friction Transactions of the American Institute of Chemical Engineers 24 174-210 1933
4 Dittus F w and L M K Boelter Heat transfer 1n automobile radiators of the tubular type University of California Publications in Engineering 2443-461 1930
5 Gurushankariah M s Local shell-side heat transfer coefficients in the vicinity of baffles in tubular heat exchangers Masters thesis Corvallis Ore gon State Colle ge 1958 97 numb leaves
6 Knudsen James G and Donald L Katz Fluid dynamics and heat transfer New York McGraw-Hill 1958 576 p
7 Lee Kyu Sung Local shell-side heat transfer coeffishycients and pressure drop in a tubular heat exchanger with orifice baffles Masters thesis Corvallis Oregon State College 1959 118 numb leaves
8 McAdams William H Heat transmission 3d ed New York McGra ~-Hill 1954 532 p
9 Sullivan F W and 0 P Bergelin Heat transfer and fluid friction in a shell-andbulltube exchanger with a single baffle Chemica l Engineer ing Progress Symposium Series 52 ( 18) 85-94 1956
10 Wiegand J H Discussion on annular heat transfer coshyef f icients for turbulent flow Transactions of American Institut e of Chemical Eng i n eers 41147-153 1945
AP PENDIX
57
TABLE III
CALCULATED HEAT TRANSFER DATA
Baffle Hole Diameter Run No (inches)
1 - 59 1 364
60 - 102 1 216
103 - 138 1 316
139 - 206 1 516
207 - 212 No orifice
213 - 218 2nd - 1 516
TABLE III
CALCULATED HEAT TRANSFER DATA
Local Heat Transfer Coefficients Run
T0 bull Po s ition CFM hr h2 h3 h4 hs he ~ hav Nuav
1 c 1026 10 59 1476 16 09 1559 1510 1435 1203 1518 8511 2 1290 1369 1738 1878 18 05 1755 1689 1515 1773 9964 3 1416 1636 198 1 2068 1977 1924 1845 1715 1959 11030 4 1627 1991 2301 2382 2268 2194 20 ~98 1929 2249 12664 5 1776 2252 2669 2863 2713 2517 2338 2126 2620 14759 6 l2ttD 1109 2311 3317 3386 3373 3387 3394 3071 3371 18888 7 1258 3089 4583 4866 4683 4701 4643 4194 4695 26301 8 1433 38 8 5 55 83 5791 5495 5430 5436 5008 5547 31192 9 1681 4992 7378 7649 6980 6864 6870 64 28 7148 40180
10 1 D 1102 2371 3332 3511 3356 3342 3427 3102 3394 19012 11 1308 3218 4379 45 24 42 53 4255 4373 3965 43 57 24446 12 14 64 38 58 5146 5142 4839 4787 4903 4597 4963 278 79 13 1706 5218 6664 6269 58 81 5884 6237 5973 61 87 34718 14 15
1 l2D 1115 1275
2131 2661
2955 3638
2972 3720
2941 3675
2913 3576
28 22 34 74
2613 3278
2921 36 17
163 09 20246
16 1498 34 87 4644 4503 4441 4371 4343 4194 4460 25010 17 1695 4449 5743 5324 5222 5154 5157 5015 5320 298 97 18 2D 1049 1715 23 90 2550 2610 2656 2624 2208 2566 14363 19 1241 2117 2964 3145 3218 3221 3203 2759 3150 17757 20 1532 28 67 3936 4100 4188 4201 4167 3676 4118 23224 21 1674 3459 4508 4598 4746 4795 4792 4299 4688 26337 22 lU 1074 253 340 380 3 86 388 377 354 374 2097 23 1287 292 392 433 440 441 429 406 427 2394 24 1508 322 439 492 498 499 487 461 48 3 2713 25 18 07 3 38 464 519 5 24 520 499 463 5 05 28 40
~~ (]I agt
TABLE III Continued
Run No Position CFM h 1 h2 ~3 h4 h5 h6 ~ h
av Nu
av 26 c 1029 1171 1491 1589 15 28 1 4 62 1377 1293 1489 83 44 27 1266 1395 1746 1853 18 02 1685 1556 1453 1728 9704 28 1430 1637 2037 2175 2060 1909 1735 1591 1983 11159 29 1729 1982 24 96 2751 2507 2268 2030 1886 2410 13579 30 12D 1054 2934 4041 4321 4326 4423 4359 3706 4298 24160 31 1294 3385 4 8 26 52 42 5326 5450 5277 4566 52 24 293 50 32 1431 3784 5347 5721 57 bull75 58 44 5700 5084 5677 31870 33 1770 52 75 7 7 33 87 35 9005 9007 8267 7059 85 49 48050 34 lD 1058 3235 4401 4444 3877 3496 3451 3294 3934 21973 35 1263 38 98 5484 5330 4347 3964 3981 3987 4621 25823 36 18 36 6701 89 17 7855 6369 5597 5769 6283 69 01 38718 37 1 12D 1029 2404 31 8 2 3333 3459 3624 3577 3045 3435 19264 38 1315 3182 4033 4162 4310 4496 4502 4015 4301 24142 39 1426 3628 4389 4510 4573 4760 4804 43 8 5 4607 25678 40 1757 4547 5559 5(35 5931 6282 63 70 6060 5975 33471 41 2 11D 1080 2034 28 38 3155 3144 3145 2966 2540 3050 17027 42 1305 2650 3 4 87 3aoz 3595 3751 3595 3153 36 46 20405 43 1434 3167 39 07 4156 4371 4320 4126 3709 4176 23395 44 1804 4096 4 9 66 5691 5714 5586 53 15 48 65 5454 30582 45 12U 1088 409 516 557 564 5 60 535 513 5 46 30 67 46 1318 470 579 6 22 631 6 17 5 97 579 6 09 3422 47 14 13 540 640 676 6 86 681 6 60 6 54 6 69 3754 48 1773 641 740 774 782 7 69 749 746 763 42 87 49 l 11 U 1054 270 356 391 397 393 3 71 346 38 2 2133 50 1240 303 399 446 449 447 4 21 398 432 2420 51 1419 361 476 522 530 528 507 467 493 2760 52 1 1(2U 1032 236 311 342 347 344 325 301 334 18 78 53 1314 270 366 403 407 408 386 351 394 2217
(Tt tO
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ h av Nu av
54 1448 301 408 447 454 452 431 403 438 24 61 55 1782 353 494 548 544 415 529 531 506 2843 56 2U 10 61 220 287 316 320 322 303 268 310 1735 57 1216 249 335 370 377 378 353 307 363 2044 58 1322 263 356 394 398 399 374 327 384 2159 59 1639 310 433 478 481 482 452 393 465 2617
60 1D 10 68 2011 2536 2657 2681 2694 2560 15 62 2625 14938 61 1399 2520 3239 3369 3371 33r82 32 39 1946 3320 18968 62 1669 2781 3655 3820 38 76 3883 3738 2355 3794 21712 63 1959 3524 42 37 4399 4438 4497 4417 3047 4397 25156 64 2295 4426 5288 5396 5372 5240 5410 3369 5341 30680 65 2636 5490 6531 6662 6565 6379 6820 4249 6591 37938 66 3390 7869 9538 9462 9387 8924 10508 62 91 9564 59601 67 1U 1190 352 368 401 413 407 395 293 397 2256 68 1559 397 422 462 475 471 456 331 4 57 2603 69 1904 434 465 5 13 529 528 504 358 508 2901 70 2211 493 526 573 5 92 588 564 4 15 569 3257 71 2289 569 587 6 30 649 6 61 6 49 460 635 36 44 72 2727 637 6 60 7 09 733 751 743 521 719 4140 73 3210 728 755 8 15 8 43 8 62 8 54 616 826 4765 74 2nD 1210 181 2256 2393 2399 2333 2206 1325 2317 13158 75 1420 2340 2752 2899 2913 2850 2728 1701 2828 16121 76 1692 2853 3306 3452 3471 3379 3217 2134 3365 19217 77 1894 3102 3588 3713 3736 3670 3557 2455 3653 20892 78 2301 3682 4259 4433 4467 43 83 4289 2892 4366 250 30 79 2621 4117 4828 5017 5012 5030 5109 3071 4999 28785
m 0
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ hav Nuav
80 3230 5158 6006 62 13 61 18 6134 6695 4094 6233 359 87 8 1 12nD 1155 15 27 1854 2028 2064 20 85 1987 1164 1968 118 31 82 1689 2046 24 8 2 2688 2739 2760 2658 1749 2665 152 73 83 1244 2088 2317 2339 2345 2373 2381 1487 2351 13432 84 2100 3211 3539 34 21 3462 3512 3696 2575 3526 20284 85 2292 3 5 05 3761 3648 36 25 36 79 3957 2933 3734 21517 86 2907 4420 48 22 4679 46 04 4705 5206 3792 48 03 27741 87 33 80 59 35 69 38 7404 77 10 7 8 36 7 0 86 5190 7394 427 44 88 1 12D 1 4 27 2 4 58 28 31 3037 3021 2987 2927 18 57 2 9 61 16913 89 18 75 34 75 3 9 87 4230 4255 4317 4337 2734 4225 24258 90 22 59 4221 4796 5046 5052 51 01 5389 3491 5077 29206 91 2682 4978 5664 5943 5966 6054 6573 408 1 60 40 34795 92 3417 63 16 71 02 7 3 93 7385 75 40 8 6 95 51 45 7623 44017 93 c 1 5 17 1240 1305 1399 1467 1479 1429 9 26 1423 8251 94 20 34 1554 1623 1720 18 21 18 53 18 72 1215 1778 10229 95 2 3 48 1795 1843 198 5 2097 2171 2274 1540 2074 11947 96 2716 2028 2048 22 01 2 3 44 2444 2661 18 90 2340 13505 97 3247 2410 2375 2663 2778 2949 3298 2378 2793 1615 98 11 35 967 1040 1124 1186 1200 1142 728 1138 6496 99 14 06 1135 1220 1318 1384 1403 1 3 61 8 77 1336 7656
100 2311 1 8 54 18 78 1980 20 90 2136 2227 1653 2062 118 31 10 1 2666 2085 2094 2227 2 3 62 2438 2626 1902 2349 13508 102 3392 2635 2582 28 01 3026 3141 3529 2567 3016 17390
103 1 U 1235 349 395 434 436 4 28 411 286 423 2416 104 20 10 434 5 02 559 577 569 5 37 345 552 3177 105 28 14 538 626 685 711 7 21 682 424 6 8 6 3966
Q) j-J
TABIE III Continued
Run No Position CFM h1 h2 h3 h4 h5 hu h7 hav Nuav
106 3492 614 7 1 6 7 84 8 13 8 33 7 85 4 88 7 87 4562 107 4395 7 86 894 964 996 1005 9 64 640 9 65 56 06 108 50 75 9 11 10 22 1081 1112 1125 1085 7 24 1085 63 16 109 G 1344 9 22 1042 1120 1 1 46 1173 1131 7 04 1120 63 87 110 1936 1162 1340 1442 1474 1509 14 7 3 9 09 1441 82 77 111 2846 1631 1797 1902 1966 2027 2079 1342 19 2 3 11108 112 3484 207e 2144 2236 2307 2385 2574 1694 2268 13138 113 4066 24 65 24 42 2535 2648 2757 31 71 2178 2 5 96 15078 114 50 12 3059 2916 30 1 5 3176 3312 4059 2849 3105 180 46 115 1D 1362 2268 26 13 2613 26 35 2605 2503 15 46 2617 14934 116 1958 2993 3580 3580 3586 3539 3 5 02 2144 3571 20492 117 2812 4430 50 32 4913 4 9 86 4991 5196 3088 4981 287 66 118 3432 58 16 62 13 6067 61 18 60 66 6698 4143 61 16 354 16 119 40 22 71 71 7 4 62 7369 7419 7329 82 74 51 8 1 7395 42909 120 5026 105 95 11456 115 81 11574 11548 14010 80 91 11540 671 15 121 2D 1244 18 57 2277 2363 2305 2210 2107 1466 2289 13038 122 1960 2622 3240 3388 33 23 3226 31 40 2)99 3294 18919 123 2817 3762 45 87 4739 46 56 45 14 4 6 47 30 15 4624 26689 124 3491 50 22 5723 58 53 57 44 5542 60 18 3871 57 16 330 73 125 4096 61 29 68 16 69 79 6805 65 90 74 79 4677 67 98 39400 126 5037 82 27 94 60 95 69 93 57 9023 11324 65 05 93 52 542 83 127 12D 1278 14 70 1 6 48 1652 1638 1 6 34 1641 9 73 1 6 43 9369 128 1947 19 63 2155 2149 2151 2131 2190 1347 2147 12342 129 2769 2615 2791 2773 28 52 2716 2954 18 96 2783 1 60 82 130 3439 3208 3265 3239 3593 3133 3624 2515 3308 19174 131 4103 3637 35 88 3577 4077 3459 42 66 3138 3676 21343 132 49 78 45 82 44 60 44 8 1 55 17 43 25 5749 4227 4700 27288
Q) tlgt
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
133 1 12D 1299 2094 2507 2622 2625 2567 2489 1465 2578 14736 134 1973 29 56 3505 3772 3790 3718 3718 2115 3700 21290 135 2788 3941 4727 5069 5099 5 0 07 5231 2984 4976 28781 136 3473 5155 59 81 6308 6339 62 39 68 96 4204 6217 36052 137 4118 6135 71 8 6 7662 7731 76 91 87 16 49 8 5 7568 43985 138 4973 7765 94 75 10396 10861 10694 13646 66 64 10357 602 25
139 1ttn 1253 1242 1493 1460 1442 1431 1424 8 84 1457 83 01 140 2366 1942 2150 1961 1910 1897 19 62 1206 1980 11400 141 3461 3007 2957 2562 2513 2606 3143 18 51 2660 15400 142 4325 3942 3571 3060 2999 3198 4248 2631 3207 18618 143 5677 508 6 4359 39 88 3800 42 29 57 78 36 26 4094 23824 144 67 59 64 55 5330 4988 47 25 5494 2517 48 09 5134 29906 145 84 08 9326 72 26 7726 85 56 9172 12319 7733 8170 47626 146 86 54 9831 7582 818 9 94 90 9869 13116 78 97 8783 512 96 147 7376 7335 58 7 6 5941 5796 68 29 81 65 5954 6111 35662 148 2 11 D 4254 4106 48 02 4994 5038 5042 56 78 3419 4969 28881 149 5708 5487 6253 6466 6524 6527 78 63 45 8 2 64 43 37566 150 69 7 8 7983 9440 9848 98 34 97 32 13249 6701 9714 566 59 151 1254 1434 18 53 1947 1915 1850 1760 1186 1891 10772 152 2713 2696 3175 32 94 3288 3237 3288 20 44 3249 18728 153 87 30 118 07 14733 15758 15504 15305 26297 9617 15325 892 71 154 5811 5278 6543 6861 69 30 69 82 7 8 74 4478 68 29 39531 155 4246 3780 4736 4975 49 66 4936 5162 3113 4903 28301 156 (v 1270 8 15 935 959 966 9 51 9 23 6 35 953 5430 157 2714 1164 1390 1427 1447 1454 1455 9 08 1430 8242 158 4310 1655 18 96 1942 1988 2002 2111 1305 1957 11349
(j) ~
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 fry hav Nuav
159 6012 2208 2400 2450 2513 2548 28 20 18 00 2478 14416 160 7279 2696 2881 2927 2989 3081 3599 2340 2970 17326 161 86 90 3257 3360 3 3 76 34 26 3558 4455 2943 3430 2000 162 12D 4368 2209 2600 2558 2518 2466 2774 1753 2536 14713 163 5833 2730 3092 3028 2974 2913 3501 2287 3002 174 78 164 7643 3320 3681 3630 3651 3530 4623 3181 3623 21116 165 87 39 3920 4303 4300 4708 4178 61 60 3937 4372 25456 166 1268 962 1203 1205 1186 1118 1084 725 1178 6693 167 2678 14 67 1785 1779 1752 1698 1726 10 70 1754 88 49 168 1 12D 12 83 936 1217 1414 1397 1239 1190 7 65 1317 7484 169 2729 2502 2930 2914 2934 2956 2979 17 52 2934 16866 170 4345 3884 4357 4283 4318 4421 4836 28 59 4345 25151 171 6036 5546 5858 5764 5791 6028 7129 4184 5860 34045 172 6578 7167 7769 7907 79 82 8263 10492 5915 7980 46437 173 87 84 10237 112 23 120 26 12727 12968 185 19 85 98 12236 71103 174 1278 1344 1803 18 72 1835 1790 1712 1063 1825 10355 175 2711 2328 2972 2932 2893 28 78 2863 1667 2919 167 51 176 4351 3934 4414 4353 4281 4321 4654 28 63 4342 25088 177 5994 5076 5824 5838 5818 59 29 6914 4205 5852 33885 178 1 11 U 1223 388 432 465 464 449 435 338 453 2585 179 2351 521 602 6 22 675 6 57 619 436 639 3687 180 34 48 6 05 1725 803 8 27 8 11 760 518 792 4593 181 4513 718 850 934 9 68 9 57 8 99 609 9 27 5386 18 2 5714 8 32 981 1060 1102 11 06 1034 6 59 1062 61 82 183 6997 1025 1182 1258 1295 1309 1234 8 18 1261 7 3 44 184 8709 1295 1487 1 5 42 1594 1626 1612 1156 1562 9080
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
185 2 12D 4249 3560 4400 4670 4791 4695 47 81 2931 4639 268 37 186 5737 4926 58 54 61 92 6248 62 38 67 78 4134 6131 35590 187 7432 6390 7726 83 46 85 44 86 34 10371 5658 8313 48310 188 8723 7718 107 88 11933 12099 13046 186 22 79 39 119 67 69505 189 1 4 35 1340 1735 18 57 18 52 17 81 1711 1144 18 06 10256 190 2718 2399 3023 3187 3207 3138 30 53 1931 3139 18025 191 7 5 07 6189 80 11 9200 9427 9703 11364 5720 9085 527 38 192 8544 78 42 10666 125 42 13312 13775 178 20 6976 125 74 729 86 193 1287 1417 16 97 18 7 18 69 18 08 1720 1046 1800 10223 194 27 17 2450 2940 3187 3214 3157 3054 1749 3125 17954 195 42 53 3560 4222 45 90 4679 46 63 4743 2741 4539 26247 196 6068 48 69 57 79 6335 65 8 6 66 04 7172 4338 63 26 366 78 197 7389 58 86 72 8 6 82 23 8584 8936 10658 50 60 8257 4798 6 198 86 88 78 91 100 27 120 56 130 29 14299 190 81 6492 12353 71850 199 5864 4694 5 6 67 61 94 6419 65 48 7192 3950 6207 360 14 200 2 D 4177 38 36 4547 48 09 4775 4628 5006 2715 46 90 261 30 201 5712 5170 62 39 66 38 6599 6604 7518 4167 65 20 378 00 202 73 63 7201 8986 98 43 9733 9914 13353 6219 9619 55810 203 8604 10043 13118 148 41 150 42 158 66 25206 82 5 3 14717 85290 204 12 68 1506 18 41 1971 1966 1868 1799 11 42 1913 10880 205 2659 2571 3127 3276 32 50 3130 3069 18 80 3196 18 350 206 39 80 36 76 4347 4573 45~67 4473 46 34 28 37 4490 25910
o 207 Orifice 11496 10 64 1360 15 39 1 5 80 1 6 15 1496 8 58 15 24 88 83 208 9433 8 95 11 78 13 26 1394 1386 1263 727 1346 78 48 209 7387 746 9 77 1123 1184 1159 1048 6 11 1111 64 74 210 52 36 566 7 66 900 934 909 8 21 499 8 27 48 02
0) CJ1
TABLE III Continued
Run No Position CFM h 1 h2 hs h4 h5 h6 h7 hav Nuav
211 212
3309 1293
414 257
563 3 19
6 68 3 57
6 91 3 37
6 72 351
7 37 337
38 4 2 46
4 40 341
3748 1942
213 214 215 216 217 218
c of 2nd 1 516 1235
1919 2712 3320 4153 4704
1532 2447 35 46 4312 5567 74 29
2 1 87 3312 4225 52 86 6902 8 6 50
2360 3555 4340 56 12 7 0 49 8 9 40
2409 3598 4 8 85 5718 7713 9593
2347 2101 35 33 3453 48 00 49 62 5562 59 86 72~6 7 8 79 93 76 11237
1243 20 64 3054 4 2 8 1 5114 6983
2326 35 00 4638 5545 7225 91 40
132 13 200 27 26672 31968 41711 52811
bull
67
TABLE IV
PRESSURE PROFILE DATA
Baffle Flow Qpening Rate ~p
(Inches) Position (CFM) (Inches 295 S G Fluid)
1 364 l2 11 U 1012 0 254 1248 0197 1493 0 141 1718 0112
c 1000 9 80 1210 1710 1436 28 75 1746 4320 1011 1080 1277 2050 1393 3020 1 6 28 4450
12D 1011 9 75 1236 1520 1450 2510 1603 3450
1 D 1011 975 1256 1700 1480 2690 158 1 4070
1 12D 1010 950 1259 1750 1462 2650 1631 3710
2 11 D 1124 1315 1360 2130 1505 2850 1689 4125
1 216 12U 1294 045 1949 0324 2374 0282 2704 0225 3367 0169
c 1326 265 18 81 5 90 2313 990 2731 1480 3439 2660
12D 1272 2 49 1957 661
68
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Pos ition (CPM) Inches 2 95 S G Fluid)
2559 1275 3033 1940 3639 3025
1 216 1nD 1257 242 16 96 476 2117 8 05 2561 1280 2990 1895 3431 26 bull00
1 316 12U 1309 0 479 2004 0422 28 28 0 352 3526 0281 42 28 0225 5199 0225
c 1308 1 43 1998 272 28 14 5 10 3478 795 4248 1235 5048 1885
l2D 1286 140 2005 3 45 2831 725 3495 1180 4194 1805 5046 2945
1 11D 1322 150 2039 352 2841 735 43 77 1980 5378 3440
1 516 12U 1278 0493 2732 0493 4315 0408 5744 0352 7494 0352 8932 0422
c 1300 0 506 2731 1985 4310 348 6080 6 45
69
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Position (CPM) (Inches 295 SG Fluid)
7607 1090 8830 1585
l2D 1343 0549 2738 225 4566 583 6112 1195 7536 2055 9043 3415
1 516 1uD 1249 0464 2713 224 4155 579 5620 1150 7428 2115 90 70 3405
1 12D 1301 0493 2735 220 4501 616 61 50 1235 7440 2065 8862 3445
2D 1265 0 478 2750 226 4366 594 6578 1270 7678 2240 8945 5280
2 12D 1295 0493 2725 222 4293 600 5807 1120 7568 2200 9070 3615
TABLE V
RATE OF HEAT TR AN SFER Ar THE BAFFL~~ CID-TT ER
Orifice Size
(Inches)
Flow Rate
( CFM)
Re d e G tU
R~) 055 Nuav NuPr-l3
1 364 10 26 12 90
8 075 10015
43400 54 600
85 11 99 64
95 83 112 19
1416 11 140 59 900 110 30 124 20 16 27 12 800 68 900 126 64 142 60 17 29 13 610 73 200 135 79 152 90 17 76 13980 75 200 147 59 166 19
1 216 11 35 14 06
8 600 10 660
27000 33500
6 4 96 76 56
73 14 8 6 12
1517 11500 36100 82 51 9291 20 34 15400 48400 10229 115 18 23 11 17500 55000 118 31 13322 2348 17 800 55900 11947 13452 2666 20 200 63400 13508 15210 27 16 20 600 64700 135 05 152 07 32 47 24600 77200 161 57 18 193 3392 25 700 80700 17390 195 8 1
1 316 1344 19 36
9898 14 260
24800 35 700
63 8 7 8 2 77
71 92 93 20
28 46 20 9 60 52 500 111 08 125 08 34 84 25 660 64200 131 38 147 93 40 66 50 12
29900 36900
74800 92400
150 78 18046
169 78 203 20
~ 0
TABLE V Continued
Orifice Flow Re Size Rate d e G R~rmiddot55 NuPr-13(Inches) (CFM) U Nuav
1 516 12 70 8 847 16800 54 ~0 61 14 2 14 18 900 35800 82 42 92 80 43 10 30 000 56900 11349 127 79 60 12 41900 79400 14416 16232 7279 50700 96100 17326 19509 86 90 60540 115000 20098 22529
TABLE VI
RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
Orifice Size
(Inches)
1 364
1 216
1 316
Flow Rate
(CFM)
1054 1294 1431 1681 1770
1068 1399 1669 1959 2295 2636 3390
1299 1973 2788 34 73 4118 4973
Re deG Mshy
8 300 9870
11260 13200 13 930
8100 10600 12650 14850 17400 19980 25700
9 570 14500 20500 25600 30300 36600
R~r-6 51900 61700 70500 82 500 87 100
28200 36900 44000 51700 60 600 69500 89400
26100 39600 56000 69900 82700 99 900
Nuav
2416 293 5 3187 4018 4805
14938 18968 21712 25156 30680 37938 59601
14736 21290 28781 36052 439 85 60225
Uu Pr-1 3
27204 33050 3589 4524 541 0
16820 21358 24448 28326 34546 427 18 67111
16593 23973 32407 40595 495 1 678 13
TABLE VI Continued
Orifice Flow Re Size Rate deG R~rmiddot6 NuPr-13(Inches) (CFM ) M- Nuav
1 516 1268 88 30 17700 108 8 1225 2689 18700 37400 1835 2066 3980 27700 55700 2591 2917 4177 29100 58 500 2713 3055 5712 39800 80000 378 0 425 6 7362 51300 103000 5581 6284 8 604 59 900 120000 8529 9604
74
TABLE VII
EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER
l 516 Inch Orifice
Center ot 2nd Baffle 4 Downstream
Plow Rate (CFM)
1235 1919 2712 3320 4153 4704
Flow Rate (CFM)
1270 2714 4310 6012 7279 8690
(Re)eb -8600 1321
13400 2003 18900 2687 23100 5197 28900 4171 32800 5281
Center ot Single Battle
-8847 543
18900 824 30000 1135 41900 1442 50700 1733 60540 2001
(Nu)(Pr)-l3
1487 2255 3003 3600 4697 5946
(Nu)(Pr)-13
611 928
1278 1623 1951 2253
75
ABLE VIII
HEAT TRANSFER IN THE TEST SECTION WITHOUT ORIFICE
CFM Ute) 0b h Nu
1293 5-951 3 41 1942
33 09 15251 649 3746
5236 24193 827 4802
7387 34001 1111 6474
9433 43419 1346 7848
11496 52-914 1524 8883
76
TABLE IX
PRESSURE DROP FUNCTION
Orltlee Size Flow Rate incbea ~CFM (Re)eb X 10bull8
1 364 1011 7957 0808 1256 9885 1468 1480 11648 2765 1581 12443 4160 1689 1_3293 4 020
1 216 1257 9530 1327 1696 12858 2663 2117 16049 4615 2561 19415 7581 2990 22668 11560 3431 26011 16440
l 316 1322 9736 1819 2039 15016 4332 2845 20952 9275 3495 25739 15300 4377 32014 26800 5378 39607 50100
1 516 1011 7 957 oaos 1256 9885 1469 1480 11646 2765 1581 12443 4160 1689 13293 4020
77
TABLE X
EXPERIMENTAL DATA
Baffle Hole Diameter Run No
1 - 59
60 - 102
103 - 138
139 - 206
207 - 212
213 - 218
(Inches)
1 364
1 216
1 316
1 516
No Baffle
2nd - 1 516
TABLE X
EXPERIMENTAL DATA
Run Thermocouple Reading s (mv) No Position CFM I tc1 tc2 tc3 tc4 t c 5 tc6 tc7 tcair
1 c 1026 530 2055 1825 1768 1782 1802 1837 1965 1198 2 1290 612 2059 18 65 1809 18 32 1851 1880 1965 1160 3 1416 714 2151 1970 1931 1965 1988 2026 209 5 1130 4 1627 8 21 2235 2084 2 049 2093 2126 2173 2266 1130 5 1776 865 2203 2033 1970 2015 2084 2159 2 264 1121 6 12D 1109 542 1636 1507 1499 1499 1498 1498 1528 1218 7 1258 651 1670 1522 1503 1513 1513 1516 1548 1221 8 1433 750 1625 1480 1467 148 3 1487 1487 1516 1153 9 168 1 8 73 1656 1494 148 1 1511 1517 1517 1543 1159
10 1rtD 1102 485 1545 1450 1437 1446 1447 1442 1466 1220 11 13 08 6 10 1571 1470 1460 1476 1476 1469 1498 1194 12 1464 730 1 623 1509 1508 1528 1 5 32 1524 1548 1173 13 11 06 8 71 1663 1559 158 1 1606 160 6 1 583 1601 1190 14 1 12D 1115 520 1698 1579 1575 1 577 1580 1590 1615 1280 15 1275 6 10 1692 1567 1558 1 561 1570 1580 1601 1234 16 1498 770 1760 1619 1630 1 635 1642 1645 1661 1204 17 1695 912 1775 1635 1670 1689 1686 168 6 1701 1165 18 2D 1049 510 1736 15~2 1567 1558 1 553 1558 1620 1236 19 12 41 610 1655 1517 149 1 148 1 148 1 148 4 1546 1108 20 1 5 32 7 35 1720 1550 1530 1520 1519 1523 158 0 1104 21 16 74 8 8 0 1900 1 727 1714 1696 1691 1692 1753 1169 22 1U 1074 38 5 3 324 2740 2534 2478 2 465 2503 258 0 1210 23 1287 4 35 3510 2 870 2682 2 610 2599 2638 27 1 9 1190 24 1 5 08 470 3 618 2920 2690 2 637 2627 2 664 2747 1177 25 18 07 525 4 088 3235 2962 2905 2910 2988 3130 1169
z ())
TABLE X Continued
Run No Position CFM I tc1 tc 2
Thermocouple Readings te3 tc4 tc5
(mv) tc6 tc7 tcair
26 c 10~29 6 32 2340 2~092 2032 2060 2~097 2152 2~213 1211 27 12 66 679 2270 2 047 1993 2013 2069 2142 2 210 1 182 28 1430 723 2336 2097 2033 2080 2153 2~255 2 356 1 138 29 1729 8 52 2318 2070 1980 2061 2158 2279 2367 1121 30 12D 1054 570 1520 1 4 20 1402 1400 1396 1400 1 443 1159 31 1294 6 69 1599 1469 1444 1439 1433 1 442 1485 1168 32 1430 7 88 1720 1562 1536 1532 1528 1537 158 0 118 5 33 1770 8 81 1641 1488 1450 1~441 1 441 1_466 1518 1 163 34 1D 1058 548 1579 1498 1495 1526 1553 1_557 1 571 1 276 35 1263 640 1609 1509 1515 1570 1599 1598 1 598 1 266 36 18 36 8 47 1538 1452 1483 1553 1602 1 590 1 558 1195 37 1 12D 1029 5 41 1 578 1499 148 4 1473 1461 1465 1-512 1200 38 1315 6 30 159 1 1504 1493 1482 1470 1470 1505 118 5 39 1 4 26 743 1765 168 1666 1660 1645 1642 1678 1270 40 1757 8 54 1744 1648 1634 1620 1598 1 593 - 1612 1223 41 2D 1080 5 30 1734 1604 1570 1 570 1570 1 588 1 640 128 1 42 1305 6 40 1744 1622 1589 1 608 1593 1 609 1 661 1240 43 1434 750 1798 1687 1658 1 636 -1641 1 661 1 711 1_220 44 18 04 8 41 1 764 1666 1607 1605 1614 1 635 1 675 1205 45 12nu 1088 415 2614 2295 2195 2 169 2174 2217 2256 1171 46 1318 477 2805 2477 2371 2342 2364 2 401 2 438 1 163 47 1413 5 28 2930 2 646 2 555 2 526 2532 2570 2 577 1 199 48 1773 550 2740 2518 2450 2431 2448 2 479 2 480 1 170 49 1 11 U 1054 380 3175 2670 2505 2 461 2467 2 534 2 621 1 258 50 1240 420 3268 2738 2 546 2 510 2 508 258 2 2 649 1214 51 1419 451 3364 2B07 2 632 2590 2 590 2 651 2773 1 215 52 1 12U 1032 360 3 165 2 629 2 450 2402 2403 2 473 2 bull568 1 163
--I lt0
TABLE X Continued
Run No Position CFM I tc1 tc2
lhermocoup1e Reading s tc3 tc4 t c 5
(mv) tc6 tc7 tc a ir
5 3 1314 38 9 3178 2592 2411 2367 2361 2432 2555 1140 54 1448 403 3095 2544 238 1 2336 2336 2390 2476 1158 55 178 2 427 3006 2434 2286 2253 255 3 2299 2397 1154 56 2 11U 1061 360 3369 2814 2619 2567 2560 2650 2833 1220 57 1216 360 3044 2512 2338 2290 2288 2374 2566 1150 58 1322 387 3196 2614 2425 2383 2382 2472 2670 1138 59 1639 403 3020 2438 2272 2238 2238 2318 2502 1127
60 1D 1068 612 1552 1424 1400 1395 1396 1426 1745 0945 61 1399 612 1355 1246 1230 1229 1230 1250 1509 0872 62 1669 710 1436 1293 1272 1265 1266 1286 1551 0847 63 1959 900 159 5 1468 1444 14 38 1432 1446 1720 0851 64 2295 730 1169 1105 1098 1099 1108 1100 1298 0781 65 2636 8 80 1202 1129 1121 1126 1 138 1115 1342 0748 66 3390 9 35 1060 o 9s7 0999 1001 1017 0971 1154 0703 67 1nu 1190 370 2225 2188 2104 2080 2120 2209 2 7 15 0990 68 1559 368 2005 1950 1871 18 48 1876 1951 2408 0916 69 1904 368 1870 18 1 4 17 34 1711 1730 18 07 2238 0875 70 22 bull11 471 228 6 2 204 2099 2063 2092 218 $ 2732 0840 71 2289 471 2030 2000 1925 1895 18 96 19 5 2498 0785 72 2727 4 71 1854 18 23 1753 17 23 1716 3758 2241 0743 73 3210 471 1680 1651 158 6 1559 1551 158 1 1950 omiddot7o9 74 2uD 1210 404 1261 1212 1198 1197 1205 1222 139 1 0978 75 14 20 540 1321 1260 1242 1 240 1249 1268 148 7 0918 76 1692 7 18 1467 138 6 1364 1361 1376 1405 1678 0883 77 18 94 903 1708 1 591 1565 1560 1575 1603 1948 0 857 78 2301 903 1530 1432 1407 1402 1415 1432 1738 0815
ro 0
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc117 tcair
79 2621 6 50 1069 1 020 1009 1009 1009 1007 1~189 o739 80 3230 901 1200 1128 1113 1119 1119 1086 1341 0694 81 82
l2D 1155 1689
360 575
1191 1345
1142 1252
1122 1218
1118 1210
1118 1209
1132 1228
1292 1446
0916 0822
83 1244 430 1163 1134 1131 1130 1129 1132 1292 0877 84 2100 645 1175 1135 1147 1 142 1138 1122 1286 0757 85 2292 8 25 1 354 1310 1327 1330 1323 1285 148 6 0728 86 2907 8 23 1180 1138 1151 1158 1149 1107 1268 0687 87 3380 902 1113 1049 1025 1011 1006 1042 1178 0673 88 89
1 12D 1427 1875
480 615
118 2 1140
1140 1095
1124 1077
1125 1075
1129 1072
1137 1072
1290 1243
0880 0790
90 2259 8 41 1296 1231 1207 1206 1203 1182 1419 0757 91 2682 8 80 1231 1170 1149 1147 1142 1112 1350 0731 92 3417 940 1142 1092 1076 1076 1069 1021 1252 0693 93 c 15 17 431 1321 1298 1268 1249 1250 1273 1522 0841 94 2034 505 1285 1263 1235 1209 1205 1206 1464 0759 95 2348 6 10 1395 1379 1334 1302 1286 1268 1536 0732 96 2716 706 1486 1480 1427 1383 1358 1311 1572 0 700 97 3247 7 56 1417 1430 1375 1320 1284 1223 1450 0660 98 1135 400 1425 1388 1352 1329 1330 1 364 1651 0893 99 14 06 440 1379 1341 1304 128 2 1281 1305 1583 0 831
100 2311 680 1602 1593 1553 1514 1502 1480 1 7 27 0 802 101 2666 680 1471 1469 1428 1390 1372 1335 1564 0761 102 3392 798 1491 1 509 1449 1395 1372 1305 1534 0 719
103 1U 1235 410 2469 2295 2173 2165 2226 2361 3120 0 897 104 2010 410 2017 1848 1 737 1706 1747 1865 2582 0753 105 28 14 410 1682 1535 1457 1427 1437 1520 2109 0 660
00 t-
TABLE X Continued
Ru n Thermocouple Rea ding s (mv No Positi on CFM I tc1 tc2 tc3 tc4 tc5 tc6 tc7 tcair
106 3492 440 1649 1499 1420 1391 1390 1470 2042 0620 107 4395 550 18 33 1679 1597 1564 1570 1640 2223 0583 108 5075 588 1779 1642 1580 1550 1552 1 615 2 191 0548 109 c 1344 398 1464 1 399 1364 1353 1350 1380 1689 0 907 110 1936 459 1369 1290 1253 1242 1 237 1259 1574 078 2 111 2846 580 1347 128 5 1251 1232 1220 1215 1 5 23 0 683 112 34 8 4 700 1392 1369 1339 1317 1299 1259 1599 0 636 113 4066 8 13 1449 1458 1427 1391 1363 1270 1595 0 591 114 5012 930 1484 1530 1500 1453 1420 1272 1580 0 580 115 1D 1362 513 1269 1218 1 217 1214 1220 1238 1460 0 893 116 19 58 600 1187 1122 1121 1120 1124 1133 1352 0798 117 2812 705 1052 1008 1015 1010 1011 1001 1218 0691 118 34 32 913 1105 1075 1085 1081 1086 1047 1301 0645 119 4022 980 1038 1021 1026 1023 1029 0983 1211 0 609 120 5026 982 0 8 61 0839 0836 0836 0837 0791 0955 0570 121 2D 1244 475 1320 1246 1233 1240 1255 1275 1434 0925 122 1 9 60 5 50 1160 1088 1074 1079 1089 1100 1260 078 7 123 2817 6 80 1096 1024 1 013 1018 1029 1022 1201 0 700 124 3491 960 1248 1175 1163 1172 1192 1153 1435 0 658 125 4096 989 1141 1089 1078 108 9 1105 1051 1310 0629 126 50 37 989 0983 0933 0929 0 936 0949 0880 1090 0 602 127 128
12D 1278 1947
402 545
1270 1261
1 230 1216
1228 1216
1230 1 215
1235 1223
1242 1219
1483 1514
0 913 0778shy
129 2769 695 1273 1234 1237 1221 1251 1212 1525 0678 130 131 132
34 39 4103 4978
8 40 9 80 9 80
1336 1448 1271
1322 1458 1 288
1328 1 462 1286
1 259 1 356 1157
1353 1492 1311
1261 1329 1138
1 555 160 7 1343
0 629 0 600 0599
(l) l)
TABLE X Continued
Run No Position CFM I tel tc 2
Thermocouple Readings tc3 tc4 tc5
( mv) tc6 tc7 tcair
133 1 l2D 1299 5 16 1 28 1 1212 1196 1195 1205 1221 1478 0869 134 1973 6 15 1163 1098 1073 1071 1079 1083 1343 0751 135 136
27 88 34 73
802 9 -_78
1187 1214
1099 1131
1069 1104
1066 1101
1075 1~110
1l061 1066
1370 1360
0662 0618
137 4118 9 81 1084 1010 0983 0979 0982 o937 1209 0581 138 4973 98 1 0969 0897 0 868 0855 0860 0799 1041 0572
139 1D 1253 409 1371 1293 1298 1301 1309 1321 1578 0928 140 2366 480 1130 1 090 1 121 1130 1137 1132 1390 0744 141 34 61 6 38 1081 1086 1152 1161 1147 1069 1382 0644 142 143 144
4325 5677 6759
7 90 939 998
1110 1115 1034
1161 1208 1139
1253 1268 1180
1265 1302 1215
1228 1230 1123
1080 1056 0970
13$913r12 8
0601 0561 0542
145 84 08 989 0863 0961 0934 0895 0871 0 785 09 9 0530 146 86 54 9 80 0808 0901 0 872 0821 0809 0733 0891 0498 147 7376 9 80 0 927 1032 1027 1 040 0961 0889 1032 0511 148 2D 4254 776 1 050 0 981 0965 0961 0962 0922 1155 0579 149 5708 991 1102 1031 1014 1009 1010 0931 1227 0528 150 69 78 990 0914 0853 0839 0 839 0843 0759 0996 0521 151 1254 490 1 479 1352 1329 1334 1351 1379 1607 0930 152 2713 7 00 1310 1220 1201 1201 1211 1209 1516 0723 153 8730 991 0809 0756 0742 0745 0 748 0663 0874 0543 154 5811 966 1219 1108 108 6 1081 1079 1033 1330 0650 155 42 46 8 02 1248 1136 1114 1114 1118 1103 1376 0 699 156 c 1270 429 1671 1571 1551 1545 1563 1600 1933 0929 157 2714 488 1398 1285 1 267 1258 1262 1275 1628 0729 158 4310 642 1424 1318 1299 1282 1283 1261 1683 0617
co ~
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc7 tc a 1r
159 60 12 780 1461 1388 1370 1349 1343 1279 1700 0 573 160 72 79 8 60 1402 1344 1330 1312 1292 1189 1 566 0 520 161 8690 982 1472 1442 1437 1 422 1392 1224 1602 0 521 162 163
12D 4368 5833
6 30 8 30
1195 1368
1105 1270
1111 1283
1117 1294
1131 1313
1081 1194
1369 1553
0613 0 553
164 76 43 959 1428 1338 1348 1341 1371 1180 1488 0535 165 8739 984 1345 1272 1272 1208 129 3 1059 1361 0550 166 1268 459 1701 1548 1541 1547 1589 1 625 1976 0 973 167 2678 570 1485 1351 1349 1356 138 1 1 385 1795 0760 168 169
1 12D 128 3 2729
448 650
1664 1314
1501 1232
1425 1233
1428 1229
1491 1229
1527 1232
1869 1571
0 962 0767
170 4345 847 1245 1179 1187 1182 1172 1132 1476 0 650 171 6036 9 76 1139 1109 1117 1114 1095 1020 1332 0588 172 6578 9 72 0982 0949 0942 0938 0926 0 8 50 1079 0560 173 87 84 9 72 0880 0854 0 8 36 0822 0818 0 749 0941 0585 174 1278 480 1564 1416 1397 1403 1417 1445 1733 0998 175 2711 590 128 3 1175 4 1178 1182 1187 1195 1493 0796 176 4351 8 90 1331 1259 1266 1275 1272 1235 1592 0 682 177 5994 9 60 1228 1152 1150 1151 1143 1075 1 360 0644 178 lU 1223 408 2282 2140 2052 2052 2106 2188 2626 0 878 179 2351 408 178 1 1623 158 5 1519 1556 1634 2068 0717 180 3448 482 1888 1675 1570 1541 1572 1665 2199 0629 181 4513 563 2026 1797 168 4 1644 1670 1770 2385 0583 182 5714 589 1913 1700 1610 1568 1580 1 682 2382 0551 middot 183 6997 653 1903 1718 1643 1611 1612 1700 2326 0 549 184 8709 6 80 1738 158 3 1543 1510 1498 1519 1 912 0577 185 186
2 12D 4249 5737
660 9 74
1055 1221
0 979 1122
0960 1093
0 952 1088
0959 1090
0 956 1054
1147 1350
0661 0602
187 7432 9 8 1 1065 0981 0951 0942 0 939 0881 1135 0582 CD ~
TABLE X Continued
Run No Position CFM I t o1 to 2
188 87 23 9 83 0944 0 879 189 1435 585 18 26 1630 190 2718 690 1433 1298 191 7507 950 1070 0961 192 85 44 964 0982 0 881 193 1287 600 1806 1668 194 2717 7 80 1579 1444 195 4253 8 81 1371 1260 196 60 68 9 78 1252 1152 197 73 89 975 1100 1000 198 86 88 973 0953 0 871 199 58 64 9 81 1269 1155 200 2D 4 1 77 915 1362 1251 201 5712 975 1213 1111 202 7363 9 78 1036 0 951 203 8 604 973 0932 0861 204 1268 6 95 2015 18 20 205 2659 6 96 1405 1295 206 39 80 7 98 1261 1174
No 207 Orifice 114 96 509 1325 1148 208 94 33 509 1477 1243 209 7487 5 09 1686 1409 210 5236 505 2094 1691 211 3309 428 2188 1 778 212 1293 392 2976 2560
Thermo ooup1e Readin g s (mv) to 3 to4 to
5 to
6 to7 toair
0 851 0847 0 8 29 0759 0987 0592 158 4 1583 1611 1647 1993 0986 1270 1266 1 279 1298 1604 0 789 0916 0908 0900 0 858 1115 0602 08 39 0 823 0 818 0 770 1035 0602 1609 1602 1629 1676 2153 0979 139 1 1385 1400 1 430 1938 0776 1212 1201 1205 1201 1601 0669 1 105 1086 1086 1 052 1371 0621 0952 0936 0923 0870 1195 0582 0 8 20 0 801 078 1 0 729 1044 0569 1108 1090 108 2 1043 1407 0610 1218 1221 1241 1202 1582 0659 1081 1083 1084 1031 1 368 0622 0921 0924 0919 0 841 1111 0 610 08 34 0831 0 821 0 751 1003 0 630 1761 1761 1 809 1861 2399 0966 1271 1271 1295 1311 1650 0797 1150 1150 1161 1149 1440 0703
1083 1057 1053 1109 1566 0~530 1158 1125 1138 1217 1763 0 526 1291 1250 1278 1383 2038 0542 1518 1478 1519 1657 2420 0 589 1596 1557 1601 1737 2441 0688 2370 2344 2409 2561 3 297 0921
()) (11
TABLE X Continued
Run Thermocouple Readings (mv) No Position CFM I tc 1 tc2 tc3 tc4 tc tc tc tc i5 6 7 a r
C of 2nd 213 516 1235 4 63 1 432 1291 1265 1258 1 268 1 308 1550 0 971 214 1919 6 17 1357 1223 1196 1191 1199 1211 1461 0 851 215 27 12 8 35 1401 1259 1278 1220 1230 1218 1511 0 762 216 3320 981 1439 1305 1270 1259 1275 1238 1450 0719 217 41 53 980 1251 1142 1132 1094 1121 1088 1305 0 695 218 404 987 1102 1042 1030 1 bull006 1014 0960 1133 0681
Supplementary Equations
Calculating temperatures from thermocouple readings
t = -026tc)2 + 3512(tc) + 3201 (26)
where t is the temp in deg F and tc is the thermocouple reading in millishyvolts
Calculation of the thermal conductivity of air
k = 00000245ta + 0 0132 (27)
where k is the thermal conductivity in Btuhr rt2 degFft and ta is the air temp 1n OF
I I
bull co m
6
variables but the r esults have ne ver satisf a ctorily been
correlated to appl y for all types of heat exchangers
Some basic 1ork has been done recently however on
the local shell-side coefficients Ambrose (1) studied
the local heat transfer coefficients i n a model heat exshy
changer with segmental baffles This study was fairly
extensive at the baffle center but the data were quite
limited for the space between the baffles Gurushankar1ah
(5) further extended Ambroses work by studying a single
baffle space in detail
The results of these two studies indicated a need for
detailed information 1n the vicinity of the baffle Hence
Lee () investigated a single baffle s pace between two
orifice baffles and obtained considerable information on
the rates of heat transfer in the annular orifices Since
his work was carried out in a multitube mode l heat ex~
changer the determination of the rate of flow through the
individual orifice was difficult because of t he outer
clearances existing in the exchanger For this reason the
present research was undertaken to study the rate of heat
transfer in a single annular orifice through which the flow
could be accurately determined
Bell and Bergelin (2) have studied i n detail the pres shy
sure drop coeff icients for the annular orifices formed beshy
tween a circular disk and a circular tube These results
also appl y to the annular orifioe formed when a rod extends
7
through a circular hole in a plata This study was extenshy
sive in the fact that it considered the baffle thickness as
well as the orifice size but no heat transfer data were
presented
Sullivan and Bergelin (9) studied flow through a
single annular orifice through multiple annular orifices
i n parallel and flow around a single baffle both with and
without leakage through the baffle A generalized expres shy
sion is presented for the pressure drop across one baffle
section of a tubular exchanger with leakage through the
tube holes in the baffle but the effect of leakage area
upon heat transfer is only discussed qualitatively The
pressure drop data is correlated by plotting cent as a funcshy
tion of the Reynolds number where cent equals
d1 )22( ~ P) s c e (d2 -
M-2
8
CHAPTER III
~PERI1ffiNTAL APr ARATUS
The heat transfer test section was essentially a
single tube heat exchanger The inner tube was a l-in
OD aluminum tube with an electrically heated probe midshy
way between the two ends of the tube
Test Section
The shell as constructed from lucite plastic tubing
2 5-in I D and 3-in O D The te t section d a total
lengt h of 54 58 inches I t consisted of two sections
The upstream section was 40 i n ches in length in order to
assure freedom from entrance effects and the downstream
section was 13 12 inches in length To further assure
uniform flow a bundle of short copper tubes was placed a
few inches downstream from the entrance Both of these
sections had 12 i nch flanges on one end so t hat a 18
i nch thick orifice plate could be clamped between them
Heat transfer coefficients were measured in the vicinity of
t h is orifice A cross section of the center of the test
section is shown in Figure 1 and the experimental appara~
tus is shown in Figure 2
Cooled air supplied by a Roots -type blower was used
as the shell-side fluid throughout this study It entered
the test section through a l-in ID 1 12-in OD plasshy
tic pipe at the upstream end of the calming section Tbs
j Jl l 6- 11 BOLTS II I nbull middot~11 I HEATING ELEMENTS
J T ( T
-f-shy - - - f-_- __L
7 777 _y A
IT 1] I
I
FIGURE I CROSS SECTION OF TEST SECTION AND PROBE
10
FIGURE 2 EXPERIMENTAL APP1Ub~fUS
11
air left the test section through nine equally spaced 12
ineh holes placed around the side of the tube at the exit
end
Sensing Probe Assembly
The sensing probe was designed to measure the local
heat transfer coefficients at any point along the tube and
around the tube in the test section The tube was designed
so that it could be easily moved up- and downstream to
measure the heat transfer coefficients at various positions
in relation to the orifice
The sensing tube assembly consisted of the sensing
probe the thermoctmple lead s and selector switch the
power lines and the two aluminum tubes between which the
probe was centered
Imbedded in the sensing probe were seven iron-constanshy
tan thermocouples for measuring the temperatures around the
tube The lead wires from these thermocouples were conshy
nected to a seleotor switch at the downstream end or the
aluminum tube A layer of Saran wrap was placed around the
tube over the t hermocouple and three lengths of Trophet C
resistance ribbon were wrapped around the tube nd conshy
nected in series to the power leads
The heating surface of the probe was formed by these
three one inch wide strips of Trophet C resistance ribbons
The ribbons were 0002 inches thick and had a resistance of
12
0 271 ohms per foot and a thermal conductivity of 763
Btuhr ft 2 degFft They were held in position by four
copper bars placed in four parallel longitudinal slots
These copper bars served as connectors for the electrical
leads A photograph of the sensing probe is shown in
Figura 3 and a drawing of the assembled probe is given in
Figure 4
Power Source
Direct current was used to heat the resistance ribbon
on the sensing probe The current was regulated by a slide
wire resistor The po er source consisted of a Raytheon
Voltage Stabilizer to stabilize the city power source at
115 volts and an automatic selenium rectifier with an alshy
ternating current input of 115 volts at 60 cycles per
second and an output of 12 volts and 35 amperes direct
current
Temperature Measuring
The temperatures around the sensing probe were calcushy
lated from the emf readings of the ironbulloonstantan thermoshy
couples The emf measuring system consisted of the seven
probe thermocouples a separate thermocouple for measuring
the inlet air temperature a thermocouple selector switch
a cold junction and a Leeds and Northrup Type K Potentishy
ometer The potentiometer was placed on a Fischer
13
THERMOCOUPLE JUNCTIONS~ ~------- HOLES FOR THERMOCOUPLE LEADS
~----- SCREWS
~ff+--- CONNECTING BARS
END VIEW
POWER LEADS SOLDERED TO LOWER CONNECTING BAR
iER PLASTIC PIECE
RESISTANCE RIBBONS LOCATION OF THERMOCOUPLES
FIGURE 4 DRAWING OF ASSEMBLED SENSING PROBE
15
Vibradamp support to absorb the vibrations produced by the
air blower
Air Source
Air was used as the shell-side cooling fluid during
the study The air was pumped through the test section by
a Roots type air blower with a rating of 280 ofm at 3 12
psig outlet pressure The hot air leaving the blower was
passed tbxfugh two finned-tube box-type coolers and one
tubular edoler to oool it to approximately room temperature
The air flow rate was measured by passing it through a
flow measuring orifice in the line Two sharpbull edged orishy
ficas were used f or flow measurements The calibration
curves for these orifices were presented by Ambrose (1
p 166)
The pressure taps on each side of the orifice were
connected to two differential manometers containing 0 83
and 2 95 specific gravity fluids respectively The presshy
sure drop through the test section and test orifice was
measured by a pressure tap placed 13 inches upstream and
one placed 6 12 inches downstream from the orifice Two
pressure ga ges were used to measure the pressure at the
inlet to the flow orifice and to indicate the statio pres~
sure at the test section inlet
16
Pressure Probe
A probe was designed to measure the pressure drop
between the pressure tap 13 i nches upstream from the ori shy
fice baff le and any point downstream from the tap The
probe eonsisted of a l~in OD copper tube with six 132
i n ch holes even l y s paced around the tube The upstream
pressure tap and the pressure probe were connected to a
differential manometer so the pressure drop to various
points up- and downstream of the orifice could be measshy
ured
17
CHAPTER IV
EXPERIMENTAL PROGRAM
The experimental program was designed to measure the
heat transfer coefficients and pressure drops in the vicinshy
ity of annular orifices The four orifice sizes studied
were 1 364 1 216 l 316 and 1 516 inches~ The inner
tube used in each case was a 1-in OD alumintim tube
Hence tube to baffle clearances were respectively 3128
232 332 and 532 of an inch
Heat transfer coefficients were measured at poait~ons
1 i nch upstream at the orifice center and at 12 1
1 12 and 2 inches downstream for all orifices In addishy
middottion the heat transfer coefficient at a point 2 12
inches downstream from the 1 516 inch orifice was measured
and at the points 12 l 12 and 2 inches upstream from
the 1 364 inch orifice
The heat transfer coefficients at each point were
measured at five different flow rates for the 1 364 inch
orifice and at six different flow rates for the other orishy
fice sizes The high pressure drop through the small orishy
fice size limited the number of flow rates which could be
studied
The flow rate was calculated from the pressure drop
across the flow orifice This flow was corrected to cubic
feet per minute at 68degF and one atmosphere pressure by
18
using the orifice pressure and the test section pressure
which were measured by pressure gages
It was desired to determine a relationship between the
heat transfer coefficient and the total pressure drop for
each orifice size The pressure drop across each orifice
at various flow rates was measured by means of the presshy
sure probe described in Chapter III It was also desired
to obtain pressure profiles for each orifice size since
these might be similar to the heat transfer profiles The
pressure drop was measured from a point 13 inches upstream
of the orifice to points at 1 and 12 ineh upstream the
orifice center 12 1 1 12 and 2 inches downstream
The experimental program is summarized in Table I
TABLE I
SUla~RY OF EXPER IMENTAL PROGRAM
Position Investigated-Distance from Orifice-Inches
Orifice Range of Flow Rate Size Heat Transfer Pressure Drop CFM at 68degF amp 1 atm
1 364 2U 1 12U 1U 12U c 12U C 12D lD 10 - 18 l2D lD 1 12D 2D 1 12D 2D
1 216 1U c 12D lD 1 l2D 2D 12U c 12D lD 10 - 35
1 316 1U c 12D lD 1 l2D 2D l2U C 12D lD 12 - 50
1 516 1U c x2D lD 1 l2D 1U 12U C 12D 12 - 90 2D 2 1 2D l D 1 l2D 2D 2 12D
20
CHAPTER v
EXPERI MENTAL PROCEDURE
The experimental procedure for measuring the heat
transfer coefficients ~d corresponding flow rates reshy
quired the following procedure
(1) Install the orifice size to be studied in the
test section
(2) Place the heat transfer probe in the position up
or downstream from the orifice where the middot heat
transfer rate is to be studied
(3) Fill the cold junction thermos with cracked ice
(4) Measure the atmospheric pressure
(5 Open bypass line from blower and close line to
test section
(6) Turn on the cooling water for the exchangers used
to cool the air leaving the blower
(7) Start the automatic selen ium rectifier by turning
on the t 1mer bull
(8 ) Connect the voltage stabilizer to the wall outlet
(9) middot Set the slide wire resistor to the maximum re shy
s1atanee I
(10) Start the blower
(11 Open the line to the test section until the de shy
sired flow rate is obtained
(12) Switch on the probe direct current power source
21
(13) Adjust the slide wire resistor to obtain the
desired current
(14) After the thermocouples have reached equilibrium
values record the e m bullf across each of the
seven probe thermocouples and also the entering
air thermocouple
(15) Record the direct current amperage
(16) Record the gage pressure at the flow orifice and
the entrance to the test section
(17) Record the manometer measurement of the pressure
drop across the flow orifice and also the presshy
sure drop through the test section
22
CHAPTER VI
CALCULAT ION OF EXPERIMENTAL DATA
The local heat transfer coefficients were calculated
from the temperatures measured on the probe surface the
air temperature and the current input The results were
calculated by using the Alwae III-E computer
The general expression for calculation of the heat
transfer coefficients was derived by Ambrose (1 p 79)
The equation is derived by making an energy balance around
a small increment of the center resistance heating ribbon
The two ribbons tnstalled adjacent to the center ribbon
reduced the amount of logitudinal conduction and assured
little longitudinal temperature variation in the center
ribbon
A heat balan ce on this small increment of resistance
ribbon yields the following
(the heat conducted in) + (heat generated) = (heat
conducted out) +(Heat convected to the fluid) + (heat
radiated to the surroundings) + (Heat conducted into
the plastic center of the probe)
This gives the equation
kzw dtdS + 12RdS kzws [ t + (~) ds] + hwdS (t-ta )
+ ~Aad wd o middot+ qcAond 1 -~- wdS 5 )
23
Hence solving for h gi~ea
i2R kz d2t Qrad qcond w + -d$2 - ~- A
h = ( 6)t - ta
Since S = re where 9 equals the enclosed angle ~n radians
dS rd9 ( 7)
and
dt - dt (8)dS - rd9
Differentiating with respect to S
d2t (9)rd9dS
from which
(10)
Substitut1ng into the equation for heat transfer coeffishy
cient gives
h = i2R Qcond A (11)
w
The rate of radial heat conduction into the plastic
tube making up the probe was assumed to have negligible
effect on the heat transfer coefficient It was also
assumed that the heat loss by radiation from the ribbon
was negligible since all data were obtained with the ribbon
at a temperature less than 125degF
24
When t he rad iation and conduction terms are neglected
Eq (11) becomes
(12)
The following con stants are known
R = 0 271 ohmsft
w = 100 i n ches
k = 763 Btuhr rt2 degFft
z = 0 002 inches
r = 12 inch
Eq (12) putting 9 in degrees then reduces to
1110 12 + 2404 d 2t d92
( 15)h = ------~--~-------t - ta
Thi s equation was programed for the Alwac III- E comshy
puter and used to calculate the local heat transfer coefshy
ficients from the observed data
The average heat transfer coefficient around the tube
at a given position in the t est section was calculated by
averaging the local coefficients calculated from Eq (13 )
It was found 1n the course of the experimental work
that thermocouple numbers 1 and 7 were indicating higher
temperatures than would be expected This resulted in h1
and ~ being lower than the other local coefficients around
the tube Since the fluid was flowing parallel to the axis
of the probe the circumferential variation i n rate of heat
25
transfer should be small Hence in obtaining the average
coefficient around the tube the values of h1 and h7 were
not used even though they were calculated and are tabulated
1n Table I II in the Appendix
Then
(14
A Nusselt number as calculated from this aver age heat
transfer coefficient using the tube diameter as the characshy
teristic dimension
(15)
The air flow rates through the test section were calshy
culated by measuring the pressure drop across the flow orishy
fice the air temperature the pressure at the flow orifice
and the pressure at the entrance to the test section The
orifice calibration curves (1 p 166 ) were used to obtain
a value of the orifice coefficient f8e where Q equals
the flow in cubic feet per minute at 68deg F and one atmosmiddot
phere pressure and te is the density of air at the exchanger
and e the density of the air at the flow orifice The
den sity of the air can be expressed by
e = 2 703 p (16)T
where T equals the temperature in OR and P equals the absoshy
lUte pressure i n lb1n2 Using the value of e Qfo from
26
the calibration charts as A and Eq (16) solving for Q
gives
( 17
This equation was used to calculate the flow rate for
each flow studied
The Reynolds number used i n the correlation of the
data was the equivalent Reynolds number defined as
Re)eb ~ d2 - dl)Uf ( 18 ) lL
where d1 is the outside diameter of the inner tube and d2
is the orifice diameter U is the flow velocity through the
annular orifice e is the density of the air and U- is t he
viscosity of the air This equation can be transformed t o
(Re) b = 1611 Q (19) e dl + d2
where d1 and d2 are in inches
The pressure drop data were calculated i nto a dimenshy
sionless pressure drop function cent where
d1 )22( ~ P)gc f av(d2 shycent 2 bull (20
M-
For air this equation reduces to
where d2 and d1 are in i nches D P is expressed i n inches of
2 95 specific gravity fluid and P av is expressed as lbft3
27
CHAPTER VII
ANALYSIS OF DATA
In analyzing the heat transfer data an attempt was
made to correlate it 1n terms of the dimensionless groups
(Nusselt number Prandtl number and Reynolds number) which
appear in Eqs (3) and (4) Consequently all of the av~
erage heat transfer coefficients hav were brought into
the form ( Nu)( Pr)~3 bull The Nusselt number was based on the
tube diameter and the thermal conductivity of the air at
the flowing temperature The tube diameter was used in the
Nusselt number because comparison could then be made with
previous experimental work on heat exchangers which have
commonly used the Nusselt number defined as in Eq (15)
From the standpoint of dimensional analysis this is
equivalent to considering the tube diameter as the characshy
teristic length so far as the heat transfer is concerned
The Prandtl number of the air was taken as 0 7 in all
cases
Variation of Heat Transfer Rate with Distance from the Baffle
Considerable variation was observed in the rate of
heat transfer in the vicinity of the baffle In order to
obtain the variation with respect to position the term
(Nu)(Pr)-13 was plotted versus the flow rate Q for each
position and orifice studied Cros s plots were then made
28
at constant flow rates in order to obtain the variation of
(Nu)(Pr) -13 with position The resulting cross plots are
shown 1n Fi gures 5 6 and 7 for the four orifices studshy
ied
About one inch upstream from the orifice the heat
transfer coefficient begins to rise rapidly and continues
to do so until it reaches a maximum some distance downshy
stream After the maximum point the heat transfer coef fi shy
cient decreased slowly The heat transfer rate was found
to reach a maximum at a different position downstream for
each orifice size These figures also show that for a
given orifice size the maximum heat transfer rate occurs
a pproximately at the same point for all flow rates The
position of the maximum point f or each or ifice size is
shown in Table II
The region immediately downstream from the orifice is
one of h i gh turbulence due to the jetting action of the air
flowing through the orifice As the air flows t hrough the
orifice the streamlines continue to converge for some dis shy
tance downstream The point of maximum heat transfer is
probably at the point where the streamlines be gin to diverge
and a boundary layer begins to build up on the tube Tle
decreasing heat transfer coefficient beyond the maximum
point indicated the formation of a boundary layer
Since the position of the maximum point is independent
of flow rate middot it is possible to correlate it with respect
_ ct 11shyz-
100
0 136 ORIFICE
(
I 0
I )
~ 00
~p 0
I 0
--r--- ~
ISCFIII
-_ OCFM
rbull abull
~ middot~ a-1 z-
12fORIFICE
100
200
100
0 0 UPITRAM ORIFICE DISTANCE CENTER
CFM
h I DOWNSTREAM
DISTANCE
FIGURE 5 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLpound
30
too
700
800
100 ~ f gtf
400
z ~
100
100
100
0
13fORIFICE
~ -~ -- ---
)
~
~
-
I ~ ~OCFM
I vI~-~ OCFM
J ---
Iamp CFM
I 0 I I UPSTREAM ORIFICE DOWNSTREAM DIITANOE GENTER DIITANCI
FIGURE 6 VARIATION OF HEAT TRANSFER RATE WITH DISllNCE FROM BAFFLE
--
--- --
31
100
100
700
100
_ 100
f 9- 400 z-
100
tOO
100
0 - I 0 I I I UHTRIAM OAtfiCI DOWIIITMAM
+ I tyl6 ORIFICE
v I
~~ ~CFM
I v ~CFMI
v v 7
~~ v ~ iOCFM
- ~~ I-shy1-shy ~ICFM
DIITMCI OINTIR DIITANCI
FIGURE 7 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLE
32
TABLE II
POSITION OF MAXIMUM HEAT TRANSFER
Position of Maximum Orifice Size Heat Transfer
(inches) (inches downstream)
1 364 050
1 216 100
1 316 125
1 516 200
33
to orifice size Figure 8 shows the effect of the orifice
size on the position and value of the maximum heat transfer
at a constant flow rate of 15 cubic feet per minute It
can be seen that the larger the orifice size the further
downstream the point of maximum heat transfer occurs
Also as the orifice size increased the rate of heat
transfer decreased for a given flow rate The broken line
indicates the variation of the point of maximum heat transshy
fer with position and size The position of the point of
maximum heat transfer rate downstream from the orifice was
correlated with orifice size by means of the dimensionless
groups (Lde) and (d1de) where L is the distance downshy
stream from the orifice where the maximum rate of heat
transfer occurs d1 is the outside diameter of the inner
tube and de is the equivalent diameter of the orifice
ie de = d2-dlbull
Figure 9 shows a plot of Ld 6 versus d1d6 for the
four orifice sizes studied The four points on this logshy
log plot are approximately in a straight line and the
equation of this line is
Lde = 0 44 d1de)028 (22)
Although the above relationship represents a correlashy
tion of dimensionless groups it is based upon only one
tube diameter and needs to be substantiated further by
studying other tube diameters and other orifice sizes
34
aoo
400
aoo ~
-~ middot-CLshyJ z
200 -
100
0
ORIFICE CENTER
l~
l
t
I J~
1pound~
I
0 I I~
AT 15 CFM
-
bull ~ 1~6~
~ v~
~
~--~~6
~~~ ___ v v V -_
~ o q
~ I 16
v
~
ogWNSTREANI STANCE
FIGURE 8 EFFECT OF ORIFICE SIZE ON POSITION AND VALUE OF MAXIMUM HEAT TRANSFER
35
50
loshy____ -~
~ ~ -shylltl-shy~ r0
2 10 30
FIGURE 9 CORRELATION OF THE POINT OF MAXIMUM HEAT TRANSFER WITH
ORIFICE SIZE
36
Correlation of Data at the Baffle
The heat transfer data were correlated by obtaining a
relationship between the group (Nu)(Pr)-13 and a
Reynolds number based on twice the clearance (d2 - d1
between the tube and the baffle It was found that the
most satisfactory correlation could be obtained when the
term - d1 was used as the length term in the Reynoldsd2
number
Figure 10 shows the variation of the heat transfer
rate at the center of the orifice e xpressed as a function
of Reynolds number and the orifice size This shows that
for a given Reynolds number the heat transfer at the center
of the orifice is greatest for the smallest orifice size
In order to obtain a general correlation of the data
shown i n F1gure 10 the effect of the dimensionless ratio
d1de was considered This ratio considers all of the
geometric factor s needed to describe the annular orifice
The thiclaless of the orifice plate is also a factor but
was constant i n this i nvestigation
The data for the heat transfer at the baffle center
are shown in Figure 11 in which (Nu)( Pr)-13 is plotted
versus (Re)ebd1 de) 0 55 This data on a log-log plot
lies on a straight line for (Re)eb( dld8 )0 55 greater
than 3 x 104 The equation for cor relating the heat
37
4XI~middot~-r~------~--~~------~
Icf t--to_+--_c-c-________ SYMBOL SIZE
0 1~4
6 ~~
9 ~~ -o ~
(Re)eb
FIGURE 10 RATE OF HEAT TRANSFER AT BAFFLE CENTER
38
500
0
4 0 lcf
~ ~
~ ~iC-
~ ~
~IL 0~ 0 SYMBOL SIZE-
p 0 1364-
r 6 1~16 -~ -
9 1~16 --o 1~16
I I
FIGURE II CORRELATION OF HEAT TRANSFER DATA AT BAFFLE CENTER
39
transfer at the center bullOf the a nnular orifice was found by
the method of least s quares to be
(Nu)( Pr)-1 3 = 0018 ( Re)ebO Bl( dlde)04~ (23)
3 x 104 ltRe)eb(a1de)055 lt 105)
Rate of Heat Transfer at the Point of Maximum Heat Transfer-The heat transfer rate at the point of maximum heat
transfer is plotted in Figure 12 to show the variation with
Reynolds number and the size of the orifice It is shown
gives the h1gh st heat transfer ~ate at its point of maxibull
that for a given Reynolds number the smallest orifice size yen il
mum heat transfer
The data ~or the maximum poi~t could be correlated by
plotting (Nu) Pr)-13 versus (Re)eb(d1de)06 This plot
is shown 1n Figure 13 and the resulting eurve shows that
(Nu(Pr)-13 is not a simple p0wer function of the Reynolds
number as was the case for heat transfer at the baffle
center The reason for this is probably because other
factors such as intensity and scala of turbulence should
be considered At the orifice center the streamlines of
the flowing stream are converging_ and thus the flow is
quite stable Downstream from the orifice is a region of
large eddy currents and probably large scale turbulence
These factors could con ceivably cause the results which
were obtained for the point of maximum heat transfer
40
If)
~middotshy Q_-I z_
10~~~--------r----~~--~--
SYMBOL SIZE
0 13$4
6 1~8
Q 13-18
-o 1~8
7)(104
(Re)eb
FIGURE 12 RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
41
Ia ~
0 I
c ~ ~ c v
~ ~lt w ~
17
~ b
v ~ ( SYMBOL SIZE
-~ 0 f-64 -v ~ 6 t211e
~ Q I~~~
-o - l~rs I I
FIGURE 13 CORRELATION OF HEAT TRANSFER DATA AT THE POINT OF MAXIMUM HEAT TRANSFER
4 2
Effect of Upstream Baffles on Heat Transfer at the Orifice Center
The heat transfer rate at the orifice center using the
single orifice in a test section is a pproximately 13 of the
value that was obtained by Lee (7) using a model heat exshy
changer with orifice baffles Lee investigated the cent r al
baffles of the heat exchanger and thus the coeff icients he
obtained would be affected by the presence of a number of
upstream baffles To determine the effect of upstream
baffles an additional l 516 inch baffle was placed four
inches upstream 1n the test section The resulting data are
shown in Figure 14 where (Nu)(Prmiddot)-13 is plotted versus
(Re) eb for the case of a single baffle 1n the test section
and also the case of an additional baffle placed four inches
upstream Comparison is made with the results obtained by
Lee middot(7) using a four-baffle and a ten-baffle model heat exshy
changer Good a greement is obtained with Lees work and the
results show the marked effect that upstream baffles have on
the downstream heat transfer rate The additional up tream
ba ffle caused sufficient turbulence 1n the test section to
i n crease the heat transfer rate nearly three-fold at the
center of the next baffle
Heat Transfer i n the Test Section with No Orifice
In order to check the accuracy 6f the equipment the
orifice baffle was removed and the heat transfer mea sured
with the probe in the empty test section The data were
43
~~BAFFLES
0 l BAFFLE -shy
ll_9 2 BAFFLES
V 4 BAFFLES-LEE
4 10 BAFFLES- LEE lJf ~
~rv ~~ ~ v flvv ~~
I ~ J ~ L v
0
v
( V
40 3XIo 7XIa
(Re)eb
FIGURE 14 EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER AT BAFFLE CENTER
44
compared with heat transfe r coefficients predicted by the
equations for annuli which are recommended in the litera shy9
ture The two equa~ ions u sed tor comparison were
(hfe)=0 023 (rltGr e (~~ur4 (~r45 (24)
which was presente~ by Wiegant (10)
and ( h ) (cnM~5(M~l o14 o 023 CPG k j Mij - (de GJMb )0 2 ( 2 5)
which was presented by McAdams (8 p 242) The comparshy
i son is s hown in Figure 15 lq (25) gives a value which
is low by about ten percent while Eq (24) g ives values
which are high by as much as twenty -five percent when comshy
pared with the experimental data The se equations are gembull
erally considered to give coefficients with an accuracy of
about twenty percent Therefore the present experimental
data are within the accuracy of these equations Also the
plot indicate s that for a Reynold s number greater than 2 x
104 the slope of the line is the same for the experimental
data as for the equations
Pressure Drop Data
The total pressure drop across the orifice was measured
as a function of the flow rate and the orifice size The
pressure drop was expressed as a d1mens1onleas quantity r)
which ie plCltted ver sus the Reynolds number in Figure 18
The pressure drop function cent correlates for all or1f1oe
45
200
100
s z
10 5XI10 10
0 EXPERIMENTAL
--McADAMS
-WIEGAND L
V
~ ~ ~
P ~ ~
LL~ L
v~
~
v v
v 1 ~ ~ v
v -gt
~
~ ~
~
6Xid
FIGURE 15 HEAT TRANSFER WITH NO BAFFLE
46
0 1~4 -~ a 6 t216
Q t316 lJ J
-0 as a )t
A LEE I -shy SULLIVAN 8
p
10bull
BERGELIN
I _ll I
I ~
i I
~middot
lo II
f fl
J j
~middot
A)101
1q
I Ill
1 I3 X 10ao1
FIGURE 16 ORIFICE PRESSURE DROP FUNCTION VS REYNOLDS NUMBER
47
sizes- The present data extends the range covered by preshy
vious workers and agrees well with their work The preshy
vious work of Lee () for a heat exchanger containing 10
orifice baffles and also the data of Su livan and Bergelin
(9) for pressure drop in a model heat exchanger with a
single baffle is shown 1n Figure 16 long with the present
results~ This figure may be used to predict the preseure
drop from the equivalent Reynolds number of the annular
orifice
The pressure drop between individual points 1n the
vicinity of the orifice and an upstream pressure tap wa s
measured to obtain a pressure drop profile As might be
expected 1n all cases the profiles showed a rapid decrea e
in static pressure immediately upstream from the orifice
There was however little or no recovery of the pressure
loss downstream The 1 364 inch orifice did show a maxishy
mum point in the pressure drop but this maximum occurred at
the orifice center and total recovery was reached about 12
inch downstream
Heat Transfer at the Baffle and Maximum Point as a Function of Pressure Drop
In order to compare the effect of the total pressure
drop on the heat transfer at the baffle and the point of
maximum heat transfer Figure 17 was plotted showing
(Nu)(Pr)-13 as a function of the total pressure drop This
shows that for a given pressure drop the largest orifice
48
1200
1000
~ a -sshyz-
100
60 100 700
AT MAXIMUM POINT I 15116 2 13116 3 1~6 4 1364
AT ORIFICE CENTER
60
1
v
r ~ ~ ~
5
~
8 7
13116
8
~
1364
v
~
e6
1~6
v
~~ v ~ ~ -~ ~
~
~ v
l
~
vamp
I ~ ~
~
v L ~
v
I-
5
k= ~~
~ ~ ~
--I
v ~
FIGURE 17 HEAT TRANSFER AT THE BAFFLE AND MAXIMUM POINT AS A FUNCTION OF
ORIFICE PRESSURE DROP
49
size has the greatest heat transfer coefficient This is
true at both the orifice center and at the point of maxishy
mum heat transfer
Another comparison can be made by plotting the heat
transfer coefficient and the pressure drop versus the orishy
fice size at a constant flow rate Figure 18 shows this
plot This graph shows that at a constant flow rate the
pressure drop as well as the heat transfer coefficient
increases as the size of the orifice is decreased In
choosing an orifice size for maximum efficiency 1t would
be necessary to know the pumping power available as well
as the heat transfer desired
70 I I 700
AT 15 CFM 60 ---
~ aug
50 ---
NV
40 ~
~ ~ ~
~ _
MAXIMUM POINT ---- --- ~
1-----t---~ _
~00Qj ~
~t--- ORIFICE CENTER 10 1100
1---~ n
u0 01 02 03 Q35
a ltl
de inches
FIGURE 18 VARIATION OF HEAT TRANSFER RATE AND PRESSURE DROP WITH ORIFICE SIZE AT A CONSTANT FLOW RATE
cn 0
51
CHAPTER VI II
SUMMARY OF RESULTS
This study revealed several significant facts about
the heat transfer in the vicinity of annular orifices
Probably the most important contribution was the presshy
entation of the heat transfer profiles in the vicinity ot
the annular orifice ~ r s shown that t~ local heat
transfer coeffieient re~ches a maximum at a point downshy
stream from the orifice The distance downstream at which
this maximum oocurs is t1ven by the equation
22
The heat transfer coefficients at the center of the
orifice were correlated and found to follow the equation
(Nu)(Pr)-13 = 00176 (Re)eb08l(d 1de) 0 middot4~ (23)
3 x 104 lt( Re) 9 b( d1d6 )055 ltlo5 )
The heat transfer at the point of maximum heat trans
fer for each orifice size was correlated and presented in
Figure 13 as a plot of (Nu)(Pr)-l3 versus (Re)eb(d1de) 06
No simple po-orer relationship exists between the terms
Intensity and scale of turbulence downstream from the orishy
fice are probably important factors which affect the heat
transfer
The large effect of an upstream orifice on the heat
transfer rate at the second orifice was demonstrated by the
52
study of two 1 516 inch orifices in the test section The
added turbulence at the center of the second orifice was
found to raise the heat transfer rate almost three times
over that obtained for a single baffle
The pressure profiles in the vicinity of the orifice
indicate that nearly all the pressure drop occurs at the
orifice center~ Total pressure drop data were correlated
by a pressure drop function cent as a function of the Reynolds
number and good agreement obtained with the results of other
workers
The pressure drop and heat transfer data were correbull
lated by plotting the heat transfer as a function of the
pressure drop for each orifice size It was shown that for
a given pressure drop the largest orifice size gives the
greatest heat transfer coefficient
As a final presentation it was shown that the pressure
drop and the heat transfer coefficient both i ncrease i n
value at a constant flow rate as the orifice size is de shy
creased This is important in choosing the optimum clearshy
ance for orifice baffles
53
CHAPTER IX
RECOMMENDATIONS
A great deal of work remains to be done in the field of
evaluating shellmiddotside heat transfer coefficients This
study included only one tube size and air was the only f luid
used It is recommended that further studies be conducted
using other fluids and tube sizes It will also be necessary
to study several baffle types
The adde d turbulence due to a s e cond baffle placed upbull
s t ream would suggest that the heat transfer coef ficients at
a certain position i n relation to a baffle would increase as
the flow progressed through the exchanger It is recomshy
mended that an extensive s t udy should be made between baffles
the full length of a model heat exchanger
It is further recommended that the pressure drop study
be continued to include other fluids tube sizes and baffle
arrangements
Effects of turbulence downstream from the baff le should
be studied by i n vestigations with hot-wire anemometer equipshy
ment to determi ne t urbulence scale and i ntensity
54
NOMENCLATURE
Area of heat transfer
Heat capacity of the fluid
Outside diameter of the tube
Orifice diameter
Equivalent diameter of the orifice (d2 - dl)
Inside diameter of the test section
Inside diameter of the tube
Gravitational constant
G Mass velocity
h Local heat transfer coefficient
Coefficient of heat transfer from surface to fluid
i Direct current amperes
k Thermal conductivity of the fluid
L Distance downstream of the point of maximum heat transfer
p Absolute pressure
L P Total pressure drop across the orifice
Q Flow in cubio feet per minute at 1 atmosphere and 680 F
q Heat transferred
Thermal energy conducted into the sensing probe
Thermal energy radiated from the resistance ribbon
Resistivity of the resistance ribbon
s Length of the resistance ribbon
T Temperature oR
55
t Temperature of the resistance ribbon deg F
ta Temperature of the bulk stream oF
tw Wall temperature of the tube OF
U Veloc ity of the fluid
w Width of the resistance ribbon
z Thickness of the resistance ribbon
eeuro Density of the fluid in the test section
Density of the fluid at the flow orificef 0
AL Viscosity of the fluid
E9 Angle measured around the tube
Dimensionl ess groups
(Nu) Nusselt number hd1k
(Pr Prandtl number C~k
(Re)eb Equivalent Reynolds number at the baffle (d2 - d1 )uejt-Lshy
(Re)e Equivalent Reynolds number in the test section ( d 8 - d 1 )U fu
cent Orifice pressure drop function 2(~P ) gc~av(d2 - d1) 2
Al
56
BI BLIOGRAPHY
1 Ambrose Tommy W Local shell-side heat transfer coefshyficients in baffled tubular heat exchanger PhD thesis Corvallis Oregon State College 1957 183 numb leaves
2 Bell K J and o P Bergelin Flow through annular orif ices Transactions of the American Society of Mechanical Engineers 70593-601 1957
3 Colburn Allan P A method of correlating forced con shyvection heat transfer data and a comparison with fluid friction Transactions of the American Institute of Chemical Engineers 24 174-210 1933
4 Dittus F w and L M K Boelter Heat transfer 1n automobile radiators of the tubular type University of California Publications in Engineering 2443-461 1930
5 Gurushankariah M s Local shell-side heat transfer coefficients in the vicinity of baffles in tubular heat exchangers Masters thesis Corvallis Ore gon State Colle ge 1958 97 numb leaves
6 Knudsen James G and Donald L Katz Fluid dynamics and heat transfer New York McGraw-Hill 1958 576 p
7 Lee Kyu Sung Local shell-side heat transfer coeffishycients and pressure drop in a tubular heat exchanger with orifice baffles Masters thesis Corvallis Oregon State College 1959 118 numb leaves
8 McAdams William H Heat transmission 3d ed New York McGra ~-Hill 1954 532 p
9 Sullivan F W and 0 P Bergelin Heat transfer and fluid friction in a shell-andbulltube exchanger with a single baffle Chemica l Engineer ing Progress Symposium Series 52 ( 18) 85-94 1956
10 Wiegand J H Discussion on annular heat transfer coshyef f icients for turbulent flow Transactions of American Institut e of Chemical Eng i n eers 41147-153 1945
AP PENDIX
57
TABLE III
CALCULATED HEAT TRANSFER DATA
Baffle Hole Diameter Run No (inches)
1 - 59 1 364
60 - 102 1 216
103 - 138 1 316
139 - 206 1 516
207 - 212 No orifice
213 - 218 2nd - 1 516
TABLE III
CALCULATED HEAT TRANSFER DATA
Local Heat Transfer Coefficients Run
T0 bull Po s ition CFM hr h2 h3 h4 hs he ~ hav Nuav
1 c 1026 10 59 1476 16 09 1559 1510 1435 1203 1518 8511 2 1290 1369 1738 1878 18 05 1755 1689 1515 1773 9964 3 1416 1636 198 1 2068 1977 1924 1845 1715 1959 11030 4 1627 1991 2301 2382 2268 2194 20 ~98 1929 2249 12664 5 1776 2252 2669 2863 2713 2517 2338 2126 2620 14759 6 l2ttD 1109 2311 3317 3386 3373 3387 3394 3071 3371 18888 7 1258 3089 4583 4866 4683 4701 4643 4194 4695 26301 8 1433 38 8 5 55 83 5791 5495 5430 5436 5008 5547 31192 9 1681 4992 7378 7649 6980 6864 6870 64 28 7148 40180
10 1 D 1102 2371 3332 3511 3356 3342 3427 3102 3394 19012 11 1308 3218 4379 45 24 42 53 4255 4373 3965 43 57 24446 12 14 64 38 58 5146 5142 4839 4787 4903 4597 4963 278 79 13 1706 5218 6664 6269 58 81 5884 6237 5973 61 87 34718 14 15
1 l2D 1115 1275
2131 2661
2955 3638
2972 3720
2941 3675
2913 3576
28 22 34 74
2613 3278
2921 36 17
163 09 20246
16 1498 34 87 4644 4503 4441 4371 4343 4194 4460 25010 17 1695 4449 5743 5324 5222 5154 5157 5015 5320 298 97 18 2D 1049 1715 23 90 2550 2610 2656 2624 2208 2566 14363 19 1241 2117 2964 3145 3218 3221 3203 2759 3150 17757 20 1532 28 67 3936 4100 4188 4201 4167 3676 4118 23224 21 1674 3459 4508 4598 4746 4795 4792 4299 4688 26337 22 lU 1074 253 340 380 3 86 388 377 354 374 2097 23 1287 292 392 433 440 441 429 406 427 2394 24 1508 322 439 492 498 499 487 461 48 3 2713 25 18 07 3 38 464 519 5 24 520 499 463 5 05 28 40
~~ (]I agt
TABLE III Continued
Run No Position CFM h 1 h2 ~3 h4 h5 h6 ~ h
av Nu
av 26 c 1029 1171 1491 1589 15 28 1 4 62 1377 1293 1489 83 44 27 1266 1395 1746 1853 18 02 1685 1556 1453 1728 9704 28 1430 1637 2037 2175 2060 1909 1735 1591 1983 11159 29 1729 1982 24 96 2751 2507 2268 2030 1886 2410 13579 30 12D 1054 2934 4041 4321 4326 4423 4359 3706 4298 24160 31 1294 3385 4 8 26 52 42 5326 5450 5277 4566 52 24 293 50 32 1431 3784 5347 5721 57 bull75 58 44 5700 5084 5677 31870 33 1770 52 75 7 7 33 87 35 9005 9007 8267 7059 85 49 48050 34 lD 1058 3235 4401 4444 3877 3496 3451 3294 3934 21973 35 1263 38 98 5484 5330 4347 3964 3981 3987 4621 25823 36 18 36 6701 89 17 7855 6369 5597 5769 6283 69 01 38718 37 1 12D 1029 2404 31 8 2 3333 3459 3624 3577 3045 3435 19264 38 1315 3182 4033 4162 4310 4496 4502 4015 4301 24142 39 1426 3628 4389 4510 4573 4760 4804 43 8 5 4607 25678 40 1757 4547 5559 5(35 5931 6282 63 70 6060 5975 33471 41 2 11D 1080 2034 28 38 3155 3144 3145 2966 2540 3050 17027 42 1305 2650 3 4 87 3aoz 3595 3751 3595 3153 36 46 20405 43 1434 3167 39 07 4156 4371 4320 4126 3709 4176 23395 44 1804 4096 4 9 66 5691 5714 5586 53 15 48 65 5454 30582 45 12U 1088 409 516 557 564 5 60 535 513 5 46 30 67 46 1318 470 579 6 22 631 6 17 5 97 579 6 09 3422 47 14 13 540 640 676 6 86 681 6 60 6 54 6 69 3754 48 1773 641 740 774 782 7 69 749 746 763 42 87 49 l 11 U 1054 270 356 391 397 393 3 71 346 38 2 2133 50 1240 303 399 446 449 447 4 21 398 432 2420 51 1419 361 476 522 530 528 507 467 493 2760 52 1 1(2U 1032 236 311 342 347 344 325 301 334 18 78 53 1314 270 366 403 407 408 386 351 394 2217
(Tt tO
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ h av Nu av
54 1448 301 408 447 454 452 431 403 438 24 61 55 1782 353 494 548 544 415 529 531 506 2843 56 2U 10 61 220 287 316 320 322 303 268 310 1735 57 1216 249 335 370 377 378 353 307 363 2044 58 1322 263 356 394 398 399 374 327 384 2159 59 1639 310 433 478 481 482 452 393 465 2617
60 1D 10 68 2011 2536 2657 2681 2694 2560 15 62 2625 14938 61 1399 2520 3239 3369 3371 33r82 32 39 1946 3320 18968 62 1669 2781 3655 3820 38 76 3883 3738 2355 3794 21712 63 1959 3524 42 37 4399 4438 4497 4417 3047 4397 25156 64 2295 4426 5288 5396 5372 5240 5410 3369 5341 30680 65 2636 5490 6531 6662 6565 6379 6820 4249 6591 37938 66 3390 7869 9538 9462 9387 8924 10508 62 91 9564 59601 67 1U 1190 352 368 401 413 407 395 293 397 2256 68 1559 397 422 462 475 471 456 331 4 57 2603 69 1904 434 465 5 13 529 528 504 358 508 2901 70 2211 493 526 573 5 92 588 564 4 15 569 3257 71 2289 569 587 6 30 649 6 61 6 49 460 635 36 44 72 2727 637 6 60 7 09 733 751 743 521 719 4140 73 3210 728 755 8 15 8 43 8 62 8 54 616 826 4765 74 2nD 1210 181 2256 2393 2399 2333 2206 1325 2317 13158 75 1420 2340 2752 2899 2913 2850 2728 1701 2828 16121 76 1692 2853 3306 3452 3471 3379 3217 2134 3365 19217 77 1894 3102 3588 3713 3736 3670 3557 2455 3653 20892 78 2301 3682 4259 4433 4467 43 83 4289 2892 4366 250 30 79 2621 4117 4828 5017 5012 5030 5109 3071 4999 28785
m 0
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ hav Nuav
80 3230 5158 6006 62 13 61 18 6134 6695 4094 6233 359 87 8 1 12nD 1155 15 27 1854 2028 2064 20 85 1987 1164 1968 118 31 82 1689 2046 24 8 2 2688 2739 2760 2658 1749 2665 152 73 83 1244 2088 2317 2339 2345 2373 2381 1487 2351 13432 84 2100 3211 3539 34 21 3462 3512 3696 2575 3526 20284 85 2292 3 5 05 3761 3648 36 25 36 79 3957 2933 3734 21517 86 2907 4420 48 22 4679 46 04 4705 5206 3792 48 03 27741 87 33 80 59 35 69 38 7404 77 10 7 8 36 7 0 86 5190 7394 427 44 88 1 12D 1 4 27 2 4 58 28 31 3037 3021 2987 2927 18 57 2 9 61 16913 89 18 75 34 75 3 9 87 4230 4255 4317 4337 2734 4225 24258 90 22 59 4221 4796 5046 5052 51 01 5389 3491 5077 29206 91 2682 4978 5664 5943 5966 6054 6573 408 1 60 40 34795 92 3417 63 16 71 02 7 3 93 7385 75 40 8 6 95 51 45 7623 44017 93 c 1 5 17 1240 1305 1399 1467 1479 1429 9 26 1423 8251 94 20 34 1554 1623 1720 18 21 18 53 18 72 1215 1778 10229 95 2 3 48 1795 1843 198 5 2097 2171 2274 1540 2074 11947 96 2716 2028 2048 22 01 2 3 44 2444 2661 18 90 2340 13505 97 3247 2410 2375 2663 2778 2949 3298 2378 2793 1615 98 11 35 967 1040 1124 1186 1200 1142 728 1138 6496 99 14 06 1135 1220 1318 1384 1403 1 3 61 8 77 1336 7656
100 2311 1 8 54 18 78 1980 20 90 2136 2227 1653 2062 118 31 10 1 2666 2085 2094 2227 2 3 62 2438 2626 1902 2349 13508 102 3392 2635 2582 28 01 3026 3141 3529 2567 3016 17390
103 1 U 1235 349 395 434 436 4 28 411 286 423 2416 104 20 10 434 5 02 559 577 569 5 37 345 552 3177 105 28 14 538 626 685 711 7 21 682 424 6 8 6 3966
Q) j-J
TABIE III Continued
Run No Position CFM h1 h2 h3 h4 h5 hu h7 hav Nuav
106 3492 614 7 1 6 7 84 8 13 8 33 7 85 4 88 7 87 4562 107 4395 7 86 894 964 996 1005 9 64 640 9 65 56 06 108 50 75 9 11 10 22 1081 1112 1125 1085 7 24 1085 63 16 109 G 1344 9 22 1042 1120 1 1 46 1173 1131 7 04 1120 63 87 110 1936 1162 1340 1442 1474 1509 14 7 3 9 09 1441 82 77 111 2846 1631 1797 1902 1966 2027 2079 1342 19 2 3 11108 112 3484 207e 2144 2236 2307 2385 2574 1694 2268 13138 113 4066 24 65 24 42 2535 2648 2757 31 71 2178 2 5 96 15078 114 50 12 3059 2916 30 1 5 3176 3312 4059 2849 3105 180 46 115 1D 1362 2268 26 13 2613 26 35 2605 2503 15 46 2617 14934 116 1958 2993 3580 3580 3586 3539 3 5 02 2144 3571 20492 117 2812 4430 50 32 4913 4 9 86 4991 5196 3088 4981 287 66 118 3432 58 16 62 13 6067 61 18 60 66 6698 4143 61 16 354 16 119 40 22 71 71 7 4 62 7369 7419 7329 82 74 51 8 1 7395 42909 120 5026 105 95 11456 115 81 11574 11548 14010 80 91 11540 671 15 121 2D 1244 18 57 2277 2363 2305 2210 2107 1466 2289 13038 122 1960 2622 3240 3388 33 23 3226 31 40 2)99 3294 18919 123 2817 3762 45 87 4739 46 56 45 14 4 6 47 30 15 4624 26689 124 3491 50 22 5723 58 53 57 44 5542 60 18 3871 57 16 330 73 125 4096 61 29 68 16 69 79 6805 65 90 74 79 4677 67 98 39400 126 5037 82 27 94 60 95 69 93 57 9023 11324 65 05 93 52 542 83 127 12D 1278 14 70 1 6 48 1652 1638 1 6 34 1641 9 73 1 6 43 9369 128 1947 19 63 2155 2149 2151 2131 2190 1347 2147 12342 129 2769 2615 2791 2773 28 52 2716 2954 18 96 2783 1 60 82 130 3439 3208 3265 3239 3593 3133 3624 2515 3308 19174 131 4103 3637 35 88 3577 4077 3459 42 66 3138 3676 21343 132 49 78 45 82 44 60 44 8 1 55 17 43 25 5749 4227 4700 27288
Q) tlgt
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
133 1 12D 1299 2094 2507 2622 2625 2567 2489 1465 2578 14736 134 1973 29 56 3505 3772 3790 3718 3718 2115 3700 21290 135 2788 3941 4727 5069 5099 5 0 07 5231 2984 4976 28781 136 3473 5155 59 81 6308 6339 62 39 68 96 4204 6217 36052 137 4118 6135 71 8 6 7662 7731 76 91 87 16 49 8 5 7568 43985 138 4973 7765 94 75 10396 10861 10694 13646 66 64 10357 602 25
139 1ttn 1253 1242 1493 1460 1442 1431 1424 8 84 1457 83 01 140 2366 1942 2150 1961 1910 1897 19 62 1206 1980 11400 141 3461 3007 2957 2562 2513 2606 3143 18 51 2660 15400 142 4325 3942 3571 3060 2999 3198 4248 2631 3207 18618 143 5677 508 6 4359 39 88 3800 42 29 57 78 36 26 4094 23824 144 67 59 64 55 5330 4988 47 25 5494 2517 48 09 5134 29906 145 84 08 9326 72 26 7726 85 56 9172 12319 7733 8170 47626 146 86 54 9831 7582 818 9 94 90 9869 13116 78 97 8783 512 96 147 7376 7335 58 7 6 5941 5796 68 29 81 65 5954 6111 35662 148 2 11 D 4254 4106 48 02 4994 5038 5042 56 78 3419 4969 28881 149 5708 5487 6253 6466 6524 6527 78 63 45 8 2 64 43 37566 150 69 7 8 7983 9440 9848 98 34 97 32 13249 6701 9714 566 59 151 1254 1434 18 53 1947 1915 1850 1760 1186 1891 10772 152 2713 2696 3175 32 94 3288 3237 3288 20 44 3249 18728 153 87 30 118 07 14733 15758 15504 15305 26297 9617 15325 892 71 154 5811 5278 6543 6861 69 30 69 82 7 8 74 4478 68 29 39531 155 4246 3780 4736 4975 49 66 4936 5162 3113 4903 28301 156 (v 1270 8 15 935 959 966 9 51 9 23 6 35 953 5430 157 2714 1164 1390 1427 1447 1454 1455 9 08 1430 8242 158 4310 1655 18 96 1942 1988 2002 2111 1305 1957 11349
(j) ~
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 fry hav Nuav
159 6012 2208 2400 2450 2513 2548 28 20 18 00 2478 14416 160 7279 2696 2881 2927 2989 3081 3599 2340 2970 17326 161 86 90 3257 3360 3 3 76 34 26 3558 4455 2943 3430 2000 162 12D 4368 2209 2600 2558 2518 2466 2774 1753 2536 14713 163 5833 2730 3092 3028 2974 2913 3501 2287 3002 174 78 164 7643 3320 3681 3630 3651 3530 4623 3181 3623 21116 165 87 39 3920 4303 4300 4708 4178 61 60 3937 4372 25456 166 1268 962 1203 1205 1186 1118 1084 725 1178 6693 167 2678 14 67 1785 1779 1752 1698 1726 10 70 1754 88 49 168 1 12D 12 83 936 1217 1414 1397 1239 1190 7 65 1317 7484 169 2729 2502 2930 2914 2934 2956 2979 17 52 2934 16866 170 4345 3884 4357 4283 4318 4421 4836 28 59 4345 25151 171 6036 5546 5858 5764 5791 6028 7129 4184 5860 34045 172 6578 7167 7769 7907 79 82 8263 10492 5915 7980 46437 173 87 84 10237 112 23 120 26 12727 12968 185 19 85 98 12236 71103 174 1278 1344 1803 18 72 1835 1790 1712 1063 1825 10355 175 2711 2328 2972 2932 2893 28 78 2863 1667 2919 167 51 176 4351 3934 4414 4353 4281 4321 4654 28 63 4342 25088 177 5994 5076 5824 5838 5818 59 29 6914 4205 5852 33885 178 1 11 U 1223 388 432 465 464 449 435 338 453 2585 179 2351 521 602 6 22 675 6 57 619 436 639 3687 180 34 48 6 05 1725 803 8 27 8 11 760 518 792 4593 181 4513 718 850 934 9 68 9 57 8 99 609 9 27 5386 18 2 5714 8 32 981 1060 1102 11 06 1034 6 59 1062 61 82 183 6997 1025 1182 1258 1295 1309 1234 8 18 1261 7 3 44 184 8709 1295 1487 1 5 42 1594 1626 1612 1156 1562 9080
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
185 2 12D 4249 3560 4400 4670 4791 4695 47 81 2931 4639 268 37 186 5737 4926 58 54 61 92 6248 62 38 67 78 4134 6131 35590 187 7432 6390 7726 83 46 85 44 86 34 10371 5658 8313 48310 188 8723 7718 107 88 11933 12099 13046 186 22 79 39 119 67 69505 189 1 4 35 1340 1735 18 57 18 52 17 81 1711 1144 18 06 10256 190 2718 2399 3023 3187 3207 3138 30 53 1931 3139 18025 191 7 5 07 6189 80 11 9200 9427 9703 11364 5720 9085 527 38 192 8544 78 42 10666 125 42 13312 13775 178 20 6976 125 74 729 86 193 1287 1417 16 97 18 7 18 69 18 08 1720 1046 1800 10223 194 27 17 2450 2940 3187 3214 3157 3054 1749 3125 17954 195 42 53 3560 4222 45 90 4679 46 63 4743 2741 4539 26247 196 6068 48 69 57 79 6335 65 8 6 66 04 7172 4338 63 26 366 78 197 7389 58 86 72 8 6 82 23 8584 8936 10658 50 60 8257 4798 6 198 86 88 78 91 100 27 120 56 130 29 14299 190 81 6492 12353 71850 199 5864 4694 5 6 67 61 94 6419 65 48 7192 3950 6207 360 14 200 2 D 4177 38 36 4547 48 09 4775 4628 5006 2715 46 90 261 30 201 5712 5170 62 39 66 38 6599 6604 7518 4167 65 20 378 00 202 73 63 7201 8986 98 43 9733 9914 13353 6219 9619 55810 203 8604 10043 13118 148 41 150 42 158 66 25206 82 5 3 14717 85290 204 12 68 1506 18 41 1971 1966 1868 1799 11 42 1913 10880 205 2659 2571 3127 3276 32 50 3130 3069 18 80 3196 18 350 206 39 80 36 76 4347 4573 45~67 4473 46 34 28 37 4490 25910
o 207 Orifice 11496 10 64 1360 15 39 1 5 80 1 6 15 1496 8 58 15 24 88 83 208 9433 8 95 11 78 13 26 1394 1386 1263 727 1346 78 48 209 7387 746 9 77 1123 1184 1159 1048 6 11 1111 64 74 210 52 36 566 7 66 900 934 909 8 21 499 8 27 48 02
0) CJ1
TABLE III Continued
Run No Position CFM h 1 h2 hs h4 h5 h6 h7 hav Nuav
211 212
3309 1293
414 257
563 3 19
6 68 3 57
6 91 3 37
6 72 351
7 37 337
38 4 2 46
4 40 341
3748 1942
213 214 215 216 217 218
c of 2nd 1 516 1235
1919 2712 3320 4153 4704
1532 2447 35 46 4312 5567 74 29
2 1 87 3312 4225 52 86 6902 8 6 50
2360 3555 4340 56 12 7 0 49 8 9 40
2409 3598 4 8 85 5718 7713 9593
2347 2101 35 33 3453 48 00 49 62 5562 59 86 72~6 7 8 79 93 76 11237
1243 20 64 3054 4 2 8 1 5114 6983
2326 35 00 4638 5545 7225 91 40
132 13 200 27 26672 31968 41711 52811
bull
67
TABLE IV
PRESSURE PROFILE DATA
Baffle Flow Qpening Rate ~p
(Inches) Position (CFM) (Inches 295 S G Fluid)
1 364 l2 11 U 1012 0 254 1248 0197 1493 0 141 1718 0112
c 1000 9 80 1210 1710 1436 28 75 1746 4320 1011 1080 1277 2050 1393 3020 1 6 28 4450
12D 1011 9 75 1236 1520 1450 2510 1603 3450
1 D 1011 975 1256 1700 1480 2690 158 1 4070
1 12D 1010 950 1259 1750 1462 2650 1631 3710
2 11 D 1124 1315 1360 2130 1505 2850 1689 4125
1 216 12U 1294 045 1949 0324 2374 0282 2704 0225 3367 0169
c 1326 265 18 81 5 90 2313 990 2731 1480 3439 2660
12D 1272 2 49 1957 661
68
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Pos ition (CPM) Inches 2 95 S G Fluid)
2559 1275 3033 1940 3639 3025
1 216 1nD 1257 242 16 96 476 2117 8 05 2561 1280 2990 1895 3431 26 bull00
1 316 12U 1309 0 479 2004 0422 28 28 0 352 3526 0281 42 28 0225 5199 0225
c 1308 1 43 1998 272 28 14 5 10 3478 795 4248 1235 5048 1885
l2D 1286 140 2005 3 45 2831 725 3495 1180 4194 1805 5046 2945
1 11D 1322 150 2039 352 2841 735 43 77 1980 5378 3440
1 516 12U 1278 0493 2732 0493 4315 0408 5744 0352 7494 0352 8932 0422
c 1300 0 506 2731 1985 4310 348 6080 6 45
69
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Position (CPM) (Inches 295 SG Fluid)
7607 1090 8830 1585
l2D 1343 0549 2738 225 4566 583 6112 1195 7536 2055 9043 3415
1 516 1uD 1249 0464 2713 224 4155 579 5620 1150 7428 2115 90 70 3405
1 12D 1301 0493 2735 220 4501 616 61 50 1235 7440 2065 8862 3445
2D 1265 0 478 2750 226 4366 594 6578 1270 7678 2240 8945 5280
2 12D 1295 0493 2725 222 4293 600 5807 1120 7568 2200 9070 3615
TABLE V
RATE OF HEAT TR AN SFER Ar THE BAFFL~~ CID-TT ER
Orifice Size
(Inches)
Flow Rate
( CFM)
Re d e G tU
R~) 055 Nuav NuPr-l3
1 364 10 26 12 90
8 075 10015
43400 54 600
85 11 99 64
95 83 112 19
1416 11 140 59 900 110 30 124 20 16 27 12 800 68 900 126 64 142 60 17 29 13 610 73 200 135 79 152 90 17 76 13980 75 200 147 59 166 19
1 216 11 35 14 06
8 600 10 660
27000 33500
6 4 96 76 56
73 14 8 6 12
1517 11500 36100 82 51 9291 20 34 15400 48400 10229 115 18 23 11 17500 55000 118 31 13322 2348 17 800 55900 11947 13452 2666 20 200 63400 13508 15210 27 16 20 600 64700 135 05 152 07 32 47 24600 77200 161 57 18 193 3392 25 700 80700 17390 195 8 1
1 316 1344 19 36
9898 14 260
24800 35 700
63 8 7 8 2 77
71 92 93 20
28 46 20 9 60 52 500 111 08 125 08 34 84 25 660 64200 131 38 147 93 40 66 50 12
29900 36900
74800 92400
150 78 18046
169 78 203 20
~ 0
TABLE V Continued
Orifice Flow Re Size Rate d e G R~rmiddot55 NuPr-13(Inches) (CFM) U Nuav
1 516 12 70 8 847 16800 54 ~0 61 14 2 14 18 900 35800 82 42 92 80 43 10 30 000 56900 11349 127 79 60 12 41900 79400 14416 16232 7279 50700 96100 17326 19509 86 90 60540 115000 20098 22529
TABLE VI
RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
Orifice Size
(Inches)
1 364
1 216
1 316
Flow Rate
(CFM)
1054 1294 1431 1681 1770
1068 1399 1669 1959 2295 2636 3390
1299 1973 2788 34 73 4118 4973
Re deG Mshy
8 300 9870
11260 13200 13 930
8100 10600 12650 14850 17400 19980 25700
9 570 14500 20500 25600 30300 36600
R~r-6 51900 61700 70500 82 500 87 100
28200 36900 44000 51700 60 600 69500 89400
26100 39600 56000 69900 82700 99 900
Nuav
2416 293 5 3187 4018 4805
14938 18968 21712 25156 30680 37938 59601
14736 21290 28781 36052 439 85 60225
Uu Pr-1 3
27204 33050 3589 4524 541 0
16820 21358 24448 28326 34546 427 18 67111
16593 23973 32407 40595 495 1 678 13
TABLE VI Continued
Orifice Flow Re Size Rate deG R~rmiddot6 NuPr-13(Inches) (CFM ) M- Nuav
1 516 1268 88 30 17700 108 8 1225 2689 18700 37400 1835 2066 3980 27700 55700 2591 2917 4177 29100 58 500 2713 3055 5712 39800 80000 378 0 425 6 7362 51300 103000 5581 6284 8 604 59 900 120000 8529 9604
74
TABLE VII
EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER
l 516 Inch Orifice
Center ot 2nd Baffle 4 Downstream
Plow Rate (CFM)
1235 1919 2712 3320 4153 4704
Flow Rate (CFM)
1270 2714 4310 6012 7279 8690
(Re)eb -8600 1321
13400 2003 18900 2687 23100 5197 28900 4171 32800 5281
Center ot Single Battle
-8847 543
18900 824 30000 1135 41900 1442 50700 1733 60540 2001
(Nu)(Pr)-l3
1487 2255 3003 3600 4697 5946
(Nu)(Pr)-13
611 928
1278 1623 1951 2253
75
ABLE VIII
HEAT TRANSFER IN THE TEST SECTION WITHOUT ORIFICE
CFM Ute) 0b h Nu
1293 5-951 3 41 1942
33 09 15251 649 3746
5236 24193 827 4802
7387 34001 1111 6474
9433 43419 1346 7848
11496 52-914 1524 8883
76
TABLE IX
PRESSURE DROP FUNCTION
Orltlee Size Flow Rate incbea ~CFM (Re)eb X 10bull8
1 364 1011 7957 0808 1256 9885 1468 1480 11648 2765 1581 12443 4160 1689 1_3293 4 020
1 216 1257 9530 1327 1696 12858 2663 2117 16049 4615 2561 19415 7581 2990 22668 11560 3431 26011 16440
l 316 1322 9736 1819 2039 15016 4332 2845 20952 9275 3495 25739 15300 4377 32014 26800 5378 39607 50100
1 516 1011 7 957 oaos 1256 9885 1469 1480 11646 2765 1581 12443 4160 1689 13293 4020
77
TABLE X
EXPERIMENTAL DATA
Baffle Hole Diameter Run No
1 - 59
60 - 102
103 - 138
139 - 206
207 - 212
213 - 218
(Inches)
1 364
1 216
1 316
1 516
No Baffle
2nd - 1 516
TABLE X
EXPERIMENTAL DATA
Run Thermocouple Reading s (mv) No Position CFM I tc1 tc2 tc3 tc4 t c 5 tc6 tc7 tcair
1 c 1026 530 2055 1825 1768 1782 1802 1837 1965 1198 2 1290 612 2059 18 65 1809 18 32 1851 1880 1965 1160 3 1416 714 2151 1970 1931 1965 1988 2026 209 5 1130 4 1627 8 21 2235 2084 2 049 2093 2126 2173 2266 1130 5 1776 865 2203 2033 1970 2015 2084 2159 2 264 1121 6 12D 1109 542 1636 1507 1499 1499 1498 1498 1528 1218 7 1258 651 1670 1522 1503 1513 1513 1516 1548 1221 8 1433 750 1625 1480 1467 148 3 1487 1487 1516 1153 9 168 1 8 73 1656 1494 148 1 1511 1517 1517 1543 1159
10 1rtD 1102 485 1545 1450 1437 1446 1447 1442 1466 1220 11 13 08 6 10 1571 1470 1460 1476 1476 1469 1498 1194 12 1464 730 1 623 1509 1508 1528 1 5 32 1524 1548 1173 13 11 06 8 71 1663 1559 158 1 1606 160 6 1 583 1601 1190 14 1 12D 1115 520 1698 1579 1575 1 577 1580 1590 1615 1280 15 1275 6 10 1692 1567 1558 1 561 1570 1580 1601 1234 16 1498 770 1760 1619 1630 1 635 1642 1645 1661 1204 17 1695 912 1775 1635 1670 1689 1686 168 6 1701 1165 18 2D 1049 510 1736 15~2 1567 1558 1 553 1558 1620 1236 19 12 41 610 1655 1517 149 1 148 1 148 1 148 4 1546 1108 20 1 5 32 7 35 1720 1550 1530 1520 1519 1523 158 0 1104 21 16 74 8 8 0 1900 1 727 1714 1696 1691 1692 1753 1169 22 1U 1074 38 5 3 324 2740 2534 2478 2 465 2503 258 0 1210 23 1287 4 35 3510 2 870 2682 2 610 2599 2638 27 1 9 1190 24 1 5 08 470 3 618 2920 2690 2 637 2627 2 664 2747 1177 25 18 07 525 4 088 3235 2962 2905 2910 2988 3130 1169
z ())
TABLE X Continued
Run No Position CFM I tc1 tc 2
Thermocouple Readings te3 tc4 tc5
(mv) tc6 tc7 tcair
26 c 10~29 6 32 2340 2~092 2032 2060 2~097 2152 2~213 1211 27 12 66 679 2270 2 047 1993 2013 2069 2142 2 210 1 182 28 1430 723 2336 2097 2033 2080 2153 2~255 2 356 1 138 29 1729 8 52 2318 2070 1980 2061 2158 2279 2367 1121 30 12D 1054 570 1520 1 4 20 1402 1400 1396 1400 1 443 1159 31 1294 6 69 1599 1469 1444 1439 1433 1 442 1485 1168 32 1430 7 88 1720 1562 1536 1532 1528 1537 158 0 118 5 33 1770 8 81 1641 1488 1450 1~441 1 441 1_466 1518 1 163 34 1D 1058 548 1579 1498 1495 1526 1553 1_557 1 571 1 276 35 1263 640 1609 1509 1515 1570 1599 1598 1 598 1 266 36 18 36 8 47 1538 1452 1483 1553 1602 1 590 1 558 1195 37 1 12D 1029 5 41 1 578 1499 148 4 1473 1461 1465 1-512 1200 38 1315 6 30 159 1 1504 1493 1482 1470 1470 1505 118 5 39 1 4 26 743 1765 168 1666 1660 1645 1642 1678 1270 40 1757 8 54 1744 1648 1634 1620 1598 1 593 - 1612 1223 41 2D 1080 5 30 1734 1604 1570 1 570 1570 1 588 1 640 128 1 42 1305 6 40 1744 1622 1589 1 608 1593 1 609 1 661 1240 43 1434 750 1798 1687 1658 1 636 -1641 1 661 1 711 1_220 44 18 04 8 41 1 764 1666 1607 1605 1614 1 635 1 675 1205 45 12nu 1088 415 2614 2295 2195 2 169 2174 2217 2256 1171 46 1318 477 2805 2477 2371 2342 2364 2 401 2 438 1 163 47 1413 5 28 2930 2 646 2 555 2 526 2532 2570 2 577 1 199 48 1773 550 2740 2518 2450 2431 2448 2 479 2 480 1 170 49 1 11 U 1054 380 3175 2670 2505 2 461 2467 2 534 2 621 1 258 50 1240 420 3268 2738 2 546 2 510 2 508 258 2 2 649 1214 51 1419 451 3364 2B07 2 632 2590 2 590 2 651 2773 1 215 52 1 12U 1032 360 3 165 2 629 2 450 2402 2403 2 473 2 bull568 1 163
--I lt0
TABLE X Continued
Run No Position CFM I tc1 tc2
lhermocoup1e Reading s tc3 tc4 t c 5
(mv) tc6 tc7 tc a ir
5 3 1314 38 9 3178 2592 2411 2367 2361 2432 2555 1140 54 1448 403 3095 2544 238 1 2336 2336 2390 2476 1158 55 178 2 427 3006 2434 2286 2253 255 3 2299 2397 1154 56 2 11U 1061 360 3369 2814 2619 2567 2560 2650 2833 1220 57 1216 360 3044 2512 2338 2290 2288 2374 2566 1150 58 1322 387 3196 2614 2425 2383 2382 2472 2670 1138 59 1639 403 3020 2438 2272 2238 2238 2318 2502 1127
60 1D 1068 612 1552 1424 1400 1395 1396 1426 1745 0945 61 1399 612 1355 1246 1230 1229 1230 1250 1509 0872 62 1669 710 1436 1293 1272 1265 1266 1286 1551 0847 63 1959 900 159 5 1468 1444 14 38 1432 1446 1720 0851 64 2295 730 1169 1105 1098 1099 1108 1100 1298 0781 65 2636 8 80 1202 1129 1121 1126 1 138 1115 1342 0748 66 3390 9 35 1060 o 9s7 0999 1001 1017 0971 1154 0703 67 1nu 1190 370 2225 2188 2104 2080 2120 2209 2 7 15 0990 68 1559 368 2005 1950 1871 18 48 1876 1951 2408 0916 69 1904 368 1870 18 1 4 17 34 1711 1730 18 07 2238 0875 70 22 bull11 471 228 6 2 204 2099 2063 2092 218 $ 2732 0840 71 2289 471 2030 2000 1925 1895 18 96 19 5 2498 0785 72 2727 4 71 1854 18 23 1753 17 23 1716 3758 2241 0743 73 3210 471 1680 1651 158 6 1559 1551 158 1 1950 omiddot7o9 74 2uD 1210 404 1261 1212 1198 1197 1205 1222 139 1 0978 75 14 20 540 1321 1260 1242 1 240 1249 1268 148 7 0918 76 1692 7 18 1467 138 6 1364 1361 1376 1405 1678 0883 77 18 94 903 1708 1 591 1565 1560 1575 1603 1948 0 857 78 2301 903 1530 1432 1407 1402 1415 1432 1738 0815
ro 0
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc117 tcair
79 2621 6 50 1069 1 020 1009 1009 1009 1007 1~189 o739 80 3230 901 1200 1128 1113 1119 1119 1086 1341 0694 81 82
l2D 1155 1689
360 575
1191 1345
1142 1252
1122 1218
1118 1210
1118 1209
1132 1228
1292 1446
0916 0822
83 1244 430 1163 1134 1131 1130 1129 1132 1292 0877 84 2100 645 1175 1135 1147 1 142 1138 1122 1286 0757 85 2292 8 25 1 354 1310 1327 1330 1323 1285 148 6 0728 86 2907 8 23 1180 1138 1151 1158 1149 1107 1268 0687 87 3380 902 1113 1049 1025 1011 1006 1042 1178 0673 88 89
1 12D 1427 1875
480 615
118 2 1140
1140 1095
1124 1077
1125 1075
1129 1072
1137 1072
1290 1243
0880 0790
90 2259 8 41 1296 1231 1207 1206 1203 1182 1419 0757 91 2682 8 80 1231 1170 1149 1147 1142 1112 1350 0731 92 3417 940 1142 1092 1076 1076 1069 1021 1252 0693 93 c 15 17 431 1321 1298 1268 1249 1250 1273 1522 0841 94 2034 505 1285 1263 1235 1209 1205 1206 1464 0759 95 2348 6 10 1395 1379 1334 1302 1286 1268 1536 0732 96 2716 706 1486 1480 1427 1383 1358 1311 1572 0 700 97 3247 7 56 1417 1430 1375 1320 1284 1223 1450 0660 98 1135 400 1425 1388 1352 1329 1330 1 364 1651 0893 99 14 06 440 1379 1341 1304 128 2 1281 1305 1583 0 831
100 2311 680 1602 1593 1553 1514 1502 1480 1 7 27 0 802 101 2666 680 1471 1469 1428 1390 1372 1335 1564 0761 102 3392 798 1491 1 509 1449 1395 1372 1305 1534 0 719
103 1U 1235 410 2469 2295 2173 2165 2226 2361 3120 0 897 104 2010 410 2017 1848 1 737 1706 1747 1865 2582 0753 105 28 14 410 1682 1535 1457 1427 1437 1520 2109 0 660
00 t-
TABLE X Continued
Ru n Thermocouple Rea ding s (mv No Positi on CFM I tc1 tc2 tc3 tc4 tc5 tc6 tc7 tcair
106 3492 440 1649 1499 1420 1391 1390 1470 2042 0620 107 4395 550 18 33 1679 1597 1564 1570 1640 2223 0583 108 5075 588 1779 1642 1580 1550 1552 1 615 2 191 0548 109 c 1344 398 1464 1 399 1364 1353 1350 1380 1689 0 907 110 1936 459 1369 1290 1253 1242 1 237 1259 1574 078 2 111 2846 580 1347 128 5 1251 1232 1220 1215 1 5 23 0 683 112 34 8 4 700 1392 1369 1339 1317 1299 1259 1599 0 636 113 4066 8 13 1449 1458 1427 1391 1363 1270 1595 0 591 114 5012 930 1484 1530 1500 1453 1420 1272 1580 0 580 115 1D 1362 513 1269 1218 1 217 1214 1220 1238 1460 0 893 116 19 58 600 1187 1122 1121 1120 1124 1133 1352 0798 117 2812 705 1052 1008 1015 1010 1011 1001 1218 0691 118 34 32 913 1105 1075 1085 1081 1086 1047 1301 0645 119 4022 980 1038 1021 1026 1023 1029 0983 1211 0 609 120 5026 982 0 8 61 0839 0836 0836 0837 0791 0955 0570 121 2D 1244 475 1320 1246 1233 1240 1255 1275 1434 0925 122 1 9 60 5 50 1160 1088 1074 1079 1089 1100 1260 078 7 123 2817 6 80 1096 1024 1 013 1018 1029 1022 1201 0 700 124 3491 960 1248 1175 1163 1172 1192 1153 1435 0 658 125 4096 989 1141 1089 1078 108 9 1105 1051 1310 0629 126 50 37 989 0983 0933 0929 0 936 0949 0880 1090 0 602 127 128
12D 1278 1947
402 545
1270 1261
1 230 1216
1228 1216
1230 1 215
1235 1223
1242 1219
1483 1514
0 913 0778shy
129 2769 695 1273 1234 1237 1221 1251 1212 1525 0678 130 131 132
34 39 4103 4978
8 40 9 80 9 80
1336 1448 1271
1322 1458 1 288
1328 1 462 1286
1 259 1 356 1157
1353 1492 1311
1261 1329 1138
1 555 160 7 1343
0 629 0 600 0599
(l) l)
TABLE X Continued
Run No Position CFM I tel tc 2
Thermocouple Readings tc3 tc4 tc5
( mv) tc6 tc7 tcair
133 1 l2D 1299 5 16 1 28 1 1212 1196 1195 1205 1221 1478 0869 134 1973 6 15 1163 1098 1073 1071 1079 1083 1343 0751 135 136
27 88 34 73
802 9 -_78
1187 1214
1099 1131
1069 1104
1066 1101
1075 1~110
1l061 1066
1370 1360
0662 0618
137 4118 9 81 1084 1010 0983 0979 0982 o937 1209 0581 138 4973 98 1 0969 0897 0 868 0855 0860 0799 1041 0572
139 1D 1253 409 1371 1293 1298 1301 1309 1321 1578 0928 140 2366 480 1130 1 090 1 121 1130 1137 1132 1390 0744 141 34 61 6 38 1081 1086 1152 1161 1147 1069 1382 0644 142 143 144
4325 5677 6759
7 90 939 998
1110 1115 1034
1161 1208 1139
1253 1268 1180
1265 1302 1215
1228 1230 1123
1080 1056 0970
13$913r12 8
0601 0561 0542
145 84 08 989 0863 0961 0934 0895 0871 0 785 09 9 0530 146 86 54 9 80 0808 0901 0 872 0821 0809 0733 0891 0498 147 7376 9 80 0 927 1032 1027 1 040 0961 0889 1032 0511 148 2D 4254 776 1 050 0 981 0965 0961 0962 0922 1155 0579 149 5708 991 1102 1031 1014 1009 1010 0931 1227 0528 150 69 78 990 0914 0853 0839 0 839 0843 0759 0996 0521 151 1254 490 1 479 1352 1329 1334 1351 1379 1607 0930 152 2713 7 00 1310 1220 1201 1201 1211 1209 1516 0723 153 8730 991 0809 0756 0742 0745 0 748 0663 0874 0543 154 5811 966 1219 1108 108 6 1081 1079 1033 1330 0650 155 42 46 8 02 1248 1136 1114 1114 1118 1103 1376 0 699 156 c 1270 429 1671 1571 1551 1545 1563 1600 1933 0929 157 2714 488 1398 1285 1 267 1258 1262 1275 1628 0729 158 4310 642 1424 1318 1299 1282 1283 1261 1683 0617
co ~
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc7 tc a 1r
159 60 12 780 1461 1388 1370 1349 1343 1279 1700 0 573 160 72 79 8 60 1402 1344 1330 1312 1292 1189 1 566 0 520 161 8690 982 1472 1442 1437 1 422 1392 1224 1602 0 521 162 163
12D 4368 5833
6 30 8 30
1195 1368
1105 1270
1111 1283
1117 1294
1131 1313
1081 1194
1369 1553
0613 0 553
164 76 43 959 1428 1338 1348 1341 1371 1180 1488 0535 165 8739 984 1345 1272 1272 1208 129 3 1059 1361 0550 166 1268 459 1701 1548 1541 1547 1589 1 625 1976 0 973 167 2678 570 1485 1351 1349 1356 138 1 1 385 1795 0760 168 169
1 12D 128 3 2729
448 650
1664 1314
1501 1232
1425 1233
1428 1229
1491 1229
1527 1232
1869 1571
0 962 0767
170 4345 847 1245 1179 1187 1182 1172 1132 1476 0 650 171 6036 9 76 1139 1109 1117 1114 1095 1020 1332 0588 172 6578 9 72 0982 0949 0942 0938 0926 0 8 50 1079 0560 173 87 84 9 72 0880 0854 0 8 36 0822 0818 0 749 0941 0585 174 1278 480 1564 1416 1397 1403 1417 1445 1733 0998 175 2711 590 128 3 1175 4 1178 1182 1187 1195 1493 0796 176 4351 8 90 1331 1259 1266 1275 1272 1235 1592 0 682 177 5994 9 60 1228 1152 1150 1151 1143 1075 1 360 0644 178 lU 1223 408 2282 2140 2052 2052 2106 2188 2626 0 878 179 2351 408 178 1 1623 158 5 1519 1556 1634 2068 0717 180 3448 482 1888 1675 1570 1541 1572 1665 2199 0629 181 4513 563 2026 1797 168 4 1644 1670 1770 2385 0583 182 5714 589 1913 1700 1610 1568 1580 1 682 2382 0551 middot 183 6997 653 1903 1718 1643 1611 1612 1700 2326 0 549 184 8709 6 80 1738 158 3 1543 1510 1498 1519 1 912 0577 185 186
2 12D 4249 5737
660 9 74
1055 1221
0 979 1122
0960 1093
0 952 1088
0959 1090
0 956 1054
1147 1350
0661 0602
187 7432 9 8 1 1065 0981 0951 0942 0 939 0881 1135 0582 CD ~
TABLE X Continued
Run No Position CFM I t o1 to 2
188 87 23 9 83 0944 0 879 189 1435 585 18 26 1630 190 2718 690 1433 1298 191 7507 950 1070 0961 192 85 44 964 0982 0 881 193 1287 600 1806 1668 194 2717 7 80 1579 1444 195 4253 8 81 1371 1260 196 60 68 9 78 1252 1152 197 73 89 975 1100 1000 198 86 88 973 0953 0 871 199 58 64 9 81 1269 1155 200 2D 4 1 77 915 1362 1251 201 5712 975 1213 1111 202 7363 9 78 1036 0 951 203 8 604 973 0932 0861 204 1268 6 95 2015 18 20 205 2659 6 96 1405 1295 206 39 80 7 98 1261 1174
No 207 Orifice 114 96 509 1325 1148 208 94 33 509 1477 1243 209 7487 5 09 1686 1409 210 5236 505 2094 1691 211 3309 428 2188 1 778 212 1293 392 2976 2560
Thermo ooup1e Readin g s (mv) to 3 to4 to
5 to
6 to7 toair
0 851 0847 0 8 29 0759 0987 0592 158 4 1583 1611 1647 1993 0986 1270 1266 1 279 1298 1604 0 789 0916 0908 0900 0 858 1115 0602 08 39 0 823 0 818 0 770 1035 0602 1609 1602 1629 1676 2153 0979 139 1 1385 1400 1 430 1938 0776 1212 1201 1205 1201 1601 0669 1 105 1086 1086 1 052 1371 0621 0952 0936 0923 0870 1195 0582 0 8 20 0 801 078 1 0 729 1044 0569 1108 1090 108 2 1043 1407 0610 1218 1221 1241 1202 1582 0659 1081 1083 1084 1031 1 368 0622 0921 0924 0919 0 841 1111 0 610 08 34 0831 0 821 0 751 1003 0 630 1761 1761 1 809 1861 2399 0966 1271 1271 1295 1311 1650 0797 1150 1150 1161 1149 1440 0703
1083 1057 1053 1109 1566 0~530 1158 1125 1138 1217 1763 0 526 1291 1250 1278 1383 2038 0542 1518 1478 1519 1657 2420 0 589 1596 1557 1601 1737 2441 0688 2370 2344 2409 2561 3 297 0921
()) (11
TABLE X Continued
Run Thermocouple Readings (mv) No Position CFM I tc 1 tc2 tc3 tc4 tc tc tc tc i5 6 7 a r
C of 2nd 213 516 1235 4 63 1 432 1291 1265 1258 1 268 1 308 1550 0 971 214 1919 6 17 1357 1223 1196 1191 1199 1211 1461 0 851 215 27 12 8 35 1401 1259 1278 1220 1230 1218 1511 0 762 216 3320 981 1439 1305 1270 1259 1275 1238 1450 0719 217 41 53 980 1251 1142 1132 1094 1121 1088 1305 0 695 218 404 987 1102 1042 1030 1 bull006 1014 0960 1133 0681
Supplementary Equations
Calculating temperatures from thermocouple readings
t = -026tc)2 + 3512(tc) + 3201 (26)
where t is the temp in deg F and tc is the thermocouple reading in millishyvolts
Calculation of the thermal conductivity of air
k = 00000245ta + 0 0132 (27)
where k is the thermal conductivity in Btuhr rt2 degFft and ta is the air temp 1n OF
I I
bull co m
7
through a circular hole in a plata This study was extenshy
sive in the fact that it considered the baffle thickness as
well as the orifice size but no heat transfer data were
presented
Sullivan and Bergelin (9) studied flow through a
single annular orifice through multiple annular orifices
i n parallel and flow around a single baffle both with and
without leakage through the baffle A generalized expres shy
sion is presented for the pressure drop across one baffle
section of a tubular exchanger with leakage through the
tube holes in the baffle but the effect of leakage area
upon heat transfer is only discussed qualitatively The
pressure drop data is correlated by plotting cent as a funcshy
tion of the Reynolds number where cent equals
d1 )22( ~ P) s c e (d2 -
M-2
8
CHAPTER III
~PERI1ffiNTAL APr ARATUS
The heat transfer test section was essentially a
single tube heat exchanger The inner tube was a l-in
OD aluminum tube with an electrically heated probe midshy
way between the two ends of the tube
Test Section
The shell as constructed from lucite plastic tubing
2 5-in I D and 3-in O D The te t section d a total
lengt h of 54 58 inches I t consisted of two sections
The upstream section was 40 i n ches in length in order to
assure freedom from entrance effects and the downstream
section was 13 12 inches in length To further assure
uniform flow a bundle of short copper tubes was placed a
few inches downstream from the entrance Both of these
sections had 12 i nch flanges on one end so t hat a 18
i nch thick orifice plate could be clamped between them
Heat transfer coefficients were measured in the vicinity of
t h is orifice A cross section of the center of the test
section is shown in Figure 1 and the experimental appara~
tus is shown in Figure 2
Cooled air supplied by a Roots -type blower was used
as the shell-side fluid throughout this study It entered
the test section through a l-in ID 1 12-in OD plasshy
tic pipe at the upstream end of the calming section Tbs
j Jl l 6- 11 BOLTS II I nbull middot~11 I HEATING ELEMENTS
J T ( T
-f-shy - - - f-_- __L
7 777 _y A
IT 1] I
I
FIGURE I CROSS SECTION OF TEST SECTION AND PROBE
10
FIGURE 2 EXPERIMENTAL APP1Ub~fUS
11
air left the test section through nine equally spaced 12
ineh holes placed around the side of the tube at the exit
end
Sensing Probe Assembly
The sensing probe was designed to measure the local
heat transfer coefficients at any point along the tube and
around the tube in the test section The tube was designed
so that it could be easily moved up- and downstream to
measure the heat transfer coefficients at various positions
in relation to the orifice
The sensing tube assembly consisted of the sensing
probe the thermoctmple lead s and selector switch the
power lines and the two aluminum tubes between which the
probe was centered
Imbedded in the sensing probe were seven iron-constanshy
tan thermocouples for measuring the temperatures around the
tube The lead wires from these thermocouples were conshy
nected to a seleotor switch at the downstream end or the
aluminum tube A layer of Saran wrap was placed around the
tube over the t hermocouple and three lengths of Trophet C
resistance ribbon were wrapped around the tube nd conshy
nected in series to the power leads
The heating surface of the probe was formed by these
three one inch wide strips of Trophet C resistance ribbons
The ribbons were 0002 inches thick and had a resistance of
12
0 271 ohms per foot and a thermal conductivity of 763
Btuhr ft 2 degFft They were held in position by four
copper bars placed in four parallel longitudinal slots
These copper bars served as connectors for the electrical
leads A photograph of the sensing probe is shown in
Figura 3 and a drawing of the assembled probe is given in
Figure 4
Power Source
Direct current was used to heat the resistance ribbon
on the sensing probe The current was regulated by a slide
wire resistor The po er source consisted of a Raytheon
Voltage Stabilizer to stabilize the city power source at
115 volts and an automatic selenium rectifier with an alshy
ternating current input of 115 volts at 60 cycles per
second and an output of 12 volts and 35 amperes direct
current
Temperature Measuring
The temperatures around the sensing probe were calcushy
lated from the emf readings of the ironbulloonstantan thermoshy
couples The emf measuring system consisted of the seven
probe thermocouples a separate thermocouple for measuring
the inlet air temperature a thermocouple selector switch
a cold junction and a Leeds and Northrup Type K Potentishy
ometer The potentiometer was placed on a Fischer
13
THERMOCOUPLE JUNCTIONS~ ~------- HOLES FOR THERMOCOUPLE LEADS
~----- SCREWS
~ff+--- CONNECTING BARS
END VIEW
POWER LEADS SOLDERED TO LOWER CONNECTING BAR
iER PLASTIC PIECE
RESISTANCE RIBBONS LOCATION OF THERMOCOUPLES
FIGURE 4 DRAWING OF ASSEMBLED SENSING PROBE
15
Vibradamp support to absorb the vibrations produced by the
air blower
Air Source
Air was used as the shell-side cooling fluid during
the study The air was pumped through the test section by
a Roots type air blower with a rating of 280 ofm at 3 12
psig outlet pressure The hot air leaving the blower was
passed tbxfugh two finned-tube box-type coolers and one
tubular edoler to oool it to approximately room temperature
The air flow rate was measured by passing it through a
flow measuring orifice in the line Two sharpbull edged orishy
ficas were used f or flow measurements The calibration
curves for these orifices were presented by Ambrose (1
p 166)
The pressure taps on each side of the orifice were
connected to two differential manometers containing 0 83
and 2 95 specific gravity fluids respectively The presshy
sure drop through the test section and test orifice was
measured by a pressure tap placed 13 inches upstream and
one placed 6 12 inches downstream from the orifice Two
pressure ga ges were used to measure the pressure at the
inlet to the flow orifice and to indicate the statio pres~
sure at the test section inlet
16
Pressure Probe
A probe was designed to measure the pressure drop
between the pressure tap 13 i nches upstream from the ori shy
fice baff le and any point downstream from the tap The
probe eonsisted of a l~in OD copper tube with six 132
i n ch holes even l y s paced around the tube The upstream
pressure tap and the pressure probe were connected to a
differential manometer so the pressure drop to various
points up- and downstream of the orifice could be measshy
ured
17
CHAPTER IV
EXPERIMENTAL PROGRAM
The experimental program was designed to measure the
heat transfer coefficients and pressure drops in the vicinshy
ity of annular orifices The four orifice sizes studied
were 1 364 1 216 l 316 and 1 516 inches~ The inner
tube used in each case was a 1-in OD alumintim tube
Hence tube to baffle clearances were respectively 3128
232 332 and 532 of an inch
Heat transfer coefficients were measured at poait~ons
1 i nch upstream at the orifice center and at 12 1
1 12 and 2 inches downstream for all orifices In addishy
middottion the heat transfer coefficient at a point 2 12
inches downstream from the 1 516 inch orifice was measured
and at the points 12 l 12 and 2 inches upstream from
the 1 364 inch orifice
The heat transfer coefficients at each point were
measured at five different flow rates for the 1 364 inch
orifice and at six different flow rates for the other orishy
fice sizes The high pressure drop through the small orishy
fice size limited the number of flow rates which could be
studied
The flow rate was calculated from the pressure drop
across the flow orifice This flow was corrected to cubic
feet per minute at 68degF and one atmosphere pressure by
18
using the orifice pressure and the test section pressure
which were measured by pressure gages
It was desired to determine a relationship between the
heat transfer coefficient and the total pressure drop for
each orifice size The pressure drop across each orifice
at various flow rates was measured by means of the presshy
sure probe described in Chapter III It was also desired
to obtain pressure profiles for each orifice size since
these might be similar to the heat transfer profiles The
pressure drop was measured from a point 13 inches upstream
of the orifice to points at 1 and 12 ineh upstream the
orifice center 12 1 1 12 and 2 inches downstream
The experimental program is summarized in Table I
TABLE I
SUla~RY OF EXPER IMENTAL PROGRAM
Position Investigated-Distance from Orifice-Inches
Orifice Range of Flow Rate Size Heat Transfer Pressure Drop CFM at 68degF amp 1 atm
1 364 2U 1 12U 1U 12U c 12U C 12D lD 10 - 18 l2D lD 1 12D 2D 1 12D 2D
1 216 1U c 12D lD 1 l2D 2D 12U c 12D lD 10 - 35
1 316 1U c 12D lD 1 l2D 2D l2U C 12D lD 12 - 50
1 516 1U c x2D lD 1 l2D 1U 12U C 12D 12 - 90 2D 2 1 2D l D 1 l2D 2D 2 12D
20
CHAPTER v
EXPERI MENTAL PROCEDURE
The experimental procedure for measuring the heat
transfer coefficients ~d corresponding flow rates reshy
quired the following procedure
(1) Install the orifice size to be studied in the
test section
(2) Place the heat transfer probe in the position up
or downstream from the orifice where the middot heat
transfer rate is to be studied
(3) Fill the cold junction thermos with cracked ice
(4) Measure the atmospheric pressure
(5 Open bypass line from blower and close line to
test section
(6) Turn on the cooling water for the exchangers used
to cool the air leaving the blower
(7) Start the automatic selen ium rectifier by turning
on the t 1mer bull
(8 ) Connect the voltage stabilizer to the wall outlet
(9) middot Set the slide wire resistor to the maximum re shy
s1atanee I
(10) Start the blower
(11 Open the line to the test section until the de shy
sired flow rate is obtained
(12) Switch on the probe direct current power source
21
(13) Adjust the slide wire resistor to obtain the
desired current
(14) After the thermocouples have reached equilibrium
values record the e m bullf across each of the
seven probe thermocouples and also the entering
air thermocouple
(15) Record the direct current amperage
(16) Record the gage pressure at the flow orifice and
the entrance to the test section
(17) Record the manometer measurement of the pressure
drop across the flow orifice and also the presshy
sure drop through the test section
22
CHAPTER VI
CALCULAT ION OF EXPERIMENTAL DATA
The local heat transfer coefficients were calculated
from the temperatures measured on the probe surface the
air temperature and the current input The results were
calculated by using the Alwae III-E computer
The general expression for calculation of the heat
transfer coefficients was derived by Ambrose (1 p 79)
The equation is derived by making an energy balance around
a small increment of the center resistance heating ribbon
The two ribbons tnstalled adjacent to the center ribbon
reduced the amount of logitudinal conduction and assured
little longitudinal temperature variation in the center
ribbon
A heat balan ce on this small increment of resistance
ribbon yields the following
(the heat conducted in) + (heat generated) = (heat
conducted out) +(Heat convected to the fluid) + (heat
radiated to the surroundings) + (Heat conducted into
the plastic center of the probe)
This gives the equation
kzw dtdS + 12RdS kzws [ t + (~) ds] + hwdS (t-ta )
+ ~Aad wd o middot+ qcAond 1 -~- wdS 5 )
23
Hence solving for h gi~ea
i2R kz d2t Qrad qcond w + -d$2 - ~- A
h = ( 6)t - ta
Since S = re where 9 equals the enclosed angle ~n radians
dS rd9 ( 7)
and
dt - dt (8)dS - rd9
Differentiating with respect to S
d2t (9)rd9dS
from which
(10)
Substitut1ng into the equation for heat transfer coeffishy
cient gives
h = i2R Qcond A (11)
w
The rate of radial heat conduction into the plastic
tube making up the probe was assumed to have negligible
effect on the heat transfer coefficient It was also
assumed that the heat loss by radiation from the ribbon
was negligible since all data were obtained with the ribbon
at a temperature less than 125degF
24
When t he rad iation and conduction terms are neglected
Eq (11) becomes
(12)
The following con stants are known
R = 0 271 ohmsft
w = 100 i n ches
k = 763 Btuhr rt2 degFft
z = 0 002 inches
r = 12 inch
Eq (12) putting 9 in degrees then reduces to
1110 12 + 2404 d 2t d92
( 15)h = ------~--~-------t - ta
Thi s equation was programed for the Alwac III- E comshy
puter and used to calculate the local heat transfer coefshy
ficients from the observed data
The average heat transfer coefficient around the tube
at a given position in the t est section was calculated by
averaging the local coefficients calculated from Eq (13 )
It was found 1n the course of the experimental work
that thermocouple numbers 1 and 7 were indicating higher
temperatures than would be expected This resulted in h1
and ~ being lower than the other local coefficients around
the tube Since the fluid was flowing parallel to the axis
of the probe the circumferential variation i n rate of heat
25
transfer should be small Hence in obtaining the average
coefficient around the tube the values of h1 and h7 were
not used even though they were calculated and are tabulated
1n Table I II in the Appendix
Then
(14
A Nusselt number as calculated from this aver age heat
transfer coefficient using the tube diameter as the characshy
teristic dimension
(15)
The air flow rates through the test section were calshy
culated by measuring the pressure drop across the flow orishy
fice the air temperature the pressure at the flow orifice
and the pressure at the entrance to the test section The
orifice calibration curves (1 p 166 ) were used to obtain
a value of the orifice coefficient f8e where Q equals
the flow in cubic feet per minute at 68deg F and one atmosmiddot
phere pressure and te is the density of air at the exchanger
and e the density of the air at the flow orifice The
den sity of the air can be expressed by
e = 2 703 p (16)T
where T equals the temperature in OR and P equals the absoshy
lUte pressure i n lb1n2 Using the value of e Qfo from
26
the calibration charts as A and Eq (16) solving for Q
gives
( 17
This equation was used to calculate the flow rate for
each flow studied
The Reynolds number used i n the correlation of the
data was the equivalent Reynolds number defined as
Re)eb ~ d2 - dl)Uf ( 18 ) lL
where d1 is the outside diameter of the inner tube and d2
is the orifice diameter U is the flow velocity through the
annular orifice e is the density of the air and U- is t he
viscosity of the air This equation can be transformed t o
(Re) b = 1611 Q (19) e dl + d2
where d1 and d2 are in inches
The pressure drop data were calculated i nto a dimenshy
sionless pressure drop function cent where
d1 )22( ~ P)gc f av(d2 shycent 2 bull (20
M-
For air this equation reduces to
where d2 and d1 are in i nches D P is expressed i n inches of
2 95 specific gravity fluid and P av is expressed as lbft3
27
CHAPTER VII
ANALYSIS OF DATA
In analyzing the heat transfer data an attempt was
made to correlate it 1n terms of the dimensionless groups
(Nusselt number Prandtl number and Reynolds number) which
appear in Eqs (3) and (4) Consequently all of the av~
erage heat transfer coefficients hav were brought into
the form ( Nu)( Pr)~3 bull The Nusselt number was based on the
tube diameter and the thermal conductivity of the air at
the flowing temperature The tube diameter was used in the
Nusselt number because comparison could then be made with
previous experimental work on heat exchangers which have
commonly used the Nusselt number defined as in Eq (15)
From the standpoint of dimensional analysis this is
equivalent to considering the tube diameter as the characshy
teristic length so far as the heat transfer is concerned
The Prandtl number of the air was taken as 0 7 in all
cases
Variation of Heat Transfer Rate with Distance from the Baffle
Considerable variation was observed in the rate of
heat transfer in the vicinity of the baffle In order to
obtain the variation with respect to position the term
(Nu)(Pr)-13 was plotted versus the flow rate Q for each
position and orifice studied Cros s plots were then made
28
at constant flow rates in order to obtain the variation of
(Nu)(Pr) -13 with position The resulting cross plots are
shown 1n Fi gures 5 6 and 7 for the four orifices studshy
ied
About one inch upstream from the orifice the heat
transfer coefficient begins to rise rapidly and continues
to do so until it reaches a maximum some distance downshy
stream After the maximum point the heat transfer coef fi shy
cient decreased slowly The heat transfer rate was found
to reach a maximum at a different position downstream for
each orifice size These figures also show that for a
given orifice size the maximum heat transfer rate occurs
a pproximately at the same point for all flow rates The
position of the maximum point f or each or ifice size is
shown in Table II
The region immediately downstream from the orifice is
one of h i gh turbulence due to the jetting action of the air
flowing through the orifice As the air flows t hrough the
orifice the streamlines continue to converge for some dis shy
tance downstream The point of maximum heat transfer is
probably at the point where the streamlines be gin to diverge
and a boundary layer begins to build up on the tube Tle
decreasing heat transfer coefficient beyond the maximum
point indicated the formation of a boundary layer
Since the position of the maximum point is independent
of flow rate middot it is possible to correlate it with respect
_ ct 11shyz-
100
0 136 ORIFICE
(
I 0
I )
~ 00
~p 0
I 0
--r--- ~
ISCFIII
-_ OCFM
rbull abull
~ middot~ a-1 z-
12fORIFICE
100
200
100
0 0 UPITRAM ORIFICE DISTANCE CENTER
CFM
h I DOWNSTREAM
DISTANCE
FIGURE 5 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLpound
30
too
700
800
100 ~ f gtf
400
z ~
100
100
100
0
13fORIFICE
~ -~ -- ---
)
~
~
-
I ~ ~OCFM
I vI~-~ OCFM
J ---
Iamp CFM
I 0 I I UPSTREAM ORIFICE DOWNSTREAM DIITANOE GENTER DIITANCI
FIGURE 6 VARIATION OF HEAT TRANSFER RATE WITH DISllNCE FROM BAFFLE
--
--- --
31
100
100
700
100
_ 100
f 9- 400 z-
100
tOO
100
0 - I 0 I I I UHTRIAM OAtfiCI DOWIIITMAM
+ I tyl6 ORIFICE
v I
~~ ~CFM
I v ~CFMI
v v 7
~~ v ~ iOCFM
- ~~ I-shy1-shy ~ICFM
DIITMCI OINTIR DIITANCI
FIGURE 7 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLE
32
TABLE II
POSITION OF MAXIMUM HEAT TRANSFER
Position of Maximum Orifice Size Heat Transfer
(inches) (inches downstream)
1 364 050
1 216 100
1 316 125
1 516 200
33
to orifice size Figure 8 shows the effect of the orifice
size on the position and value of the maximum heat transfer
at a constant flow rate of 15 cubic feet per minute It
can be seen that the larger the orifice size the further
downstream the point of maximum heat transfer occurs
Also as the orifice size increased the rate of heat
transfer decreased for a given flow rate The broken line
indicates the variation of the point of maximum heat transshy
fer with position and size The position of the point of
maximum heat transfer rate downstream from the orifice was
correlated with orifice size by means of the dimensionless
groups (Lde) and (d1de) where L is the distance downshy
stream from the orifice where the maximum rate of heat
transfer occurs d1 is the outside diameter of the inner
tube and de is the equivalent diameter of the orifice
ie de = d2-dlbull
Figure 9 shows a plot of Ld 6 versus d1d6 for the
four orifice sizes studied The four points on this logshy
log plot are approximately in a straight line and the
equation of this line is
Lde = 0 44 d1de)028 (22)
Although the above relationship represents a correlashy
tion of dimensionless groups it is based upon only one
tube diameter and needs to be substantiated further by
studying other tube diameters and other orifice sizes
34
aoo
400
aoo ~
-~ middot-CLshyJ z
200 -
100
0
ORIFICE CENTER
l~
l
t
I J~
1pound~
I
0 I I~
AT 15 CFM
-
bull ~ 1~6~
~ v~
~
~--~~6
~~~ ___ v v V -_
~ o q
~ I 16
v
~
ogWNSTREANI STANCE
FIGURE 8 EFFECT OF ORIFICE SIZE ON POSITION AND VALUE OF MAXIMUM HEAT TRANSFER
35
50
loshy____ -~
~ ~ -shylltl-shy~ r0
2 10 30
FIGURE 9 CORRELATION OF THE POINT OF MAXIMUM HEAT TRANSFER WITH
ORIFICE SIZE
36
Correlation of Data at the Baffle
The heat transfer data were correlated by obtaining a
relationship between the group (Nu)(Pr)-13 and a
Reynolds number based on twice the clearance (d2 - d1
between the tube and the baffle It was found that the
most satisfactory correlation could be obtained when the
term - d1 was used as the length term in the Reynoldsd2
number
Figure 10 shows the variation of the heat transfer
rate at the center of the orifice e xpressed as a function
of Reynolds number and the orifice size This shows that
for a given Reynolds number the heat transfer at the center
of the orifice is greatest for the smallest orifice size
In order to obtain a general correlation of the data
shown i n F1gure 10 the effect of the dimensionless ratio
d1de was considered This ratio considers all of the
geometric factor s needed to describe the annular orifice
The thiclaless of the orifice plate is also a factor but
was constant i n this i nvestigation
The data for the heat transfer at the baffle center
are shown in Figure 11 in which (Nu)( Pr)-13 is plotted
versus (Re)ebd1 de) 0 55 This data on a log-log plot
lies on a straight line for (Re)eb( dld8 )0 55 greater
than 3 x 104 The equation for cor relating the heat
37
4XI~middot~-r~------~--~~------~
Icf t--to_+--_c-c-________ SYMBOL SIZE
0 1~4
6 ~~
9 ~~ -o ~
(Re)eb
FIGURE 10 RATE OF HEAT TRANSFER AT BAFFLE CENTER
38
500
0
4 0 lcf
~ ~
~ ~iC-
~ ~
~IL 0~ 0 SYMBOL SIZE-
p 0 1364-
r 6 1~16 -~ -
9 1~16 --o 1~16
I I
FIGURE II CORRELATION OF HEAT TRANSFER DATA AT BAFFLE CENTER
39
transfer at the center bullOf the a nnular orifice was found by
the method of least s quares to be
(Nu)( Pr)-1 3 = 0018 ( Re)ebO Bl( dlde)04~ (23)
3 x 104 ltRe)eb(a1de)055 lt 105)
Rate of Heat Transfer at the Point of Maximum Heat Transfer-The heat transfer rate at the point of maximum heat
transfer is plotted in Figure 12 to show the variation with
Reynolds number and the size of the orifice It is shown
gives the h1gh st heat transfer ~ate at its point of maxibull
that for a given Reynolds number the smallest orifice size yen il
mum heat transfer
The data ~or the maximum poi~t could be correlated by
plotting (Nu) Pr)-13 versus (Re)eb(d1de)06 This plot
is shown 1n Figure 13 and the resulting eurve shows that
(Nu(Pr)-13 is not a simple p0wer function of the Reynolds
number as was the case for heat transfer at the baffle
center The reason for this is probably because other
factors such as intensity and scala of turbulence should
be considered At the orifice center the streamlines of
the flowing stream are converging_ and thus the flow is
quite stable Downstream from the orifice is a region of
large eddy currents and probably large scale turbulence
These factors could con ceivably cause the results which
were obtained for the point of maximum heat transfer
40
If)
~middotshy Q_-I z_
10~~~--------r----~~--~--
SYMBOL SIZE
0 13$4
6 1~8
Q 13-18
-o 1~8
7)(104
(Re)eb
FIGURE 12 RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
41
Ia ~
0 I
c ~ ~ c v
~ ~lt w ~
17
~ b
v ~ ( SYMBOL SIZE
-~ 0 f-64 -v ~ 6 t211e
~ Q I~~~
-o - l~rs I I
FIGURE 13 CORRELATION OF HEAT TRANSFER DATA AT THE POINT OF MAXIMUM HEAT TRANSFER
4 2
Effect of Upstream Baffles on Heat Transfer at the Orifice Center
The heat transfer rate at the orifice center using the
single orifice in a test section is a pproximately 13 of the
value that was obtained by Lee (7) using a model heat exshy
changer with orifice baffles Lee investigated the cent r al
baffles of the heat exchanger and thus the coeff icients he
obtained would be affected by the presence of a number of
upstream baffles To determine the effect of upstream
baffles an additional l 516 inch baffle was placed four
inches upstream 1n the test section The resulting data are
shown in Figure 14 where (Nu)(Prmiddot)-13 is plotted versus
(Re) eb for the case of a single baffle 1n the test section
and also the case of an additional baffle placed four inches
upstream Comparison is made with the results obtained by
Lee middot(7) using a four-baffle and a ten-baffle model heat exshy
changer Good a greement is obtained with Lees work and the
results show the marked effect that upstream baffles have on
the downstream heat transfer rate The additional up tream
ba ffle caused sufficient turbulence 1n the test section to
i n crease the heat transfer rate nearly three-fold at the
center of the next baffle
Heat Transfer i n the Test Section with No Orifice
In order to check the accuracy 6f the equipment the
orifice baffle was removed and the heat transfer mea sured
with the probe in the empty test section The data were
43
~~BAFFLES
0 l BAFFLE -shy
ll_9 2 BAFFLES
V 4 BAFFLES-LEE
4 10 BAFFLES- LEE lJf ~
~rv ~~ ~ v flvv ~~
I ~ J ~ L v
0
v
( V
40 3XIo 7XIa
(Re)eb
FIGURE 14 EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER AT BAFFLE CENTER
44
compared with heat transfe r coefficients predicted by the
equations for annuli which are recommended in the litera shy9
ture The two equa~ ions u sed tor comparison were
(hfe)=0 023 (rltGr e (~~ur4 (~r45 (24)
which was presente~ by Wiegant (10)
and ( h ) (cnM~5(M~l o14 o 023 CPG k j Mij - (de GJMb )0 2 ( 2 5)
which was presented by McAdams (8 p 242) The comparshy
i son is s hown in Figure 15 lq (25) gives a value which
is low by about ten percent while Eq (24) g ives values
which are high by as much as twenty -five percent when comshy
pared with the experimental data The se equations are gembull
erally considered to give coefficients with an accuracy of
about twenty percent Therefore the present experimental
data are within the accuracy of these equations Also the
plot indicate s that for a Reynold s number greater than 2 x
104 the slope of the line is the same for the experimental
data as for the equations
Pressure Drop Data
The total pressure drop across the orifice was measured
as a function of the flow rate and the orifice size The
pressure drop was expressed as a d1mens1onleas quantity r)
which ie plCltted ver sus the Reynolds number in Figure 18
The pressure drop function cent correlates for all or1f1oe
45
200
100
s z
10 5XI10 10
0 EXPERIMENTAL
--McADAMS
-WIEGAND L
V
~ ~ ~
P ~ ~
LL~ L
v~
~
v v
v 1 ~ ~ v
v -gt
~
~ ~
~
6Xid
FIGURE 15 HEAT TRANSFER WITH NO BAFFLE
46
0 1~4 -~ a 6 t216
Q t316 lJ J
-0 as a )t
A LEE I -shy SULLIVAN 8
p
10bull
BERGELIN
I _ll I
I ~
i I
~middot
lo II
f fl
J j
~middot
A)101
1q
I Ill
1 I3 X 10ao1
FIGURE 16 ORIFICE PRESSURE DROP FUNCTION VS REYNOLDS NUMBER
47
sizes- The present data extends the range covered by preshy
vious workers and agrees well with their work The preshy
vious work of Lee () for a heat exchanger containing 10
orifice baffles and also the data of Su livan and Bergelin
(9) for pressure drop in a model heat exchanger with a
single baffle is shown 1n Figure 16 long with the present
results~ This figure may be used to predict the preseure
drop from the equivalent Reynolds number of the annular
orifice
The pressure drop between individual points 1n the
vicinity of the orifice and an upstream pressure tap wa s
measured to obtain a pressure drop profile As might be
expected 1n all cases the profiles showed a rapid decrea e
in static pressure immediately upstream from the orifice
There was however little or no recovery of the pressure
loss downstream The 1 364 inch orifice did show a maxishy
mum point in the pressure drop but this maximum occurred at
the orifice center and total recovery was reached about 12
inch downstream
Heat Transfer at the Baffle and Maximum Point as a Function of Pressure Drop
In order to compare the effect of the total pressure
drop on the heat transfer at the baffle and the point of
maximum heat transfer Figure 17 was plotted showing
(Nu)(Pr)-13 as a function of the total pressure drop This
shows that for a given pressure drop the largest orifice
48
1200
1000
~ a -sshyz-
100
60 100 700
AT MAXIMUM POINT I 15116 2 13116 3 1~6 4 1364
AT ORIFICE CENTER
60
1
v
r ~ ~ ~
5
~
8 7
13116
8
~
1364
v
~
e6
1~6
v
~~ v ~ ~ -~ ~
~
~ v
l
~
vamp
I ~ ~
~
v L ~
v
I-
5
k= ~~
~ ~ ~
--I
v ~
FIGURE 17 HEAT TRANSFER AT THE BAFFLE AND MAXIMUM POINT AS A FUNCTION OF
ORIFICE PRESSURE DROP
49
size has the greatest heat transfer coefficient This is
true at both the orifice center and at the point of maxishy
mum heat transfer
Another comparison can be made by plotting the heat
transfer coefficient and the pressure drop versus the orishy
fice size at a constant flow rate Figure 18 shows this
plot This graph shows that at a constant flow rate the
pressure drop as well as the heat transfer coefficient
increases as the size of the orifice is decreased In
choosing an orifice size for maximum efficiency 1t would
be necessary to know the pumping power available as well
as the heat transfer desired
70 I I 700
AT 15 CFM 60 ---
~ aug
50 ---
NV
40 ~
~ ~ ~
~ _
MAXIMUM POINT ---- --- ~
1-----t---~ _
~00Qj ~
~t--- ORIFICE CENTER 10 1100
1---~ n
u0 01 02 03 Q35
a ltl
de inches
FIGURE 18 VARIATION OF HEAT TRANSFER RATE AND PRESSURE DROP WITH ORIFICE SIZE AT A CONSTANT FLOW RATE
cn 0
51
CHAPTER VI II
SUMMARY OF RESULTS
This study revealed several significant facts about
the heat transfer in the vicinity of annular orifices
Probably the most important contribution was the presshy
entation of the heat transfer profiles in the vicinity ot
the annular orifice ~ r s shown that t~ local heat
transfer coeffieient re~ches a maximum at a point downshy
stream from the orifice The distance downstream at which
this maximum oocurs is t1ven by the equation
22
The heat transfer coefficients at the center of the
orifice were correlated and found to follow the equation
(Nu)(Pr)-13 = 00176 (Re)eb08l(d 1de) 0 middot4~ (23)
3 x 104 lt( Re) 9 b( d1d6 )055 ltlo5 )
The heat transfer at the point of maximum heat trans
fer for each orifice size was correlated and presented in
Figure 13 as a plot of (Nu)(Pr)-l3 versus (Re)eb(d1de) 06
No simple po-orer relationship exists between the terms
Intensity and scale of turbulence downstream from the orishy
fice are probably important factors which affect the heat
transfer
The large effect of an upstream orifice on the heat
transfer rate at the second orifice was demonstrated by the
52
study of two 1 516 inch orifices in the test section The
added turbulence at the center of the second orifice was
found to raise the heat transfer rate almost three times
over that obtained for a single baffle
The pressure profiles in the vicinity of the orifice
indicate that nearly all the pressure drop occurs at the
orifice center~ Total pressure drop data were correlated
by a pressure drop function cent as a function of the Reynolds
number and good agreement obtained with the results of other
workers
The pressure drop and heat transfer data were correbull
lated by plotting the heat transfer as a function of the
pressure drop for each orifice size It was shown that for
a given pressure drop the largest orifice size gives the
greatest heat transfer coefficient
As a final presentation it was shown that the pressure
drop and the heat transfer coefficient both i ncrease i n
value at a constant flow rate as the orifice size is de shy
creased This is important in choosing the optimum clearshy
ance for orifice baffles
53
CHAPTER IX
RECOMMENDATIONS
A great deal of work remains to be done in the field of
evaluating shellmiddotside heat transfer coefficients This
study included only one tube size and air was the only f luid
used It is recommended that further studies be conducted
using other fluids and tube sizes It will also be necessary
to study several baffle types
The adde d turbulence due to a s e cond baffle placed upbull
s t ream would suggest that the heat transfer coef ficients at
a certain position i n relation to a baffle would increase as
the flow progressed through the exchanger It is recomshy
mended that an extensive s t udy should be made between baffles
the full length of a model heat exchanger
It is further recommended that the pressure drop study
be continued to include other fluids tube sizes and baffle
arrangements
Effects of turbulence downstream from the baff le should
be studied by i n vestigations with hot-wire anemometer equipshy
ment to determi ne t urbulence scale and i ntensity
54
NOMENCLATURE
Area of heat transfer
Heat capacity of the fluid
Outside diameter of the tube
Orifice diameter
Equivalent diameter of the orifice (d2 - dl)
Inside diameter of the test section
Inside diameter of the tube
Gravitational constant
G Mass velocity
h Local heat transfer coefficient
Coefficient of heat transfer from surface to fluid
i Direct current amperes
k Thermal conductivity of the fluid
L Distance downstream of the point of maximum heat transfer
p Absolute pressure
L P Total pressure drop across the orifice
Q Flow in cubio feet per minute at 1 atmosphere and 680 F
q Heat transferred
Thermal energy conducted into the sensing probe
Thermal energy radiated from the resistance ribbon
Resistivity of the resistance ribbon
s Length of the resistance ribbon
T Temperature oR
55
t Temperature of the resistance ribbon deg F
ta Temperature of the bulk stream oF
tw Wall temperature of the tube OF
U Veloc ity of the fluid
w Width of the resistance ribbon
z Thickness of the resistance ribbon
eeuro Density of the fluid in the test section
Density of the fluid at the flow orificef 0
AL Viscosity of the fluid
E9 Angle measured around the tube
Dimensionl ess groups
(Nu) Nusselt number hd1k
(Pr Prandtl number C~k
(Re)eb Equivalent Reynolds number at the baffle (d2 - d1 )uejt-Lshy
(Re)e Equivalent Reynolds number in the test section ( d 8 - d 1 )U fu
cent Orifice pressure drop function 2(~P ) gc~av(d2 - d1) 2
Al
56
BI BLIOGRAPHY
1 Ambrose Tommy W Local shell-side heat transfer coefshyficients in baffled tubular heat exchanger PhD thesis Corvallis Oregon State College 1957 183 numb leaves
2 Bell K J and o P Bergelin Flow through annular orif ices Transactions of the American Society of Mechanical Engineers 70593-601 1957
3 Colburn Allan P A method of correlating forced con shyvection heat transfer data and a comparison with fluid friction Transactions of the American Institute of Chemical Engineers 24 174-210 1933
4 Dittus F w and L M K Boelter Heat transfer 1n automobile radiators of the tubular type University of California Publications in Engineering 2443-461 1930
5 Gurushankariah M s Local shell-side heat transfer coefficients in the vicinity of baffles in tubular heat exchangers Masters thesis Corvallis Ore gon State Colle ge 1958 97 numb leaves
6 Knudsen James G and Donald L Katz Fluid dynamics and heat transfer New York McGraw-Hill 1958 576 p
7 Lee Kyu Sung Local shell-side heat transfer coeffishycients and pressure drop in a tubular heat exchanger with orifice baffles Masters thesis Corvallis Oregon State College 1959 118 numb leaves
8 McAdams William H Heat transmission 3d ed New York McGra ~-Hill 1954 532 p
9 Sullivan F W and 0 P Bergelin Heat transfer and fluid friction in a shell-andbulltube exchanger with a single baffle Chemica l Engineer ing Progress Symposium Series 52 ( 18) 85-94 1956
10 Wiegand J H Discussion on annular heat transfer coshyef f icients for turbulent flow Transactions of American Institut e of Chemical Eng i n eers 41147-153 1945
AP PENDIX
57
TABLE III
CALCULATED HEAT TRANSFER DATA
Baffle Hole Diameter Run No (inches)
1 - 59 1 364
60 - 102 1 216
103 - 138 1 316
139 - 206 1 516
207 - 212 No orifice
213 - 218 2nd - 1 516
TABLE III
CALCULATED HEAT TRANSFER DATA
Local Heat Transfer Coefficients Run
T0 bull Po s ition CFM hr h2 h3 h4 hs he ~ hav Nuav
1 c 1026 10 59 1476 16 09 1559 1510 1435 1203 1518 8511 2 1290 1369 1738 1878 18 05 1755 1689 1515 1773 9964 3 1416 1636 198 1 2068 1977 1924 1845 1715 1959 11030 4 1627 1991 2301 2382 2268 2194 20 ~98 1929 2249 12664 5 1776 2252 2669 2863 2713 2517 2338 2126 2620 14759 6 l2ttD 1109 2311 3317 3386 3373 3387 3394 3071 3371 18888 7 1258 3089 4583 4866 4683 4701 4643 4194 4695 26301 8 1433 38 8 5 55 83 5791 5495 5430 5436 5008 5547 31192 9 1681 4992 7378 7649 6980 6864 6870 64 28 7148 40180
10 1 D 1102 2371 3332 3511 3356 3342 3427 3102 3394 19012 11 1308 3218 4379 45 24 42 53 4255 4373 3965 43 57 24446 12 14 64 38 58 5146 5142 4839 4787 4903 4597 4963 278 79 13 1706 5218 6664 6269 58 81 5884 6237 5973 61 87 34718 14 15
1 l2D 1115 1275
2131 2661
2955 3638
2972 3720
2941 3675
2913 3576
28 22 34 74
2613 3278
2921 36 17
163 09 20246
16 1498 34 87 4644 4503 4441 4371 4343 4194 4460 25010 17 1695 4449 5743 5324 5222 5154 5157 5015 5320 298 97 18 2D 1049 1715 23 90 2550 2610 2656 2624 2208 2566 14363 19 1241 2117 2964 3145 3218 3221 3203 2759 3150 17757 20 1532 28 67 3936 4100 4188 4201 4167 3676 4118 23224 21 1674 3459 4508 4598 4746 4795 4792 4299 4688 26337 22 lU 1074 253 340 380 3 86 388 377 354 374 2097 23 1287 292 392 433 440 441 429 406 427 2394 24 1508 322 439 492 498 499 487 461 48 3 2713 25 18 07 3 38 464 519 5 24 520 499 463 5 05 28 40
~~ (]I agt
TABLE III Continued
Run No Position CFM h 1 h2 ~3 h4 h5 h6 ~ h
av Nu
av 26 c 1029 1171 1491 1589 15 28 1 4 62 1377 1293 1489 83 44 27 1266 1395 1746 1853 18 02 1685 1556 1453 1728 9704 28 1430 1637 2037 2175 2060 1909 1735 1591 1983 11159 29 1729 1982 24 96 2751 2507 2268 2030 1886 2410 13579 30 12D 1054 2934 4041 4321 4326 4423 4359 3706 4298 24160 31 1294 3385 4 8 26 52 42 5326 5450 5277 4566 52 24 293 50 32 1431 3784 5347 5721 57 bull75 58 44 5700 5084 5677 31870 33 1770 52 75 7 7 33 87 35 9005 9007 8267 7059 85 49 48050 34 lD 1058 3235 4401 4444 3877 3496 3451 3294 3934 21973 35 1263 38 98 5484 5330 4347 3964 3981 3987 4621 25823 36 18 36 6701 89 17 7855 6369 5597 5769 6283 69 01 38718 37 1 12D 1029 2404 31 8 2 3333 3459 3624 3577 3045 3435 19264 38 1315 3182 4033 4162 4310 4496 4502 4015 4301 24142 39 1426 3628 4389 4510 4573 4760 4804 43 8 5 4607 25678 40 1757 4547 5559 5(35 5931 6282 63 70 6060 5975 33471 41 2 11D 1080 2034 28 38 3155 3144 3145 2966 2540 3050 17027 42 1305 2650 3 4 87 3aoz 3595 3751 3595 3153 36 46 20405 43 1434 3167 39 07 4156 4371 4320 4126 3709 4176 23395 44 1804 4096 4 9 66 5691 5714 5586 53 15 48 65 5454 30582 45 12U 1088 409 516 557 564 5 60 535 513 5 46 30 67 46 1318 470 579 6 22 631 6 17 5 97 579 6 09 3422 47 14 13 540 640 676 6 86 681 6 60 6 54 6 69 3754 48 1773 641 740 774 782 7 69 749 746 763 42 87 49 l 11 U 1054 270 356 391 397 393 3 71 346 38 2 2133 50 1240 303 399 446 449 447 4 21 398 432 2420 51 1419 361 476 522 530 528 507 467 493 2760 52 1 1(2U 1032 236 311 342 347 344 325 301 334 18 78 53 1314 270 366 403 407 408 386 351 394 2217
(Tt tO
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ h av Nu av
54 1448 301 408 447 454 452 431 403 438 24 61 55 1782 353 494 548 544 415 529 531 506 2843 56 2U 10 61 220 287 316 320 322 303 268 310 1735 57 1216 249 335 370 377 378 353 307 363 2044 58 1322 263 356 394 398 399 374 327 384 2159 59 1639 310 433 478 481 482 452 393 465 2617
60 1D 10 68 2011 2536 2657 2681 2694 2560 15 62 2625 14938 61 1399 2520 3239 3369 3371 33r82 32 39 1946 3320 18968 62 1669 2781 3655 3820 38 76 3883 3738 2355 3794 21712 63 1959 3524 42 37 4399 4438 4497 4417 3047 4397 25156 64 2295 4426 5288 5396 5372 5240 5410 3369 5341 30680 65 2636 5490 6531 6662 6565 6379 6820 4249 6591 37938 66 3390 7869 9538 9462 9387 8924 10508 62 91 9564 59601 67 1U 1190 352 368 401 413 407 395 293 397 2256 68 1559 397 422 462 475 471 456 331 4 57 2603 69 1904 434 465 5 13 529 528 504 358 508 2901 70 2211 493 526 573 5 92 588 564 4 15 569 3257 71 2289 569 587 6 30 649 6 61 6 49 460 635 36 44 72 2727 637 6 60 7 09 733 751 743 521 719 4140 73 3210 728 755 8 15 8 43 8 62 8 54 616 826 4765 74 2nD 1210 181 2256 2393 2399 2333 2206 1325 2317 13158 75 1420 2340 2752 2899 2913 2850 2728 1701 2828 16121 76 1692 2853 3306 3452 3471 3379 3217 2134 3365 19217 77 1894 3102 3588 3713 3736 3670 3557 2455 3653 20892 78 2301 3682 4259 4433 4467 43 83 4289 2892 4366 250 30 79 2621 4117 4828 5017 5012 5030 5109 3071 4999 28785
m 0
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ hav Nuav
80 3230 5158 6006 62 13 61 18 6134 6695 4094 6233 359 87 8 1 12nD 1155 15 27 1854 2028 2064 20 85 1987 1164 1968 118 31 82 1689 2046 24 8 2 2688 2739 2760 2658 1749 2665 152 73 83 1244 2088 2317 2339 2345 2373 2381 1487 2351 13432 84 2100 3211 3539 34 21 3462 3512 3696 2575 3526 20284 85 2292 3 5 05 3761 3648 36 25 36 79 3957 2933 3734 21517 86 2907 4420 48 22 4679 46 04 4705 5206 3792 48 03 27741 87 33 80 59 35 69 38 7404 77 10 7 8 36 7 0 86 5190 7394 427 44 88 1 12D 1 4 27 2 4 58 28 31 3037 3021 2987 2927 18 57 2 9 61 16913 89 18 75 34 75 3 9 87 4230 4255 4317 4337 2734 4225 24258 90 22 59 4221 4796 5046 5052 51 01 5389 3491 5077 29206 91 2682 4978 5664 5943 5966 6054 6573 408 1 60 40 34795 92 3417 63 16 71 02 7 3 93 7385 75 40 8 6 95 51 45 7623 44017 93 c 1 5 17 1240 1305 1399 1467 1479 1429 9 26 1423 8251 94 20 34 1554 1623 1720 18 21 18 53 18 72 1215 1778 10229 95 2 3 48 1795 1843 198 5 2097 2171 2274 1540 2074 11947 96 2716 2028 2048 22 01 2 3 44 2444 2661 18 90 2340 13505 97 3247 2410 2375 2663 2778 2949 3298 2378 2793 1615 98 11 35 967 1040 1124 1186 1200 1142 728 1138 6496 99 14 06 1135 1220 1318 1384 1403 1 3 61 8 77 1336 7656
100 2311 1 8 54 18 78 1980 20 90 2136 2227 1653 2062 118 31 10 1 2666 2085 2094 2227 2 3 62 2438 2626 1902 2349 13508 102 3392 2635 2582 28 01 3026 3141 3529 2567 3016 17390
103 1 U 1235 349 395 434 436 4 28 411 286 423 2416 104 20 10 434 5 02 559 577 569 5 37 345 552 3177 105 28 14 538 626 685 711 7 21 682 424 6 8 6 3966
Q) j-J
TABIE III Continued
Run No Position CFM h1 h2 h3 h4 h5 hu h7 hav Nuav
106 3492 614 7 1 6 7 84 8 13 8 33 7 85 4 88 7 87 4562 107 4395 7 86 894 964 996 1005 9 64 640 9 65 56 06 108 50 75 9 11 10 22 1081 1112 1125 1085 7 24 1085 63 16 109 G 1344 9 22 1042 1120 1 1 46 1173 1131 7 04 1120 63 87 110 1936 1162 1340 1442 1474 1509 14 7 3 9 09 1441 82 77 111 2846 1631 1797 1902 1966 2027 2079 1342 19 2 3 11108 112 3484 207e 2144 2236 2307 2385 2574 1694 2268 13138 113 4066 24 65 24 42 2535 2648 2757 31 71 2178 2 5 96 15078 114 50 12 3059 2916 30 1 5 3176 3312 4059 2849 3105 180 46 115 1D 1362 2268 26 13 2613 26 35 2605 2503 15 46 2617 14934 116 1958 2993 3580 3580 3586 3539 3 5 02 2144 3571 20492 117 2812 4430 50 32 4913 4 9 86 4991 5196 3088 4981 287 66 118 3432 58 16 62 13 6067 61 18 60 66 6698 4143 61 16 354 16 119 40 22 71 71 7 4 62 7369 7419 7329 82 74 51 8 1 7395 42909 120 5026 105 95 11456 115 81 11574 11548 14010 80 91 11540 671 15 121 2D 1244 18 57 2277 2363 2305 2210 2107 1466 2289 13038 122 1960 2622 3240 3388 33 23 3226 31 40 2)99 3294 18919 123 2817 3762 45 87 4739 46 56 45 14 4 6 47 30 15 4624 26689 124 3491 50 22 5723 58 53 57 44 5542 60 18 3871 57 16 330 73 125 4096 61 29 68 16 69 79 6805 65 90 74 79 4677 67 98 39400 126 5037 82 27 94 60 95 69 93 57 9023 11324 65 05 93 52 542 83 127 12D 1278 14 70 1 6 48 1652 1638 1 6 34 1641 9 73 1 6 43 9369 128 1947 19 63 2155 2149 2151 2131 2190 1347 2147 12342 129 2769 2615 2791 2773 28 52 2716 2954 18 96 2783 1 60 82 130 3439 3208 3265 3239 3593 3133 3624 2515 3308 19174 131 4103 3637 35 88 3577 4077 3459 42 66 3138 3676 21343 132 49 78 45 82 44 60 44 8 1 55 17 43 25 5749 4227 4700 27288
Q) tlgt
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
133 1 12D 1299 2094 2507 2622 2625 2567 2489 1465 2578 14736 134 1973 29 56 3505 3772 3790 3718 3718 2115 3700 21290 135 2788 3941 4727 5069 5099 5 0 07 5231 2984 4976 28781 136 3473 5155 59 81 6308 6339 62 39 68 96 4204 6217 36052 137 4118 6135 71 8 6 7662 7731 76 91 87 16 49 8 5 7568 43985 138 4973 7765 94 75 10396 10861 10694 13646 66 64 10357 602 25
139 1ttn 1253 1242 1493 1460 1442 1431 1424 8 84 1457 83 01 140 2366 1942 2150 1961 1910 1897 19 62 1206 1980 11400 141 3461 3007 2957 2562 2513 2606 3143 18 51 2660 15400 142 4325 3942 3571 3060 2999 3198 4248 2631 3207 18618 143 5677 508 6 4359 39 88 3800 42 29 57 78 36 26 4094 23824 144 67 59 64 55 5330 4988 47 25 5494 2517 48 09 5134 29906 145 84 08 9326 72 26 7726 85 56 9172 12319 7733 8170 47626 146 86 54 9831 7582 818 9 94 90 9869 13116 78 97 8783 512 96 147 7376 7335 58 7 6 5941 5796 68 29 81 65 5954 6111 35662 148 2 11 D 4254 4106 48 02 4994 5038 5042 56 78 3419 4969 28881 149 5708 5487 6253 6466 6524 6527 78 63 45 8 2 64 43 37566 150 69 7 8 7983 9440 9848 98 34 97 32 13249 6701 9714 566 59 151 1254 1434 18 53 1947 1915 1850 1760 1186 1891 10772 152 2713 2696 3175 32 94 3288 3237 3288 20 44 3249 18728 153 87 30 118 07 14733 15758 15504 15305 26297 9617 15325 892 71 154 5811 5278 6543 6861 69 30 69 82 7 8 74 4478 68 29 39531 155 4246 3780 4736 4975 49 66 4936 5162 3113 4903 28301 156 (v 1270 8 15 935 959 966 9 51 9 23 6 35 953 5430 157 2714 1164 1390 1427 1447 1454 1455 9 08 1430 8242 158 4310 1655 18 96 1942 1988 2002 2111 1305 1957 11349
(j) ~
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 fry hav Nuav
159 6012 2208 2400 2450 2513 2548 28 20 18 00 2478 14416 160 7279 2696 2881 2927 2989 3081 3599 2340 2970 17326 161 86 90 3257 3360 3 3 76 34 26 3558 4455 2943 3430 2000 162 12D 4368 2209 2600 2558 2518 2466 2774 1753 2536 14713 163 5833 2730 3092 3028 2974 2913 3501 2287 3002 174 78 164 7643 3320 3681 3630 3651 3530 4623 3181 3623 21116 165 87 39 3920 4303 4300 4708 4178 61 60 3937 4372 25456 166 1268 962 1203 1205 1186 1118 1084 725 1178 6693 167 2678 14 67 1785 1779 1752 1698 1726 10 70 1754 88 49 168 1 12D 12 83 936 1217 1414 1397 1239 1190 7 65 1317 7484 169 2729 2502 2930 2914 2934 2956 2979 17 52 2934 16866 170 4345 3884 4357 4283 4318 4421 4836 28 59 4345 25151 171 6036 5546 5858 5764 5791 6028 7129 4184 5860 34045 172 6578 7167 7769 7907 79 82 8263 10492 5915 7980 46437 173 87 84 10237 112 23 120 26 12727 12968 185 19 85 98 12236 71103 174 1278 1344 1803 18 72 1835 1790 1712 1063 1825 10355 175 2711 2328 2972 2932 2893 28 78 2863 1667 2919 167 51 176 4351 3934 4414 4353 4281 4321 4654 28 63 4342 25088 177 5994 5076 5824 5838 5818 59 29 6914 4205 5852 33885 178 1 11 U 1223 388 432 465 464 449 435 338 453 2585 179 2351 521 602 6 22 675 6 57 619 436 639 3687 180 34 48 6 05 1725 803 8 27 8 11 760 518 792 4593 181 4513 718 850 934 9 68 9 57 8 99 609 9 27 5386 18 2 5714 8 32 981 1060 1102 11 06 1034 6 59 1062 61 82 183 6997 1025 1182 1258 1295 1309 1234 8 18 1261 7 3 44 184 8709 1295 1487 1 5 42 1594 1626 1612 1156 1562 9080
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
185 2 12D 4249 3560 4400 4670 4791 4695 47 81 2931 4639 268 37 186 5737 4926 58 54 61 92 6248 62 38 67 78 4134 6131 35590 187 7432 6390 7726 83 46 85 44 86 34 10371 5658 8313 48310 188 8723 7718 107 88 11933 12099 13046 186 22 79 39 119 67 69505 189 1 4 35 1340 1735 18 57 18 52 17 81 1711 1144 18 06 10256 190 2718 2399 3023 3187 3207 3138 30 53 1931 3139 18025 191 7 5 07 6189 80 11 9200 9427 9703 11364 5720 9085 527 38 192 8544 78 42 10666 125 42 13312 13775 178 20 6976 125 74 729 86 193 1287 1417 16 97 18 7 18 69 18 08 1720 1046 1800 10223 194 27 17 2450 2940 3187 3214 3157 3054 1749 3125 17954 195 42 53 3560 4222 45 90 4679 46 63 4743 2741 4539 26247 196 6068 48 69 57 79 6335 65 8 6 66 04 7172 4338 63 26 366 78 197 7389 58 86 72 8 6 82 23 8584 8936 10658 50 60 8257 4798 6 198 86 88 78 91 100 27 120 56 130 29 14299 190 81 6492 12353 71850 199 5864 4694 5 6 67 61 94 6419 65 48 7192 3950 6207 360 14 200 2 D 4177 38 36 4547 48 09 4775 4628 5006 2715 46 90 261 30 201 5712 5170 62 39 66 38 6599 6604 7518 4167 65 20 378 00 202 73 63 7201 8986 98 43 9733 9914 13353 6219 9619 55810 203 8604 10043 13118 148 41 150 42 158 66 25206 82 5 3 14717 85290 204 12 68 1506 18 41 1971 1966 1868 1799 11 42 1913 10880 205 2659 2571 3127 3276 32 50 3130 3069 18 80 3196 18 350 206 39 80 36 76 4347 4573 45~67 4473 46 34 28 37 4490 25910
o 207 Orifice 11496 10 64 1360 15 39 1 5 80 1 6 15 1496 8 58 15 24 88 83 208 9433 8 95 11 78 13 26 1394 1386 1263 727 1346 78 48 209 7387 746 9 77 1123 1184 1159 1048 6 11 1111 64 74 210 52 36 566 7 66 900 934 909 8 21 499 8 27 48 02
0) CJ1
TABLE III Continued
Run No Position CFM h 1 h2 hs h4 h5 h6 h7 hav Nuav
211 212
3309 1293
414 257
563 3 19
6 68 3 57
6 91 3 37
6 72 351
7 37 337
38 4 2 46
4 40 341
3748 1942
213 214 215 216 217 218
c of 2nd 1 516 1235
1919 2712 3320 4153 4704
1532 2447 35 46 4312 5567 74 29
2 1 87 3312 4225 52 86 6902 8 6 50
2360 3555 4340 56 12 7 0 49 8 9 40
2409 3598 4 8 85 5718 7713 9593
2347 2101 35 33 3453 48 00 49 62 5562 59 86 72~6 7 8 79 93 76 11237
1243 20 64 3054 4 2 8 1 5114 6983
2326 35 00 4638 5545 7225 91 40
132 13 200 27 26672 31968 41711 52811
bull
67
TABLE IV
PRESSURE PROFILE DATA
Baffle Flow Qpening Rate ~p
(Inches) Position (CFM) (Inches 295 S G Fluid)
1 364 l2 11 U 1012 0 254 1248 0197 1493 0 141 1718 0112
c 1000 9 80 1210 1710 1436 28 75 1746 4320 1011 1080 1277 2050 1393 3020 1 6 28 4450
12D 1011 9 75 1236 1520 1450 2510 1603 3450
1 D 1011 975 1256 1700 1480 2690 158 1 4070
1 12D 1010 950 1259 1750 1462 2650 1631 3710
2 11 D 1124 1315 1360 2130 1505 2850 1689 4125
1 216 12U 1294 045 1949 0324 2374 0282 2704 0225 3367 0169
c 1326 265 18 81 5 90 2313 990 2731 1480 3439 2660
12D 1272 2 49 1957 661
68
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Pos ition (CPM) Inches 2 95 S G Fluid)
2559 1275 3033 1940 3639 3025
1 216 1nD 1257 242 16 96 476 2117 8 05 2561 1280 2990 1895 3431 26 bull00
1 316 12U 1309 0 479 2004 0422 28 28 0 352 3526 0281 42 28 0225 5199 0225
c 1308 1 43 1998 272 28 14 5 10 3478 795 4248 1235 5048 1885
l2D 1286 140 2005 3 45 2831 725 3495 1180 4194 1805 5046 2945
1 11D 1322 150 2039 352 2841 735 43 77 1980 5378 3440
1 516 12U 1278 0493 2732 0493 4315 0408 5744 0352 7494 0352 8932 0422
c 1300 0 506 2731 1985 4310 348 6080 6 45
69
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Position (CPM) (Inches 295 SG Fluid)
7607 1090 8830 1585
l2D 1343 0549 2738 225 4566 583 6112 1195 7536 2055 9043 3415
1 516 1uD 1249 0464 2713 224 4155 579 5620 1150 7428 2115 90 70 3405
1 12D 1301 0493 2735 220 4501 616 61 50 1235 7440 2065 8862 3445
2D 1265 0 478 2750 226 4366 594 6578 1270 7678 2240 8945 5280
2 12D 1295 0493 2725 222 4293 600 5807 1120 7568 2200 9070 3615
TABLE V
RATE OF HEAT TR AN SFER Ar THE BAFFL~~ CID-TT ER
Orifice Size
(Inches)
Flow Rate
( CFM)
Re d e G tU
R~) 055 Nuav NuPr-l3
1 364 10 26 12 90
8 075 10015
43400 54 600
85 11 99 64
95 83 112 19
1416 11 140 59 900 110 30 124 20 16 27 12 800 68 900 126 64 142 60 17 29 13 610 73 200 135 79 152 90 17 76 13980 75 200 147 59 166 19
1 216 11 35 14 06
8 600 10 660
27000 33500
6 4 96 76 56
73 14 8 6 12
1517 11500 36100 82 51 9291 20 34 15400 48400 10229 115 18 23 11 17500 55000 118 31 13322 2348 17 800 55900 11947 13452 2666 20 200 63400 13508 15210 27 16 20 600 64700 135 05 152 07 32 47 24600 77200 161 57 18 193 3392 25 700 80700 17390 195 8 1
1 316 1344 19 36
9898 14 260
24800 35 700
63 8 7 8 2 77
71 92 93 20
28 46 20 9 60 52 500 111 08 125 08 34 84 25 660 64200 131 38 147 93 40 66 50 12
29900 36900
74800 92400
150 78 18046
169 78 203 20
~ 0
TABLE V Continued
Orifice Flow Re Size Rate d e G R~rmiddot55 NuPr-13(Inches) (CFM) U Nuav
1 516 12 70 8 847 16800 54 ~0 61 14 2 14 18 900 35800 82 42 92 80 43 10 30 000 56900 11349 127 79 60 12 41900 79400 14416 16232 7279 50700 96100 17326 19509 86 90 60540 115000 20098 22529
TABLE VI
RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
Orifice Size
(Inches)
1 364
1 216
1 316
Flow Rate
(CFM)
1054 1294 1431 1681 1770
1068 1399 1669 1959 2295 2636 3390
1299 1973 2788 34 73 4118 4973
Re deG Mshy
8 300 9870
11260 13200 13 930
8100 10600 12650 14850 17400 19980 25700
9 570 14500 20500 25600 30300 36600
R~r-6 51900 61700 70500 82 500 87 100
28200 36900 44000 51700 60 600 69500 89400
26100 39600 56000 69900 82700 99 900
Nuav
2416 293 5 3187 4018 4805
14938 18968 21712 25156 30680 37938 59601
14736 21290 28781 36052 439 85 60225
Uu Pr-1 3
27204 33050 3589 4524 541 0
16820 21358 24448 28326 34546 427 18 67111
16593 23973 32407 40595 495 1 678 13
TABLE VI Continued
Orifice Flow Re Size Rate deG R~rmiddot6 NuPr-13(Inches) (CFM ) M- Nuav
1 516 1268 88 30 17700 108 8 1225 2689 18700 37400 1835 2066 3980 27700 55700 2591 2917 4177 29100 58 500 2713 3055 5712 39800 80000 378 0 425 6 7362 51300 103000 5581 6284 8 604 59 900 120000 8529 9604
74
TABLE VII
EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER
l 516 Inch Orifice
Center ot 2nd Baffle 4 Downstream
Plow Rate (CFM)
1235 1919 2712 3320 4153 4704
Flow Rate (CFM)
1270 2714 4310 6012 7279 8690
(Re)eb -8600 1321
13400 2003 18900 2687 23100 5197 28900 4171 32800 5281
Center ot Single Battle
-8847 543
18900 824 30000 1135 41900 1442 50700 1733 60540 2001
(Nu)(Pr)-l3
1487 2255 3003 3600 4697 5946
(Nu)(Pr)-13
611 928
1278 1623 1951 2253
75
ABLE VIII
HEAT TRANSFER IN THE TEST SECTION WITHOUT ORIFICE
CFM Ute) 0b h Nu
1293 5-951 3 41 1942
33 09 15251 649 3746
5236 24193 827 4802
7387 34001 1111 6474
9433 43419 1346 7848
11496 52-914 1524 8883
76
TABLE IX
PRESSURE DROP FUNCTION
Orltlee Size Flow Rate incbea ~CFM (Re)eb X 10bull8
1 364 1011 7957 0808 1256 9885 1468 1480 11648 2765 1581 12443 4160 1689 1_3293 4 020
1 216 1257 9530 1327 1696 12858 2663 2117 16049 4615 2561 19415 7581 2990 22668 11560 3431 26011 16440
l 316 1322 9736 1819 2039 15016 4332 2845 20952 9275 3495 25739 15300 4377 32014 26800 5378 39607 50100
1 516 1011 7 957 oaos 1256 9885 1469 1480 11646 2765 1581 12443 4160 1689 13293 4020
77
TABLE X
EXPERIMENTAL DATA
Baffle Hole Diameter Run No
1 - 59
60 - 102
103 - 138
139 - 206
207 - 212
213 - 218
(Inches)
1 364
1 216
1 316
1 516
No Baffle
2nd - 1 516
TABLE X
EXPERIMENTAL DATA
Run Thermocouple Reading s (mv) No Position CFM I tc1 tc2 tc3 tc4 t c 5 tc6 tc7 tcair
1 c 1026 530 2055 1825 1768 1782 1802 1837 1965 1198 2 1290 612 2059 18 65 1809 18 32 1851 1880 1965 1160 3 1416 714 2151 1970 1931 1965 1988 2026 209 5 1130 4 1627 8 21 2235 2084 2 049 2093 2126 2173 2266 1130 5 1776 865 2203 2033 1970 2015 2084 2159 2 264 1121 6 12D 1109 542 1636 1507 1499 1499 1498 1498 1528 1218 7 1258 651 1670 1522 1503 1513 1513 1516 1548 1221 8 1433 750 1625 1480 1467 148 3 1487 1487 1516 1153 9 168 1 8 73 1656 1494 148 1 1511 1517 1517 1543 1159
10 1rtD 1102 485 1545 1450 1437 1446 1447 1442 1466 1220 11 13 08 6 10 1571 1470 1460 1476 1476 1469 1498 1194 12 1464 730 1 623 1509 1508 1528 1 5 32 1524 1548 1173 13 11 06 8 71 1663 1559 158 1 1606 160 6 1 583 1601 1190 14 1 12D 1115 520 1698 1579 1575 1 577 1580 1590 1615 1280 15 1275 6 10 1692 1567 1558 1 561 1570 1580 1601 1234 16 1498 770 1760 1619 1630 1 635 1642 1645 1661 1204 17 1695 912 1775 1635 1670 1689 1686 168 6 1701 1165 18 2D 1049 510 1736 15~2 1567 1558 1 553 1558 1620 1236 19 12 41 610 1655 1517 149 1 148 1 148 1 148 4 1546 1108 20 1 5 32 7 35 1720 1550 1530 1520 1519 1523 158 0 1104 21 16 74 8 8 0 1900 1 727 1714 1696 1691 1692 1753 1169 22 1U 1074 38 5 3 324 2740 2534 2478 2 465 2503 258 0 1210 23 1287 4 35 3510 2 870 2682 2 610 2599 2638 27 1 9 1190 24 1 5 08 470 3 618 2920 2690 2 637 2627 2 664 2747 1177 25 18 07 525 4 088 3235 2962 2905 2910 2988 3130 1169
z ())
TABLE X Continued
Run No Position CFM I tc1 tc 2
Thermocouple Readings te3 tc4 tc5
(mv) tc6 tc7 tcair
26 c 10~29 6 32 2340 2~092 2032 2060 2~097 2152 2~213 1211 27 12 66 679 2270 2 047 1993 2013 2069 2142 2 210 1 182 28 1430 723 2336 2097 2033 2080 2153 2~255 2 356 1 138 29 1729 8 52 2318 2070 1980 2061 2158 2279 2367 1121 30 12D 1054 570 1520 1 4 20 1402 1400 1396 1400 1 443 1159 31 1294 6 69 1599 1469 1444 1439 1433 1 442 1485 1168 32 1430 7 88 1720 1562 1536 1532 1528 1537 158 0 118 5 33 1770 8 81 1641 1488 1450 1~441 1 441 1_466 1518 1 163 34 1D 1058 548 1579 1498 1495 1526 1553 1_557 1 571 1 276 35 1263 640 1609 1509 1515 1570 1599 1598 1 598 1 266 36 18 36 8 47 1538 1452 1483 1553 1602 1 590 1 558 1195 37 1 12D 1029 5 41 1 578 1499 148 4 1473 1461 1465 1-512 1200 38 1315 6 30 159 1 1504 1493 1482 1470 1470 1505 118 5 39 1 4 26 743 1765 168 1666 1660 1645 1642 1678 1270 40 1757 8 54 1744 1648 1634 1620 1598 1 593 - 1612 1223 41 2D 1080 5 30 1734 1604 1570 1 570 1570 1 588 1 640 128 1 42 1305 6 40 1744 1622 1589 1 608 1593 1 609 1 661 1240 43 1434 750 1798 1687 1658 1 636 -1641 1 661 1 711 1_220 44 18 04 8 41 1 764 1666 1607 1605 1614 1 635 1 675 1205 45 12nu 1088 415 2614 2295 2195 2 169 2174 2217 2256 1171 46 1318 477 2805 2477 2371 2342 2364 2 401 2 438 1 163 47 1413 5 28 2930 2 646 2 555 2 526 2532 2570 2 577 1 199 48 1773 550 2740 2518 2450 2431 2448 2 479 2 480 1 170 49 1 11 U 1054 380 3175 2670 2505 2 461 2467 2 534 2 621 1 258 50 1240 420 3268 2738 2 546 2 510 2 508 258 2 2 649 1214 51 1419 451 3364 2B07 2 632 2590 2 590 2 651 2773 1 215 52 1 12U 1032 360 3 165 2 629 2 450 2402 2403 2 473 2 bull568 1 163
--I lt0
TABLE X Continued
Run No Position CFM I tc1 tc2
lhermocoup1e Reading s tc3 tc4 t c 5
(mv) tc6 tc7 tc a ir
5 3 1314 38 9 3178 2592 2411 2367 2361 2432 2555 1140 54 1448 403 3095 2544 238 1 2336 2336 2390 2476 1158 55 178 2 427 3006 2434 2286 2253 255 3 2299 2397 1154 56 2 11U 1061 360 3369 2814 2619 2567 2560 2650 2833 1220 57 1216 360 3044 2512 2338 2290 2288 2374 2566 1150 58 1322 387 3196 2614 2425 2383 2382 2472 2670 1138 59 1639 403 3020 2438 2272 2238 2238 2318 2502 1127
60 1D 1068 612 1552 1424 1400 1395 1396 1426 1745 0945 61 1399 612 1355 1246 1230 1229 1230 1250 1509 0872 62 1669 710 1436 1293 1272 1265 1266 1286 1551 0847 63 1959 900 159 5 1468 1444 14 38 1432 1446 1720 0851 64 2295 730 1169 1105 1098 1099 1108 1100 1298 0781 65 2636 8 80 1202 1129 1121 1126 1 138 1115 1342 0748 66 3390 9 35 1060 o 9s7 0999 1001 1017 0971 1154 0703 67 1nu 1190 370 2225 2188 2104 2080 2120 2209 2 7 15 0990 68 1559 368 2005 1950 1871 18 48 1876 1951 2408 0916 69 1904 368 1870 18 1 4 17 34 1711 1730 18 07 2238 0875 70 22 bull11 471 228 6 2 204 2099 2063 2092 218 $ 2732 0840 71 2289 471 2030 2000 1925 1895 18 96 19 5 2498 0785 72 2727 4 71 1854 18 23 1753 17 23 1716 3758 2241 0743 73 3210 471 1680 1651 158 6 1559 1551 158 1 1950 omiddot7o9 74 2uD 1210 404 1261 1212 1198 1197 1205 1222 139 1 0978 75 14 20 540 1321 1260 1242 1 240 1249 1268 148 7 0918 76 1692 7 18 1467 138 6 1364 1361 1376 1405 1678 0883 77 18 94 903 1708 1 591 1565 1560 1575 1603 1948 0 857 78 2301 903 1530 1432 1407 1402 1415 1432 1738 0815
ro 0
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc117 tcair
79 2621 6 50 1069 1 020 1009 1009 1009 1007 1~189 o739 80 3230 901 1200 1128 1113 1119 1119 1086 1341 0694 81 82
l2D 1155 1689
360 575
1191 1345
1142 1252
1122 1218
1118 1210
1118 1209
1132 1228
1292 1446
0916 0822
83 1244 430 1163 1134 1131 1130 1129 1132 1292 0877 84 2100 645 1175 1135 1147 1 142 1138 1122 1286 0757 85 2292 8 25 1 354 1310 1327 1330 1323 1285 148 6 0728 86 2907 8 23 1180 1138 1151 1158 1149 1107 1268 0687 87 3380 902 1113 1049 1025 1011 1006 1042 1178 0673 88 89
1 12D 1427 1875
480 615
118 2 1140
1140 1095
1124 1077
1125 1075
1129 1072
1137 1072
1290 1243
0880 0790
90 2259 8 41 1296 1231 1207 1206 1203 1182 1419 0757 91 2682 8 80 1231 1170 1149 1147 1142 1112 1350 0731 92 3417 940 1142 1092 1076 1076 1069 1021 1252 0693 93 c 15 17 431 1321 1298 1268 1249 1250 1273 1522 0841 94 2034 505 1285 1263 1235 1209 1205 1206 1464 0759 95 2348 6 10 1395 1379 1334 1302 1286 1268 1536 0732 96 2716 706 1486 1480 1427 1383 1358 1311 1572 0 700 97 3247 7 56 1417 1430 1375 1320 1284 1223 1450 0660 98 1135 400 1425 1388 1352 1329 1330 1 364 1651 0893 99 14 06 440 1379 1341 1304 128 2 1281 1305 1583 0 831
100 2311 680 1602 1593 1553 1514 1502 1480 1 7 27 0 802 101 2666 680 1471 1469 1428 1390 1372 1335 1564 0761 102 3392 798 1491 1 509 1449 1395 1372 1305 1534 0 719
103 1U 1235 410 2469 2295 2173 2165 2226 2361 3120 0 897 104 2010 410 2017 1848 1 737 1706 1747 1865 2582 0753 105 28 14 410 1682 1535 1457 1427 1437 1520 2109 0 660
00 t-
TABLE X Continued
Ru n Thermocouple Rea ding s (mv No Positi on CFM I tc1 tc2 tc3 tc4 tc5 tc6 tc7 tcair
106 3492 440 1649 1499 1420 1391 1390 1470 2042 0620 107 4395 550 18 33 1679 1597 1564 1570 1640 2223 0583 108 5075 588 1779 1642 1580 1550 1552 1 615 2 191 0548 109 c 1344 398 1464 1 399 1364 1353 1350 1380 1689 0 907 110 1936 459 1369 1290 1253 1242 1 237 1259 1574 078 2 111 2846 580 1347 128 5 1251 1232 1220 1215 1 5 23 0 683 112 34 8 4 700 1392 1369 1339 1317 1299 1259 1599 0 636 113 4066 8 13 1449 1458 1427 1391 1363 1270 1595 0 591 114 5012 930 1484 1530 1500 1453 1420 1272 1580 0 580 115 1D 1362 513 1269 1218 1 217 1214 1220 1238 1460 0 893 116 19 58 600 1187 1122 1121 1120 1124 1133 1352 0798 117 2812 705 1052 1008 1015 1010 1011 1001 1218 0691 118 34 32 913 1105 1075 1085 1081 1086 1047 1301 0645 119 4022 980 1038 1021 1026 1023 1029 0983 1211 0 609 120 5026 982 0 8 61 0839 0836 0836 0837 0791 0955 0570 121 2D 1244 475 1320 1246 1233 1240 1255 1275 1434 0925 122 1 9 60 5 50 1160 1088 1074 1079 1089 1100 1260 078 7 123 2817 6 80 1096 1024 1 013 1018 1029 1022 1201 0 700 124 3491 960 1248 1175 1163 1172 1192 1153 1435 0 658 125 4096 989 1141 1089 1078 108 9 1105 1051 1310 0629 126 50 37 989 0983 0933 0929 0 936 0949 0880 1090 0 602 127 128
12D 1278 1947
402 545
1270 1261
1 230 1216
1228 1216
1230 1 215
1235 1223
1242 1219
1483 1514
0 913 0778shy
129 2769 695 1273 1234 1237 1221 1251 1212 1525 0678 130 131 132
34 39 4103 4978
8 40 9 80 9 80
1336 1448 1271
1322 1458 1 288
1328 1 462 1286
1 259 1 356 1157
1353 1492 1311
1261 1329 1138
1 555 160 7 1343
0 629 0 600 0599
(l) l)
TABLE X Continued
Run No Position CFM I tel tc 2
Thermocouple Readings tc3 tc4 tc5
( mv) tc6 tc7 tcair
133 1 l2D 1299 5 16 1 28 1 1212 1196 1195 1205 1221 1478 0869 134 1973 6 15 1163 1098 1073 1071 1079 1083 1343 0751 135 136
27 88 34 73
802 9 -_78
1187 1214
1099 1131
1069 1104
1066 1101
1075 1~110
1l061 1066
1370 1360
0662 0618
137 4118 9 81 1084 1010 0983 0979 0982 o937 1209 0581 138 4973 98 1 0969 0897 0 868 0855 0860 0799 1041 0572
139 1D 1253 409 1371 1293 1298 1301 1309 1321 1578 0928 140 2366 480 1130 1 090 1 121 1130 1137 1132 1390 0744 141 34 61 6 38 1081 1086 1152 1161 1147 1069 1382 0644 142 143 144
4325 5677 6759
7 90 939 998
1110 1115 1034
1161 1208 1139
1253 1268 1180
1265 1302 1215
1228 1230 1123
1080 1056 0970
13$913r12 8
0601 0561 0542
145 84 08 989 0863 0961 0934 0895 0871 0 785 09 9 0530 146 86 54 9 80 0808 0901 0 872 0821 0809 0733 0891 0498 147 7376 9 80 0 927 1032 1027 1 040 0961 0889 1032 0511 148 2D 4254 776 1 050 0 981 0965 0961 0962 0922 1155 0579 149 5708 991 1102 1031 1014 1009 1010 0931 1227 0528 150 69 78 990 0914 0853 0839 0 839 0843 0759 0996 0521 151 1254 490 1 479 1352 1329 1334 1351 1379 1607 0930 152 2713 7 00 1310 1220 1201 1201 1211 1209 1516 0723 153 8730 991 0809 0756 0742 0745 0 748 0663 0874 0543 154 5811 966 1219 1108 108 6 1081 1079 1033 1330 0650 155 42 46 8 02 1248 1136 1114 1114 1118 1103 1376 0 699 156 c 1270 429 1671 1571 1551 1545 1563 1600 1933 0929 157 2714 488 1398 1285 1 267 1258 1262 1275 1628 0729 158 4310 642 1424 1318 1299 1282 1283 1261 1683 0617
co ~
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc7 tc a 1r
159 60 12 780 1461 1388 1370 1349 1343 1279 1700 0 573 160 72 79 8 60 1402 1344 1330 1312 1292 1189 1 566 0 520 161 8690 982 1472 1442 1437 1 422 1392 1224 1602 0 521 162 163
12D 4368 5833
6 30 8 30
1195 1368
1105 1270
1111 1283
1117 1294
1131 1313
1081 1194
1369 1553
0613 0 553
164 76 43 959 1428 1338 1348 1341 1371 1180 1488 0535 165 8739 984 1345 1272 1272 1208 129 3 1059 1361 0550 166 1268 459 1701 1548 1541 1547 1589 1 625 1976 0 973 167 2678 570 1485 1351 1349 1356 138 1 1 385 1795 0760 168 169
1 12D 128 3 2729
448 650
1664 1314
1501 1232
1425 1233
1428 1229
1491 1229
1527 1232
1869 1571
0 962 0767
170 4345 847 1245 1179 1187 1182 1172 1132 1476 0 650 171 6036 9 76 1139 1109 1117 1114 1095 1020 1332 0588 172 6578 9 72 0982 0949 0942 0938 0926 0 8 50 1079 0560 173 87 84 9 72 0880 0854 0 8 36 0822 0818 0 749 0941 0585 174 1278 480 1564 1416 1397 1403 1417 1445 1733 0998 175 2711 590 128 3 1175 4 1178 1182 1187 1195 1493 0796 176 4351 8 90 1331 1259 1266 1275 1272 1235 1592 0 682 177 5994 9 60 1228 1152 1150 1151 1143 1075 1 360 0644 178 lU 1223 408 2282 2140 2052 2052 2106 2188 2626 0 878 179 2351 408 178 1 1623 158 5 1519 1556 1634 2068 0717 180 3448 482 1888 1675 1570 1541 1572 1665 2199 0629 181 4513 563 2026 1797 168 4 1644 1670 1770 2385 0583 182 5714 589 1913 1700 1610 1568 1580 1 682 2382 0551 middot 183 6997 653 1903 1718 1643 1611 1612 1700 2326 0 549 184 8709 6 80 1738 158 3 1543 1510 1498 1519 1 912 0577 185 186
2 12D 4249 5737
660 9 74
1055 1221
0 979 1122
0960 1093
0 952 1088
0959 1090
0 956 1054
1147 1350
0661 0602
187 7432 9 8 1 1065 0981 0951 0942 0 939 0881 1135 0582 CD ~
TABLE X Continued
Run No Position CFM I t o1 to 2
188 87 23 9 83 0944 0 879 189 1435 585 18 26 1630 190 2718 690 1433 1298 191 7507 950 1070 0961 192 85 44 964 0982 0 881 193 1287 600 1806 1668 194 2717 7 80 1579 1444 195 4253 8 81 1371 1260 196 60 68 9 78 1252 1152 197 73 89 975 1100 1000 198 86 88 973 0953 0 871 199 58 64 9 81 1269 1155 200 2D 4 1 77 915 1362 1251 201 5712 975 1213 1111 202 7363 9 78 1036 0 951 203 8 604 973 0932 0861 204 1268 6 95 2015 18 20 205 2659 6 96 1405 1295 206 39 80 7 98 1261 1174
No 207 Orifice 114 96 509 1325 1148 208 94 33 509 1477 1243 209 7487 5 09 1686 1409 210 5236 505 2094 1691 211 3309 428 2188 1 778 212 1293 392 2976 2560
Thermo ooup1e Readin g s (mv) to 3 to4 to
5 to
6 to7 toair
0 851 0847 0 8 29 0759 0987 0592 158 4 1583 1611 1647 1993 0986 1270 1266 1 279 1298 1604 0 789 0916 0908 0900 0 858 1115 0602 08 39 0 823 0 818 0 770 1035 0602 1609 1602 1629 1676 2153 0979 139 1 1385 1400 1 430 1938 0776 1212 1201 1205 1201 1601 0669 1 105 1086 1086 1 052 1371 0621 0952 0936 0923 0870 1195 0582 0 8 20 0 801 078 1 0 729 1044 0569 1108 1090 108 2 1043 1407 0610 1218 1221 1241 1202 1582 0659 1081 1083 1084 1031 1 368 0622 0921 0924 0919 0 841 1111 0 610 08 34 0831 0 821 0 751 1003 0 630 1761 1761 1 809 1861 2399 0966 1271 1271 1295 1311 1650 0797 1150 1150 1161 1149 1440 0703
1083 1057 1053 1109 1566 0~530 1158 1125 1138 1217 1763 0 526 1291 1250 1278 1383 2038 0542 1518 1478 1519 1657 2420 0 589 1596 1557 1601 1737 2441 0688 2370 2344 2409 2561 3 297 0921
()) (11
TABLE X Continued
Run Thermocouple Readings (mv) No Position CFM I tc 1 tc2 tc3 tc4 tc tc tc tc i5 6 7 a r
C of 2nd 213 516 1235 4 63 1 432 1291 1265 1258 1 268 1 308 1550 0 971 214 1919 6 17 1357 1223 1196 1191 1199 1211 1461 0 851 215 27 12 8 35 1401 1259 1278 1220 1230 1218 1511 0 762 216 3320 981 1439 1305 1270 1259 1275 1238 1450 0719 217 41 53 980 1251 1142 1132 1094 1121 1088 1305 0 695 218 404 987 1102 1042 1030 1 bull006 1014 0960 1133 0681
Supplementary Equations
Calculating temperatures from thermocouple readings
t = -026tc)2 + 3512(tc) + 3201 (26)
where t is the temp in deg F and tc is the thermocouple reading in millishyvolts
Calculation of the thermal conductivity of air
k = 00000245ta + 0 0132 (27)
where k is the thermal conductivity in Btuhr rt2 degFft and ta is the air temp 1n OF
I I
bull co m
8
CHAPTER III
~PERI1ffiNTAL APr ARATUS
The heat transfer test section was essentially a
single tube heat exchanger The inner tube was a l-in
OD aluminum tube with an electrically heated probe midshy
way between the two ends of the tube
Test Section
The shell as constructed from lucite plastic tubing
2 5-in I D and 3-in O D The te t section d a total
lengt h of 54 58 inches I t consisted of two sections
The upstream section was 40 i n ches in length in order to
assure freedom from entrance effects and the downstream
section was 13 12 inches in length To further assure
uniform flow a bundle of short copper tubes was placed a
few inches downstream from the entrance Both of these
sections had 12 i nch flanges on one end so t hat a 18
i nch thick orifice plate could be clamped between them
Heat transfer coefficients were measured in the vicinity of
t h is orifice A cross section of the center of the test
section is shown in Figure 1 and the experimental appara~
tus is shown in Figure 2
Cooled air supplied by a Roots -type blower was used
as the shell-side fluid throughout this study It entered
the test section through a l-in ID 1 12-in OD plasshy
tic pipe at the upstream end of the calming section Tbs
j Jl l 6- 11 BOLTS II I nbull middot~11 I HEATING ELEMENTS
J T ( T
-f-shy - - - f-_- __L
7 777 _y A
IT 1] I
I
FIGURE I CROSS SECTION OF TEST SECTION AND PROBE
10
FIGURE 2 EXPERIMENTAL APP1Ub~fUS
11
air left the test section through nine equally spaced 12
ineh holes placed around the side of the tube at the exit
end
Sensing Probe Assembly
The sensing probe was designed to measure the local
heat transfer coefficients at any point along the tube and
around the tube in the test section The tube was designed
so that it could be easily moved up- and downstream to
measure the heat transfer coefficients at various positions
in relation to the orifice
The sensing tube assembly consisted of the sensing
probe the thermoctmple lead s and selector switch the
power lines and the two aluminum tubes between which the
probe was centered
Imbedded in the sensing probe were seven iron-constanshy
tan thermocouples for measuring the temperatures around the
tube The lead wires from these thermocouples were conshy
nected to a seleotor switch at the downstream end or the
aluminum tube A layer of Saran wrap was placed around the
tube over the t hermocouple and three lengths of Trophet C
resistance ribbon were wrapped around the tube nd conshy
nected in series to the power leads
The heating surface of the probe was formed by these
three one inch wide strips of Trophet C resistance ribbons
The ribbons were 0002 inches thick and had a resistance of
12
0 271 ohms per foot and a thermal conductivity of 763
Btuhr ft 2 degFft They were held in position by four
copper bars placed in four parallel longitudinal slots
These copper bars served as connectors for the electrical
leads A photograph of the sensing probe is shown in
Figura 3 and a drawing of the assembled probe is given in
Figure 4
Power Source
Direct current was used to heat the resistance ribbon
on the sensing probe The current was regulated by a slide
wire resistor The po er source consisted of a Raytheon
Voltage Stabilizer to stabilize the city power source at
115 volts and an automatic selenium rectifier with an alshy
ternating current input of 115 volts at 60 cycles per
second and an output of 12 volts and 35 amperes direct
current
Temperature Measuring
The temperatures around the sensing probe were calcushy
lated from the emf readings of the ironbulloonstantan thermoshy
couples The emf measuring system consisted of the seven
probe thermocouples a separate thermocouple for measuring
the inlet air temperature a thermocouple selector switch
a cold junction and a Leeds and Northrup Type K Potentishy
ometer The potentiometer was placed on a Fischer
13
THERMOCOUPLE JUNCTIONS~ ~------- HOLES FOR THERMOCOUPLE LEADS
~----- SCREWS
~ff+--- CONNECTING BARS
END VIEW
POWER LEADS SOLDERED TO LOWER CONNECTING BAR
iER PLASTIC PIECE
RESISTANCE RIBBONS LOCATION OF THERMOCOUPLES
FIGURE 4 DRAWING OF ASSEMBLED SENSING PROBE
15
Vibradamp support to absorb the vibrations produced by the
air blower
Air Source
Air was used as the shell-side cooling fluid during
the study The air was pumped through the test section by
a Roots type air blower with a rating of 280 ofm at 3 12
psig outlet pressure The hot air leaving the blower was
passed tbxfugh two finned-tube box-type coolers and one
tubular edoler to oool it to approximately room temperature
The air flow rate was measured by passing it through a
flow measuring orifice in the line Two sharpbull edged orishy
ficas were used f or flow measurements The calibration
curves for these orifices were presented by Ambrose (1
p 166)
The pressure taps on each side of the orifice were
connected to two differential manometers containing 0 83
and 2 95 specific gravity fluids respectively The presshy
sure drop through the test section and test orifice was
measured by a pressure tap placed 13 inches upstream and
one placed 6 12 inches downstream from the orifice Two
pressure ga ges were used to measure the pressure at the
inlet to the flow orifice and to indicate the statio pres~
sure at the test section inlet
16
Pressure Probe
A probe was designed to measure the pressure drop
between the pressure tap 13 i nches upstream from the ori shy
fice baff le and any point downstream from the tap The
probe eonsisted of a l~in OD copper tube with six 132
i n ch holes even l y s paced around the tube The upstream
pressure tap and the pressure probe were connected to a
differential manometer so the pressure drop to various
points up- and downstream of the orifice could be measshy
ured
17
CHAPTER IV
EXPERIMENTAL PROGRAM
The experimental program was designed to measure the
heat transfer coefficients and pressure drops in the vicinshy
ity of annular orifices The four orifice sizes studied
were 1 364 1 216 l 316 and 1 516 inches~ The inner
tube used in each case was a 1-in OD alumintim tube
Hence tube to baffle clearances were respectively 3128
232 332 and 532 of an inch
Heat transfer coefficients were measured at poait~ons
1 i nch upstream at the orifice center and at 12 1
1 12 and 2 inches downstream for all orifices In addishy
middottion the heat transfer coefficient at a point 2 12
inches downstream from the 1 516 inch orifice was measured
and at the points 12 l 12 and 2 inches upstream from
the 1 364 inch orifice
The heat transfer coefficients at each point were
measured at five different flow rates for the 1 364 inch
orifice and at six different flow rates for the other orishy
fice sizes The high pressure drop through the small orishy
fice size limited the number of flow rates which could be
studied
The flow rate was calculated from the pressure drop
across the flow orifice This flow was corrected to cubic
feet per minute at 68degF and one atmosphere pressure by
18
using the orifice pressure and the test section pressure
which were measured by pressure gages
It was desired to determine a relationship between the
heat transfer coefficient and the total pressure drop for
each orifice size The pressure drop across each orifice
at various flow rates was measured by means of the presshy
sure probe described in Chapter III It was also desired
to obtain pressure profiles for each orifice size since
these might be similar to the heat transfer profiles The
pressure drop was measured from a point 13 inches upstream
of the orifice to points at 1 and 12 ineh upstream the
orifice center 12 1 1 12 and 2 inches downstream
The experimental program is summarized in Table I
TABLE I
SUla~RY OF EXPER IMENTAL PROGRAM
Position Investigated-Distance from Orifice-Inches
Orifice Range of Flow Rate Size Heat Transfer Pressure Drop CFM at 68degF amp 1 atm
1 364 2U 1 12U 1U 12U c 12U C 12D lD 10 - 18 l2D lD 1 12D 2D 1 12D 2D
1 216 1U c 12D lD 1 l2D 2D 12U c 12D lD 10 - 35
1 316 1U c 12D lD 1 l2D 2D l2U C 12D lD 12 - 50
1 516 1U c x2D lD 1 l2D 1U 12U C 12D 12 - 90 2D 2 1 2D l D 1 l2D 2D 2 12D
20
CHAPTER v
EXPERI MENTAL PROCEDURE
The experimental procedure for measuring the heat
transfer coefficients ~d corresponding flow rates reshy
quired the following procedure
(1) Install the orifice size to be studied in the
test section
(2) Place the heat transfer probe in the position up
or downstream from the orifice where the middot heat
transfer rate is to be studied
(3) Fill the cold junction thermos with cracked ice
(4) Measure the atmospheric pressure
(5 Open bypass line from blower and close line to
test section
(6) Turn on the cooling water for the exchangers used
to cool the air leaving the blower
(7) Start the automatic selen ium rectifier by turning
on the t 1mer bull
(8 ) Connect the voltage stabilizer to the wall outlet
(9) middot Set the slide wire resistor to the maximum re shy
s1atanee I
(10) Start the blower
(11 Open the line to the test section until the de shy
sired flow rate is obtained
(12) Switch on the probe direct current power source
21
(13) Adjust the slide wire resistor to obtain the
desired current
(14) After the thermocouples have reached equilibrium
values record the e m bullf across each of the
seven probe thermocouples and also the entering
air thermocouple
(15) Record the direct current amperage
(16) Record the gage pressure at the flow orifice and
the entrance to the test section
(17) Record the manometer measurement of the pressure
drop across the flow orifice and also the presshy
sure drop through the test section
22
CHAPTER VI
CALCULAT ION OF EXPERIMENTAL DATA
The local heat transfer coefficients were calculated
from the temperatures measured on the probe surface the
air temperature and the current input The results were
calculated by using the Alwae III-E computer
The general expression for calculation of the heat
transfer coefficients was derived by Ambrose (1 p 79)
The equation is derived by making an energy balance around
a small increment of the center resistance heating ribbon
The two ribbons tnstalled adjacent to the center ribbon
reduced the amount of logitudinal conduction and assured
little longitudinal temperature variation in the center
ribbon
A heat balan ce on this small increment of resistance
ribbon yields the following
(the heat conducted in) + (heat generated) = (heat
conducted out) +(Heat convected to the fluid) + (heat
radiated to the surroundings) + (Heat conducted into
the plastic center of the probe)
This gives the equation
kzw dtdS + 12RdS kzws [ t + (~) ds] + hwdS (t-ta )
+ ~Aad wd o middot+ qcAond 1 -~- wdS 5 )
23
Hence solving for h gi~ea
i2R kz d2t Qrad qcond w + -d$2 - ~- A
h = ( 6)t - ta
Since S = re where 9 equals the enclosed angle ~n radians
dS rd9 ( 7)
and
dt - dt (8)dS - rd9
Differentiating with respect to S
d2t (9)rd9dS
from which
(10)
Substitut1ng into the equation for heat transfer coeffishy
cient gives
h = i2R Qcond A (11)
w
The rate of radial heat conduction into the plastic
tube making up the probe was assumed to have negligible
effect on the heat transfer coefficient It was also
assumed that the heat loss by radiation from the ribbon
was negligible since all data were obtained with the ribbon
at a temperature less than 125degF
24
When t he rad iation and conduction terms are neglected
Eq (11) becomes
(12)
The following con stants are known
R = 0 271 ohmsft
w = 100 i n ches
k = 763 Btuhr rt2 degFft
z = 0 002 inches
r = 12 inch
Eq (12) putting 9 in degrees then reduces to
1110 12 + 2404 d 2t d92
( 15)h = ------~--~-------t - ta
Thi s equation was programed for the Alwac III- E comshy
puter and used to calculate the local heat transfer coefshy
ficients from the observed data
The average heat transfer coefficient around the tube
at a given position in the t est section was calculated by
averaging the local coefficients calculated from Eq (13 )
It was found 1n the course of the experimental work
that thermocouple numbers 1 and 7 were indicating higher
temperatures than would be expected This resulted in h1
and ~ being lower than the other local coefficients around
the tube Since the fluid was flowing parallel to the axis
of the probe the circumferential variation i n rate of heat
25
transfer should be small Hence in obtaining the average
coefficient around the tube the values of h1 and h7 were
not used even though they were calculated and are tabulated
1n Table I II in the Appendix
Then
(14
A Nusselt number as calculated from this aver age heat
transfer coefficient using the tube diameter as the characshy
teristic dimension
(15)
The air flow rates through the test section were calshy
culated by measuring the pressure drop across the flow orishy
fice the air temperature the pressure at the flow orifice
and the pressure at the entrance to the test section The
orifice calibration curves (1 p 166 ) were used to obtain
a value of the orifice coefficient f8e where Q equals
the flow in cubic feet per minute at 68deg F and one atmosmiddot
phere pressure and te is the density of air at the exchanger
and e the density of the air at the flow orifice The
den sity of the air can be expressed by
e = 2 703 p (16)T
where T equals the temperature in OR and P equals the absoshy
lUte pressure i n lb1n2 Using the value of e Qfo from
26
the calibration charts as A and Eq (16) solving for Q
gives
( 17
This equation was used to calculate the flow rate for
each flow studied
The Reynolds number used i n the correlation of the
data was the equivalent Reynolds number defined as
Re)eb ~ d2 - dl)Uf ( 18 ) lL
where d1 is the outside diameter of the inner tube and d2
is the orifice diameter U is the flow velocity through the
annular orifice e is the density of the air and U- is t he
viscosity of the air This equation can be transformed t o
(Re) b = 1611 Q (19) e dl + d2
where d1 and d2 are in inches
The pressure drop data were calculated i nto a dimenshy
sionless pressure drop function cent where
d1 )22( ~ P)gc f av(d2 shycent 2 bull (20
M-
For air this equation reduces to
where d2 and d1 are in i nches D P is expressed i n inches of
2 95 specific gravity fluid and P av is expressed as lbft3
27
CHAPTER VII
ANALYSIS OF DATA
In analyzing the heat transfer data an attempt was
made to correlate it 1n terms of the dimensionless groups
(Nusselt number Prandtl number and Reynolds number) which
appear in Eqs (3) and (4) Consequently all of the av~
erage heat transfer coefficients hav were brought into
the form ( Nu)( Pr)~3 bull The Nusselt number was based on the
tube diameter and the thermal conductivity of the air at
the flowing temperature The tube diameter was used in the
Nusselt number because comparison could then be made with
previous experimental work on heat exchangers which have
commonly used the Nusselt number defined as in Eq (15)
From the standpoint of dimensional analysis this is
equivalent to considering the tube diameter as the characshy
teristic length so far as the heat transfer is concerned
The Prandtl number of the air was taken as 0 7 in all
cases
Variation of Heat Transfer Rate with Distance from the Baffle
Considerable variation was observed in the rate of
heat transfer in the vicinity of the baffle In order to
obtain the variation with respect to position the term
(Nu)(Pr)-13 was plotted versus the flow rate Q for each
position and orifice studied Cros s plots were then made
28
at constant flow rates in order to obtain the variation of
(Nu)(Pr) -13 with position The resulting cross plots are
shown 1n Fi gures 5 6 and 7 for the four orifices studshy
ied
About one inch upstream from the orifice the heat
transfer coefficient begins to rise rapidly and continues
to do so until it reaches a maximum some distance downshy
stream After the maximum point the heat transfer coef fi shy
cient decreased slowly The heat transfer rate was found
to reach a maximum at a different position downstream for
each orifice size These figures also show that for a
given orifice size the maximum heat transfer rate occurs
a pproximately at the same point for all flow rates The
position of the maximum point f or each or ifice size is
shown in Table II
The region immediately downstream from the orifice is
one of h i gh turbulence due to the jetting action of the air
flowing through the orifice As the air flows t hrough the
orifice the streamlines continue to converge for some dis shy
tance downstream The point of maximum heat transfer is
probably at the point where the streamlines be gin to diverge
and a boundary layer begins to build up on the tube Tle
decreasing heat transfer coefficient beyond the maximum
point indicated the formation of a boundary layer
Since the position of the maximum point is independent
of flow rate middot it is possible to correlate it with respect
_ ct 11shyz-
100
0 136 ORIFICE
(
I 0
I )
~ 00
~p 0
I 0
--r--- ~
ISCFIII
-_ OCFM
rbull abull
~ middot~ a-1 z-
12fORIFICE
100
200
100
0 0 UPITRAM ORIFICE DISTANCE CENTER
CFM
h I DOWNSTREAM
DISTANCE
FIGURE 5 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLpound
30
too
700
800
100 ~ f gtf
400
z ~
100
100
100
0
13fORIFICE
~ -~ -- ---
)
~
~
-
I ~ ~OCFM
I vI~-~ OCFM
J ---
Iamp CFM
I 0 I I UPSTREAM ORIFICE DOWNSTREAM DIITANOE GENTER DIITANCI
FIGURE 6 VARIATION OF HEAT TRANSFER RATE WITH DISllNCE FROM BAFFLE
--
--- --
31
100
100
700
100
_ 100
f 9- 400 z-
100
tOO
100
0 - I 0 I I I UHTRIAM OAtfiCI DOWIIITMAM
+ I tyl6 ORIFICE
v I
~~ ~CFM
I v ~CFMI
v v 7
~~ v ~ iOCFM
- ~~ I-shy1-shy ~ICFM
DIITMCI OINTIR DIITANCI
FIGURE 7 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLE
32
TABLE II
POSITION OF MAXIMUM HEAT TRANSFER
Position of Maximum Orifice Size Heat Transfer
(inches) (inches downstream)
1 364 050
1 216 100
1 316 125
1 516 200
33
to orifice size Figure 8 shows the effect of the orifice
size on the position and value of the maximum heat transfer
at a constant flow rate of 15 cubic feet per minute It
can be seen that the larger the orifice size the further
downstream the point of maximum heat transfer occurs
Also as the orifice size increased the rate of heat
transfer decreased for a given flow rate The broken line
indicates the variation of the point of maximum heat transshy
fer with position and size The position of the point of
maximum heat transfer rate downstream from the orifice was
correlated with orifice size by means of the dimensionless
groups (Lde) and (d1de) where L is the distance downshy
stream from the orifice where the maximum rate of heat
transfer occurs d1 is the outside diameter of the inner
tube and de is the equivalent diameter of the orifice
ie de = d2-dlbull
Figure 9 shows a plot of Ld 6 versus d1d6 for the
four orifice sizes studied The four points on this logshy
log plot are approximately in a straight line and the
equation of this line is
Lde = 0 44 d1de)028 (22)
Although the above relationship represents a correlashy
tion of dimensionless groups it is based upon only one
tube diameter and needs to be substantiated further by
studying other tube diameters and other orifice sizes
34
aoo
400
aoo ~
-~ middot-CLshyJ z
200 -
100
0
ORIFICE CENTER
l~
l
t
I J~
1pound~
I
0 I I~
AT 15 CFM
-
bull ~ 1~6~
~ v~
~
~--~~6
~~~ ___ v v V -_
~ o q
~ I 16
v
~
ogWNSTREANI STANCE
FIGURE 8 EFFECT OF ORIFICE SIZE ON POSITION AND VALUE OF MAXIMUM HEAT TRANSFER
35
50
loshy____ -~
~ ~ -shylltl-shy~ r0
2 10 30
FIGURE 9 CORRELATION OF THE POINT OF MAXIMUM HEAT TRANSFER WITH
ORIFICE SIZE
36
Correlation of Data at the Baffle
The heat transfer data were correlated by obtaining a
relationship between the group (Nu)(Pr)-13 and a
Reynolds number based on twice the clearance (d2 - d1
between the tube and the baffle It was found that the
most satisfactory correlation could be obtained when the
term - d1 was used as the length term in the Reynoldsd2
number
Figure 10 shows the variation of the heat transfer
rate at the center of the orifice e xpressed as a function
of Reynolds number and the orifice size This shows that
for a given Reynolds number the heat transfer at the center
of the orifice is greatest for the smallest orifice size
In order to obtain a general correlation of the data
shown i n F1gure 10 the effect of the dimensionless ratio
d1de was considered This ratio considers all of the
geometric factor s needed to describe the annular orifice
The thiclaless of the orifice plate is also a factor but
was constant i n this i nvestigation
The data for the heat transfer at the baffle center
are shown in Figure 11 in which (Nu)( Pr)-13 is plotted
versus (Re)ebd1 de) 0 55 This data on a log-log plot
lies on a straight line for (Re)eb( dld8 )0 55 greater
than 3 x 104 The equation for cor relating the heat
37
4XI~middot~-r~------~--~~------~
Icf t--to_+--_c-c-________ SYMBOL SIZE
0 1~4
6 ~~
9 ~~ -o ~
(Re)eb
FIGURE 10 RATE OF HEAT TRANSFER AT BAFFLE CENTER
38
500
0
4 0 lcf
~ ~
~ ~iC-
~ ~
~IL 0~ 0 SYMBOL SIZE-
p 0 1364-
r 6 1~16 -~ -
9 1~16 --o 1~16
I I
FIGURE II CORRELATION OF HEAT TRANSFER DATA AT BAFFLE CENTER
39
transfer at the center bullOf the a nnular orifice was found by
the method of least s quares to be
(Nu)( Pr)-1 3 = 0018 ( Re)ebO Bl( dlde)04~ (23)
3 x 104 ltRe)eb(a1de)055 lt 105)
Rate of Heat Transfer at the Point of Maximum Heat Transfer-The heat transfer rate at the point of maximum heat
transfer is plotted in Figure 12 to show the variation with
Reynolds number and the size of the orifice It is shown
gives the h1gh st heat transfer ~ate at its point of maxibull
that for a given Reynolds number the smallest orifice size yen il
mum heat transfer
The data ~or the maximum poi~t could be correlated by
plotting (Nu) Pr)-13 versus (Re)eb(d1de)06 This plot
is shown 1n Figure 13 and the resulting eurve shows that
(Nu(Pr)-13 is not a simple p0wer function of the Reynolds
number as was the case for heat transfer at the baffle
center The reason for this is probably because other
factors such as intensity and scala of turbulence should
be considered At the orifice center the streamlines of
the flowing stream are converging_ and thus the flow is
quite stable Downstream from the orifice is a region of
large eddy currents and probably large scale turbulence
These factors could con ceivably cause the results which
were obtained for the point of maximum heat transfer
40
If)
~middotshy Q_-I z_
10~~~--------r----~~--~--
SYMBOL SIZE
0 13$4
6 1~8
Q 13-18
-o 1~8
7)(104
(Re)eb
FIGURE 12 RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
41
Ia ~
0 I
c ~ ~ c v
~ ~lt w ~
17
~ b
v ~ ( SYMBOL SIZE
-~ 0 f-64 -v ~ 6 t211e
~ Q I~~~
-o - l~rs I I
FIGURE 13 CORRELATION OF HEAT TRANSFER DATA AT THE POINT OF MAXIMUM HEAT TRANSFER
4 2
Effect of Upstream Baffles on Heat Transfer at the Orifice Center
The heat transfer rate at the orifice center using the
single orifice in a test section is a pproximately 13 of the
value that was obtained by Lee (7) using a model heat exshy
changer with orifice baffles Lee investigated the cent r al
baffles of the heat exchanger and thus the coeff icients he
obtained would be affected by the presence of a number of
upstream baffles To determine the effect of upstream
baffles an additional l 516 inch baffle was placed four
inches upstream 1n the test section The resulting data are
shown in Figure 14 where (Nu)(Prmiddot)-13 is plotted versus
(Re) eb for the case of a single baffle 1n the test section
and also the case of an additional baffle placed four inches
upstream Comparison is made with the results obtained by
Lee middot(7) using a four-baffle and a ten-baffle model heat exshy
changer Good a greement is obtained with Lees work and the
results show the marked effect that upstream baffles have on
the downstream heat transfer rate The additional up tream
ba ffle caused sufficient turbulence 1n the test section to
i n crease the heat transfer rate nearly three-fold at the
center of the next baffle
Heat Transfer i n the Test Section with No Orifice
In order to check the accuracy 6f the equipment the
orifice baffle was removed and the heat transfer mea sured
with the probe in the empty test section The data were
43
~~BAFFLES
0 l BAFFLE -shy
ll_9 2 BAFFLES
V 4 BAFFLES-LEE
4 10 BAFFLES- LEE lJf ~
~rv ~~ ~ v flvv ~~
I ~ J ~ L v
0
v
( V
40 3XIo 7XIa
(Re)eb
FIGURE 14 EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER AT BAFFLE CENTER
44
compared with heat transfe r coefficients predicted by the
equations for annuli which are recommended in the litera shy9
ture The two equa~ ions u sed tor comparison were
(hfe)=0 023 (rltGr e (~~ur4 (~r45 (24)
which was presente~ by Wiegant (10)
and ( h ) (cnM~5(M~l o14 o 023 CPG k j Mij - (de GJMb )0 2 ( 2 5)
which was presented by McAdams (8 p 242) The comparshy
i son is s hown in Figure 15 lq (25) gives a value which
is low by about ten percent while Eq (24) g ives values
which are high by as much as twenty -five percent when comshy
pared with the experimental data The se equations are gembull
erally considered to give coefficients with an accuracy of
about twenty percent Therefore the present experimental
data are within the accuracy of these equations Also the
plot indicate s that for a Reynold s number greater than 2 x
104 the slope of the line is the same for the experimental
data as for the equations
Pressure Drop Data
The total pressure drop across the orifice was measured
as a function of the flow rate and the orifice size The
pressure drop was expressed as a d1mens1onleas quantity r)
which ie plCltted ver sus the Reynolds number in Figure 18
The pressure drop function cent correlates for all or1f1oe
45
200
100
s z
10 5XI10 10
0 EXPERIMENTAL
--McADAMS
-WIEGAND L
V
~ ~ ~
P ~ ~
LL~ L
v~
~
v v
v 1 ~ ~ v
v -gt
~
~ ~
~
6Xid
FIGURE 15 HEAT TRANSFER WITH NO BAFFLE
46
0 1~4 -~ a 6 t216
Q t316 lJ J
-0 as a )t
A LEE I -shy SULLIVAN 8
p
10bull
BERGELIN
I _ll I
I ~
i I
~middot
lo II
f fl
J j
~middot
A)101
1q
I Ill
1 I3 X 10ao1
FIGURE 16 ORIFICE PRESSURE DROP FUNCTION VS REYNOLDS NUMBER
47
sizes- The present data extends the range covered by preshy
vious workers and agrees well with their work The preshy
vious work of Lee () for a heat exchanger containing 10
orifice baffles and also the data of Su livan and Bergelin
(9) for pressure drop in a model heat exchanger with a
single baffle is shown 1n Figure 16 long with the present
results~ This figure may be used to predict the preseure
drop from the equivalent Reynolds number of the annular
orifice
The pressure drop between individual points 1n the
vicinity of the orifice and an upstream pressure tap wa s
measured to obtain a pressure drop profile As might be
expected 1n all cases the profiles showed a rapid decrea e
in static pressure immediately upstream from the orifice
There was however little or no recovery of the pressure
loss downstream The 1 364 inch orifice did show a maxishy
mum point in the pressure drop but this maximum occurred at
the orifice center and total recovery was reached about 12
inch downstream
Heat Transfer at the Baffle and Maximum Point as a Function of Pressure Drop
In order to compare the effect of the total pressure
drop on the heat transfer at the baffle and the point of
maximum heat transfer Figure 17 was plotted showing
(Nu)(Pr)-13 as a function of the total pressure drop This
shows that for a given pressure drop the largest orifice
48
1200
1000
~ a -sshyz-
100
60 100 700
AT MAXIMUM POINT I 15116 2 13116 3 1~6 4 1364
AT ORIFICE CENTER
60
1
v
r ~ ~ ~
5
~
8 7
13116
8
~
1364
v
~
e6
1~6
v
~~ v ~ ~ -~ ~
~
~ v
l
~
vamp
I ~ ~
~
v L ~
v
I-
5
k= ~~
~ ~ ~
--I
v ~
FIGURE 17 HEAT TRANSFER AT THE BAFFLE AND MAXIMUM POINT AS A FUNCTION OF
ORIFICE PRESSURE DROP
49
size has the greatest heat transfer coefficient This is
true at both the orifice center and at the point of maxishy
mum heat transfer
Another comparison can be made by plotting the heat
transfer coefficient and the pressure drop versus the orishy
fice size at a constant flow rate Figure 18 shows this
plot This graph shows that at a constant flow rate the
pressure drop as well as the heat transfer coefficient
increases as the size of the orifice is decreased In
choosing an orifice size for maximum efficiency 1t would
be necessary to know the pumping power available as well
as the heat transfer desired
70 I I 700
AT 15 CFM 60 ---
~ aug
50 ---
NV
40 ~
~ ~ ~
~ _
MAXIMUM POINT ---- --- ~
1-----t---~ _
~00Qj ~
~t--- ORIFICE CENTER 10 1100
1---~ n
u0 01 02 03 Q35
a ltl
de inches
FIGURE 18 VARIATION OF HEAT TRANSFER RATE AND PRESSURE DROP WITH ORIFICE SIZE AT A CONSTANT FLOW RATE
cn 0
51
CHAPTER VI II
SUMMARY OF RESULTS
This study revealed several significant facts about
the heat transfer in the vicinity of annular orifices
Probably the most important contribution was the presshy
entation of the heat transfer profiles in the vicinity ot
the annular orifice ~ r s shown that t~ local heat
transfer coeffieient re~ches a maximum at a point downshy
stream from the orifice The distance downstream at which
this maximum oocurs is t1ven by the equation
22
The heat transfer coefficients at the center of the
orifice were correlated and found to follow the equation
(Nu)(Pr)-13 = 00176 (Re)eb08l(d 1de) 0 middot4~ (23)
3 x 104 lt( Re) 9 b( d1d6 )055 ltlo5 )
The heat transfer at the point of maximum heat trans
fer for each orifice size was correlated and presented in
Figure 13 as a plot of (Nu)(Pr)-l3 versus (Re)eb(d1de) 06
No simple po-orer relationship exists between the terms
Intensity and scale of turbulence downstream from the orishy
fice are probably important factors which affect the heat
transfer
The large effect of an upstream orifice on the heat
transfer rate at the second orifice was demonstrated by the
52
study of two 1 516 inch orifices in the test section The
added turbulence at the center of the second orifice was
found to raise the heat transfer rate almost three times
over that obtained for a single baffle
The pressure profiles in the vicinity of the orifice
indicate that nearly all the pressure drop occurs at the
orifice center~ Total pressure drop data were correlated
by a pressure drop function cent as a function of the Reynolds
number and good agreement obtained with the results of other
workers
The pressure drop and heat transfer data were correbull
lated by plotting the heat transfer as a function of the
pressure drop for each orifice size It was shown that for
a given pressure drop the largest orifice size gives the
greatest heat transfer coefficient
As a final presentation it was shown that the pressure
drop and the heat transfer coefficient both i ncrease i n
value at a constant flow rate as the orifice size is de shy
creased This is important in choosing the optimum clearshy
ance for orifice baffles
53
CHAPTER IX
RECOMMENDATIONS
A great deal of work remains to be done in the field of
evaluating shellmiddotside heat transfer coefficients This
study included only one tube size and air was the only f luid
used It is recommended that further studies be conducted
using other fluids and tube sizes It will also be necessary
to study several baffle types
The adde d turbulence due to a s e cond baffle placed upbull
s t ream would suggest that the heat transfer coef ficients at
a certain position i n relation to a baffle would increase as
the flow progressed through the exchanger It is recomshy
mended that an extensive s t udy should be made between baffles
the full length of a model heat exchanger
It is further recommended that the pressure drop study
be continued to include other fluids tube sizes and baffle
arrangements
Effects of turbulence downstream from the baff le should
be studied by i n vestigations with hot-wire anemometer equipshy
ment to determi ne t urbulence scale and i ntensity
54
NOMENCLATURE
Area of heat transfer
Heat capacity of the fluid
Outside diameter of the tube
Orifice diameter
Equivalent diameter of the orifice (d2 - dl)
Inside diameter of the test section
Inside diameter of the tube
Gravitational constant
G Mass velocity
h Local heat transfer coefficient
Coefficient of heat transfer from surface to fluid
i Direct current amperes
k Thermal conductivity of the fluid
L Distance downstream of the point of maximum heat transfer
p Absolute pressure
L P Total pressure drop across the orifice
Q Flow in cubio feet per minute at 1 atmosphere and 680 F
q Heat transferred
Thermal energy conducted into the sensing probe
Thermal energy radiated from the resistance ribbon
Resistivity of the resistance ribbon
s Length of the resistance ribbon
T Temperature oR
55
t Temperature of the resistance ribbon deg F
ta Temperature of the bulk stream oF
tw Wall temperature of the tube OF
U Veloc ity of the fluid
w Width of the resistance ribbon
z Thickness of the resistance ribbon
eeuro Density of the fluid in the test section
Density of the fluid at the flow orificef 0
AL Viscosity of the fluid
E9 Angle measured around the tube
Dimensionl ess groups
(Nu) Nusselt number hd1k
(Pr Prandtl number C~k
(Re)eb Equivalent Reynolds number at the baffle (d2 - d1 )uejt-Lshy
(Re)e Equivalent Reynolds number in the test section ( d 8 - d 1 )U fu
cent Orifice pressure drop function 2(~P ) gc~av(d2 - d1) 2
Al
56
BI BLIOGRAPHY
1 Ambrose Tommy W Local shell-side heat transfer coefshyficients in baffled tubular heat exchanger PhD thesis Corvallis Oregon State College 1957 183 numb leaves
2 Bell K J and o P Bergelin Flow through annular orif ices Transactions of the American Society of Mechanical Engineers 70593-601 1957
3 Colburn Allan P A method of correlating forced con shyvection heat transfer data and a comparison with fluid friction Transactions of the American Institute of Chemical Engineers 24 174-210 1933
4 Dittus F w and L M K Boelter Heat transfer 1n automobile radiators of the tubular type University of California Publications in Engineering 2443-461 1930
5 Gurushankariah M s Local shell-side heat transfer coefficients in the vicinity of baffles in tubular heat exchangers Masters thesis Corvallis Ore gon State Colle ge 1958 97 numb leaves
6 Knudsen James G and Donald L Katz Fluid dynamics and heat transfer New York McGraw-Hill 1958 576 p
7 Lee Kyu Sung Local shell-side heat transfer coeffishycients and pressure drop in a tubular heat exchanger with orifice baffles Masters thesis Corvallis Oregon State College 1959 118 numb leaves
8 McAdams William H Heat transmission 3d ed New York McGra ~-Hill 1954 532 p
9 Sullivan F W and 0 P Bergelin Heat transfer and fluid friction in a shell-andbulltube exchanger with a single baffle Chemica l Engineer ing Progress Symposium Series 52 ( 18) 85-94 1956
10 Wiegand J H Discussion on annular heat transfer coshyef f icients for turbulent flow Transactions of American Institut e of Chemical Eng i n eers 41147-153 1945
AP PENDIX
57
TABLE III
CALCULATED HEAT TRANSFER DATA
Baffle Hole Diameter Run No (inches)
1 - 59 1 364
60 - 102 1 216
103 - 138 1 316
139 - 206 1 516
207 - 212 No orifice
213 - 218 2nd - 1 516
TABLE III
CALCULATED HEAT TRANSFER DATA
Local Heat Transfer Coefficients Run
T0 bull Po s ition CFM hr h2 h3 h4 hs he ~ hav Nuav
1 c 1026 10 59 1476 16 09 1559 1510 1435 1203 1518 8511 2 1290 1369 1738 1878 18 05 1755 1689 1515 1773 9964 3 1416 1636 198 1 2068 1977 1924 1845 1715 1959 11030 4 1627 1991 2301 2382 2268 2194 20 ~98 1929 2249 12664 5 1776 2252 2669 2863 2713 2517 2338 2126 2620 14759 6 l2ttD 1109 2311 3317 3386 3373 3387 3394 3071 3371 18888 7 1258 3089 4583 4866 4683 4701 4643 4194 4695 26301 8 1433 38 8 5 55 83 5791 5495 5430 5436 5008 5547 31192 9 1681 4992 7378 7649 6980 6864 6870 64 28 7148 40180
10 1 D 1102 2371 3332 3511 3356 3342 3427 3102 3394 19012 11 1308 3218 4379 45 24 42 53 4255 4373 3965 43 57 24446 12 14 64 38 58 5146 5142 4839 4787 4903 4597 4963 278 79 13 1706 5218 6664 6269 58 81 5884 6237 5973 61 87 34718 14 15
1 l2D 1115 1275
2131 2661
2955 3638
2972 3720
2941 3675
2913 3576
28 22 34 74
2613 3278
2921 36 17
163 09 20246
16 1498 34 87 4644 4503 4441 4371 4343 4194 4460 25010 17 1695 4449 5743 5324 5222 5154 5157 5015 5320 298 97 18 2D 1049 1715 23 90 2550 2610 2656 2624 2208 2566 14363 19 1241 2117 2964 3145 3218 3221 3203 2759 3150 17757 20 1532 28 67 3936 4100 4188 4201 4167 3676 4118 23224 21 1674 3459 4508 4598 4746 4795 4792 4299 4688 26337 22 lU 1074 253 340 380 3 86 388 377 354 374 2097 23 1287 292 392 433 440 441 429 406 427 2394 24 1508 322 439 492 498 499 487 461 48 3 2713 25 18 07 3 38 464 519 5 24 520 499 463 5 05 28 40
~~ (]I agt
TABLE III Continued
Run No Position CFM h 1 h2 ~3 h4 h5 h6 ~ h
av Nu
av 26 c 1029 1171 1491 1589 15 28 1 4 62 1377 1293 1489 83 44 27 1266 1395 1746 1853 18 02 1685 1556 1453 1728 9704 28 1430 1637 2037 2175 2060 1909 1735 1591 1983 11159 29 1729 1982 24 96 2751 2507 2268 2030 1886 2410 13579 30 12D 1054 2934 4041 4321 4326 4423 4359 3706 4298 24160 31 1294 3385 4 8 26 52 42 5326 5450 5277 4566 52 24 293 50 32 1431 3784 5347 5721 57 bull75 58 44 5700 5084 5677 31870 33 1770 52 75 7 7 33 87 35 9005 9007 8267 7059 85 49 48050 34 lD 1058 3235 4401 4444 3877 3496 3451 3294 3934 21973 35 1263 38 98 5484 5330 4347 3964 3981 3987 4621 25823 36 18 36 6701 89 17 7855 6369 5597 5769 6283 69 01 38718 37 1 12D 1029 2404 31 8 2 3333 3459 3624 3577 3045 3435 19264 38 1315 3182 4033 4162 4310 4496 4502 4015 4301 24142 39 1426 3628 4389 4510 4573 4760 4804 43 8 5 4607 25678 40 1757 4547 5559 5(35 5931 6282 63 70 6060 5975 33471 41 2 11D 1080 2034 28 38 3155 3144 3145 2966 2540 3050 17027 42 1305 2650 3 4 87 3aoz 3595 3751 3595 3153 36 46 20405 43 1434 3167 39 07 4156 4371 4320 4126 3709 4176 23395 44 1804 4096 4 9 66 5691 5714 5586 53 15 48 65 5454 30582 45 12U 1088 409 516 557 564 5 60 535 513 5 46 30 67 46 1318 470 579 6 22 631 6 17 5 97 579 6 09 3422 47 14 13 540 640 676 6 86 681 6 60 6 54 6 69 3754 48 1773 641 740 774 782 7 69 749 746 763 42 87 49 l 11 U 1054 270 356 391 397 393 3 71 346 38 2 2133 50 1240 303 399 446 449 447 4 21 398 432 2420 51 1419 361 476 522 530 528 507 467 493 2760 52 1 1(2U 1032 236 311 342 347 344 325 301 334 18 78 53 1314 270 366 403 407 408 386 351 394 2217
(Tt tO
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ h av Nu av
54 1448 301 408 447 454 452 431 403 438 24 61 55 1782 353 494 548 544 415 529 531 506 2843 56 2U 10 61 220 287 316 320 322 303 268 310 1735 57 1216 249 335 370 377 378 353 307 363 2044 58 1322 263 356 394 398 399 374 327 384 2159 59 1639 310 433 478 481 482 452 393 465 2617
60 1D 10 68 2011 2536 2657 2681 2694 2560 15 62 2625 14938 61 1399 2520 3239 3369 3371 33r82 32 39 1946 3320 18968 62 1669 2781 3655 3820 38 76 3883 3738 2355 3794 21712 63 1959 3524 42 37 4399 4438 4497 4417 3047 4397 25156 64 2295 4426 5288 5396 5372 5240 5410 3369 5341 30680 65 2636 5490 6531 6662 6565 6379 6820 4249 6591 37938 66 3390 7869 9538 9462 9387 8924 10508 62 91 9564 59601 67 1U 1190 352 368 401 413 407 395 293 397 2256 68 1559 397 422 462 475 471 456 331 4 57 2603 69 1904 434 465 5 13 529 528 504 358 508 2901 70 2211 493 526 573 5 92 588 564 4 15 569 3257 71 2289 569 587 6 30 649 6 61 6 49 460 635 36 44 72 2727 637 6 60 7 09 733 751 743 521 719 4140 73 3210 728 755 8 15 8 43 8 62 8 54 616 826 4765 74 2nD 1210 181 2256 2393 2399 2333 2206 1325 2317 13158 75 1420 2340 2752 2899 2913 2850 2728 1701 2828 16121 76 1692 2853 3306 3452 3471 3379 3217 2134 3365 19217 77 1894 3102 3588 3713 3736 3670 3557 2455 3653 20892 78 2301 3682 4259 4433 4467 43 83 4289 2892 4366 250 30 79 2621 4117 4828 5017 5012 5030 5109 3071 4999 28785
m 0
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ hav Nuav
80 3230 5158 6006 62 13 61 18 6134 6695 4094 6233 359 87 8 1 12nD 1155 15 27 1854 2028 2064 20 85 1987 1164 1968 118 31 82 1689 2046 24 8 2 2688 2739 2760 2658 1749 2665 152 73 83 1244 2088 2317 2339 2345 2373 2381 1487 2351 13432 84 2100 3211 3539 34 21 3462 3512 3696 2575 3526 20284 85 2292 3 5 05 3761 3648 36 25 36 79 3957 2933 3734 21517 86 2907 4420 48 22 4679 46 04 4705 5206 3792 48 03 27741 87 33 80 59 35 69 38 7404 77 10 7 8 36 7 0 86 5190 7394 427 44 88 1 12D 1 4 27 2 4 58 28 31 3037 3021 2987 2927 18 57 2 9 61 16913 89 18 75 34 75 3 9 87 4230 4255 4317 4337 2734 4225 24258 90 22 59 4221 4796 5046 5052 51 01 5389 3491 5077 29206 91 2682 4978 5664 5943 5966 6054 6573 408 1 60 40 34795 92 3417 63 16 71 02 7 3 93 7385 75 40 8 6 95 51 45 7623 44017 93 c 1 5 17 1240 1305 1399 1467 1479 1429 9 26 1423 8251 94 20 34 1554 1623 1720 18 21 18 53 18 72 1215 1778 10229 95 2 3 48 1795 1843 198 5 2097 2171 2274 1540 2074 11947 96 2716 2028 2048 22 01 2 3 44 2444 2661 18 90 2340 13505 97 3247 2410 2375 2663 2778 2949 3298 2378 2793 1615 98 11 35 967 1040 1124 1186 1200 1142 728 1138 6496 99 14 06 1135 1220 1318 1384 1403 1 3 61 8 77 1336 7656
100 2311 1 8 54 18 78 1980 20 90 2136 2227 1653 2062 118 31 10 1 2666 2085 2094 2227 2 3 62 2438 2626 1902 2349 13508 102 3392 2635 2582 28 01 3026 3141 3529 2567 3016 17390
103 1 U 1235 349 395 434 436 4 28 411 286 423 2416 104 20 10 434 5 02 559 577 569 5 37 345 552 3177 105 28 14 538 626 685 711 7 21 682 424 6 8 6 3966
Q) j-J
TABIE III Continued
Run No Position CFM h1 h2 h3 h4 h5 hu h7 hav Nuav
106 3492 614 7 1 6 7 84 8 13 8 33 7 85 4 88 7 87 4562 107 4395 7 86 894 964 996 1005 9 64 640 9 65 56 06 108 50 75 9 11 10 22 1081 1112 1125 1085 7 24 1085 63 16 109 G 1344 9 22 1042 1120 1 1 46 1173 1131 7 04 1120 63 87 110 1936 1162 1340 1442 1474 1509 14 7 3 9 09 1441 82 77 111 2846 1631 1797 1902 1966 2027 2079 1342 19 2 3 11108 112 3484 207e 2144 2236 2307 2385 2574 1694 2268 13138 113 4066 24 65 24 42 2535 2648 2757 31 71 2178 2 5 96 15078 114 50 12 3059 2916 30 1 5 3176 3312 4059 2849 3105 180 46 115 1D 1362 2268 26 13 2613 26 35 2605 2503 15 46 2617 14934 116 1958 2993 3580 3580 3586 3539 3 5 02 2144 3571 20492 117 2812 4430 50 32 4913 4 9 86 4991 5196 3088 4981 287 66 118 3432 58 16 62 13 6067 61 18 60 66 6698 4143 61 16 354 16 119 40 22 71 71 7 4 62 7369 7419 7329 82 74 51 8 1 7395 42909 120 5026 105 95 11456 115 81 11574 11548 14010 80 91 11540 671 15 121 2D 1244 18 57 2277 2363 2305 2210 2107 1466 2289 13038 122 1960 2622 3240 3388 33 23 3226 31 40 2)99 3294 18919 123 2817 3762 45 87 4739 46 56 45 14 4 6 47 30 15 4624 26689 124 3491 50 22 5723 58 53 57 44 5542 60 18 3871 57 16 330 73 125 4096 61 29 68 16 69 79 6805 65 90 74 79 4677 67 98 39400 126 5037 82 27 94 60 95 69 93 57 9023 11324 65 05 93 52 542 83 127 12D 1278 14 70 1 6 48 1652 1638 1 6 34 1641 9 73 1 6 43 9369 128 1947 19 63 2155 2149 2151 2131 2190 1347 2147 12342 129 2769 2615 2791 2773 28 52 2716 2954 18 96 2783 1 60 82 130 3439 3208 3265 3239 3593 3133 3624 2515 3308 19174 131 4103 3637 35 88 3577 4077 3459 42 66 3138 3676 21343 132 49 78 45 82 44 60 44 8 1 55 17 43 25 5749 4227 4700 27288
Q) tlgt
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
133 1 12D 1299 2094 2507 2622 2625 2567 2489 1465 2578 14736 134 1973 29 56 3505 3772 3790 3718 3718 2115 3700 21290 135 2788 3941 4727 5069 5099 5 0 07 5231 2984 4976 28781 136 3473 5155 59 81 6308 6339 62 39 68 96 4204 6217 36052 137 4118 6135 71 8 6 7662 7731 76 91 87 16 49 8 5 7568 43985 138 4973 7765 94 75 10396 10861 10694 13646 66 64 10357 602 25
139 1ttn 1253 1242 1493 1460 1442 1431 1424 8 84 1457 83 01 140 2366 1942 2150 1961 1910 1897 19 62 1206 1980 11400 141 3461 3007 2957 2562 2513 2606 3143 18 51 2660 15400 142 4325 3942 3571 3060 2999 3198 4248 2631 3207 18618 143 5677 508 6 4359 39 88 3800 42 29 57 78 36 26 4094 23824 144 67 59 64 55 5330 4988 47 25 5494 2517 48 09 5134 29906 145 84 08 9326 72 26 7726 85 56 9172 12319 7733 8170 47626 146 86 54 9831 7582 818 9 94 90 9869 13116 78 97 8783 512 96 147 7376 7335 58 7 6 5941 5796 68 29 81 65 5954 6111 35662 148 2 11 D 4254 4106 48 02 4994 5038 5042 56 78 3419 4969 28881 149 5708 5487 6253 6466 6524 6527 78 63 45 8 2 64 43 37566 150 69 7 8 7983 9440 9848 98 34 97 32 13249 6701 9714 566 59 151 1254 1434 18 53 1947 1915 1850 1760 1186 1891 10772 152 2713 2696 3175 32 94 3288 3237 3288 20 44 3249 18728 153 87 30 118 07 14733 15758 15504 15305 26297 9617 15325 892 71 154 5811 5278 6543 6861 69 30 69 82 7 8 74 4478 68 29 39531 155 4246 3780 4736 4975 49 66 4936 5162 3113 4903 28301 156 (v 1270 8 15 935 959 966 9 51 9 23 6 35 953 5430 157 2714 1164 1390 1427 1447 1454 1455 9 08 1430 8242 158 4310 1655 18 96 1942 1988 2002 2111 1305 1957 11349
(j) ~
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 fry hav Nuav
159 6012 2208 2400 2450 2513 2548 28 20 18 00 2478 14416 160 7279 2696 2881 2927 2989 3081 3599 2340 2970 17326 161 86 90 3257 3360 3 3 76 34 26 3558 4455 2943 3430 2000 162 12D 4368 2209 2600 2558 2518 2466 2774 1753 2536 14713 163 5833 2730 3092 3028 2974 2913 3501 2287 3002 174 78 164 7643 3320 3681 3630 3651 3530 4623 3181 3623 21116 165 87 39 3920 4303 4300 4708 4178 61 60 3937 4372 25456 166 1268 962 1203 1205 1186 1118 1084 725 1178 6693 167 2678 14 67 1785 1779 1752 1698 1726 10 70 1754 88 49 168 1 12D 12 83 936 1217 1414 1397 1239 1190 7 65 1317 7484 169 2729 2502 2930 2914 2934 2956 2979 17 52 2934 16866 170 4345 3884 4357 4283 4318 4421 4836 28 59 4345 25151 171 6036 5546 5858 5764 5791 6028 7129 4184 5860 34045 172 6578 7167 7769 7907 79 82 8263 10492 5915 7980 46437 173 87 84 10237 112 23 120 26 12727 12968 185 19 85 98 12236 71103 174 1278 1344 1803 18 72 1835 1790 1712 1063 1825 10355 175 2711 2328 2972 2932 2893 28 78 2863 1667 2919 167 51 176 4351 3934 4414 4353 4281 4321 4654 28 63 4342 25088 177 5994 5076 5824 5838 5818 59 29 6914 4205 5852 33885 178 1 11 U 1223 388 432 465 464 449 435 338 453 2585 179 2351 521 602 6 22 675 6 57 619 436 639 3687 180 34 48 6 05 1725 803 8 27 8 11 760 518 792 4593 181 4513 718 850 934 9 68 9 57 8 99 609 9 27 5386 18 2 5714 8 32 981 1060 1102 11 06 1034 6 59 1062 61 82 183 6997 1025 1182 1258 1295 1309 1234 8 18 1261 7 3 44 184 8709 1295 1487 1 5 42 1594 1626 1612 1156 1562 9080
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
185 2 12D 4249 3560 4400 4670 4791 4695 47 81 2931 4639 268 37 186 5737 4926 58 54 61 92 6248 62 38 67 78 4134 6131 35590 187 7432 6390 7726 83 46 85 44 86 34 10371 5658 8313 48310 188 8723 7718 107 88 11933 12099 13046 186 22 79 39 119 67 69505 189 1 4 35 1340 1735 18 57 18 52 17 81 1711 1144 18 06 10256 190 2718 2399 3023 3187 3207 3138 30 53 1931 3139 18025 191 7 5 07 6189 80 11 9200 9427 9703 11364 5720 9085 527 38 192 8544 78 42 10666 125 42 13312 13775 178 20 6976 125 74 729 86 193 1287 1417 16 97 18 7 18 69 18 08 1720 1046 1800 10223 194 27 17 2450 2940 3187 3214 3157 3054 1749 3125 17954 195 42 53 3560 4222 45 90 4679 46 63 4743 2741 4539 26247 196 6068 48 69 57 79 6335 65 8 6 66 04 7172 4338 63 26 366 78 197 7389 58 86 72 8 6 82 23 8584 8936 10658 50 60 8257 4798 6 198 86 88 78 91 100 27 120 56 130 29 14299 190 81 6492 12353 71850 199 5864 4694 5 6 67 61 94 6419 65 48 7192 3950 6207 360 14 200 2 D 4177 38 36 4547 48 09 4775 4628 5006 2715 46 90 261 30 201 5712 5170 62 39 66 38 6599 6604 7518 4167 65 20 378 00 202 73 63 7201 8986 98 43 9733 9914 13353 6219 9619 55810 203 8604 10043 13118 148 41 150 42 158 66 25206 82 5 3 14717 85290 204 12 68 1506 18 41 1971 1966 1868 1799 11 42 1913 10880 205 2659 2571 3127 3276 32 50 3130 3069 18 80 3196 18 350 206 39 80 36 76 4347 4573 45~67 4473 46 34 28 37 4490 25910
o 207 Orifice 11496 10 64 1360 15 39 1 5 80 1 6 15 1496 8 58 15 24 88 83 208 9433 8 95 11 78 13 26 1394 1386 1263 727 1346 78 48 209 7387 746 9 77 1123 1184 1159 1048 6 11 1111 64 74 210 52 36 566 7 66 900 934 909 8 21 499 8 27 48 02
0) CJ1
TABLE III Continued
Run No Position CFM h 1 h2 hs h4 h5 h6 h7 hav Nuav
211 212
3309 1293
414 257
563 3 19
6 68 3 57
6 91 3 37
6 72 351
7 37 337
38 4 2 46
4 40 341
3748 1942
213 214 215 216 217 218
c of 2nd 1 516 1235
1919 2712 3320 4153 4704
1532 2447 35 46 4312 5567 74 29
2 1 87 3312 4225 52 86 6902 8 6 50
2360 3555 4340 56 12 7 0 49 8 9 40
2409 3598 4 8 85 5718 7713 9593
2347 2101 35 33 3453 48 00 49 62 5562 59 86 72~6 7 8 79 93 76 11237
1243 20 64 3054 4 2 8 1 5114 6983
2326 35 00 4638 5545 7225 91 40
132 13 200 27 26672 31968 41711 52811
bull
67
TABLE IV
PRESSURE PROFILE DATA
Baffle Flow Qpening Rate ~p
(Inches) Position (CFM) (Inches 295 S G Fluid)
1 364 l2 11 U 1012 0 254 1248 0197 1493 0 141 1718 0112
c 1000 9 80 1210 1710 1436 28 75 1746 4320 1011 1080 1277 2050 1393 3020 1 6 28 4450
12D 1011 9 75 1236 1520 1450 2510 1603 3450
1 D 1011 975 1256 1700 1480 2690 158 1 4070
1 12D 1010 950 1259 1750 1462 2650 1631 3710
2 11 D 1124 1315 1360 2130 1505 2850 1689 4125
1 216 12U 1294 045 1949 0324 2374 0282 2704 0225 3367 0169
c 1326 265 18 81 5 90 2313 990 2731 1480 3439 2660
12D 1272 2 49 1957 661
68
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Pos ition (CPM) Inches 2 95 S G Fluid)
2559 1275 3033 1940 3639 3025
1 216 1nD 1257 242 16 96 476 2117 8 05 2561 1280 2990 1895 3431 26 bull00
1 316 12U 1309 0 479 2004 0422 28 28 0 352 3526 0281 42 28 0225 5199 0225
c 1308 1 43 1998 272 28 14 5 10 3478 795 4248 1235 5048 1885
l2D 1286 140 2005 3 45 2831 725 3495 1180 4194 1805 5046 2945
1 11D 1322 150 2039 352 2841 735 43 77 1980 5378 3440
1 516 12U 1278 0493 2732 0493 4315 0408 5744 0352 7494 0352 8932 0422
c 1300 0 506 2731 1985 4310 348 6080 6 45
69
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Position (CPM) (Inches 295 SG Fluid)
7607 1090 8830 1585
l2D 1343 0549 2738 225 4566 583 6112 1195 7536 2055 9043 3415
1 516 1uD 1249 0464 2713 224 4155 579 5620 1150 7428 2115 90 70 3405
1 12D 1301 0493 2735 220 4501 616 61 50 1235 7440 2065 8862 3445
2D 1265 0 478 2750 226 4366 594 6578 1270 7678 2240 8945 5280
2 12D 1295 0493 2725 222 4293 600 5807 1120 7568 2200 9070 3615
TABLE V
RATE OF HEAT TR AN SFER Ar THE BAFFL~~ CID-TT ER
Orifice Size
(Inches)
Flow Rate
( CFM)
Re d e G tU
R~) 055 Nuav NuPr-l3
1 364 10 26 12 90
8 075 10015
43400 54 600
85 11 99 64
95 83 112 19
1416 11 140 59 900 110 30 124 20 16 27 12 800 68 900 126 64 142 60 17 29 13 610 73 200 135 79 152 90 17 76 13980 75 200 147 59 166 19
1 216 11 35 14 06
8 600 10 660
27000 33500
6 4 96 76 56
73 14 8 6 12
1517 11500 36100 82 51 9291 20 34 15400 48400 10229 115 18 23 11 17500 55000 118 31 13322 2348 17 800 55900 11947 13452 2666 20 200 63400 13508 15210 27 16 20 600 64700 135 05 152 07 32 47 24600 77200 161 57 18 193 3392 25 700 80700 17390 195 8 1
1 316 1344 19 36
9898 14 260
24800 35 700
63 8 7 8 2 77
71 92 93 20
28 46 20 9 60 52 500 111 08 125 08 34 84 25 660 64200 131 38 147 93 40 66 50 12
29900 36900
74800 92400
150 78 18046
169 78 203 20
~ 0
TABLE V Continued
Orifice Flow Re Size Rate d e G R~rmiddot55 NuPr-13(Inches) (CFM) U Nuav
1 516 12 70 8 847 16800 54 ~0 61 14 2 14 18 900 35800 82 42 92 80 43 10 30 000 56900 11349 127 79 60 12 41900 79400 14416 16232 7279 50700 96100 17326 19509 86 90 60540 115000 20098 22529
TABLE VI
RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
Orifice Size
(Inches)
1 364
1 216
1 316
Flow Rate
(CFM)
1054 1294 1431 1681 1770
1068 1399 1669 1959 2295 2636 3390
1299 1973 2788 34 73 4118 4973
Re deG Mshy
8 300 9870
11260 13200 13 930
8100 10600 12650 14850 17400 19980 25700
9 570 14500 20500 25600 30300 36600
R~r-6 51900 61700 70500 82 500 87 100
28200 36900 44000 51700 60 600 69500 89400
26100 39600 56000 69900 82700 99 900
Nuav
2416 293 5 3187 4018 4805
14938 18968 21712 25156 30680 37938 59601
14736 21290 28781 36052 439 85 60225
Uu Pr-1 3
27204 33050 3589 4524 541 0
16820 21358 24448 28326 34546 427 18 67111
16593 23973 32407 40595 495 1 678 13
TABLE VI Continued
Orifice Flow Re Size Rate deG R~rmiddot6 NuPr-13(Inches) (CFM ) M- Nuav
1 516 1268 88 30 17700 108 8 1225 2689 18700 37400 1835 2066 3980 27700 55700 2591 2917 4177 29100 58 500 2713 3055 5712 39800 80000 378 0 425 6 7362 51300 103000 5581 6284 8 604 59 900 120000 8529 9604
74
TABLE VII
EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER
l 516 Inch Orifice
Center ot 2nd Baffle 4 Downstream
Plow Rate (CFM)
1235 1919 2712 3320 4153 4704
Flow Rate (CFM)
1270 2714 4310 6012 7279 8690
(Re)eb -8600 1321
13400 2003 18900 2687 23100 5197 28900 4171 32800 5281
Center ot Single Battle
-8847 543
18900 824 30000 1135 41900 1442 50700 1733 60540 2001
(Nu)(Pr)-l3
1487 2255 3003 3600 4697 5946
(Nu)(Pr)-13
611 928
1278 1623 1951 2253
75
ABLE VIII
HEAT TRANSFER IN THE TEST SECTION WITHOUT ORIFICE
CFM Ute) 0b h Nu
1293 5-951 3 41 1942
33 09 15251 649 3746
5236 24193 827 4802
7387 34001 1111 6474
9433 43419 1346 7848
11496 52-914 1524 8883
76
TABLE IX
PRESSURE DROP FUNCTION
Orltlee Size Flow Rate incbea ~CFM (Re)eb X 10bull8
1 364 1011 7957 0808 1256 9885 1468 1480 11648 2765 1581 12443 4160 1689 1_3293 4 020
1 216 1257 9530 1327 1696 12858 2663 2117 16049 4615 2561 19415 7581 2990 22668 11560 3431 26011 16440
l 316 1322 9736 1819 2039 15016 4332 2845 20952 9275 3495 25739 15300 4377 32014 26800 5378 39607 50100
1 516 1011 7 957 oaos 1256 9885 1469 1480 11646 2765 1581 12443 4160 1689 13293 4020
77
TABLE X
EXPERIMENTAL DATA
Baffle Hole Diameter Run No
1 - 59
60 - 102
103 - 138
139 - 206
207 - 212
213 - 218
(Inches)
1 364
1 216
1 316
1 516
No Baffle
2nd - 1 516
TABLE X
EXPERIMENTAL DATA
Run Thermocouple Reading s (mv) No Position CFM I tc1 tc2 tc3 tc4 t c 5 tc6 tc7 tcair
1 c 1026 530 2055 1825 1768 1782 1802 1837 1965 1198 2 1290 612 2059 18 65 1809 18 32 1851 1880 1965 1160 3 1416 714 2151 1970 1931 1965 1988 2026 209 5 1130 4 1627 8 21 2235 2084 2 049 2093 2126 2173 2266 1130 5 1776 865 2203 2033 1970 2015 2084 2159 2 264 1121 6 12D 1109 542 1636 1507 1499 1499 1498 1498 1528 1218 7 1258 651 1670 1522 1503 1513 1513 1516 1548 1221 8 1433 750 1625 1480 1467 148 3 1487 1487 1516 1153 9 168 1 8 73 1656 1494 148 1 1511 1517 1517 1543 1159
10 1rtD 1102 485 1545 1450 1437 1446 1447 1442 1466 1220 11 13 08 6 10 1571 1470 1460 1476 1476 1469 1498 1194 12 1464 730 1 623 1509 1508 1528 1 5 32 1524 1548 1173 13 11 06 8 71 1663 1559 158 1 1606 160 6 1 583 1601 1190 14 1 12D 1115 520 1698 1579 1575 1 577 1580 1590 1615 1280 15 1275 6 10 1692 1567 1558 1 561 1570 1580 1601 1234 16 1498 770 1760 1619 1630 1 635 1642 1645 1661 1204 17 1695 912 1775 1635 1670 1689 1686 168 6 1701 1165 18 2D 1049 510 1736 15~2 1567 1558 1 553 1558 1620 1236 19 12 41 610 1655 1517 149 1 148 1 148 1 148 4 1546 1108 20 1 5 32 7 35 1720 1550 1530 1520 1519 1523 158 0 1104 21 16 74 8 8 0 1900 1 727 1714 1696 1691 1692 1753 1169 22 1U 1074 38 5 3 324 2740 2534 2478 2 465 2503 258 0 1210 23 1287 4 35 3510 2 870 2682 2 610 2599 2638 27 1 9 1190 24 1 5 08 470 3 618 2920 2690 2 637 2627 2 664 2747 1177 25 18 07 525 4 088 3235 2962 2905 2910 2988 3130 1169
z ())
TABLE X Continued
Run No Position CFM I tc1 tc 2
Thermocouple Readings te3 tc4 tc5
(mv) tc6 tc7 tcair
26 c 10~29 6 32 2340 2~092 2032 2060 2~097 2152 2~213 1211 27 12 66 679 2270 2 047 1993 2013 2069 2142 2 210 1 182 28 1430 723 2336 2097 2033 2080 2153 2~255 2 356 1 138 29 1729 8 52 2318 2070 1980 2061 2158 2279 2367 1121 30 12D 1054 570 1520 1 4 20 1402 1400 1396 1400 1 443 1159 31 1294 6 69 1599 1469 1444 1439 1433 1 442 1485 1168 32 1430 7 88 1720 1562 1536 1532 1528 1537 158 0 118 5 33 1770 8 81 1641 1488 1450 1~441 1 441 1_466 1518 1 163 34 1D 1058 548 1579 1498 1495 1526 1553 1_557 1 571 1 276 35 1263 640 1609 1509 1515 1570 1599 1598 1 598 1 266 36 18 36 8 47 1538 1452 1483 1553 1602 1 590 1 558 1195 37 1 12D 1029 5 41 1 578 1499 148 4 1473 1461 1465 1-512 1200 38 1315 6 30 159 1 1504 1493 1482 1470 1470 1505 118 5 39 1 4 26 743 1765 168 1666 1660 1645 1642 1678 1270 40 1757 8 54 1744 1648 1634 1620 1598 1 593 - 1612 1223 41 2D 1080 5 30 1734 1604 1570 1 570 1570 1 588 1 640 128 1 42 1305 6 40 1744 1622 1589 1 608 1593 1 609 1 661 1240 43 1434 750 1798 1687 1658 1 636 -1641 1 661 1 711 1_220 44 18 04 8 41 1 764 1666 1607 1605 1614 1 635 1 675 1205 45 12nu 1088 415 2614 2295 2195 2 169 2174 2217 2256 1171 46 1318 477 2805 2477 2371 2342 2364 2 401 2 438 1 163 47 1413 5 28 2930 2 646 2 555 2 526 2532 2570 2 577 1 199 48 1773 550 2740 2518 2450 2431 2448 2 479 2 480 1 170 49 1 11 U 1054 380 3175 2670 2505 2 461 2467 2 534 2 621 1 258 50 1240 420 3268 2738 2 546 2 510 2 508 258 2 2 649 1214 51 1419 451 3364 2B07 2 632 2590 2 590 2 651 2773 1 215 52 1 12U 1032 360 3 165 2 629 2 450 2402 2403 2 473 2 bull568 1 163
--I lt0
TABLE X Continued
Run No Position CFM I tc1 tc2
lhermocoup1e Reading s tc3 tc4 t c 5
(mv) tc6 tc7 tc a ir
5 3 1314 38 9 3178 2592 2411 2367 2361 2432 2555 1140 54 1448 403 3095 2544 238 1 2336 2336 2390 2476 1158 55 178 2 427 3006 2434 2286 2253 255 3 2299 2397 1154 56 2 11U 1061 360 3369 2814 2619 2567 2560 2650 2833 1220 57 1216 360 3044 2512 2338 2290 2288 2374 2566 1150 58 1322 387 3196 2614 2425 2383 2382 2472 2670 1138 59 1639 403 3020 2438 2272 2238 2238 2318 2502 1127
60 1D 1068 612 1552 1424 1400 1395 1396 1426 1745 0945 61 1399 612 1355 1246 1230 1229 1230 1250 1509 0872 62 1669 710 1436 1293 1272 1265 1266 1286 1551 0847 63 1959 900 159 5 1468 1444 14 38 1432 1446 1720 0851 64 2295 730 1169 1105 1098 1099 1108 1100 1298 0781 65 2636 8 80 1202 1129 1121 1126 1 138 1115 1342 0748 66 3390 9 35 1060 o 9s7 0999 1001 1017 0971 1154 0703 67 1nu 1190 370 2225 2188 2104 2080 2120 2209 2 7 15 0990 68 1559 368 2005 1950 1871 18 48 1876 1951 2408 0916 69 1904 368 1870 18 1 4 17 34 1711 1730 18 07 2238 0875 70 22 bull11 471 228 6 2 204 2099 2063 2092 218 $ 2732 0840 71 2289 471 2030 2000 1925 1895 18 96 19 5 2498 0785 72 2727 4 71 1854 18 23 1753 17 23 1716 3758 2241 0743 73 3210 471 1680 1651 158 6 1559 1551 158 1 1950 omiddot7o9 74 2uD 1210 404 1261 1212 1198 1197 1205 1222 139 1 0978 75 14 20 540 1321 1260 1242 1 240 1249 1268 148 7 0918 76 1692 7 18 1467 138 6 1364 1361 1376 1405 1678 0883 77 18 94 903 1708 1 591 1565 1560 1575 1603 1948 0 857 78 2301 903 1530 1432 1407 1402 1415 1432 1738 0815
ro 0
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc117 tcair
79 2621 6 50 1069 1 020 1009 1009 1009 1007 1~189 o739 80 3230 901 1200 1128 1113 1119 1119 1086 1341 0694 81 82
l2D 1155 1689
360 575
1191 1345
1142 1252
1122 1218
1118 1210
1118 1209
1132 1228
1292 1446
0916 0822
83 1244 430 1163 1134 1131 1130 1129 1132 1292 0877 84 2100 645 1175 1135 1147 1 142 1138 1122 1286 0757 85 2292 8 25 1 354 1310 1327 1330 1323 1285 148 6 0728 86 2907 8 23 1180 1138 1151 1158 1149 1107 1268 0687 87 3380 902 1113 1049 1025 1011 1006 1042 1178 0673 88 89
1 12D 1427 1875
480 615
118 2 1140
1140 1095
1124 1077
1125 1075
1129 1072
1137 1072
1290 1243
0880 0790
90 2259 8 41 1296 1231 1207 1206 1203 1182 1419 0757 91 2682 8 80 1231 1170 1149 1147 1142 1112 1350 0731 92 3417 940 1142 1092 1076 1076 1069 1021 1252 0693 93 c 15 17 431 1321 1298 1268 1249 1250 1273 1522 0841 94 2034 505 1285 1263 1235 1209 1205 1206 1464 0759 95 2348 6 10 1395 1379 1334 1302 1286 1268 1536 0732 96 2716 706 1486 1480 1427 1383 1358 1311 1572 0 700 97 3247 7 56 1417 1430 1375 1320 1284 1223 1450 0660 98 1135 400 1425 1388 1352 1329 1330 1 364 1651 0893 99 14 06 440 1379 1341 1304 128 2 1281 1305 1583 0 831
100 2311 680 1602 1593 1553 1514 1502 1480 1 7 27 0 802 101 2666 680 1471 1469 1428 1390 1372 1335 1564 0761 102 3392 798 1491 1 509 1449 1395 1372 1305 1534 0 719
103 1U 1235 410 2469 2295 2173 2165 2226 2361 3120 0 897 104 2010 410 2017 1848 1 737 1706 1747 1865 2582 0753 105 28 14 410 1682 1535 1457 1427 1437 1520 2109 0 660
00 t-
TABLE X Continued
Ru n Thermocouple Rea ding s (mv No Positi on CFM I tc1 tc2 tc3 tc4 tc5 tc6 tc7 tcair
106 3492 440 1649 1499 1420 1391 1390 1470 2042 0620 107 4395 550 18 33 1679 1597 1564 1570 1640 2223 0583 108 5075 588 1779 1642 1580 1550 1552 1 615 2 191 0548 109 c 1344 398 1464 1 399 1364 1353 1350 1380 1689 0 907 110 1936 459 1369 1290 1253 1242 1 237 1259 1574 078 2 111 2846 580 1347 128 5 1251 1232 1220 1215 1 5 23 0 683 112 34 8 4 700 1392 1369 1339 1317 1299 1259 1599 0 636 113 4066 8 13 1449 1458 1427 1391 1363 1270 1595 0 591 114 5012 930 1484 1530 1500 1453 1420 1272 1580 0 580 115 1D 1362 513 1269 1218 1 217 1214 1220 1238 1460 0 893 116 19 58 600 1187 1122 1121 1120 1124 1133 1352 0798 117 2812 705 1052 1008 1015 1010 1011 1001 1218 0691 118 34 32 913 1105 1075 1085 1081 1086 1047 1301 0645 119 4022 980 1038 1021 1026 1023 1029 0983 1211 0 609 120 5026 982 0 8 61 0839 0836 0836 0837 0791 0955 0570 121 2D 1244 475 1320 1246 1233 1240 1255 1275 1434 0925 122 1 9 60 5 50 1160 1088 1074 1079 1089 1100 1260 078 7 123 2817 6 80 1096 1024 1 013 1018 1029 1022 1201 0 700 124 3491 960 1248 1175 1163 1172 1192 1153 1435 0 658 125 4096 989 1141 1089 1078 108 9 1105 1051 1310 0629 126 50 37 989 0983 0933 0929 0 936 0949 0880 1090 0 602 127 128
12D 1278 1947
402 545
1270 1261
1 230 1216
1228 1216
1230 1 215
1235 1223
1242 1219
1483 1514
0 913 0778shy
129 2769 695 1273 1234 1237 1221 1251 1212 1525 0678 130 131 132
34 39 4103 4978
8 40 9 80 9 80
1336 1448 1271
1322 1458 1 288
1328 1 462 1286
1 259 1 356 1157
1353 1492 1311
1261 1329 1138
1 555 160 7 1343
0 629 0 600 0599
(l) l)
TABLE X Continued
Run No Position CFM I tel tc 2
Thermocouple Readings tc3 tc4 tc5
( mv) tc6 tc7 tcair
133 1 l2D 1299 5 16 1 28 1 1212 1196 1195 1205 1221 1478 0869 134 1973 6 15 1163 1098 1073 1071 1079 1083 1343 0751 135 136
27 88 34 73
802 9 -_78
1187 1214
1099 1131
1069 1104
1066 1101
1075 1~110
1l061 1066
1370 1360
0662 0618
137 4118 9 81 1084 1010 0983 0979 0982 o937 1209 0581 138 4973 98 1 0969 0897 0 868 0855 0860 0799 1041 0572
139 1D 1253 409 1371 1293 1298 1301 1309 1321 1578 0928 140 2366 480 1130 1 090 1 121 1130 1137 1132 1390 0744 141 34 61 6 38 1081 1086 1152 1161 1147 1069 1382 0644 142 143 144
4325 5677 6759
7 90 939 998
1110 1115 1034
1161 1208 1139
1253 1268 1180
1265 1302 1215
1228 1230 1123
1080 1056 0970
13$913r12 8
0601 0561 0542
145 84 08 989 0863 0961 0934 0895 0871 0 785 09 9 0530 146 86 54 9 80 0808 0901 0 872 0821 0809 0733 0891 0498 147 7376 9 80 0 927 1032 1027 1 040 0961 0889 1032 0511 148 2D 4254 776 1 050 0 981 0965 0961 0962 0922 1155 0579 149 5708 991 1102 1031 1014 1009 1010 0931 1227 0528 150 69 78 990 0914 0853 0839 0 839 0843 0759 0996 0521 151 1254 490 1 479 1352 1329 1334 1351 1379 1607 0930 152 2713 7 00 1310 1220 1201 1201 1211 1209 1516 0723 153 8730 991 0809 0756 0742 0745 0 748 0663 0874 0543 154 5811 966 1219 1108 108 6 1081 1079 1033 1330 0650 155 42 46 8 02 1248 1136 1114 1114 1118 1103 1376 0 699 156 c 1270 429 1671 1571 1551 1545 1563 1600 1933 0929 157 2714 488 1398 1285 1 267 1258 1262 1275 1628 0729 158 4310 642 1424 1318 1299 1282 1283 1261 1683 0617
co ~
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc7 tc a 1r
159 60 12 780 1461 1388 1370 1349 1343 1279 1700 0 573 160 72 79 8 60 1402 1344 1330 1312 1292 1189 1 566 0 520 161 8690 982 1472 1442 1437 1 422 1392 1224 1602 0 521 162 163
12D 4368 5833
6 30 8 30
1195 1368
1105 1270
1111 1283
1117 1294
1131 1313
1081 1194
1369 1553
0613 0 553
164 76 43 959 1428 1338 1348 1341 1371 1180 1488 0535 165 8739 984 1345 1272 1272 1208 129 3 1059 1361 0550 166 1268 459 1701 1548 1541 1547 1589 1 625 1976 0 973 167 2678 570 1485 1351 1349 1356 138 1 1 385 1795 0760 168 169
1 12D 128 3 2729
448 650
1664 1314
1501 1232
1425 1233
1428 1229
1491 1229
1527 1232
1869 1571
0 962 0767
170 4345 847 1245 1179 1187 1182 1172 1132 1476 0 650 171 6036 9 76 1139 1109 1117 1114 1095 1020 1332 0588 172 6578 9 72 0982 0949 0942 0938 0926 0 8 50 1079 0560 173 87 84 9 72 0880 0854 0 8 36 0822 0818 0 749 0941 0585 174 1278 480 1564 1416 1397 1403 1417 1445 1733 0998 175 2711 590 128 3 1175 4 1178 1182 1187 1195 1493 0796 176 4351 8 90 1331 1259 1266 1275 1272 1235 1592 0 682 177 5994 9 60 1228 1152 1150 1151 1143 1075 1 360 0644 178 lU 1223 408 2282 2140 2052 2052 2106 2188 2626 0 878 179 2351 408 178 1 1623 158 5 1519 1556 1634 2068 0717 180 3448 482 1888 1675 1570 1541 1572 1665 2199 0629 181 4513 563 2026 1797 168 4 1644 1670 1770 2385 0583 182 5714 589 1913 1700 1610 1568 1580 1 682 2382 0551 middot 183 6997 653 1903 1718 1643 1611 1612 1700 2326 0 549 184 8709 6 80 1738 158 3 1543 1510 1498 1519 1 912 0577 185 186
2 12D 4249 5737
660 9 74
1055 1221
0 979 1122
0960 1093
0 952 1088
0959 1090
0 956 1054
1147 1350
0661 0602
187 7432 9 8 1 1065 0981 0951 0942 0 939 0881 1135 0582 CD ~
TABLE X Continued
Run No Position CFM I t o1 to 2
188 87 23 9 83 0944 0 879 189 1435 585 18 26 1630 190 2718 690 1433 1298 191 7507 950 1070 0961 192 85 44 964 0982 0 881 193 1287 600 1806 1668 194 2717 7 80 1579 1444 195 4253 8 81 1371 1260 196 60 68 9 78 1252 1152 197 73 89 975 1100 1000 198 86 88 973 0953 0 871 199 58 64 9 81 1269 1155 200 2D 4 1 77 915 1362 1251 201 5712 975 1213 1111 202 7363 9 78 1036 0 951 203 8 604 973 0932 0861 204 1268 6 95 2015 18 20 205 2659 6 96 1405 1295 206 39 80 7 98 1261 1174
No 207 Orifice 114 96 509 1325 1148 208 94 33 509 1477 1243 209 7487 5 09 1686 1409 210 5236 505 2094 1691 211 3309 428 2188 1 778 212 1293 392 2976 2560
Thermo ooup1e Readin g s (mv) to 3 to4 to
5 to
6 to7 toair
0 851 0847 0 8 29 0759 0987 0592 158 4 1583 1611 1647 1993 0986 1270 1266 1 279 1298 1604 0 789 0916 0908 0900 0 858 1115 0602 08 39 0 823 0 818 0 770 1035 0602 1609 1602 1629 1676 2153 0979 139 1 1385 1400 1 430 1938 0776 1212 1201 1205 1201 1601 0669 1 105 1086 1086 1 052 1371 0621 0952 0936 0923 0870 1195 0582 0 8 20 0 801 078 1 0 729 1044 0569 1108 1090 108 2 1043 1407 0610 1218 1221 1241 1202 1582 0659 1081 1083 1084 1031 1 368 0622 0921 0924 0919 0 841 1111 0 610 08 34 0831 0 821 0 751 1003 0 630 1761 1761 1 809 1861 2399 0966 1271 1271 1295 1311 1650 0797 1150 1150 1161 1149 1440 0703
1083 1057 1053 1109 1566 0~530 1158 1125 1138 1217 1763 0 526 1291 1250 1278 1383 2038 0542 1518 1478 1519 1657 2420 0 589 1596 1557 1601 1737 2441 0688 2370 2344 2409 2561 3 297 0921
()) (11
TABLE X Continued
Run Thermocouple Readings (mv) No Position CFM I tc 1 tc2 tc3 tc4 tc tc tc tc i5 6 7 a r
C of 2nd 213 516 1235 4 63 1 432 1291 1265 1258 1 268 1 308 1550 0 971 214 1919 6 17 1357 1223 1196 1191 1199 1211 1461 0 851 215 27 12 8 35 1401 1259 1278 1220 1230 1218 1511 0 762 216 3320 981 1439 1305 1270 1259 1275 1238 1450 0719 217 41 53 980 1251 1142 1132 1094 1121 1088 1305 0 695 218 404 987 1102 1042 1030 1 bull006 1014 0960 1133 0681
Supplementary Equations
Calculating temperatures from thermocouple readings
t = -026tc)2 + 3512(tc) + 3201 (26)
where t is the temp in deg F and tc is the thermocouple reading in millishyvolts
Calculation of the thermal conductivity of air
k = 00000245ta + 0 0132 (27)
where k is the thermal conductivity in Btuhr rt2 degFft and ta is the air temp 1n OF
I I
bull co m
j Jl l 6- 11 BOLTS II I nbull middot~11 I HEATING ELEMENTS
J T ( T
-f-shy - - - f-_- __L
7 777 _y A
IT 1] I
I
FIGURE I CROSS SECTION OF TEST SECTION AND PROBE
10
FIGURE 2 EXPERIMENTAL APP1Ub~fUS
11
air left the test section through nine equally spaced 12
ineh holes placed around the side of the tube at the exit
end
Sensing Probe Assembly
The sensing probe was designed to measure the local
heat transfer coefficients at any point along the tube and
around the tube in the test section The tube was designed
so that it could be easily moved up- and downstream to
measure the heat transfer coefficients at various positions
in relation to the orifice
The sensing tube assembly consisted of the sensing
probe the thermoctmple lead s and selector switch the
power lines and the two aluminum tubes between which the
probe was centered
Imbedded in the sensing probe were seven iron-constanshy
tan thermocouples for measuring the temperatures around the
tube The lead wires from these thermocouples were conshy
nected to a seleotor switch at the downstream end or the
aluminum tube A layer of Saran wrap was placed around the
tube over the t hermocouple and three lengths of Trophet C
resistance ribbon were wrapped around the tube nd conshy
nected in series to the power leads
The heating surface of the probe was formed by these
three one inch wide strips of Trophet C resistance ribbons
The ribbons were 0002 inches thick and had a resistance of
12
0 271 ohms per foot and a thermal conductivity of 763
Btuhr ft 2 degFft They were held in position by four
copper bars placed in four parallel longitudinal slots
These copper bars served as connectors for the electrical
leads A photograph of the sensing probe is shown in
Figura 3 and a drawing of the assembled probe is given in
Figure 4
Power Source
Direct current was used to heat the resistance ribbon
on the sensing probe The current was regulated by a slide
wire resistor The po er source consisted of a Raytheon
Voltage Stabilizer to stabilize the city power source at
115 volts and an automatic selenium rectifier with an alshy
ternating current input of 115 volts at 60 cycles per
second and an output of 12 volts and 35 amperes direct
current
Temperature Measuring
The temperatures around the sensing probe were calcushy
lated from the emf readings of the ironbulloonstantan thermoshy
couples The emf measuring system consisted of the seven
probe thermocouples a separate thermocouple for measuring
the inlet air temperature a thermocouple selector switch
a cold junction and a Leeds and Northrup Type K Potentishy
ometer The potentiometer was placed on a Fischer
13
THERMOCOUPLE JUNCTIONS~ ~------- HOLES FOR THERMOCOUPLE LEADS
~----- SCREWS
~ff+--- CONNECTING BARS
END VIEW
POWER LEADS SOLDERED TO LOWER CONNECTING BAR
iER PLASTIC PIECE
RESISTANCE RIBBONS LOCATION OF THERMOCOUPLES
FIGURE 4 DRAWING OF ASSEMBLED SENSING PROBE
15
Vibradamp support to absorb the vibrations produced by the
air blower
Air Source
Air was used as the shell-side cooling fluid during
the study The air was pumped through the test section by
a Roots type air blower with a rating of 280 ofm at 3 12
psig outlet pressure The hot air leaving the blower was
passed tbxfugh two finned-tube box-type coolers and one
tubular edoler to oool it to approximately room temperature
The air flow rate was measured by passing it through a
flow measuring orifice in the line Two sharpbull edged orishy
ficas were used f or flow measurements The calibration
curves for these orifices were presented by Ambrose (1
p 166)
The pressure taps on each side of the orifice were
connected to two differential manometers containing 0 83
and 2 95 specific gravity fluids respectively The presshy
sure drop through the test section and test orifice was
measured by a pressure tap placed 13 inches upstream and
one placed 6 12 inches downstream from the orifice Two
pressure ga ges were used to measure the pressure at the
inlet to the flow orifice and to indicate the statio pres~
sure at the test section inlet
16
Pressure Probe
A probe was designed to measure the pressure drop
between the pressure tap 13 i nches upstream from the ori shy
fice baff le and any point downstream from the tap The
probe eonsisted of a l~in OD copper tube with six 132
i n ch holes even l y s paced around the tube The upstream
pressure tap and the pressure probe were connected to a
differential manometer so the pressure drop to various
points up- and downstream of the orifice could be measshy
ured
17
CHAPTER IV
EXPERIMENTAL PROGRAM
The experimental program was designed to measure the
heat transfer coefficients and pressure drops in the vicinshy
ity of annular orifices The four orifice sizes studied
were 1 364 1 216 l 316 and 1 516 inches~ The inner
tube used in each case was a 1-in OD alumintim tube
Hence tube to baffle clearances were respectively 3128
232 332 and 532 of an inch
Heat transfer coefficients were measured at poait~ons
1 i nch upstream at the orifice center and at 12 1
1 12 and 2 inches downstream for all orifices In addishy
middottion the heat transfer coefficient at a point 2 12
inches downstream from the 1 516 inch orifice was measured
and at the points 12 l 12 and 2 inches upstream from
the 1 364 inch orifice
The heat transfer coefficients at each point were
measured at five different flow rates for the 1 364 inch
orifice and at six different flow rates for the other orishy
fice sizes The high pressure drop through the small orishy
fice size limited the number of flow rates which could be
studied
The flow rate was calculated from the pressure drop
across the flow orifice This flow was corrected to cubic
feet per minute at 68degF and one atmosphere pressure by
18
using the orifice pressure and the test section pressure
which were measured by pressure gages
It was desired to determine a relationship between the
heat transfer coefficient and the total pressure drop for
each orifice size The pressure drop across each orifice
at various flow rates was measured by means of the presshy
sure probe described in Chapter III It was also desired
to obtain pressure profiles for each orifice size since
these might be similar to the heat transfer profiles The
pressure drop was measured from a point 13 inches upstream
of the orifice to points at 1 and 12 ineh upstream the
orifice center 12 1 1 12 and 2 inches downstream
The experimental program is summarized in Table I
TABLE I
SUla~RY OF EXPER IMENTAL PROGRAM
Position Investigated-Distance from Orifice-Inches
Orifice Range of Flow Rate Size Heat Transfer Pressure Drop CFM at 68degF amp 1 atm
1 364 2U 1 12U 1U 12U c 12U C 12D lD 10 - 18 l2D lD 1 12D 2D 1 12D 2D
1 216 1U c 12D lD 1 l2D 2D 12U c 12D lD 10 - 35
1 316 1U c 12D lD 1 l2D 2D l2U C 12D lD 12 - 50
1 516 1U c x2D lD 1 l2D 1U 12U C 12D 12 - 90 2D 2 1 2D l D 1 l2D 2D 2 12D
20
CHAPTER v
EXPERI MENTAL PROCEDURE
The experimental procedure for measuring the heat
transfer coefficients ~d corresponding flow rates reshy
quired the following procedure
(1) Install the orifice size to be studied in the
test section
(2) Place the heat transfer probe in the position up
or downstream from the orifice where the middot heat
transfer rate is to be studied
(3) Fill the cold junction thermos with cracked ice
(4) Measure the atmospheric pressure
(5 Open bypass line from blower and close line to
test section
(6) Turn on the cooling water for the exchangers used
to cool the air leaving the blower
(7) Start the automatic selen ium rectifier by turning
on the t 1mer bull
(8 ) Connect the voltage stabilizer to the wall outlet
(9) middot Set the slide wire resistor to the maximum re shy
s1atanee I
(10) Start the blower
(11 Open the line to the test section until the de shy
sired flow rate is obtained
(12) Switch on the probe direct current power source
21
(13) Adjust the slide wire resistor to obtain the
desired current
(14) After the thermocouples have reached equilibrium
values record the e m bullf across each of the
seven probe thermocouples and also the entering
air thermocouple
(15) Record the direct current amperage
(16) Record the gage pressure at the flow orifice and
the entrance to the test section
(17) Record the manometer measurement of the pressure
drop across the flow orifice and also the presshy
sure drop through the test section
22
CHAPTER VI
CALCULAT ION OF EXPERIMENTAL DATA
The local heat transfer coefficients were calculated
from the temperatures measured on the probe surface the
air temperature and the current input The results were
calculated by using the Alwae III-E computer
The general expression for calculation of the heat
transfer coefficients was derived by Ambrose (1 p 79)
The equation is derived by making an energy balance around
a small increment of the center resistance heating ribbon
The two ribbons tnstalled adjacent to the center ribbon
reduced the amount of logitudinal conduction and assured
little longitudinal temperature variation in the center
ribbon
A heat balan ce on this small increment of resistance
ribbon yields the following
(the heat conducted in) + (heat generated) = (heat
conducted out) +(Heat convected to the fluid) + (heat
radiated to the surroundings) + (Heat conducted into
the plastic center of the probe)
This gives the equation
kzw dtdS + 12RdS kzws [ t + (~) ds] + hwdS (t-ta )
+ ~Aad wd o middot+ qcAond 1 -~- wdS 5 )
23
Hence solving for h gi~ea
i2R kz d2t Qrad qcond w + -d$2 - ~- A
h = ( 6)t - ta
Since S = re where 9 equals the enclosed angle ~n radians
dS rd9 ( 7)
and
dt - dt (8)dS - rd9
Differentiating with respect to S
d2t (9)rd9dS
from which
(10)
Substitut1ng into the equation for heat transfer coeffishy
cient gives
h = i2R Qcond A (11)
w
The rate of radial heat conduction into the plastic
tube making up the probe was assumed to have negligible
effect on the heat transfer coefficient It was also
assumed that the heat loss by radiation from the ribbon
was negligible since all data were obtained with the ribbon
at a temperature less than 125degF
24
When t he rad iation and conduction terms are neglected
Eq (11) becomes
(12)
The following con stants are known
R = 0 271 ohmsft
w = 100 i n ches
k = 763 Btuhr rt2 degFft
z = 0 002 inches
r = 12 inch
Eq (12) putting 9 in degrees then reduces to
1110 12 + 2404 d 2t d92
( 15)h = ------~--~-------t - ta
Thi s equation was programed for the Alwac III- E comshy
puter and used to calculate the local heat transfer coefshy
ficients from the observed data
The average heat transfer coefficient around the tube
at a given position in the t est section was calculated by
averaging the local coefficients calculated from Eq (13 )
It was found 1n the course of the experimental work
that thermocouple numbers 1 and 7 were indicating higher
temperatures than would be expected This resulted in h1
and ~ being lower than the other local coefficients around
the tube Since the fluid was flowing parallel to the axis
of the probe the circumferential variation i n rate of heat
25
transfer should be small Hence in obtaining the average
coefficient around the tube the values of h1 and h7 were
not used even though they were calculated and are tabulated
1n Table I II in the Appendix
Then
(14
A Nusselt number as calculated from this aver age heat
transfer coefficient using the tube diameter as the characshy
teristic dimension
(15)
The air flow rates through the test section were calshy
culated by measuring the pressure drop across the flow orishy
fice the air temperature the pressure at the flow orifice
and the pressure at the entrance to the test section The
orifice calibration curves (1 p 166 ) were used to obtain
a value of the orifice coefficient f8e where Q equals
the flow in cubic feet per minute at 68deg F and one atmosmiddot
phere pressure and te is the density of air at the exchanger
and e the density of the air at the flow orifice The
den sity of the air can be expressed by
e = 2 703 p (16)T
where T equals the temperature in OR and P equals the absoshy
lUte pressure i n lb1n2 Using the value of e Qfo from
26
the calibration charts as A and Eq (16) solving for Q
gives
( 17
This equation was used to calculate the flow rate for
each flow studied
The Reynolds number used i n the correlation of the
data was the equivalent Reynolds number defined as
Re)eb ~ d2 - dl)Uf ( 18 ) lL
where d1 is the outside diameter of the inner tube and d2
is the orifice diameter U is the flow velocity through the
annular orifice e is the density of the air and U- is t he
viscosity of the air This equation can be transformed t o
(Re) b = 1611 Q (19) e dl + d2
where d1 and d2 are in inches
The pressure drop data were calculated i nto a dimenshy
sionless pressure drop function cent where
d1 )22( ~ P)gc f av(d2 shycent 2 bull (20
M-
For air this equation reduces to
where d2 and d1 are in i nches D P is expressed i n inches of
2 95 specific gravity fluid and P av is expressed as lbft3
27
CHAPTER VII
ANALYSIS OF DATA
In analyzing the heat transfer data an attempt was
made to correlate it 1n terms of the dimensionless groups
(Nusselt number Prandtl number and Reynolds number) which
appear in Eqs (3) and (4) Consequently all of the av~
erage heat transfer coefficients hav were brought into
the form ( Nu)( Pr)~3 bull The Nusselt number was based on the
tube diameter and the thermal conductivity of the air at
the flowing temperature The tube diameter was used in the
Nusselt number because comparison could then be made with
previous experimental work on heat exchangers which have
commonly used the Nusselt number defined as in Eq (15)
From the standpoint of dimensional analysis this is
equivalent to considering the tube diameter as the characshy
teristic length so far as the heat transfer is concerned
The Prandtl number of the air was taken as 0 7 in all
cases
Variation of Heat Transfer Rate with Distance from the Baffle
Considerable variation was observed in the rate of
heat transfer in the vicinity of the baffle In order to
obtain the variation with respect to position the term
(Nu)(Pr)-13 was plotted versus the flow rate Q for each
position and orifice studied Cros s plots were then made
28
at constant flow rates in order to obtain the variation of
(Nu)(Pr) -13 with position The resulting cross plots are
shown 1n Fi gures 5 6 and 7 for the four orifices studshy
ied
About one inch upstream from the orifice the heat
transfer coefficient begins to rise rapidly and continues
to do so until it reaches a maximum some distance downshy
stream After the maximum point the heat transfer coef fi shy
cient decreased slowly The heat transfer rate was found
to reach a maximum at a different position downstream for
each orifice size These figures also show that for a
given orifice size the maximum heat transfer rate occurs
a pproximately at the same point for all flow rates The
position of the maximum point f or each or ifice size is
shown in Table II
The region immediately downstream from the orifice is
one of h i gh turbulence due to the jetting action of the air
flowing through the orifice As the air flows t hrough the
orifice the streamlines continue to converge for some dis shy
tance downstream The point of maximum heat transfer is
probably at the point where the streamlines be gin to diverge
and a boundary layer begins to build up on the tube Tle
decreasing heat transfer coefficient beyond the maximum
point indicated the formation of a boundary layer
Since the position of the maximum point is independent
of flow rate middot it is possible to correlate it with respect
_ ct 11shyz-
100
0 136 ORIFICE
(
I 0
I )
~ 00
~p 0
I 0
--r--- ~
ISCFIII
-_ OCFM
rbull abull
~ middot~ a-1 z-
12fORIFICE
100
200
100
0 0 UPITRAM ORIFICE DISTANCE CENTER
CFM
h I DOWNSTREAM
DISTANCE
FIGURE 5 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLpound
30
too
700
800
100 ~ f gtf
400
z ~
100
100
100
0
13fORIFICE
~ -~ -- ---
)
~
~
-
I ~ ~OCFM
I vI~-~ OCFM
J ---
Iamp CFM
I 0 I I UPSTREAM ORIFICE DOWNSTREAM DIITANOE GENTER DIITANCI
FIGURE 6 VARIATION OF HEAT TRANSFER RATE WITH DISllNCE FROM BAFFLE
--
--- --
31
100
100
700
100
_ 100
f 9- 400 z-
100
tOO
100
0 - I 0 I I I UHTRIAM OAtfiCI DOWIIITMAM
+ I tyl6 ORIFICE
v I
~~ ~CFM
I v ~CFMI
v v 7
~~ v ~ iOCFM
- ~~ I-shy1-shy ~ICFM
DIITMCI OINTIR DIITANCI
FIGURE 7 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLE
32
TABLE II
POSITION OF MAXIMUM HEAT TRANSFER
Position of Maximum Orifice Size Heat Transfer
(inches) (inches downstream)
1 364 050
1 216 100
1 316 125
1 516 200
33
to orifice size Figure 8 shows the effect of the orifice
size on the position and value of the maximum heat transfer
at a constant flow rate of 15 cubic feet per minute It
can be seen that the larger the orifice size the further
downstream the point of maximum heat transfer occurs
Also as the orifice size increased the rate of heat
transfer decreased for a given flow rate The broken line
indicates the variation of the point of maximum heat transshy
fer with position and size The position of the point of
maximum heat transfer rate downstream from the orifice was
correlated with orifice size by means of the dimensionless
groups (Lde) and (d1de) where L is the distance downshy
stream from the orifice where the maximum rate of heat
transfer occurs d1 is the outside diameter of the inner
tube and de is the equivalent diameter of the orifice
ie de = d2-dlbull
Figure 9 shows a plot of Ld 6 versus d1d6 for the
four orifice sizes studied The four points on this logshy
log plot are approximately in a straight line and the
equation of this line is
Lde = 0 44 d1de)028 (22)
Although the above relationship represents a correlashy
tion of dimensionless groups it is based upon only one
tube diameter and needs to be substantiated further by
studying other tube diameters and other orifice sizes
34
aoo
400
aoo ~
-~ middot-CLshyJ z
200 -
100
0
ORIFICE CENTER
l~
l
t
I J~
1pound~
I
0 I I~
AT 15 CFM
-
bull ~ 1~6~
~ v~
~
~--~~6
~~~ ___ v v V -_
~ o q
~ I 16
v
~
ogWNSTREANI STANCE
FIGURE 8 EFFECT OF ORIFICE SIZE ON POSITION AND VALUE OF MAXIMUM HEAT TRANSFER
35
50
loshy____ -~
~ ~ -shylltl-shy~ r0
2 10 30
FIGURE 9 CORRELATION OF THE POINT OF MAXIMUM HEAT TRANSFER WITH
ORIFICE SIZE
36
Correlation of Data at the Baffle
The heat transfer data were correlated by obtaining a
relationship between the group (Nu)(Pr)-13 and a
Reynolds number based on twice the clearance (d2 - d1
between the tube and the baffle It was found that the
most satisfactory correlation could be obtained when the
term - d1 was used as the length term in the Reynoldsd2
number
Figure 10 shows the variation of the heat transfer
rate at the center of the orifice e xpressed as a function
of Reynolds number and the orifice size This shows that
for a given Reynolds number the heat transfer at the center
of the orifice is greatest for the smallest orifice size
In order to obtain a general correlation of the data
shown i n F1gure 10 the effect of the dimensionless ratio
d1de was considered This ratio considers all of the
geometric factor s needed to describe the annular orifice
The thiclaless of the orifice plate is also a factor but
was constant i n this i nvestigation
The data for the heat transfer at the baffle center
are shown in Figure 11 in which (Nu)( Pr)-13 is plotted
versus (Re)ebd1 de) 0 55 This data on a log-log plot
lies on a straight line for (Re)eb( dld8 )0 55 greater
than 3 x 104 The equation for cor relating the heat
37
4XI~middot~-r~------~--~~------~
Icf t--to_+--_c-c-________ SYMBOL SIZE
0 1~4
6 ~~
9 ~~ -o ~
(Re)eb
FIGURE 10 RATE OF HEAT TRANSFER AT BAFFLE CENTER
38
500
0
4 0 lcf
~ ~
~ ~iC-
~ ~
~IL 0~ 0 SYMBOL SIZE-
p 0 1364-
r 6 1~16 -~ -
9 1~16 --o 1~16
I I
FIGURE II CORRELATION OF HEAT TRANSFER DATA AT BAFFLE CENTER
39
transfer at the center bullOf the a nnular orifice was found by
the method of least s quares to be
(Nu)( Pr)-1 3 = 0018 ( Re)ebO Bl( dlde)04~ (23)
3 x 104 ltRe)eb(a1de)055 lt 105)
Rate of Heat Transfer at the Point of Maximum Heat Transfer-The heat transfer rate at the point of maximum heat
transfer is plotted in Figure 12 to show the variation with
Reynolds number and the size of the orifice It is shown
gives the h1gh st heat transfer ~ate at its point of maxibull
that for a given Reynolds number the smallest orifice size yen il
mum heat transfer
The data ~or the maximum poi~t could be correlated by
plotting (Nu) Pr)-13 versus (Re)eb(d1de)06 This plot
is shown 1n Figure 13 and the resulting eurve shows that
(Nu(Pr)-13 is not a simple p0wer function of the Reynolds
number as was the case for heat transfer at the baffle
center The reason for this is probably because other
factors such as intensity and scala of turbulence should
be considered At the orifice center the streamlines of
the flowing stream are converging_ and thus the flow is
quite stable Downstream from the orifice is a region of
large eddy currents and probably large scale turbulence
These factors could con ceivably cause the results which
were obtained for the point of maximum heat transfer
40
If)
~middotshy Q_-I z_
10~~~--------r----~~--~--
SYMBOL SIZE
0 13$4
6 1~8
Q 13-18
-o 1~8
7)(104
(Re)eb
FIGURE 12 RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
41
Ia ~
0 I
c ~ ~ c v
~ ~lt w ~
17
~ b
v ~ ( SYMBOL SIZE
-~ 0 f-64 -v ~ 6 t211e
~ Q I~~~
-o - l~rs I I
FIGURE 13 CORRELATION OF HEAT TRANSFER DATA AT THE POINT OF MAXIMUM HEAT TRANSFER
4 2
Effect of Upstream Baffles on Heat Transfer at the Orifice Center
The heat transfer rate at the orifice center using the
single orifice in a test section is a pproximately 13 of the
value that was obtained by Lee (7) using a model heat exshy
changer with orifice baffles Lee investigated the cent r al
baffles of the heat exchanger and thus the coeff icients he
obtained would be affected by the presence of a number of
upstream baffles To determine the effect of upstream
baffles an additional l 516 inch baffle was placed four
inches upstream 1n the test section The resulting data are
shown in Figure 14 where (Nu)(Prmiddot)-13 is plotted versus
(Re) eb for the case of a single baffle 1n the test section
and also the case of an additional baffle placed four inches
upstream Comparison is made with the results obtained by
Lee middot(7) using a four-baffle and a ten-baffle model heat exshy
changer Good a greement is obtained with Lees work and the
results show the marked effect that upstream baffles have on
the downstream heat transfer rate The additional up tream
ba ffle caused sufficient turbulence 1n the test section to
i n crease the heat transfer rate nearly three-fold at the
center of the next baffle
Heat Transfer i n the Test Section with No Orifice
In order to check the accuracy 6f the equipment the
orifice baffle was removed and the heat transfer mea sured
with the probe in the empty test section The data were
43
~~BAFFLES
0 l BAFFLE -shy
ll_9 2 BAFFLES
V 4 BAFFLES-LEE
4 10 BAFFLES- LEE lJf ~
~rv ~~ ~ v flvv ~~
I ~ J ~ L v
0
v
( V
40 3XIo 7XIa
(Re)eb
FIGURE 14 EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER AT BAFFLE CENTER
44
compared with heat transfe r coefficients predicted by the
equations for annuli which are recommended in the litera shy9
ture The two equa~ ions u sed tor comparison were
(hfe)=0 023 (rltGr e (~~ur4 (~r45 (24)
which was presente~ by Wiegant (10)
and ( h ) (cnM~5(M~l o14 o 023 CPG k j Mij - (de GJMb )0 2 ( 2 5)
which was presented by McAdams (8 p 242) The comparshy
i son is s hown in Figure 15 lq (25) gives a value which
is low by about ten percent while Eq (24) g ives values
which are high by as much as twenty -five percent when comshy
pared with the experimental data The se equations are gembull
erally considered to give coefficients with an accuracy of
about twenty percent Therefore the present experimental
data are within the accuracy of these equations Also the
plot indicate s that for a Reynold s number greater than 2 x
104 the slope of the line is the same for the experimental
data as for the equations
Pressure Drop Data
The total pressure drop across the orifice was measured
as a function of the flow rate and the orifice size The
pressure drop was expressed as a d1mens1onleas quantity r)
which ie plCltted ver sus the Reynolds number in Figure 18
The pressure drop function cent correlates for all or1f1oe
45
200
100
s z
10 5XI10 10
0 EXPERIMENTAL
--McADAMS
-WIEGAND L
V
~ ~ ~
P ~ ~
LL~ L
v~
~
v v
v 1 ~ ~ v
v -gt
~
~ ~
~
6Xid
FIGURE 15 HEAT TRANSFER WITH NO BAFFLE
46
0 1~4 -~ a 6 t216
Q t316 lJ J
-0 as a )t
A LEE I -shy SULLIVAN 8
p
10bull
BERGELIN
I _ll I
I ~
i I
~middot
lo II
f fl
J j
~middot
A)101
1q
I Ill
1 I3 X 10ao1
FIGURE 16 ORIFICE PRESSURE DROP FUNCTION VS REYNOLDS NUMBER
47
sizes- The present data extends the range covered by preshy
vious workers and agrees well with their work The preshy
vious work of Lee () for a heat exchanger containing 10
orifice baffles and also the data of Su livan and Bergelin
(9) for pressure drop in a model heat exchanger with a
single baffle is shown 1n Figure 16 long with the present
results~ This figure may be used to predict the preseure
drop from the equivalent Reynolds number of the annular
orifice
The pressure drop between individual points 1n the
vicinity of the orifice and an upstream pressure tap wa s
measured to obtain a pressure drop profile As might be
expected 1n all cases the profiles showed a rapid decrea e
in static pressure immediately upstream from the orifice
There was however little or no recovery of the pressure
loss downstream The 1 364 inch orifice did show a maxishy
mum point in the pressure drop but this maximum occurred at
the orifice center and total recovery was reached about 12
inch downstream
Heat Transfer at the Baffle and Maximum Point as a Function of Pressure Drop
In order to compare the effect of the total pressure
drop on the heat transfer at the baffle and the point of
maximum heat transfer Figure 17 was plotted showing
(Nu)(Pr)-13 as a function of the total pressure drop This
shows that for a given pressure drop the largest orifice
48
1200
1000
~ a -sshyz-
100
60 100 700
AT MAXIMUM POINT I 15116 2 13116 3 1~6 4 1364
AT ORIFICE CENTER
60
1
v
r ~ ~ ~
5
~
8 7
13116
8
~
1364
v
~
e6
1~6
v
~~ v ~ ~ -~ ~
~
~ v
l
~
vamp
I ~ ~
~
v L ~
v
I-
5
k= ~~
~ ~ ~
--I
v ~
FIGURE 17 HEAT TRANSFER AT THE BAFFLE AND MAXIMUM POINT AS A FUNCTION OF
ORIFICE PRESSURE DROP
49
size has the greatest heat transfer coefficient This is
true at both the orifice center and at the point of maxishy
mum heat transfer
Another comparison can be made by plotting the heat
transfer coefficient and the pressure drop versus the orishy
fice size at a constant flow rate Figure 18 shows this
plot This graph shows that at a constant flow rate the
pressure drop as well as the heat transfer coefficient
increases as the size of the orifice is decreased In
choosing an orifice size for maximum efficiency 1t would
be necessary to know the pumping power available as well
as the heat transfer desired
70 I I 700
AT 15 CFM 60 ---
~ aug
50 ---
NV
40 ~
~ ~ ~
~ _
MAXIMUM POINT ---- --- ~
1-----t---~ _
~00Qj ~
~t--- ORIFICE CENTER 10 1100
1---~ n
u0 01 02 03 Q35
a ltl
de inches
FIGURE 18 VARIATION OF HEAT TRANSFER RATE AND PRESSURE DROP WITH ORIFICE SIZE AT A CONSTANT FLOW RATE
cn 0
51
CHAPTER VI II
SUMMARY OF RESULTS
This study revealed several significant facts about
the heat transfer in the vicinity of annular orifices
Probably the most important contribution was the presshy
entation of the heat transfer profiles in the vicinity ot
the annular orifice ~ r s shown that t~ local heat
transfer coeffieient re~ches a maximum at a point downshy
stream from the orifice The distance downstream at which
this maximum oocurs is t1ven by the equation
22
The heat transfer coefficients at the center of the
orifice were correlated and found to follow the equation
(Nu)(Pr)-13 = 00176 (Re)eb08l(d 1de) 0 middot4~ (23)
3 x 104 lt( Re) 9 b( d1d6 )055 ltlo5 )
The heat transfer at the point of maximum heat trans
fer for each orifice size was correlated and presented in
Figure 13 as a plot of (Nu)(Pr)-l3 versus (Re)eb(d1de) 06
No simple po-orer relationship exists between the terms
Intensity and scale of turbulence downstream from the orishy
fice are probably important factors which affect the heat
transfer
The large effect of an upstream orifice on the heat
transfer rate at the second orifice was demonstrated by the
52
study of two 1 516 inch orifices in the test section The
added turbulence at the center of the second orifice was
found to raise the heat transfer rate almost three times
over that obtained for a single baffle
The pressure profiles in the vicinity of the orifice
indicate that nearly all the pressure drop occurs at the
orifice center~ Total pressure drop data were correlated
by a pressure drop function cent as a function of the Reynolds
number and good agreement obtained with the results of other
workers
The pressure drop and heat transfer data were correbull
lated by plotting the heat transfer as a function of the
pressure drop for each orifice size It was shown that for
a given pressure drop the largest orifice size gives the
greatest heat transfer coefficient
As a final presentation it was shown that the pressure
drop and the heat transfer coefficient both i ncrease i n
value at a constant flow rate as the orifice size is de shy
creased This is important in choosing the optimum clearshy
ance for orifice baffles
53
CHAPTER IX
RECOMMENDATIONS
A great deal of work remains to be done in the field of
evaluating shellmiddotside heat transfer coefficients This
study included only one tube size and air was the only f luid
used It is recommended that further studies be conducted
using other fluids and tube sizes It will also be necessary
to study several baffle types
The adde d turbulence due to a s e cond baffle placed upbull
s t ream would suggest that the heat transfer coef ficients at
a certain position i n relation to a baffle would increase as
the flow progressed through the exchanger It is recomshy
mended that an extensive s t udy should be made between baffles
the full length of a model heat exchanger
It is further recommended that the pressure drop study
be continued to include other fluids tube sizes and baffle
arrangements
Effects of turbulence downstream from the baff le should
be studied by i n vestigations with hot-wire anemometer equipshy
ment to determi ne t urbulence scale and i ntensity
54
NOMENCLATURE
Area of heat transfer
Heat capacity of the fluid
Outside diameter of the tube
Orifice diameter
Equivalent diameter of the orifice (d2 - dl)
Inside diameter of the test section
Inside diameter of the tube
Gravitational constant
G Mass velocity
h Local heat transfer coefficient
Coefficient of heat transfer from surface to fluid
i Direct current amperes
k Thermal conductivity of the fluid
L Distance downstream of the point of maximum heat transfer
p Absolute pressure
L P Total pressure drop across the orifice
Q Flow in cubio feet per minute at 1 atmosphere and 680 F
q Heat transferred
Thermal energy conducted into the sensing probe
Thermal energy radiated from the resistance ribbon
Resistivity of the resistance ribbon
s Length of the resistance ribbon
T Temperature oR
55
t Temperature of the resistance ribbon deg F
ta Temperature of the bulk stream oF
tw Wall temperature of the tube OF
U Veloc ity of the fluid
w Width of the resistance ribbon
z Thickness of the resistance ribbon
eeuro Density of the fluid in the test section
Density of the fluid at the flow orificef 0
AL Viscosity of the fluid
E9 Angle measured around the tube
Dimensionl ess groups
(Nu) Nusselt number hd1k
(Pr Prandtl number C~k
(Re)eb Equivalent Reynolds number at the baffle (d2 - d1 )uejt-Lshy
(Re)e Equivalent Reynolds number in the test section ( d 8 - d 1 )U fu
cent Orifice pressure drop function 2(~P ) gc~av(d2 - d1) 2
Al
56
BI BLIOGRAPHY
1 Ambrose Tommy W Local shell-side heat transfer coefshyficients in baffled tubular heat exchanger PhD thesis Corvallis Oregon State College 1957 183 numb leaves
2 Bell K J and o P Bergelin Flow through annular orif ices Transactions of the American Society of Mechanical Engineers 70593-601 1957
3 Colburn Allan P A method of correlating forced con shyvection heat transfer data and a comparison with fluid friction Transactions of the American Institute of Chemical Engineers 24 174-210 1933
4 Dittus F w and L M K Boelter Heat transfer 1n automobile radiators of the tubular type University of California Publications in Engineering 2443-461 1930
5 Gurushankariah M s Local shell-side heat transfer coefficients in the vicinity of baffles in tubular heat exchangers Masters thesis Corvallis Ore gon State Colle ge 1958 97 numb leaves
6 Knudsen James G and Donald L Katz Fluid dynamics and heat transfer New York McGraw-Hill 1958 576 p
7 Lee Kyu Sung Local shell-side heat transfer coeffishycients and pressure drop in a tubular heat exchanger with orifice baffles Masters thesis Corvallis Oregon State College 1959 118 numb leaves
8 McAdams William H Heat transmission 3d ed New York McGra ~-Hill 1954 532 p
9 Sullivan F W and 0 P Bergelin Heat transfer and fluid friction in a shell-andbulltube exchanger with a single baffle Chemica l Engineer ing Progress Symposium Series 52 ( 18) 85-94 1956
10 Wiegand J H Discussion on annular heat transfer coshyef f icients for turbulent flow Transactions of American Institut e of Chemical Eng i n eers 41147-153 1945
AP PENDIX
57
TABLE III
CALCULATED HEAT TRANSFER DATA
Baffle Hole Diameter Run No (inches)
1 - 59 1 364
60 - 102 1 216
103 - 138 1 316
139 - 206 1 516
207 - 212 No orifice
213 - 218 2nd - 1 516
TABLE III
CALCULATED HEAT TRANSFER DATA
Local Heat Transfer Coefficients Run
T0 bull Po s ition CFM hr h2 h3 h4 hs he ~ hav Nuav
1 c 1026 10 59 1476 16 09 1559 1510 1435 1203 1518 8511 2 1290 1369 1738 1878 18 05 1755 1689 1515 1773 9964 3 1416 1636 198 1 2068 1977 1924 1845 1715 1959 11030 4 1627 1991 2301 2382 2268 2194 20 ~98 1929 2249 12664 5 1776 2252 2669 2863 2713 2517 2338 2126 2620 14759 6 l2ttD 1109 2311 3317 3386 3373 3387 3394 3071 3371 18888 7 1258 3089 4583 4866 4683 4701 4643 4194 4695 26301 8 1433 38 8 5 55 83 5791 5495 5430 5436 5008 5547 31192 9 1681 4992 7378 7649 6980 6864 6870 64 28 7148 40180
10 1 D 1102 2371 3332 3511 3356 3342 3427 3102 3394 19012 11 1308 3218 4379 45 24 42 53 4255 4373 3965 43 57 24446 12 14 64 38 58 5146 5142 4839 4787 4903 4597 4963 278 79 13 1706 5218 6664 6269 58 81 5884 6237 5973 61 87 34718 14 15
1 l2D 1115 1275
2131 2661
2955 3638
2972 3720
2941 3675
2913 3576
28 22 34 74
2613 3278
2921 36 17
163 09 20246
16 1498 34 87 4644 4503 4441 4371 4343 4194 4460 25010 17 1695 4449 5743 5324 5222 5154 5157 5015 5320 298 97 18 2D 1049 1715 23 90 2550 2610 2656 2624 2208 2566 14363 19 1241 2117 2964 3145 3218 3221 3203 2759 3150 17757 20 1532 28 67 3936 4100 4188 4201 4167 3676 4118 23224 21 1674 3459 4508 4598 4746 4795 4792 4299 4688 26337 22 lU 1074 253 340 380 3 86 388 377 354 374 2097 23 1287 292 392 433 440 441 429 406 427 2394 24 1508 322 439 492 498 499 487 461 48 3 2713 25 18 07 3 38 464 519 5 24 520 499 463 5 05 28 40
~~ (]I agt
TABLE III Continued
Run No Position CFM h 1 h2 ~3 h4 h5 h6 ~ h
av Nu
av 26 c 1029 1171 1491 1589 15 28 1 4 62 1377 1293 1489 83 44 27 1266 1395 1746 1853 18 02 1685 1556 1453 1728 9704 28 1430 1637 2037 2175 2060 1909 1735 1591 1983 11159 29 1729 1982 24 96 2751 2507 2268 2030 1886 2410 13579 30 12D 1054 2934 4041 4321 4326 4423 4359 3706 4298 24160 31 1294 3385 4 8 26 52 42 5326 5450 5277 4566 52 24 293 50 32 1431 3784 5347 5721 57 bull75 58 44 5700 5084 5677 31870 33 1770 52 75 7 7 33 87 35 9005 9007 8267 7059 85 49 48050 34 lD 1058 3235 4401 4444 3877 3496 3451 3294 3934 21973 35 1263 38 98 5484 5330 4347 3964 3981 3987 4621 25823 36 18 36 6701 89 17 7855 6369 5597 5769 6283 69 01 38718 37 1 12D 1029 2404 31 8 2 3333 3459 3624 3577 3045 3435 19264 38 1315 3182 4033 4162 4310 4496 4502 4015 4301 24142 39 1426 3628 4389 4510 4573 4760 4804 43 8 5 4607 25678 40 1757 4547 5559 5(35 5931 6282 63 70 6060 5975 33471 41 2 11D 1080 2034 28 38 3155 3144 3145 2966 2540 3050 17027 42 1305 2650 3 4 87 3aoz 3595 3751 3595 3153 36 46 20405 43 1434 3167 39 07 4156 4371 4320 4126 3709 4176 23395 44 1804 4096 4 9 66 5691 5714 5586 53 15 48 65 5454 30582 45 12U 1088 409 516 557 564 5 60 535 513 5 46 30 67 46 1318 470 579 6 22 631 6 17 5 97 579 6 09 3422 47 14 13 540 640 676 6 86 681 6 60 6 54 6 69 3754 48 1773 641 740 774 782 7 69 749 746 763 42 87 49 l 11 U 1054 270 356 391 397 393 3 71 346 38 2 2133 50 1240 303 399 446 449 447 4 21 398 432 2420 51 1419 361 476 522 530 528 507 467 493 2760 52 1 1(2U 1032 236 311 342 347 344 325 301 334 18 78 53 1314 270 366 403 407 408 386 351 394 2217
(Tt tO
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ h av Nu av
54 1448 301 408 447 454 452 431 403 438 24 61 55 1782 353 494 548 544 415 529 531 506 2843 56 2U 10 61 220 287 316 320 322 303 268 310 1735 57 1216 249 335 370 377 378 353 307 363 2044 58 1322 263 356 394 398 399 374 327 384 2159 59 1639 310 433 478 481 482 452 393 465 2617
60 1D 10 68 2011 2536 2657 2681 2694 2560 15 62 2625 14938 61 1399 2520 3239 3369 3371 33r82 32 39 1946 3320 18968 62 1669 2781 3655 3820 38 76 3883 3738 2355 3794 21712 63 1959 3524 42 37 4399 4438 4497 4417 3047 4397 25156 64 2295 4426 5288 5396 5372 5240 5410 3369 5341 30680 65 2636 5490 6531 6662 6565 6379 6820 4249 6591 37938 66 3390 7869 9538 9462 9387 8924 10508 62 91 9564 59601 67 1U 1190 352 368 401 413 407 395 293 397 2256 68 1559 397 422 462 475 471 456 331 4 57 2603 69 1904 434 465 5 13 529 528 504 358 508 2901 70 2211 493 526 573 5 92 588 564 4 15 569 3257 71 2289 569 587 6 30 649 6 61 6 49 460 635 36 44 72 2727 637 6 60 7 09 733 751 743 521 719 4140 73 3210 728 755 8 15 8 43 8 62 8 54 616 826 4765 74 2nD 1210 181 2256 2393 2399 2333 2206 1325 2317 13158 75 1420 2340 2752 2899 2913 2850 2728 1701 2828 16121 76 1692 2853 3306 3452 3471 3379 3217 2134 3365 19217 77 1894 3102 3588 3713 3736 3670 3557 2455 3653 20892 78 2301 3682 4259 4433 4467 43 83 4289 2892 4366 250 30 79 2621 4117 4828 5017 5012 5030 5109 3071 4999 28785
m 0
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ hav Nuav
80 3230 5158 6006 62 13 61 18 6134 6695 4094 6233 359 87 8 1 12nD 1155 15 27 1854 2028 2064 20 85 1987 1164 1968 118 31 82 1689 2046 24 8 2 2688 2739 2760 2658 1749 2665 152 73 83 1244 2088 2317 2339 2345 2373 2381 1487 2351 13432 84 2100 3211 3539 34 21 3462 3512 3696 2575 3526 20284 85 2292 3 5 05 3761 3648 36 25 36 79 3957 2933 3734 21517 86 2907 4420 48 22 4679 46 04 4705 5206 3792 48 03 27741 87 33 80 59 35 69 38 7404 77 10 7 8 36 7 0 86 5190 7394 427 44 88 1 12D 1 4 27 2 4 58 28 31 3037 3021 2987 2927 18 57 2 9 61 16913 89 18 75 34 75 3 9 87 4230 4255 4317 4337 2734 4225 24258 90 22 59 4221 4796 5046 5052 51 01 5389 3491 5077 29206 91 2682 4978 5664 5943 5966 6054 6573 408 1 60 40 34795 92 3417 63 16 71 02 7 3 93 7385 75 40 8 6 95 51 45 7623 44017 93 c 1 5 17 1240 1305 1399 1467 1479 1429 9 26 1423 8251 94 20 34 1554 1623 1720 18 21 18 53 18 72 1215 1778 10229 95 2 3 48 1795 1843 198 5 2097 2171 2274 1540 2074 11947 96 2716 2028 2048 22 01 2 3 44 2444 2661 18 90 2340 13505 97 3247 2410 2375 2663 2778 2949 3298 2378 2793 1615 98 11 35 967 1040 1124 1186 1200 1142 728 1138 6496 99 14 06 1135 1220 1318 1384 1403 1 3 61 8 77 1336 7656
100 2311 1 8 54 18 78 1980 20 90 2136 2227 1653 2062 118 31 10 1 2666 2085 2094 2227 2 3 62 2438 2626 1902 2349 13508 102 3392 2635 2582 28 01 3026 3141 3529 2567 3016 17390
103 1 U 1235 349 395 434 436 4 28 411 286 423 2416 104 20 10 434 5 02 559 577 569 5 37 345 552 3177 105 28 14 538 626 685 711 7 21 682 424 6 8 6 3966
Q) j-J
TABIE III Continued
Run No Position CFM h1 h2 h3 h4 h5 hu h7 hav Nuav
106 3492 614 7 1 6 7 84 8 13 8 33 7 85 4 88 7 87 4562 107 4395 7 86 894 964 996 1005 9 64 640 9 65 56 06 108 50 75 9 11 10 22 1081 1112 1125 1085 7 24 1085 63 16 109 G 1344 9 22 1042 1120 1 1 46 1173 1131 7 04 1120 63 87 110 1936 1162 1340 1442 1474 1509 14 7 3 9 09 1441 82 77 111 2846 1631 1797 1902 1966 2027 2079 1342 19 2 3 11108 112 3484 207e 2144 2236 2307 2385 2574 1694 2268 13138 113 4066 24 65 24 42 2535 2648 2757 31 71 2178 2 5 96 15078 114 50 12 3059 2916 30 1 5 3176 3312 4059 2849 3105 180 46 115 1D 1362 2268 26 13 2613 26 35 2605 2503 15 46 2617 14934 116 1958 2993 3580 3580 3586 3539 3 5 02 2144 3571 20492 117 2812 4430 50 32 4913 4 9 86 4991 5196 3088 4981 287 66 118 3432 58 16 62 13 6067 61 18 60 66 6698 4143 61 16 354 16 119 40 22 71 71 7 4 62 7369 7419 7329 82 74 51 8 1 7395 42909 120 5026 105 95 11456 115 81 11574 11548 14010 80 91 11540 671 15 121 2D 1244 18 57 2277 2363 2305 2210 2107 1466 2289 13038 122 1960 2622 3240 3388 33 23 3226 31 40 2)99 3294 18919 123 2817 3762 45 87 4739 46 56 45 14 4 6 47 30 15 4624 26689 124 3491 50 22 5723 58 53 57 44 5542 60 18 3871 57 16 330 73 125 4096 61 29 68 16 69 79 6805 65 90 74 79 4677 67 98 39400 126 5037 82 27 94 60 95 69 93 57 9023 11324 65 05 93 52 542 83 127 12D 1278 14 70 1 6 48 1652 1638 1 6 34 1641 9 73 1 6 43 9369 128 1947 19 63 2155 2149 2151 2131 2190 1347 2147 12342 129 2769 2615 2791 2773 28 52 2716 2954 18 96 2783 1 60 82 130 3439 3208 3265 3239 3593 3133 3624 2515 3308 19174 131 4103 3637 35 88 3577 4077 3459 42 66 3138 3676 21343 132 49 78 45 82 44 60 44 8 1 55 17 43 25 5749 4227 4700 27288
Q) tlgt
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
133 1 12D 1299 2094 2507 2622 2625 2567 2489 1465 2578 14736 134 1973 29 56 3505 3772 3790 3718 3718 2115 3700 21290 135 2788 3941 4727 5069 5099 5 0 07 5231 2984 4976 28781 136 3473 5155 59 81 6308 6339 62 39 68 96 4204 6217 36052 137 4118 6135 71 8 6 7662 7731 76 91 87 16 49 8 5 7568 43985 138 4973 7765 94 75 10396 10861 10694 13646 66 64 10357 602 25
139 1ttn 1253 1242 1493 1460 1442 1431 1424 8 84 1457 83 01 140 2366 1942 2150 1961 1910 1897 19 62 1206 1980 11400 141 3461 3007 2957 2562 2513 2606 3143 18 51 2660 15400 142 4325 3942 3571 3060 2999 3198 4248 2631 3207 18618 143 5677 508 6 4359 39 88 3800 42 29 57 78 36 26 4094 23824 144 67 59 64 55 5330 4988 47 25 5494 2517 48 09 5134 29906 145 84 08 9326 72 26 7726 85 56 9172 12319 7733 8170 47626 146 86 54 9831 7582 818 9 94 90 9869 13116 78 97 8783 512 96 147 7376 7335 58 7 6 5941 5796 68 29 81 65 5954 6111 35662 148 2 11 D 4254 4106 48 02 4994 5038 5042 56 78 3419 4969 28881 149 5708 5487 6253 6466 6524 6527 78 63 45 8 2 64 43 37566 150 69 7 8 7983 9440 9848 98 34 97 32 13249 6701 9714 566 59 151 1254 1434 18 53 1947 1915 1850 1760 1186 1891 10772 152 2713 2696 3175 32 94 3288 3237 3288 20 44 3249 18728 153 87 30 118 07 14733 15758 15504 15305 26297 9617 15325 892 71 154 5811 5278 6543 6861 69 30 69 82 7 8 74 4478 68 29 39531 155 4246 3780 4736 4975 49 66 4936 5162 3113 4903 28301 156 (v 1270 8 15 935 959 966 9 51 9 23 6 35 953 5430 157 2714 1164 1390 1427 1447 1454 1455 9 08 1430 8242 158 4310 1655 18 96 1942 1988 2002 2111 1305 1957 11349
(j) ~
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 fry hav Nuav
159 6012 2208 2400 2450 2513 2548 28 20 18 00 2478 14416 160 7279 2696 2881 2927 2989 3081 3599 2340 2970 17326 161 86 90 3257 3360 3 3 76 34 26 3558 4455 2943 3430 2000 162 12D 4368 2209 2600 2558 2518 2466 2774 1753 2536 14713 163 5833 2730 3092 3028 2974 2913 3501 2287 3002 174 78 164 7643 3320 3681 3630 3651 3530 4623 3181 3623 21116 165 87 39 3920 4303 4300 4708 4178 61 60 3937 4372 25456 166 1268 962 1203 1205 1186 1118 1084 725 1178 6693 167 2678 14 67 1785 1779 1752 1698 1726 10 70 1754 88 49 168 1 12D 12 83 936 1217 1414 1397 1239 1190 7 65 1317 7484 169 2729 2502 2930 2914 2934 2956 2979 17 52 2934 16866 170 4345 3884 4357 4283 4318 4421 4836 28 59 4345 25151 171 6036 5546 5858 5764 5791 6028 7129 4184 5860 34045 172 6578 7167 7769 7907 79 82 8263 10492 5915 7980 46437 173 87 84 10237 112 23 120 26 12727 12968 185 19 85 98 12236 71103 174 1278 1344 1803 18 72 1835 1790 1712 1063 1825 10355 175 2711 2328 2972 2932 2893 28 78 2863 1667 2919 167 51 176 4351 3934 4414 4353 4281 4321 4654 28 63 4342 25088 177 5994 5076 5824 5838 5818 59 29 6914 4205 5852 33885 178 1 11 U 1223 388 432 465 464 449 435 338 453 2585 179 2351 521 602 6 22 675 6 57 619 436 639 3687 180 34 48 6 05 1725 803 8 27 8 11 760 518 792 4593 181 4513 718 850 934 9 68 9 57 8 99 609 9 27 5386 18 2 5714 8 32 981 1060 1102 11 06 1034 6 59 1062 61 82 183 6997 1025 1182 1258 1295 1309 1234 8 18 1261 7 3 44 184 8709 1295 1487 1 5 42 1594 1626 1612 1156 1562 9080
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
185 2 12D 4249 3560 4400 4670 4791 4695 47 81 2931 4639 268 37 186 5737 4926 58 54 61 92 6248 62 38 67 78 4134 6131 35590 187 7432 6390 7726 83 46 85 44 86 34 10371 5658 8313 48310 188 8723 7718 107 88 11933 12099 13046 186 22 79 39 119 67 69505 189 1 4 35 1340 1735 18 57 18 52 17 81 1711 1144 18 06 10256 190 2718 2399 3023 3187 3207 3138 30 53 1931 3139 18025 191 7 5 07 6189 80 11 9200 9427 9703 11364 5720 9085 527 38 192 8544 78 42 10666 125 42 13312 13775 178 20 6976 125 74 729 86 193 1287 1417 16 97 18 7 18 69 18 08 1720 1046 1800 10223 194 27 17 2450 2940 3187 3214 3157 3054 1749 3125 17954 195 42 53 3560 4222 45 90 4679 46 63 4743 2741 4539 26247 196 6068 48 69 57 79 6335 65 8 6 66 04 7172 4338 63 26 366 78 197 7389 58 86 72 8 6 82 23 8584 8936 10658 50 60 8257 4798 6 198 86 88 78 91 100 27 120 56 130 29 14299 190 81 6492 12353 71850 199 5864 4694 5 6 67 61 94 6419 65 48 7192 3950 6207 360 14 200 2 D 4177 38 36 4547 48 09 4775 4628 5006 2715 46 90 261 30 201 5712 5170 62 39 66 38 6599 6604 7518 4167 65 20 378 00 202 73 63 7201 8986 98 43 9733 9914 13353 6219 9619 55810 203 8604 10043 13118 148 41 150 42 158 66 25206 82 5 3 14717 85290 204 12 68 1506 18 41 1971 1966 1868 1799 11 42 1913 10880 205 2659 2571 3127 3276 32 50 3130 3069 18 80 3196 18 350 206 39 80 36 76 4347 4573 45~67 4473 46 34 28 37 4490 25910
o 207 Orifice 11496 10 64 1360 15 39 1 5 80 1 6 15 1496 8 58 15 24 88 83 208 9433 8 95 11 78 13 26 1394 1386 1263 727 1346 78 48 209 7387 746 9 77 1123 1184 1159 1048 6 11 1111 64 74 210 52 36 566 7 66 900 934 909 8 21 499 8 27 48 02
0) CJ1
TABLE III Continued
Run No Position CFM h 1 h2 hs h4 h5 h6 h7 hav Nuav
211 212
3309 1293
414 257
563 3 19
6 68 3 57
6 91 3 37
6 72 351
7 37 337
38 4 2 46
4 40 341
3748 1942
213 214 215 216 217 218
c of 2nd 1 516 1235
1919 2712 3320 4153 4704
1532 2447 35 46 4312 5567 74 29
2 1 87 3312 4225 52 86 6902 8 6 50
2360 3555 4340 56 12 7 0 49 8 9 40
2409 3598 4 8 85 5718 7713 9593
2347 2101 35 33 3453 48 00 49 62 5562 59 86 72~6 7 8 79 93 76 11237
1243 20 64 3054 4 2 8 1 5114 6983
2326 35 00 4638 5545 7225 91 40
132 13 200 27 26672 31968 41711 52811
bull
67
TABLE IV
PRESSURE PROFILE DATA
Baffle Flow Qpening Rate ~p
(Inches) Position (CFM) (Inches 295 S G Fluid)
1 364 l2 11 U 1012 0 254 1248 0197 1493 0 141 1718 0112
c 1000 9 80 1210 1710 1436 28 75 1746 4320 1011 1080 1277 2050 1393 3020 1 6 28 4450
12D 1011 9 75 1236 1520 1450 2510 1603 3450
1 D 1011 975 1256 1700 1480 2690 158 1 4070
1 12D 1010 950 1259 1750 1462 2650 1631 3710
2 11 D 1124 1315 1360 2130 1505 2850 1689 4125
1 216 12U 1294 045 1949 0324 2374 0282 2704 0225 3367 0169
c 1326 265 18 81 5 90 2313 990 2731 1480 3439 2660
12D 1272 2 49 1957 661
68
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Pos ition (CPM) Inches 2 95 S G Fluid)
2559 1275 3033 1940 3639 3025
1 216 1nD 1257 242 16 96 476 2117 8 05 2561 1280 2990 1895 3431 26 bull00
1 316 12U 1309 0 479 2004 0422 28 28 0 352 3526 0281 42 28 0225 5199 0225
c 1308 1 43 1998 272 28 14 5 10 3478 795 4248 1235 5048 1885
l2D 1286 140 2005 3 45 2831 725 3495 1180 4194 1805 5046 2945
1 11D 1322 150 2039 352 2841 735 43 77 1980 5378 3440
1 516 12U 1278 0493 2732 0493 4315 0408 5744 0352 7494 0352 8932 0422
c 1300 0 506 2731 1985 4310 348 6080 6 45
69
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Position (CPM) (Inches 295 SG Fluid)
7607 1090 8830 1585
l2D 1343 0549 2738 225 4566 583 6112 1195 7536 2055 9043 3415
1 516 1uD 1249 0464 2713 224 4155 579 5620 1150 7428 2115 90 70 3405
1 12D 1301 0493 2735 220 4501 616 61 50 1235 7440 2065 8862 3445
2D 1265 0 478 2750 226 4366 594 6578 1270 7678 2240 8945 5280
2 12D 1295 0493 2725 222 4293 600 5807 1120 7568 2200 9070 3615
TABLE V
RATE OF HEAT TR AN SFER Ar THE BAFFL~~ CID-TT ER
Orifice Size
(Inches)
Flow Rate
( CFM)
Re d e G tU
R~) 055 Nuav NuPr-l3
1 364 10 26 12 90
8 075 10015
43400 54 600
85 11 99 64
95 83 112 19
1416 11 140 59 900 110 30 124 20 16 27 12 800 68 900 126 64 142 60 17 29 13 610 73 200 135 79 152 90 17 76 13980 75 200 147 59 166 19
1 216 11 35 14 06
8 600 10 660
27000 33500
6 4 96 76 56
73 14 8 6 12
1517 11500 36100 82 51 9291 20 34 15400 48400 10229 115 18 23 11 17500 55000 118 31 13322 2348 17 800 55900 11947 13452 2666 20 200 63400 13508 15210 27 16 20 600 64700 135 05 152 07 32 47 24600 77200 161 57 18 193 3392 25 700 80700 17390 195 8 1
1 316 1344 19 36
9898 14 260
24800 35 700
63 8 7 8 2 77
71 92 93 20
28 46 20 9 60 52 500 111 08 125 08 34 84 25 660 64200 131 38 147 93 40 66 50 12
29900 36900
74800 92400
150 78 18046
169 78 203 20
~ 0
TABLE V Continued
Orifice Flow Re Size Rate d e G R~rmiddot55 NuPr-13(Inches) (CFM) U Nuav
1 516 12 70 8 847 16800 54 ~0 61 14 2 14 18 900 35800 82 42 92 80 43 10 30 000 56900 11349 127 79 60 12 41900 79400 14416 16232 7279 50700 96100 17326 19509 86 90 60540 115000 20098 22529
TABLE VI
RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
Orifice Size
(Inches)
1 364
1 216
1 316
Flow Rate
(CFM)
1054 1294 1431 1681 1770
1068 1399 1669 1959 2295 2636 3390
1299 1973 2788 34 73 4118 4973
Re deG Mshy
8 300 9870
11260 13200 13 930
8100 10600 12650 14850 17400 19980 25700
9 570 14500 20500 25600 30300 36600
R~r-6 51900 61700 70500 82 500 87 100
28200 36900 44000 51700 60 600 69500 89400
26100 39600 56000 69900 82700 99 900
Nuav
2416 293 5 3187 4018 4805
14938 18968 21712 25156 30680 37938 59601
14736 21290 28781 36052 439 85 60225
Uu Pr-1 3
27204 33050 3589 4524 541 0
16820 21358 24448 28326 34546 427 18 67111
16593 23973 32407 40595 495 1 678 13
TABLE VI Continued
Orifice Flow Re Size Rate deG R~rmiddot6 NuPr-13(Inches) (CFM ) M- Nuav
1 516 1268 88 30 17700 108 8 1225 2689 18700 37400 1835 2066 3980 27700 55700 2591 2917 4177 29100 58 500 2713 3055 5712 39800 80000 378 0 425 6 7362 51300 103000 5581 6284 8 604 59 900 120000 8529 9604
74
TABLE VII
EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER
l 516 Inch Orifice
Center ot 2nd Baffle 4 Downstream
Plow Rate (CFM)
1235 1919 2712 3320 4153 4704
Flow Rate (CFM)
1270 2714 4310 6012 7279 8690
(Re)eb -8600 1321
13400 2003 18900 2687 23100 5197 28900 4171 32800 5281
Center ot Single Battle
-8847 543
18900 824 30000 1135 41900 1442 50700 1733 60540 2001
(Nu)(Pr)-l3
1487 2255 3003 3600 4697 5946
(Nu)(Pr)-13
611 928
1278 1623 1951 2253
75
ABLE VIII
HEAT TRANSFER IN THE TEST SECTION WITHOUT ORIFICE
CFM Ute) 0b h Nu
1293 5-951 3 41 1942
33 09 15251 649 3746
5236 24193 827 4802
7387 34001 1111 6474
9433 43419 1346 7848
11496 52-914 1524 8883
76
TABLE IX
PRESSURE DROP FUNCTION
Orltlee Size Flow Rate incbea ~CFM (Re)eb X 10bull8
1 364 1011 7957 0808 1256 9885 1468 1480 11648 2765 1581 12443 4160 1689 1_3293 4 020
1 216 1257 9530 1327 1696 12858 2663 2117 16049 4615 2561 19415 7581 2990 22668 11560 3431 26011 16440
l 316 1322 9736 1819 2039 15016 4332 2845 20952 9275 3495 25739 15300 4377 32014 26800 5378 39607 50100
1 516 1011 7 957 oaos 1256 9885 1469 1480 11646 2765 1581 12443 4160 1689 13293 4020
77
TABLE X
EXPERIMENTAL DATA
Baffle Hole Diameter Run No
1 - 59
60 - 102
103 - 138
139 - 206
207 - 212
213 - 218
(Inches)
1 364
1 216
1 316
1 516
No Baffle
2nd - 1 516
TABLE X
EXPERIMENTAL DATA
Run Thermocouple Reading s (mv) No Position CFM I tc1 tc2 tc3 tc4 t c 5 tc6 tc7 tcair
1 c 1026 530 2055 1825 1768 1782 1802 1837 1965 1198 2 1290 612 2059 18 65 1809 18 32 1851 1880 1965 1160 3 1416 714 2151 1970 1931 1965 1988 2026 209 5 1130 4 1627 8 21 2235 2084 2 049 2093 2126 2173 2266 1130 5 1776 865 2203 2033 1970 2015 2084 2159 2 264 1121 6 12D 1109 542 1636 1507 1499 1499 1498 1498 1528 1218 7 1258 651 1670 1522 1503 1513 1513 1516 1548 1221 8 1433 750 1625 1480 1467 148 3 1487 1487 1516 1153 9 168 1 8 73 1656 1494 148 1 1511 1517 1517 1543 1159
10 1rtD 1102 485 1545 1450 1437 1446 1447 1442 1466 1220 11 13 08 6 10 1571 1470 1460 1476 1476 1469 1498 1194 12 1464 730 1 623 1509 1508 1528 1 5 32 1524 1548 1173 13 11 06 8 71 1663 1559 158 1 1606 160 6 1 583 1601 1190 14 1 12D 1115 520 1698 1579 1575 1 577 1580 1590 1615 1280 15 1275 6 10 1692 1567 1558 1 561 1570 1580 1601 1234 16 1498 770 1760 1619 1630 1 635 1642 1645 1661 1204 17 1695 912 1775 1635 1670 1689 1686 168 6 1701 1165 18 2D 1049 510 1736 15~2 1567 1558 1 553 1558 1620 1236 19 12 41 610 1655 1517 149 1 148 1 148 1 148 4 1546 1108 20 1 5 32 7 35 1720 1550 1530 1520 1519 1523 158 0 1104 21 16 74 8 8 0 1900 1 727 1714 1696 1691 1692 1753 1169 22 1U 1074 38 5 3 324 2740 2534 2478 2 465 2503 258 0 1210 23 1287 4 35 3510 2 870 2682 2 610 2599 2638 27 1 9 1190 24 1 5 08 470 3 618 2920 2690 2 637 2627 2 664 2747 1177 25 18 07 525 4 088 3235 2962 2905 2910 2988 3130 1169
z ())
TABLE X Continued
Run No Position CFM I tc1 tc 2
Thermocouple Readings te3 tc4 tc5
(mv) tc6 tc7 tcair
26 c 10~29 6 32 2340 2~092 2032 2060 2~097 2152 2~213 1211 27 12 66 679 2270 2 047 1993 2013 2069 2142 2 210 1 182 28 1430 723 2336 2097 2033 2080 2153 2~255 2 356 1 138 29 1729 8 52 2318 2070 1980 2061 2158 2279 2367 1121 30 12D 1054 570 1520 1 4 20 1402 1400 1396 1400 1 443 1159 31 1294 6 69 1599 1469 1444 1439 1433 1 442 1485 1168 32 1430 7 88 1720 1562 1536 1532 1528 1537 158 0 118 5 33 1770 8 81 1641 1488 1450 1~441 1 441 1_466 1518 1 163 34 1D 1058 548 1579 1498 1495 1526 1553 1_557 1 571 1 276 35 1263 640 1609 1509 1515 1570 1599 1598 1 598 1 266 36 18 36 8 47 1538 1452 1483 1553 1602 1 590 1 558 1195 37 1 12D 1029 5 41 1 578 1499 148 4 1473 1461 1465 1-512 1200 38 1315 6 30 159 1 1504 1493 1482 1470 1470 1505 118 5 39 1 4 26 743 1765 168 1666 1660 1645 1642 1678 1270 40 1757 8 54 1744 1648 1634 1620 1598 1 593 - 1612 1223 41 2D 1080 5 30 1734 1604 1570 1 570 1570 1 588 1 640 128 1 42 1305 6 40 1744 1622 1589 1 608 1593 1 609 1 661 1240 43 1434 750 1798 1687 1658 1 636 -1641 1 661 1 711 1_220 44 18 04 8 41 1 764 1666 1607 1605 1614 1 635 1 675 1205 45 12nu 1088 415 2614 2295 2195 2 169 2174 2217 2256 1171 46 1318 477 2805 2477 2371 2342 2364 2 401 2 438 1 163 47 1413 5 28 2930 2 646 2 555 2 526 2532 2570 2 577 1 199 48 1773 550 2740 2518 2450 2431 2448 2 479 2 480 1 170 49 1 11 U 1054 380 3175 2670 2505 2 461 2467 2 534 2 621 1 258 50 1240 420 3268 2738 2 546 2 510 2 508 258 2 2 649 1214 51 1419 451 3364 2B07 2 632 2590 2 590 2 651 2773 1 215 52 1 12U 1032 360 3 165 2 629 2 450 2402 2403 2 473 2 bull568 1 163
--I lt0
TABLE X Continued
Run No Position CFM I tc1 tc2
lhermocoup1e Reading s tc3 tc4 t c 5
(mv) tc6 tc7 tc a ir
5 3 1314 38 9 3178 2592 2411 2367 2361 2432 2555 1140 54 1448 403 3095 2544 238 1 2336 2336 2390 2476 1158 55 178 2 427 3006 2434 2286 2253 255 3 2299 2397 1154 56 2 11U 1061 360 3369 2814 2619 2567 2560 2650 2833 1220 57 1216 360 3044 2512 2338 2290 2288 2374 2566 1150 58 1322 387 3196 2614 2425 2383 2382 2472 2670 1138 59 1639 403 3020 2438 2272 2238 2238 2318 2502 1127
60 1D 1068 612 1552 1424 1400 1395 1396 1426 1745 0945 61 1399 612 1355 1246 1230 1229 1230 1250 1509 0872 62 1669 710 1436 1293 1272 1265 1266 1286 1551 0847 63 1959 900 159 5 1468 1444 14 38 1432 1446 1720 0851 64 2295 730 1169 1105 1098 1099 1108 1100 1298 0781 65 2636 8 80 1202 1129 1121 1126 1 138 1115 1342 0748 66 3390 9 35 1060 o 9s7 0999 1001 1017 0971 1154 0703 67 1nu 1190 370 2225 2188 2104 2080 2120 2209 2 7 15 0990 68 1559 368 2005 1950 1871 18 48 1876 1951 2408 0916 69 1904 368 1870 18 1 4 17 34 1711 1730 18 07 2238 0875 70 22 bull11 471 228 6 2 204 2099 2063 2092 218 $ 2732 0840 71 2289 471 2030 2000 1925 1895 18 96 19 5 2498 0785 72 2727 4 71 1854 18 23 1753 17 23 1716 3758 2241 0743 73 3210 471 1680 1651 158 6 1559 1551 158 1 1950 omiddot7o9 74 2uD 1210 404 1261 1212 1198 1197 1205 1222 139 1 0978 75 14 20 540 1321 1260 1242 1 240 1249 1268 148 7 0918 76 1692 7 18 1467 138 6 1364 1361 1376 1405 1678 0883 77 18 94 903 1708 1 591 1565 1560 1575 1603 1948 0 857 78 2301 903 1530 1432 1407 1402 1415 1432 1738 0815
ro 0
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc117 tcair
79 2621 6 50 1069 1 020 1009 1009 1009 1007 1~189 o739 80 3230 901 1200 1128 1113 1119 1119 1086 1341 0694 81 82
l2D 1155 1689
360 575
1191 1345
1142 1252
1122 1218
1118 1210
1118 1209
1132 1228
1292 1446
0916 0822
83 1244 430 1163 1134 1131 1130 1129 1132 1292 0877 84 2100 645 1175 1135 1147 1 142 1138 1122 1286 0757 85 2292 8 25 1 354 1310 1327 1330 1323 1285 148 6 0728 86 2907 8 23 1180 1138 1151 1158 1149 1107 1268 0687 87 3380 902 1113 1049 1025 1011 1006 1042 1178 0673 88 89
1 12D 1427 1875
480 615
118 2 1140
1140 1095
1124 1077
1125 1075
1129 1072
1137 1072
1290 1243
0880 0790
90 2259 8 41 1296 1231 1207 1206 1203 1182 1419 0757 91 2682 8 80 1231 1170 1149 1147 1142 1112 1350 0731 92 3417 940 1142 1092 1076 1076 1069 1021 1252 0693 93 c 15 17 431 1321 1298 1268 1249 1250 1273 1522 0841 94 2034 505 1285 1263 1235 1209 1205 1206 1464 0759 95 2348 6 10 1395 1379 1334 1302 1286 1268 1536 0732 96 2716 706 1486 1480 1427 1383 1358 1311 1572 0 700 97 3247 7 56 1417 1430 1375 1320 1284 1223 1450 0660 98 1135 400 1425 1388 1352 1329 1330 1 364 1651 0893 99 14 06 440 1379 1341 1304 128 2 1281 1305 1583 0 831
100 2311 680 1602 1593 1553 1514 1502 1480 1 7 27 0 802 101 2666 680 1471 1469 1428 1390 1372 1335 1564 0761 102 3392 798 1491 1 509 1449 1395 1372 1305 1534 0 719
103 1U 1235 410 2469 2295 2173 2165 2226 2361 3120 0 897 104 2010 410 2017 1848 1 737 1706 1747 1865 2582 0753 105 28 14 410 1682 1535 1457 1427 1437 1520 2109 0 660
00 t-
TABLE X Continued
Ru n Thermocouple Rea ding s (mv No Positi on CFM I tc1 tc2 tc3 tc4 tc5 tc6 tc7 tcair
106 3492 440 1649 1499 1420 1391 1390 1470 2042 0620 107 4395 550 18 33 1679 1597 1564 1570 1640 2223 0583 108 5075 588 1779 1642 1580 1550 1552 1 615 2 191 0548 109 c 1344 398 1464 1 399 1364 1353 1350 1380 1689 0 907 110 1936 459 1369 1290 1253 1242 1 237 1259 1574 078 2 111 2846 580 1347 128 5 1251 1232 1220 1215 1 5 23 0 683 112 34 8 4 700 1392 1369 1339 1317 1299 1259 1599 0 636 113 4066 8 13 1449 1458 1427 1391 1363 1270 1595 0 591 114 5012 930 1484 1530 1500 1453 1420 1272 1580 0 580 115 1D 1362 513 1269 1218 1 217 1214 1220 1238 1460 0 893 116 19 58 600 1187 1122 1121 1120 1124 1133 1352 0798 117 2812 705 1052 1008 1015 1010 1011 1001 1218 0691 118 34 32 913 1105 1075 1085 1081 1086 1047 1301 0645 119 4022 980 1038 1021 1026 1023 1029 0983 1211 0 609 120 5026 982 0 8 61 0839 0836 0836 0837 0791 0955 0570 121 2D 1244 475 1320 1246 1233 1240 1255 1275 1434 0925 122 1 9 60 5 50 1160 1088 1074 1079 1089 1100 1260 078 7 123 2817 6 80 1096 1024 1 013 1018 1029 1022 1201 0 700 124 3491 960 1248 1175 1163 1172 1192 1153 1435 0 658 125 4096 989 1141 1089 1078 108 9 1105 1051 1310 0629 126 50 37 989 0983 0933 0929 0 936 0949 0880 1090 0 602 127 128
12D 1278 1947
402 545
1270 1261
1 230 1216
1228 1216
1230 1 215
1235 1223
1242 1219
1483 1514
0 913 0778shy
129 2769 695 1273 1234 1237 1221 1251 1212 1525 0678 130 131 132
34 39 4103 4978
8 40 9 80 9 80
1336 1448 1271
1322 1458 1 288
1328 1 462 1286
1 259 1 356 1157
1353 1492 1311
1261 1329 1138
1 555 160 7 1343
0 629 0 600 0599
(l) l)
TABLE X Continued
Run No Position CFM I tel tc 2
Thermocouple Readings tc3 tc4 tc5
( mv) tc6 tc7 tcair
133 1 l2D 1299 5 16 1 28 1 1212 1196 1195 1205 1221 1478 0869 134 1973 6 15 1163 1098 1073 1071 1079 1083 1343 0751 135 136
27 88 34 73
802 9 -_78
1187 1214
1099 1131
1069 1104
1066 1101
1075 1~110
1l061 1066
1370 1360
0662 0618
137 4118 9 81 1084 1010 0983 0979 0982 o937 1209 0581 138 4973 98 1 0969 0897 0 868 0855 0860 0799 1041 0572
139 1D 1253 409 1371 1293 1298 1301 1309 1321 1578 0928 140 2366 480 1130 1 090 1 121 1130 1137 1132 1390 0744 141 34 61 6 38 1081 1086 1152 1161 1147 1069 1382 0644 142 143 144
4325 5677 6759
7 90 939 998
1110 1115 1034
1161 1208 1139
1253 1268 1180
1265 1302 1215
1228 1230 1123
1080 1056 0970
13$913r12 8
0601 0561 0542
145 84 08 989 0863 0961 0934 0895 0871 0 785 09 9 0530 146 86 54 9 80 0808 0901 0 872 0821 0809 0733 0891 0498 147 7376 9 80 0 927 1032 1027 1 040 0961 0889 1032 0511 148 2D 4254 776 1 050 0 981 0965 0961 0962 0922 1155 0579 149 5708 991 1102 1031 1014 1009 1010 0931 1227 0528 150 69 78 990 0914 0853 0839 0 839 0843 0759 0996 0521 151 1254 490 1 479 1352 1329 1334 1351 1379 1607 0930 152 2713 7 00 1310 1220 1201 1201 1211 1209 1516 0723 153 8730 991 0809 0756 0742 0745 0 748 0663 0874 0543 154 5811 966 1219 1108 108 6 1081 1079 1033 1330 0650 155 42 46 8 02 1248 1136 1114 1114 1118 1103 1376 0 699 156 c 1270 429 1671 1571 1551 1545 1563 1600 1933 0929 157 2714 488 1398 1285 1 267 1258 1262 1275 1628 0729 158 4310 642 1424 1318 1299 1282 1283 1261 1683 0617
co ~
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc7 tc a 1r
159 60 12 780 1461 1388 1370 1349 1343 1279 1700 0 573 160 72 79 8 60 1402 1344 1330 1312 1292 1189 1 566 0 520 161 8690 982 1472 1442 1437 1 422 1392 1224 1602 0 521 162 163
12D 4368 5833
6 30 8 30
1195 1368
1105 1270
1111 1283
1117 1294
1131 1313
1081 1194
1369 1553
0613 0 553
164 76 43 959 1428 1338 1348 1341 1371 1180 1488 0535 165 8739 984 1345 1272 1272 1208 129 3 1059 1361 0550 166 1268 459 1701 1548 1541 1547 1589 1 625 1976 0 973 167 2678 570 1485 1351 1349 1356 138 1 1 385 1795 0760 168 169
1 12D 128 3 2729
448 650
1664 1314
1501 1232
1425 1233
1428 1229
1491 1229
1527 1232
1869 1571
0 962 0767
170 4345 847 1245 1179 1187 1182 1172 1132 1476 0 650 171 6036 9 76 1139 1109 1117 1114 1095 1020 1332 0588 172 6578 9 72 0982 0949 0942 0938 0926 0 8 50 1079 0560 173 87 84 9 72 0880 0854 0 8 36 0822 0818 0 749 0941 0585 174 1278 480 1564 1416 1397 1403 1417 1445 1733 0998 175 2711 590 128 3 1175 4 1178 1182 1187 1195 1493 0796 176 4351 8 90 1331 1259 1266 1275 1272 1235 1592 0 682 177 5994 9 60 1228 1152 1150 1151 1143 1075 1 360 0644 178 lU 1223 408 2282 2140 2052 2052 2106 2188 2626 0 878 179 2351 408 178 1 1623 158 5 1519 1556 1634 2068 0717 180 3448 482 1888 1675 1570 1541 1572 1665 2199 0629 181 4513 563 2026 1797 168 4 1644 1670 1770 2385 0583 182 5714 589 1913 1700 1610 1568 1580 1 682 2382 0551 middot 183 6997 653 1903 1718 1643 1611 1612 1700 2326 0 549 184 8709 6 80 1738 158 3 1543 1510 1498 1519 1 912 0577 185 186
2 12D 4249 5737
660 9 74
1055 1221
0 979 1122
0960 1093
0 952 1088
0959 1090
0 956 1054
1147 1350
0661 0602
187 7432 9 8 1 1065 0981 0951 0942 0 939 0881 1135 0582 CD ~
TABLE X Continued
Run No Position CFM I t o1 to 2
188 87 23 9 83 0944 0 879 189 1435 585 18 26 1630 190 2718 690 1433 1298 191 7507 950 1070 0961 192 85 44 964 0982 0 881 193 1287 600 1806 1668 194 2717 7 80 1579 1444 195 4253 8 81 1371 1260 196 60 68 9 78 1252 1152 197 73 89 975 1100 1000 198 86 88 973 0953 0 871 199 58 64 9 81 1269 1155 200 2D 4 1 77 915 1362 1251 201 5712 975 1213 1111 202 7363 9 78 1036 0 951 203 8 604 973 0932 0861 204 1268 6 95 2015 18 20 205 2659 6 96 1405 1295 206 39 80 7 98 1261 1174
No 207 Orifice 114 96 509 1325 1148 208 94 33 509 1477 1243 209 7487 5 09 1686 1409 210 5236 505 2094 1691 211 3309 428 2188 1 778 212 1293 392 2976 2560
Thermo ooup1e Readin g s (mv) to 3 to4 to
5 to
6 to7 toair
0 851 0847 0 8 29 0759 0987 0592 158 4 1583 1611 1647 1993 0986 1270 1266 1 279 1298 1604 0 789 0916 0908 0900 0 858 1115 0602 08 39 0 823 0 818 0 770 1035 0602 1609 1602 1629 1676 2153 0979 139 1 1385 1400 1 430 1938 0776 1212 1201 1205 1201 1601 0669 1 105 1086 1086 1 052 1371 0621 0952 0936 0923 0870 1195 0582 0 8 20 0 801 078 1 0 729 1044 0569 1108 1090 108 2 1043 1407 0610 1218 1221 1241 1202 1582 0659 1081 1083 1084 1031 1 368 0622 0921 0924 0919 0 841 1111 0 610 08 34 0831 0 821 0 751 1003 0 630 1761 1761 1 809 1861 2399 0966 1271 1271 1295 1311 1650 0797 1150 1150 1161 1149 1440 0703
1083 1057 1053 1109 1566 0~530 1158 1125 1138 1217 1763 0 526 1291 1250 1278 1383 2038 0542 1518 1478 1519 1657 2420 0 589 1596 1557 1601 1737 2441 0688 2370 2344 2409 2561 3 297 0921
()) (11
TABLE X Continued
Run Thermocouple Readings (mv) No Position CFM I tc 1 tc2 tc3 tc4 tc tc tc tc i5 6 7 a r
C of 2nd 213 516 1235 4 63 1 432 1291 1265 1258 1 268 1 308 1550 0 971 214 1919 6 17 1357 1223 1196 1191 1199 1211 1461 0 851 215 27 12 8 35 1401 1259 1278 1220 1230 1218 1511 0 762 216 3320 981 1439 1305 1270 1259 1275 1238 1450 0719 217 41 53 980 1251 1142 1132 1094 1121 1088 1305 0 695 218 404 987 1102 1042 1030 1 bull006 1014 0960 1133 0681
Supplementary Equations
Calculating temperatures from thermocouple readings
t = -026tc)2 + 3512(tc) + 3201 (26)
where t is the temp in deg F and tc is the thermocouple reading in millishyvolts
Calculation of the thermal conductivity of air
k = 00000245ta + 0 0132 (27)
where k is the thermal conductivity in Btuhr rt2 degFft and ta is the air temp 1n OF
I I
bull co m
10
FIGURE 2 EXPERIMENTAL APP1Ub~fUS
11
air left the test section through nine equally spaced 12
ineh holes placed around the side of the tube at the exit
end
Sensing Probe Assembly
The sensing probe was designed to measure the local
heat transfer coefficients at any point along the tube and
around the tube in the test section The tube was designed
so that it could be easily moved up- and downstream to
measure the heat transfer coefficients at various positions
in relation to the orifice
The sensing tube assembly consisted of the sensing
probe the thermoctmple lead s and selector switch the
power lines and the two aluminum tubes between which the
probe was centered
Imbedded in the sensing probe were seven iron-constanshy
tan thermocouples for measuring the temperatures around the
tube The lead wires from these thermocouples were conshy
nected to a seleotor switch at the downstream end or the
aluminum tube A layer of Saran wrap was placed around the
tube over the t hermocouple and three lengths of Trophet C
resistance ribbon were wrapped around the tube nd conshy
nected in series to the power leads
The heating surface of the probe was formed by these
three one inch wide strips of Trophet C resistance ribbons
The ribbons were 0002 inches thick and had a resistance of
12
0 271 ohms per foot and a thermal conductivity of 763
Btuhr ft 2 degFft They were held in position by four
copper bars placed in four parallel longitudinal slots
These copper bars served as connectors for the electrical
leads A photograph of the sensing probe is shown in
Figura 3 and a drawing of the assembled probe is given in
Figure 4
Power Source
Direct current was used to heat the resistance ribbon
on the sensing probe The current was regulated by a slide
wire resistor The po er source consisted of a Raytheon
Voltage Stabilizer to stabilize the city power source at
115 volts and an automatic selenium rectifier with an alshy
ternating current input of 115 volts at 60 cycles per
second and an output of 12 volts and 35 amperes direct
current
Temperature Measuring
The temperatures around the sensing probe were calcushy
lated from the emf readings of the ironbulloonstantan thermoshy
couples The emf measuring system consisted of the seven
probe thermocouples a separate thermocouple for measuring
the inlet air temperature a thermocouple selector switch
a cold junction and a Leeds and Northrup Type K Potentishy
ometer The potentiometer was placed on a Fischer
13
THERMOCOUPLE JUNCTIONS~ ~------- HOLES FOR THERMOCOUPLE LEADS
~----- SCREWS
~ff+--- CONNECTING BARS
END VIEW
POWER LEADS SOLDERED TO LOWER CONNECTING BAR
iER PLASTIC PIECE
RESISTANCE RIBBONS LOCATION OF THERMOCOUPLES
FIGURE 4 DRAWING OF ASSEMBLED SENSING PROBE
15
Vibradamp support to absorb the vibrations produced by the
air blower
Air Source
Air was used as the shell-side cooling fluid during
the study The air was pumped through the test section by
a Roots type air blower with a rating of 280 ofm at 3 12
psig outlet pressure The hot air leaving the blower was
passed tbxfugh two finned-tube box-type coolers and one
tubular edoler to oool it to approximately room temperature
The air flow rate was measured by passing it through a
flow measuring orifice in the line Two sharpbull edged orishy
ficas were used f or flow measurements The calibration
curves for these orifices were presented by Ambrose (1
p 166)
The pressure taps on each side of the orifice were
connected to two differential manometers containing 0 83
and 2 95 specific gravity fluids respectively The presshy
sure drop through the test section and test orifice was
measured by a pressure tap placed 13 inches upstream and
one placed 6 12 inches downstream from the orifice Two
pressure ga ges were used to measure the pressure at the
inlet to the flow orifice and to indicate the statio pres~
sure at the test section inlet
16
Pressure Probe
A probe was designed to measure the pressure drop
between the pressure tap 13 i nches upstream from the ori shy
fice baff le and any point downstream from the tap The
probe eonsisted of a l~in OD copper tube with six 132
i n ch holes even l y s paced around the tube The upstream
pressure tap and the pressure probe were connected to a
differential manometer so the pressure drop to various
points up- and downstream of the orifice could be measshy
ured
17
CHAPTER IV
EXPERIMENTAL PROGRAM
The experimental program was designed to measure the
heat transfer coefficients and pressure drops in the vicinshy
ity of annular orifices The four orifice sizes studied
were 1 364 1 216 l 316 and 1 516 inches~ The inner
tube used in each case was a 1-in OD alumintim tube
Hence tube to baffle clearances were respectively 3128
232 332 and 532 of an inch
Heat transfer coefficients were measured at poait~ons
1 i nch upstream at the orifice center and at 12 1
1 12 and 2 inches downstream for all orifices In addishy
middottion the heat transfer coefficient at a point 2 12
inches downstream from the 1 516 inch orifice was measured
and at the points 12 l 12 and 2 inches upstream from
the 1 364 inch orifice
The heat transfer coefficients at each point were
measured at five different flow rates for the 1 364 inch
orifice and at six different flow rates for the other orishy
fice sizes The high pressure drop through the small orishy
fice size limited the number of flow rates which could be
studied
The flow rate was calculated from the pressure drop
across the flow orifice This flow was corrected to cubic
feet per minute at 68degF and one atmosphere pressure by
18
using the orifice pressure and the test section pressure
which were measured by pressure gages
It was desired to determine a relationship between the
heat transfer coefficient and the total pressure drop for
each orifice size The pressure drop across each orifice
at various flow rates was measured by means of the presshy
sure probe described in Chapter III It was also desired
to obtain pressure profiles for each orifice size since
these might be similar to the heat transfer profiles The
pressure drop was measured from a point 13 inches upstream
of the orifice to points at 1 and 12 ineh upstream the
orifice center 12 1 1 12 and 2 inches downstream
The experimental program is summarized in Table I
TABLE I
SUla~RY OF EXPER IMENTAL PROGRAM
Position Investigated-Distance from Orifice-Inches
Orifice Range of Flow Rate Size Heat Transfer Pressure Drop CFM at 68degF amp 1 atm
1 364 2U 1 12U 1U 12U c 12U C 12D lD 10 - 18 l2D lD 1 12D 2D 1 12D 2D
1 216 1U c 12D lD 1 l2D 2D 12U c 12D lD 10 - 35
1 316 1U c 12D lD 1 l2D 2D l2U C 12D lD 12 - 50
1 516 1U c x2D lD 1 l2D 1U 12U C 12D 12 - 90 2D 2 1 2D l D 1 l2D 2D 2 12D
20
CHAPTER v
EXPERI MENTAL PROCEDURE
The experimental procedure for measuring the heat
transfer coefficients ~d corresponding flow rates reshy
quired the following procedure
(1) Install the orifice size to be studied in the
test section
(2) Place the heat transfer probe in the position up
or downstream from the orifice where the middot heat
transfer rate is to be studied
(3) Fill the cold junction thermos with cracked ice
(4) Measure the atmospheric pressure
(5 Open bypass line from blower and close line to
test section
(6) Turn on the cooling water for the exchangers used
to cool the air leaving the blower
(7) Start the automatic selen ium rectifier by turning
on the t 1mer bull
(8 ) Connect the voltage stabilizer to the wall outlet
(9) middot Set the slide wire resistor to the maximum re shy
s1atanee I
(10) Start the blower
(11 Open the line to the test section until the de shy
sired flow rate is obtained
(12) Switch on the probe direct current power source
21
(13) Adjust the slide wire resistor to obtain the
desired current
(14) After the thermocouples have reached equilibrium
values record the e m bullf across each of the
seven probe thermocouples and also the entering
air thermocouple
(15) Record the direct current amperage
(16) Record the gage pressure at the flow orifice and
the entrance to the test section
(17) Record the manometer measurement of the pressure
drop across the flow orifice and also the presshy
sure drop through the test section
22
CHAPTER VI
CALCULAT ION OF EXPERIMENTAL DATA
The local heat transfer coefficients were calculated
from the temperatures measured on the probe surface the
air temperature and the current input The results were
calculated by using the Alwae III-E computer
The general expression for calculation of the heat
transfer coefficients was derived by Ambrose (1 p 79)
The equation is derived by making an energy balance around
a small increment of the center resistance heating ribbon
The two ribbons tnstalled adjacent to the center ribbon
reduced the amount of logitudinal conduction and assured
little longitudinal temperature variation in the center
ribbon
A heat balan ce on this small increment of resistance
ribbon yields the following
(the heat conducted in) + (heat generated) = (heat
conducted out) +(Heat convected to the fluid) + (heat
radiated to the surroundings) + (Heat conducted into
the plastic center of the probe)
This gives the equation
kzw dtdS + 12RdS kzws [ t + (~) ds] + hwdS (t-ta )
+ ~Aad wd o middot+ qcAond 1 -~- wdS 5 )
23
Hence solving for h gi~ea
i2R kz d2t Qrad qcond w + -d$2 - ~- A
h = ( 6)t - ta
Since S = re where 9 equals the enclosed angle ~n radians
dS rd9 ( 7)
and
dt - dt (8)dS - rd9
Differentiating with respect to S
d2t (9)rd9dS
from which
(10)
Substitut1ng into the equation for heat transfer coeffishy
cient gives
h = i2R Qcond A (11)
w
The rate of radial heat conduction into the plastic
tube making up the probe was assumed to have negligible
effect on the heat transfer coefficient It was also
assumed that the heat loss by radiation from the ribbon
was negligible since all data were obtained with the ribbon
at a temperature less than 125degF
24
When t he rad iation and conduction terms are neglected
Eq (11) becomes
(12)
The following con stants are known
R = 0 271 ohmsft
w = 100 i n ches
k = 763 Btuhr rt2 degFft
z = 0 002 inches
r = 12 inch
Eq (12) putting 9 in degrees then reduces to
1110 12 + 2404 d 2t d92
( 15)h = ------~--~-------t - ta
Thi s equation was programed for the Alwac III- E comshy
puter and used to calculate the local heat transfer coefshy
ficients from the observed data
The average heat transfer coefficient around the tube
at a given position in the t est section was calculated by
averaging the local coefficients calculated from Eq (13 )
It was found 1n the course of the experimental work
that thermocouple numbers 1 and 7 were indicating higher
temperatures than would be expected This resulted in h1
and ~ being lower than the other local coefficients around
the tube Since the fluid was flowing parallel to the axis
of the probe the circumferential variation i n rate of heat
25
transfer should be small Hence in obtaining the average
coefficient around the tube the values of h1 and h7 were
not used even though they were calculated and are tabulated
1n Table I II in the Appendix
Then
(14
A Nusselt number as calculated from this aver age heat
transfer coefficient using the tube diameter as the characshy
teristic dimension
(15)
The air flow rates through the test section were calshy
culated by measuring the pressure drop across the flow orishy
fice the air temperature the pressure at the flow orifice
and the pressure at the entrance to the test section The
orifice calibration curves (1 p 166 ) were used to obtain
a value of the orifice coefficient f8e where Q equals
the flow in cubic feet per minute at 68deg F and one atmosmiddot
phere pressure and te is the density of air at the exchanger
and e the density of the air at the flow orifice The
den sity of the air can be expressed by
e = 2 703 p (16)T
where T equals the temperature in OR and P equals the absoshy
lUte pressure i n lb1n2 Using the value of e Qfo from
26
the calibration charts as A and Eq (16) solving for Q
gives
( 17
This equation was used to calculate the flow rate for
each flow studied
The Reynolds number used i n the correlation of the
data was the equivalent Reynolds number defined as
Re)eb ~ d2 - dl)Uf ( 18 ) lL
where d1 is the outside diameter of the inner tube and d2
is the orifice diameter U is the flow velocity through the
annular orifice e is the density of the air and U- is t he
viscosity of the air This equation can be transformed t o
(Re) b = 1611 Q (19) e dl + d2
where d1 and d2 are in inches
The pressure drop data were calculated i nto a dimenshy
sionless pressure drop function cent where
d1 )22( ~ P)gc f av(d2 shycent 2 bull (20
M-
For air this equation reduces to
where d2 and d1 are in i nches D P is expressed i n inches of
2 95 specific gravity fluid and P av is expressed as lbft3
27
CHAPTER VII
ANALYSIS OF DATA
In analyzing the heat transfer data an attempt was
made to correlate it 1n terms of the dimensionless groups
(Nusselt number Prandtl number and Reynolds number) which
appear in Eqs (3) and (4) Consequently all of the av~
erage heat transfer coefficients hav were brought into
the form ( Nu)( Pr)~3 bull The Nusselt number was based on the
tube diameter and the thermal conductivity of the air at
the flowing temperature The tube diameter was used in the
Nusselt number because comparison could then be made with
previous experimental work on heat exchangers which have
commonly used the Nusselt number defined as in Eq (15)
From the standpoint of dimensional analysis this is
equivalent to considering the tube diameter as the characshy
teristic length so far as the heat transfer is concerned
The Prandtl number of the air was taken as 0 7 in all
cases
Variation of Heat Transfer Rate with Distance from the Baffle
Considerable variation was observed in the rate of
heat transfer in the vicinity of the baffle In order to
obtain the variation with respect to position the term
(Nu)(Pr)-13 was plotted versus the flow rate Q for each
position and orifice studied Cros s plots were then made
28
at constant flow rates in order to obtain the variation of
(Nu)(Pr) -13 with position The resulting cross plots are
shown 1n Fi gures 5 6 and 7 for the four orifices studshy
ied
About one inch upstream from the orifice the heat
transfer coefficient begins to rise rapidly and continues
to do so until it reaches a maximum some distance downshy
stream After the maximum point the heat transfer coef fi shy
cient decreased slowly The heat transfer rate was found
to reach a maximum at a different position downstream for
each orifice size These figures also show that for a
given orifice size the maximum heat transfer rate occurs
a pproximately at the same point for all flow rates The
position of the maximum point f or each or ifice size is
shown in Table II
The region immediately downstream from the orifice is
one of h i gh turbulence due to the jetting action of the air
flowing through the orifice As the air flows t hrough the
orifice the streamlines continue to converge for some dis shy
tance downstream The point of maximum heat transfer is
probably at the point where the streamlines be gin to diverge
and a boundary layer begins to build up on the tube Tle
decreasing heat transfer coefficient beyond the maximum
point indicated the formation of a boundary layer
Since the position of the maximum point is independent
of flow rate middot it is possible to correlate it with respect
_ ct 11shyz-
100
0 136 ORIFICE
(
I 0
I )
~ 00
~p 0
I 0
--r--- ~
ISCFIII
-_ OCFM
rbull abull
~ middot~ a-1 z-
12fORIFICE
100
200
100
0 0 UPITRAM ORIFICE DISTANCE CENTER
CFM
h I DOWNSTREAM
DISTANCE
FIGURE 5 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLpound
30
too
700
800
100 ~ f gtf
400
z ~
100
100
100
0
13fORIFICE
~ -~ -- ---
)
~
~
-
I ~ ~OCFM
I vI~-~ OCFM
J ---
Iamp CFM
I 0 I I UPSTREAM ORIFICE DOWNSTREAM DIITANOE GENTER DIITANCI
FIGURE 6 VARIATION OF HEAT TRANSFER RATE WITH DISllNCE FROM BAFFLE
--
--- --
31
100
100
700
100
_ 100
f 9- 400 z-
100
tOO
100
0 - I 0 I I I UHTRIAM OAtfiCI DOWIIITMAM
+ I tyl6 ORIFICE
v I
~~ ~CFM
I v ~CFMI
v v 7
~~ v ~ iOCFM
- ~~ I-shy1-shy ~ICFM
DIITMCI OINTIR DIITANCI
FIGURE 7 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLE
32
TABLE II
POSITION OF MAXIMUM HEAT TRANSFER
Position of Maximum Orifice Size Heat Transfer
(inches) (inches downstream)
1 364 050
1 216 100
1 316 125
1 516 200
33
to orifice size Figure 8 shows the effect of the orifice
size on the position and value of the maximum heat transfer
at a constant flow rate of 15 cubic feet per minute It
can be seen that the larger the orifice size the further
downstream the point of maximum heat transfer occurs
Also as the orifice size increased the rate of heat
transfer decreased for a given flow rate The broken line
indicates the variation of the point of maximum heat transshy
fer with position and size The position of the point of
maximum heat transfer rate downstream from the orifice was
correlated with orifice size by means of the dimensionless
groups (Lde) and (d1de) where L is the distance downshy
stream from the orifice where the maximum rate of heat
transfer occurs d1 is the outside diameter of the inner
tube and de is the equivalent diameter of the orifice
ie de = d2-dlbull
Figure 9 shows a plot of Ld 6 versus d1d6 for the
four orifice sizes studied The four points on this logshy
log plot are approximately in a straight line and the
equation of this line is
Lde = 0 44 d1de)028 (22)
Although the above relationship represents a correlashy
tion of dimensionless groups it is based upon only one
tube diameter and needs to be substantiated further by
studying other tube diameters and other orifice sizes
34
aoo
400
aoo ~
-~ middot-CLshyJ z
200 -
100
0
ORIFICE CENTER
l~
l
t
I J~
1pound~
I
0 I I~
AT 15 CFM
-
bull ~ 1~6~
~ v~
~
~--~~6
~~~ ___ v v V -_
~ o q
~ I 16
v
~
ogWNSTREANI STANCE
FIGURE 8 EFFECT OF ORIFICE SIZE ON POSITION AND VALUE OF MAXIMUM HEAT TRANSFER
35
50
loshy____ -~
~ ~ -shylltl-shy~ r0
2 10 30
FIGURE 9 CORRELATION OF THE POINT OF MAXIMUM HEAT TRANSFER WITH
ORIFICE SIZE
36
Correlation of Data at the Baffle
The heat transfer data were correlated by obtaining a
relationship between the group (Nu)(Pr)-13 and a
Reynolds number based on twice the clearance (d2 - d1
between the tube and the baffle It was found that the
most satisfactory correlation could be obtained when the
term - d1 was used as the length term in the Reynoldsd2
number
Figure 10 shows the variation of the heat transfer
rate at the center of the orifice e xpressed as a function
of Reynolds number and the orifice size This shows that
for a given Reynolds number the heat transfer at the center
of the orifice is greatest for the smallest orifice size
In order to obtain a general correlation of the data
shown i n F1gure 10 the effect of the dimensionless ratio
d1de was considered This ratio considers all of the
geometric factor s needed to describe the annular orifice
The thiclaless of the orifice plate is also a factor but
was constant i n this i nvestigation
The data for the heat transfer at the baffle center
are shown in Figure 11 in which (Nu)( Pr)-13 is plotted
versus (Re)ebd1 de) 0 55 This data on a log-log plot
lies on a straight line for (Re)eb( dld8 )0 55 greater
than 3 x 104 The equation for cor relating the heat
37
4XI~middot~-r~------~--~~------~
Icf t--to_+--_c-c-________ SYMBOL SIZE
0 1~4
6 ~~
9 ~~ -o ~
(Re)eb
FIGURE 10 RATE OF HEAT TRANSFER AT BAFFLE CENTER
38
500
0
4 0 lcf
~ ~
~ ~iC-
~ ~
~IL 0~ 0 SYMBOL SIZE-
p 0 1364-
r 6 1~16 -~ -
9 1~16 --o 1~16
I I
FIGURE II CORRELATION OF HEAT TRANSFER DATA AT BAFFLE CENTER
39
transfer at the center bullOf the a nnular orifice was found by
the method of least s quares to be
(Nu)( Pr)-1 3 = 0018 ( Re)ebO Bl( dlde)04~ (23)
3 x 104 ltRe)eb(a1de)055 lt 105)
Rate of Heat Transfer at the Point of Maximum Heat Transfer-The heat transfer rate at the point of maximum heat
transfer is plotted in Figure 12 to show the variation with
Reynolds number and the size of the orifice It is shown
gives the h1gh st heat transfer ~ate at its point of maxibull
that for a given Reynolds number the smallest orifice size yen il
mum heat transfer
The data ~or the maximum poi~t could be correlated by
plotting (Nu) Pr)-13 versus (Re)eb(d1de)06 This plot
is shown 1n Figure 13 and the resulting eurve shows that
(Nu(Pr)-13 is not a simple p0wer function of the Reynolds
number as was the case for heat transfer at the baffle
center The reason for this is probably because other
factors such as intensity and scala of turbulence should
be considered At the orifice center the streamlines of
the flowing stream are converging_ and thus the flow is
quite stable Downstream from the orifice is a region of
large eddy currents and probably large scale turbulence
These factors could con ceivably cause the results which
were obtained for the point of maximum heat transfer
40
If)
~middotshy Q_-I z_
10~~~--------r----~~--~--
SYMBOL SIZE
0 13$4
6 1~8
Q 13-18
-o 1~8
7)(104
(Re)eb
FIGURE 12 RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
41
Ia ~
0 I
c ~ ~ c v
~ ~lt w ~
17
~ b
v ~ ( SYMBOL SIZE
-~ 0 f-64 -v ~ 6 t211e
~ Q I~~~
-o - l~rs I I
FIGURE 13 CORRELATION OF HEAT TRANSFER DATA AT THE POINT OF MAXIMUM HEAT TRANSFER
4 2
Effect of Upstream Baffles on Heat Transfer at the Orifice Center
The heat transfer rate at the orifice center using the
single orifice in a test section is a pproximately 13 of the
value that was obtained by Lee (7) using a model heat exshy
changer with orifice baffles Lee investigated the cent r al
baffles of the heat exchanger and thus the coeff icients he
obtained would be affected by the presence of a number of
upstream baffles To determine the effect of upstream
baffles an additional l 516 inch baffle was placed four
inches upstream 1n the test section The resulting data are
shown in Figure 14 where (Nu)(Prmiddot)-13 is plotted versus
(Re) eb for the case of a single baffle 1n the test section
and also the case of an additional baffle placed four inches
upstream Comparison is made with the results obtained by
Lee middot(7) using a four-baffle and a ten-baffle model heat exshy
changer Good a greement is obtained with Lees work and the
results show the marked effect that upstream baffles have on
the downstream heat transfer rate The additional up tream
ba ffle caused sufficient turbulence 1n the test section to
i n crease the heat transfer rate nearly three-fold at the
center of the next baffle
Heat Transfer i n the Test Section with No Orifice
In order to check the accuracy 6f the equipment the
orifice baffle was removed and the heat transfer mea sured
with the probe in the empty test section The data were
43
~~BAFFLES
0 l BAFFLE -shy
ll_9 2 BAFFLES
V 4 BAFFLES-LEE
4 10 BAFFLES- LEE lJf ~
~rv ~~ ~ v flvv ~~
I ~ J ~ L v
0
v
( V
40 3XIo 7XIa
(Re)eb
FIGURE 14 EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER AT BAFFLE CENTER
44
compared with heat transfe r coefficients predicted by the
equations for annuli which are recommended in the litera shy9
ture The two equa~ ions u sed tor comparison were
(hfe)=0 023 (rltGr e (~~ur4 (~r45 (24)
which was presente~ by Wiegant (10)
and ( h ) (cnM~5(M~l o14 o 023 CPG k j Mij - (de GJMb )0 2 ( 2 5)
which was presented by McAdams (8 p 242) The comparshy
i son is s hown in Figure 15 lq (25) gives a value which
is low by about ten percent while Eq (24) g ives values
which are high by as much as twenty -five percent when comshy
pared with the experimental data The se equations are gembull
erally considered to give coefficients with an accuracy of
about twenty percent Therefore the present experimental
data are within the accuracy of these equations Also the
plot indicate s that for a Reynold s number greater than 2 x
104 the slope of the line is the same for the experimental
data as for the equations
Pressure Drop Data
The total pressure drop across the orifice was measured
as a function of the flow rate and the orifice size The
pressure drop was expressed as a d1mens1onleas quantity r)
which ie plCltted ver sus the Reynolds number in Figure 18
The pressure drop function cent correlates for all or1f1oe
45
200
100
s z
10 5XI10 10
0 EXPERIMENTAL
--McADAMS
-WIEGAND L
V
~ ~ ~
P ~ ~
LL~ L
v~
~
v v
v 1 ~ ~ v
v -gt
~
~ ~
~
6Xid
FIGURE 15 HEAT TRANSFER WITH NO BAFFLE
46
0 1~4 -~ a 6 t216
Q t316 lJ J
-0 as a )t
A LEE I -shy SULLIVAN 8
p
10bull
BERGELIN
I _ll I
I ~
i I
~middot
lo II
f fl
J j
~middot
A)101
1q
I Ill
1 I3 X 10ao1
FIGURE 16 ORIFICE PRESSURE DROP FUNCTION VS REYNOLDS NUMBER
47
sizes- The present data extends the range covered by preshy
vious workers and agrees well with their work The preshy
vious work of Lee () for a heat exchanger containing 10
orifice baffles and also the data of Su livan and Bergelin
(9) for pressure drop in a model heat exchanger with a
single baffle is shown 1n Figure 16 long with the present
results~ This figure may be used to predict the preseure
drop from the equivalent Reynolds number of the annular
orifice
The pressure drop between individual points 1n the
vicinity of the orifice and an upstream pressure tap wa s
measured to obtain a pressure drop profile As might be
expected 1n all cases the profiles showed a rapid decrea e
in static pressure immediately upstream from the orifice
There was however little or no recovery of the pressure
loss downstream The 1 364 inch orifice did show a maxishy
mum point in the pressure drop but this maximum occurred at
the orifice center and total recovery was reached about 12
inch downstream
Heat Transfer at the Baffle and Maximum Point as a Function of Pressure Drop
In order to compare the effect of the total pressure
drop on the heat transfer at the baffle and the point of
maximum heat transfer Figure 17 was plotted showing
(Nu)(Pr)-13 as a function of the total pressure drop This
shows that for a given pressure drop the largest orifice
48
1200
1000
~ a -sshyz-
100
60 100 700
AT MAXIMUM POINT I 15116 2 13116 3 1~6 4 1364
AT ORIFICE CENTER
60
1
v
r ~ ~ ~
5
~
8 7
13116
8
~
1364
v
~
e6
1~6
v
~~ v ~ ~ -~ ~
~
~ v
l
~
vamp
I ~ ~
~
v L ~
v
I-
5
k= ~~
~ ~ ~
--I
v ~
FIGURE 17 HEAT TRANSFER AT THE BAFFLE AND MAXIMUM POINT AS A FUNCTION OF
ORIFICE PRESSURE DROP
49
size has the greatest heat transfer coefficient This is
true at both the orifice center and at the point of maxishy
mum heat transfer
Another comparison can be made by plotting the heat
transfer coefficient and the pressure drop versus the orishy
fice size at a constant flow rate Figure 18 shows this
plot This graph shows that at a constant flow rate the
pressure drop as well as the heat transfer coefficient
increases as the size of the orifice is decreased In
choosing an orifice size for maximum efficiency 1t would
be necessary to know the pumping power available as well
as the heat transfer desired
70 I I 700
AT 15 CFM 60 ---
~ aug
50 ---
NV
40 ~
~ ~ ~
~ _
MAXIMUM POINT ---- --- ~
1-----t---~ _
~00Qj ~
~t--- ORIFICE CENTER 10 1100
1---~ n
u0 01 02 03 Q35
a ltl
de inches
FIGURE 18 VARIATION OF HEAT TRANSFER RATE AND PRESSURE DROP WITH ORIFICE SIZE AT A CONSTANT FLOW RATE
cn 0
51
CHAPTER VI II
SUMMARY OF RESULTS
This study revealed several significant facts about
the heat transfer in the vicinity of annular orifices
Probably the most important contribution was the presshy
entation of the heat transfer profiles in the vicinity ot
the annular orifice ~ r s shown that t~ local heat
transfer coeffieient re~ches a maximum at a point downshy
stream from the orifice The distance downstream at which
this maximum oocurs is t1ven by the equation
22
The heat transfer coefficients at the center of the
orifice were correlated and found to follow the equation
(Nu)(Pr)-13 = 00176 (Re)eb08l(d 1de) 0 middot4~ (23)
3 x 104 lt( Re) 9 b( d1d6 )055 ltlo5 )
The heat transfer at the point of maximum heat trans
fer for each orifice size was correlated and presented in
Figure 13 as a plot of (Nu)(Pr)-l3 versus (Re)eb(d1de) 06
No simple po-orer relationship exists between the terms
Intensity and scale of turbulence downstream from the orishy
fice are probably important factors which affect the heat
transfer
The large effect of an upstream orifice on the heat
transfer rate at the second orifice was demonstrated by the
52
study of two 1 516 inch orifices in the test section The
added turbulence at the center of the second orifice was
found to raise the heat transfer rate almost three times
over that obtained for a single baffle
The pressure profiles in the vicinity of the orifice
indicate that nearly all the pressure drop occurs at the
orifice center~ Total pressure drop data were correlated
by a pressure drop function cent as a function of the Reynolds
number and good agreement obtained with the results of other
workers
The pressure drop and heat transfer data were correbull
lated by plotting the heat transfer as a function of the
pressure drop for each orifice size It was shown that for
a given pressure drop the largest orifice size gives the
greatest heat transfer coefficient
As a final presentation it was shown that the pressure
drop and the heat transfer coefficient both i ncrease i n
value at a constant flow rate as the orifice size is de shy
creased This is important in choosing the optimum clearshy
ance for orifice baffles
53
CHAPTER IX
RECOMMENDATIONS
A great deal of work remains to be done in the field of
evaluating shellmiddotside heat transfer coefficients This
study included only one tube size and air was the only f luid
used It is recommended that further studies be conducted
using other fluids and tube sizes It will also be necessary
to study several baffle types
The adde d turbulence due to a s e cond baffle placed upbull
s t ream would suggest that the heat transfer coef ficients at
a certain position i n relation to a baffle would increase as
the flow progressed through the exchanger It is recomshy
mended that an extensive s t udy should be made between baffles
the full length of a model heat exchanger
It is further recommended that the pressure drop study
be continued to include other fluids tube sizes and baffle
arrangements
Effects of turbulence downstream from the baff le should
be studied by i n vestigations with hot-wire anemometer equipshy
ment to determi ne t urbulence scale and i ntensity
54
NOMENCLATURE
Area of heat transfer
Heat capacity of the fluid
Outside diameter of the tube
Orifice diameter
Equivalent diameter of the orifice (d2 - dl)
Inside diameter of the test section
Inside diameter of the tube
Gravitational constant
G Mass velocity
h Local heat transfer coefficient
Coefficient of heat transfer from surface to fluid
i Direct current amperes
k Thermal conductivity of the fluid
L Distance downstream of the point of maximum heat transfer
p Absolute pressure
L P Total pressure drop across the orifice
Q Flow in cubio feet per minute at 1 atmosphere and 680 F
q Heat transferred
Thermal energy conducted into the sensing probe
Thermal energy radiated from the resistance ribbon
Resistivity of the resistance ribbon
s Length of the resistance ribbon
T Temperature oR
55
t Temperature of the resistance ribbon deg F
ta Temperature of the bulk stream oF
tw Wall temperature of the tube OF
U Veloc ity of the fluid
w Width of the resistance ribbon
z Thickness of the resistance ribbon
eeuro Density of the fluid in the test section
Density of the fluid at the flow orificef 0
AL Viscosity of the fluid
E9 Angle measured around the tube
Dimensionl ess groups
(Nu) Nusselt number hd1k
(Pr Prandtl number C~k
(Re)eb Equivalent Reynolds number at the baffle (d2 - d1 )uejt-Lshy
(Re)e Equivalent Reynolds number in the test section ( d 8 - d 1 )U fu
cent Orifice pressure drop function 2(~P ) gc~av(d2 - d1) 2
Al
56
BI BLIOGRAPHY
1 Ambrose Tommy W Local shell-side heat transfer coefshyficients in baffled tubular heat exchanger PhD thesis Corvallis Oregon State College 1957 183 numb leaves
2 Bell K J and o P Bergelin Flow through annular orif ices Transactions of the American Society of Mechanical Engineers 70593-601 1957
3 Colburn Allan P A method of correlating forced con shyvection heat transfer data and a comparison with fluid friction Transactions of the American Institute of Chemical Engineers 24 174-210 1933
4 Dittus F w and L M K Boelter Heat transfer 1n automobile radiators of the tubular type University of California Publications in Engineering 2443-461 1930
5 Gurushankariah M s Local shell-side heat transfer coefficients in the vicinity of baffles in tubular heat exchangers Masters thesis Corvallis Ore gon State Colle ge 1958 97 numb leaves
6 Knudsen James G and Donald L Katz Fluid dynamics and heat transfer New York McGraw-Hill 1958 576 p
7 Lee Kyu Sung Local shell-side heat transfer coeffishycients and pressure drop in a tubular heat exchanger with orifice baffles Masters thesis Corvallis Oregon State College 1959 118 numb leaves
8 McAdams William H Heat transmission 3d ed New York McGra ~-Hill 1954 532 p
9 Sullivan F W and 0 P Bergelin Heat transfer and fluid friction in a shell-andbulltube exchanger with a single baffle Chemica l Engineer ing Progress Symposium Series 52 ( 18) 85-94 1956
10 Wiegand J H Discussion on annular heat transfer coshyef f icients for turbulent flow Transactions of American Institut e of Chemical Eng i n eers 41147-153 1945
AP PENDIX
57
TABLE III
CALCULATED HEAT TRANSFER DATA
Baffle Hole Diameter Run No (inches)
1 - 59 1 364
60 - 102 1 216
103 - 138 1 316
139 - 206 1 516
207 - 212 No orifice
213 - 218 2nd - 1 516
TABLE III
CALCULATED HEAT TRANSFER DATA
Local Heat Transfer Coefficients Run
T0 bull Po s ition CFM hr h2 h3 h4 hs he ~ hav Nuav
1 c 1026 10 59 1476 16 09 1559 1510 1435 1203 1518 8511 2 1290 1369 1738 1878 18 05 1755 1689 1515 1773 9964 3 1416 1636 198 1 2068 1977 1924 1845 1715 1959 11030 4 1627 1991 2301 2382 2268 2194 20 ~98 1929 2249 12664 5 1776 2252 2669 2863 2713 2517 2338 2126 2620 14759 6 l2ttD 1109 2311 3317 3386 3373 3387 3394 3071 3371 18888 7 1258 3089 4583 4866 4683 4701 4643 4194 4695 26301 8 1433 38 8 5 55 83 5791 5495 5430 5436 5008 5547 31192 9 1681 4992 7378 7649 6980 6864 6870 64 28 7148 40180
10 1 D 1102 2371 3332 3511 3356 3342 3427 3102 3394 19012 11 1308 3218 4379 45 24 42 53 4255 4373 3965 43 57 24446 12 14 64 38 58 5146 5142 4839 4787 4903 4597 4963 278 79 13 1706 5218 6664 6269 58 81 5884 6237 5973 61 87 34718 14 15
1 l2D 1115 1275
2131 2661
2955 3638
2972 3720
2941 3675
2913 3576
28 22 34 74
2613 3278
2921 36 17
163 09 20246
16 1498 34 87 4644 4503 4441 4371 4343 4194 4460 25010 17 1695 4449 5743 5324 5222 5154 5157 5015 5320 298 97 18 2D 1049 1715 23 90 2550 2610 2656 2624 2208 2566 14363 19 1241 2117 2964 3145 3218 3221 3203 2759 3150 17757 20 1532 28 67 3936 4100 4188 4201 4167 3676 4118 23224 21 1674 3459 4508 4598 4746 4795 4792 4299 4688 26337 22 lU 1074 253 340 380 3 86 388 377 354 374 2097 23 1287 292 392 433 440 441 429 406 427 2394 24 1508 322 439 492 498 499 487 461 48 3 2713 25 18 07 3 38 464 519 5 24 520 499 463 5 05 28 40
~~ (]I agt
TABLE III Continued
Run No Position CFM h 1 h2 ~3 h4 h5 h6 ~ h
av Nu
av 26 c 1029 1171 1491 1589 15 28 1 4 62 1377 1293 1489 83 44 27 1266 1395 1746 1853 18 02 1685 1556 1453 1728 9704 28 1430 1637 2037 2175 2060 1909 1735 1591 1983 11159 29 1729 1982 24 96 2751 2507 2268 2030 1886 2410 13579 30 12D 1054 2934 4041 4321 4326 4423 4359 3706 4298 24160 31 1294 3385 4 8 26 52 42 5326 5450 5277 4566 52 24 293 50 32 1431 3784 5347 5721 57 bull75 58 44 5700 5084 5677 31870 33 1770 52 75 7 7 33 87 35 9005 9007 8267 7059 85 49 48050 34 lD 1058 3235 4401 4444 3877 3496 3451 3294 3934 21973 35 1263 38 98 5484 5330 4347 3964 3981 3987 4621 25823 36 18 36 6701 89 17 7855 6369 5597 5769 6283 69 01 38718 37 1 12D 1029 2404 31 8 2 3333 3459 3624 3577 3045 3435 19264 38 1315 3182 4033 4162 4310 4496 4502 4015 4301 24142 39 1426 3628 4389 4510 4573 4760 4804 43 8 5 4607 25678 40 1757 4547 5559 5(35 5931 6282 63 70 6060 5975 33471 41 2 11D 1080 2034 28 38 3155 3144 3145 2966 2540 3050 17027 42 1305 2650 3 4 87 3aoz 3595 3751 3595 3153 36 46 20405 43 1434 3167 39 07 4156 4371 4320 4126 3709 4176 23395 44 1804 4096 4 9 66 5691 5714 5586 53 15 48 65 5454 30582 45 12U 1088 409 516 557 564 5 60 535 513 5 46 30 67 46 1318 470 579 6 22 631 6 17 5 97 579 6 09 3422 47 14 13 540 640 676 6 86 681 6 60 6 54 6 69 3754 48 1773 641 740 774 782 7 69 749 746 763 42 87 49 l 11 U 1054 270 356 391 397 393 3 71 346 38 2 2133 50 1240 303 399 446 449 447 4 21 398 432 2420 51 1419 361 476 522 530 528 507 467 493 2760 52 1 1(2U 1032 236 311 342 347 344 325 301 334 18 78 53 1314 270 366 403 407 408 386 351 394 2217
(Tt tO
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ h av Nu av
54 1448 301 408 447 454 452 431 403 438 24 61 55 1782 353 494 548 544 415 529 531 506 2843 56 2U 10 61 220 287 316 320 322 303 268 310 1735 57 1216 249 335 370 377 378 353 307 363 2044 58 1322 263 356 394 398 399 374 327 384 2159 59 1639 310 433 478 481 482 452 393 465 2617
60 1D 10 68 2011 2536 2657 2681 2694 2560 15 62 2625 14938 61 1399 2520 3239 3369 3371 33r82 32 39 1946 3320 18968 62 1669 2781 3655 3820 38 76 3883 3738 2355 3794 21712 63 1959 3524 42 37 4399 4438 4497 4417 3047 4397 25156 64 2295 4426 5288 5396 5372 5240 5410 3369 5341 30680 65 2636 5490 6531 6662 6565 6379 6820 4249 6591 37938 66 3390 7869 9538 9462 9387 8924 10508 62 91 9564 59601 67 1U 1190 352 368 401 413 407 395 293 397 2256 68 1559 397 422 462 475 471 456 331 4 57 2603 69 1904 434 465 5 13 529 528 504 358 508 2901 70 2211 493 526 573 5 92 588 564 4 15 569 3257 71 2289 569 587 6 30 649 6 61 6 49 460 635 36 44 72 2727 637 6 60 7 09 733 751 743 521 719 4140 73 3210 728 755 8 15 8 43 8 62 8 54 616 826 4765 74 2nD 1210 181 2256 2393 2399 2333 2206 1325 2317 13158 75 1420 2340 2752 2899 2913 2850 2728 1701 2828 16121 76 1692 2853 3306 3452 3471 3379 3217 2134 3365 19217 77 1894 3102 3588 3713 3736 3670 3557 2455 3653 20892 78 2301 3682 4259 4433 4467 43 83 4289 2892 4366 250 30 79 2621 4117 4828 5017 5012 5030 5109 3071 4999 28785
m 0
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ hav Nuav
80 3230 5158 6006 62 13 61 18 6134 6695 4094 6233 359 87 8 1 12nD 1155 15 27 1854 2028 2064 20 85 1987 1164 1968 118 31 82 1689 2046 24 8 2 2688 2739 2760 2658 1749 2665 152 73 83 1244 2088 2317 2339 2345 2373 2381 1487 2351 13432 84 2100 3211 3539 34 21 3462 3512 3696 2575 3526 20284 85 2292 3 5 05 3761 3648 36 25 36 79 3957 2933 3734 21517 86 2907 4420 48 22 4679 46 04 4705 5206 3792 48 03 27741 87 33 80 59 35 69 38 7404 77 10 7 8 36 7 0 86 5190 7394 427 44 88 1 12D 1 4 27 2 4 58 28 31 3037 3021 2987 2927 18 57 2 9 61 16913 89 18 75 34 75 3 9 87 4230 4255 4317 4337 2734 4225 24258 90 22 59 4221 4796 5046 5052 51 01 5389 3491 5077 29206 91 2682 4978 5664 5943 5966 6054 6573 408 1 60 40 34795 92 3417 63 16 71 02 7 3 93 7385 75 40 8 6 95 51 45 7623 44017 93 c 1 5 17 1240 1305 1399 1467 1479 1429 9 26 1423 8251 94 20 34 1554 1623 1720 18 21 18 53 18 72 1215 1778 10229 95 2 3 48 1795 1843 198 5 2097 2171 2274 1540 2074 11947 96 2716 2028 2048 22 01 2 3 44 2444 2661 18 90 2340 13505 97 3247 2410 2375 2663 2778 2949 3298 2378 2793 1615 98 11 35 967 1040 1124 1186 1200 1142 728 1138 6496 99 14 06 1135 1220 1318 1384 1403 1 3 61 8 77 1336 7656
100 2311 1 8 54 18 78 1980 20 90 2136 2227 1653 2062 118 31 10 1 2666 2085 2094 2227 2 3 62 2438 2626 1902 2349 13508 102 3392 2635 2582 28 01 3026 3141 3529 2567 3016 17390
103 1 U 1235 349 395 434 436 4 28 411 286 423 2416 104 20 10 434 5 02 559 577 569 5 37 345 552 3177 105 28 14 538 626 685 711 7 21 682 424 6 8 6 3966
Q) j-J
TABIE III Continued
Run No Position CFM h1 h2 h3 h4 h5 hu h7 hav Nuav
106 3492 614 7 1 6 7 84 8 13 8 33 7 85 4 88 7 87 4562 107 4395 7 86 894 964 996 1005 9 64 640 9 65 56 06 108 50 75 9 11 10 22 1081 1112 1125 1085 7 24 1085 63 16 109 G 1344 9 22 1042 1120 1 1 46 1173 1131 7 04 1120 63 87 110 1936 1162 1340 1442 1474 1509 14 7 3 9 09 1441 82 77 111 2846 1631 1797 1902 1966 2027 2079 1342 19 2 3 11108 112 3484 207e 2144 2236 2307 2385 2574 1694 2268 13138 113 4066 24 65 24 42 2535 2648 2757 31 71 2178 2 5 96 15078 114 50 12 3059 2916 30 1 5 3176 3312 4059 2849 3105 180 46 115 1D 1362 2268 26 13 2613 26 35 2605 2503 15 46 2617 14934 116 1958 2993 3580 3580 3586 3539 3 5 02 2144 3571 20492 117 2812 4430 50 32 4913 4 9 86 4991 5196 3088 4981 287 66 118 3432 58 16 62 13 6067 61 18 60 66 6698 4143 61 16 354 16 119 40 22 71 71 7 4 62 7369 7419 7329 82 74 51 8 1 7395 42909 120 5026 105 95 11456 115 81 11574 11548 14010 80 91 11540 671 15 121 2D 1244 18 57 2277 2363 2305 2210 2107 1466 2289 13038 122 1960 2622 3240 3388 33 23 3226 31 40 2)99 3294 18919 123 2817 3762 45 87 4739 46 56 45 14 4 6 47 30 15 4624 26689 124 3491 50 22 5723 58 53 57 44 5542 60 18 3871 57 16 330 73 125 4096 61 29 68 16 69 79 6805 65 90 74 79 4677 67 98 39400 126 5037 82 27 94 60 95 69 93 57 9023 11324 65 05 93 52 542 83 127 12D 1278 14 70 1 6 48 1652 1638 1 6 34 1641 9 73 1 6 43 9369 128 1947 19 63 2155 2149 2151 2131 2190 1347 2147 12342 129 2769 2615 2791 2773 28 52 2716 2954 18 96 2783 1 60 82 130 3439 3208 3265 3239 3593 3133 3624 2515 3308 19174 131 4103 3637 35 88 3577 4077 3459 42 66 3138 3676 21343 132 49 78 45 82 44 60 44 8 1 55 17 43 25 5749 4227 4700 27288
Q) tlgt
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
133 1 12D 1299 2094 2507 2622 2625 2567 2489 1465 2578 14736 134 1973 29 56 3505 3772 3790 3718 3718 2115 3700 21290 135 2788 3941 4727 5069 5099 5 0 07 5231 2984 4976 28781 136 3473 5155 59 81 6308 6339 62 39 68 96 4204 6217 36052 137 4118 6135 71 8 6 7662 7731 76 91 87 16 49 8 5 7568 43985 138 4973 7765 94 75 10396 10861 10694 13646 66 64 10357 602 25
139 1ttn 1253 1242 1493 1460 1442 1431 1424 8 84 1457 83 01 140 2366 1942 2150 1961 1910 1897 19 62 1206 1980 11400 141 3461 3007 2957 2562 2513 2606 3143 18 51 2660 15400 142 4325 3942 3571 3060 2999 3198 4248 2631 3207 18618 143 5677 508 6 4359 39 88 3800 42 29 57 78 36 26 4094 23824 144 67 59 64 55 5330 4988 47 25 5494 2517 48 09 5134 29906 145 84 08 9326 72 26 7726 85 56 9172 12319 7733 8170 47626 146 86 54 9831 7582 818 9 94 90 9869 13116 78 97 8783 512 96 147 7376 7335 58 7 6 5941 5796 68 29 81 65 5954 6111 35662 148 2 11 D 4254 4106 48 02 4994 5038 5042 56 78 3419 4969 28881 149 5708 5487 6253 6466 6524 6527 78 63 45 8 2 64 43 37566 150 69 7 8 7983 9440 9848 98 34 97 32 13249 6701 9714 566 59 151 1254 1434 18 53 1947 1915 1850 1760 1186 1891 10772 152 2713 2696 3175 32 94 3288 3237 3288 20 44 3249 18728 153 87 30 118 07 14733 15758 15504 15305 26297 9617 15325 892 71 154 5811 5278 6543 6861 69 30 69 82 7 8 74 4478 68 29 39531 155 4246 3780 4736 4975 49 66 4936 5162 3113 4903 28301 156 (v 1270 8 15 935 959 966 9 51 9 23 6 35 953 5430 157 2714 1164 1390 1427 1447 1454 1455 9 08 1430 8242 158 4310 1655 18 96 1942 1988 2002 2111 1305 1957 11349
(j) ~
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 fry hav Nuav
159 6012 2208 2400 2450 2513 2548 28 20 18 00 2478 14416 160 7279 2696 2881 2927 2989 3081 3599 2340 2970 17326 161 86 90 3257 3360 3 3 76 34 26 3558 4455 2943 3430 2000 162 12D 4368 2209 2600 2558 2518 2466 2774 1753 2536 14713 163 5833 2730 3092 3028 2974 2913 3501 2287 3002 174 78 164 7643 3320 3681 3630 3651 3530 4623 3181 3623 21116 165 87 39 3920 4303 4300 4708 4178 61 60 3937 4372 25456 166 1268 962 1203 1205 1186 1118 1084 725 1178 6693 167 2678 14 67 1785 1779 1752 1698 1726 10 70 1754 88 49 168 1 12D 12 83 936 1217 1414 1397 1239 1190 7 65 1317 7484 169 2729 2502 2930 2914 2934 2956 2979 17 52 2934 16866 170 4345 3884 4357 4283 4318 4421 4836 28 59 4345 25151 171 6036 5546 5858 5764 5791 6028 7129 4184 5860 34045 172 6578 7167 7769 7907 79 82 8263 10492 5915 7980 46437 173 87 84 10237 112 23 120 26 12727 12968 185 19 85 98 12236 71103 174 1278 1344 1803 18 72 1835 1790 1712 1063 1825 10355 175 2711 2328 2972 2932 2893 28 78 2863 1667 2919 167 51 176 4351 3934 4414 4353 4281 4321 4654 28 63 4342 25088 177 5994 5076 5824 5838 5818 59 29 6914 4205 5852 33885 178 1 11 U 1223 388 432 465 464 449 435 338 453 2585 179 2351 521 602 6 22 675 6 57 619 436 639 3687 180 34 48 6 05 1725 803 8 27 8 11 760 518 792 4593 181 4513 718 850 934 9 68 9 57 8 99 609 9 27 5386 18 2 5714 8 32 981 1060 1102 11 06 1034 6 59 1062 61 82 183 6997 1025 1182 1258 1295 1309 1234 8 18 1261 7 3 44 184 8709 1295 1487 1 5 42 1594 1626 1612 1156 1562 9080
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
185 2 12D 4249 3560 4400 4670 4791 4695 47 81 2931 4639 268 37 186 5737 4926 58 54 61 92 6248 62 38 67 78 4134 6131 35590 187 7432 6390 7726 83 46 85 44 86 34 10371 5658 8313 48310 188 8723 7718 107 88 11933 12099 13046 186 22 79 39 119 67 69505 189 1 4 35 1340 1735 18 57 18 52 17 81 1711 1144 18 06 10256 190 2718 2399 3023 3187 3207 3138 30 53 1931 3139 18025 191 7 5 07 6189 80 11 9200 9427 9703 11364 5720 9085 527 38 192 8544 78 42 10666 125 42 13312 13775 178 20 6976 125 74 729 86 193 1287 1417 16 97 18 7 18 69 18 08 1720 1046 1800 10223 194 27 17 2450 2940 3187 3214 3157 3054 1749 3125 17954 195 42 53 3560 4222 45 90 4679 46 63 4743 2741 4539 26247 196 6068 48 69 57 79 6335 65 8 6 66 04 7172 4338 63 26 366 78 197 7389 58 86 72 8 6 82 23 8584 8936 10658 50 60 8257 4798 6 198 86 88 78 91 100 27 120 56 130 29 14299 190 81 6492 12353 71850 199 5864 4694 5 6 67 61 94 6419 65 48 7192 3950 6207 360 14 200 2 D 4177 38 36 4547 48 09 4775 4628 5006 2715 46 90 261 30 201 5712 5170 62 39 66 38 6599 6604 7518 4167 65 20 378 00 202 73 63 7201 8986 98 43 9733 9914 13353 6219 9619 55810 203 8604 10043 13118 148 41 150 42 158 66 25206 82 5 3 14717 85290 204 12 68 1506 18 41 1971 1966 1868 1799 11 42 1913 10880 205 2659 2571 3127 3276 32 50 3130 3069 18 80 3196 18 350 206 39 80 36 76 4347 4573 45~67 4473 46 34 28 37 4490 25910
o 207 Orifice 11496 10 64 1360 15 39 1 5 80 1 6 15 1496 8 58 15 24 88 83 208 9433 8 95 11 78 13 26 1394 1386 1263 727 1346 78 48 209 7387 746 9 77 1123 1184 1159 1048 6 11 1111 64 74 210 52 36 566 7 66 900 934 909 8 21 499 8 27 48 02
0) CJ1
TABLE III Continued
Run No Position CFM h 1 h2 hs h4 h5 h6 h7 hav Nuav
211 212
3309 1293
414 257
563 3 19
6 68 3 57
6 91 3 37
6 72 351
7 37 337
38 4 2 46
4 40 341
3748 1942
213 214 215 216 217 218
c of 2nd 1 516 1235
1919 2712 3320 4153 4704
1532 2447 35 46 4312 5567 74 29
2 1 87 3312 4225 52 86 6902 8 6 50
2360 3555 4340 56 12 7 0 49 8 9 40
2409 3598 4 8 85 5718 7713 9593
2347 2101 35 33 3453 48 00 49 62 5562 59 86 72~6 7 8 79 93 76 11237
1243 20 64 3054 4 2 8 1 5114 6983
2326 35 00 4638 5545 7225 91 40
132 13 200 27 26672 31968 41711 52811
bull
67
TABLE IV
PRESSURE PROFILE DATA
Baffle Flow Qpening Rate ~p
(Inches) Position (CFM) (Inches 295 S G Fluid)
1 364 l2 11 U 1012 0 254 1248 0197 1493 0 141 1718 0112
c 1000 9 80 1210 1710 1436 28 75 1746 4320 1011 1080 1277 2050 1393 3020 1 6 28 4450
12D 1011 9 75 1236 1520 1450 2510 1603 3450
1 D 1011 975 1256 1700 1480 2690 158 1 4070
1 12D 1010 950 1259 1750 1462 2650 1631 3710
2 11 D 1124 1315 1360 2130 1505 2850 1689 4125
1 216 12U 1294 045 1949 0324 2374 0282 2704 0225 3367 0169
c 1326 265 18 81 5 90 2313 990 2731 1480 3439 2660
12D 1272 2 49 1957 661
68
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Pos ition (CPM) Inches 2 95 S G Fluid)
2559 1275 3033 1940 3639 3025
1 216 1nD 1257 242 16 96 476 2117 8 05 2561 1280 2990 1895 3431 26 bull00
1 316 12U 1309 0 479 2004 0422 28 28 0 352 3526 0281 42 28 0225 5199 0225
c 1308 1 43 1998 272 28 14 5 10 3478 795 4248 1235 5048 1885
l2D 1286 140 2005 3 45 2831 725 3495 1180 4194 1805 5046 2945
1 11D 1322 150 2039 352 2841 735 43 77 1980 5378 3440
1 516 12U 1278 0493 2732 0493 4315 0408 5744 0352 7494 0352 8932 0422
c 1300 0 506 2731 1985 4310 348 6080 6 45
69
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Position (CPM) (Inches 295 SG Fluid)
7607 1090 8830 1585
l2D 1343 0549 2738 225 4566 583 6112 1195 7536 2055 9043 3415
1 516 1uD 1249 0464 2713 224 4155 579 5620 1150 7428 2115 90 70 3405
1 12D 1301 0493 2735 220 4501 616 61 50 1235 7440 2065 8862 3445
2D 1265 0 478 2750 226 4366 594 6578 1270 7678 2240 8945 5280
2 12D 1295 0493 2725 222 4293 600 5807 1120 7568 2200 9070 3615
TABLE V
RATE OF HEAT TR AN SFER Ar THE BAFFL~~ CID-TT ER
Orifice Size
(Inches)
Flow Rate
( CFM)
Re d e G tU
R~) 055 Nuav NuPr-l3
1 364 10 26 12 90
8 075 10015
43400 54 600
85 11 99 64
95 83 112 19
1416 11 140 59 900 110 30 124 20 16 27 12 800 68 900 126 64 142 60 17 29 13 610 73 200 135 79 152 90 17 76 13980 75 200 147 59 166 19
1 216 11 35 14 06
8 600 10 660
27000 33500
6 4 96 76 56
73 14 8 6 12
1517 11500 36100 82 51 9291 20 34 15400 48400 10229 115 18 23 11 17500 55000 118 31 13322 2348 17 800 55900 11947 13452 2666 20 200 63400 13508 15210 27 16 20 600 64700 135 05 152 07 32 47 24600 77200 161 57 18 193 3392 25 700 80700 17390 195 8 1
1 316 1344 19 36
9898 14 260
24800 35 700
63 8 7 8 2 77
71 92 93 20
28 46 20 9 60 52 500 111 08 125 08 34 84 25 660 64200 131 38 147 93 40 66 50 12
29900 36900
74800 92400
150 78 18046
169 78 203 20
~ 0
TABLE V Continued
Orifice Flow Re Size Rate d e G R~rmiddot55 NuPr-13(Inches) (CFM) U Nuav
1 516 12 70 8 847 16800 54 ~0 61 14 2 14 18 900 35800 82 42 92 80 43 10 30 000 56900 11349 127 79 60 12 41900 79400 14416 16232 7279 50700 96100 17326 19509 86 90 60540 115000 20098 22529
TABLE VI
RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
Orifice Size
(Inches)
1 364
1 216
1 316
Flow Rate
(CFM)
1054 1294 1431 1681 1770
1068 1399 1669 1959 2295 2636 3390
1299 1973 2788 34 73 4118 4973
Re deG Mshy
8 300 9870
11260 13200 13 930
8100 10600 12650 14850 17400 19980 25700
9 570 14500 20500 25600 30300 36600
R~r-6 51900 61700 70500 82 500 87 100
28200 36900 44000 51700 60 600 69500 89400
26100 39600 56000 69900 82700 99 900
Nuav
2416 293 5 3187 4018 4805
14938 18968 21712 25156 30680 37938 59601
14736 21290 28781 36052 439 85 60225
Uu Pr-1 3
27204 33050 3589 4524 541 0
16820 21358 24448 28326 34546 427 18 67111
16593 23973 32407 40595 495 1 678 13
TABLE VI Continued
Orifice Flow Re Size Rate deG R~rmiddot6 NuPr-13(Inches) (CFM ) M- Nuav
1 516 1268 88 30 17700 108 8 1225 2689 18700 37400 1835 2066 3980 27700 55700 2591 2917 4177 29100 58 500 2713 3055 5712 39800 80000 378 0 425 6 7362 51300 103000 5581 6284 8 604 59 900 120000 8529 9604
74
TABLE VII
EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER
l 516 Inch Orifice
Center ot 2nd Baffle 4 Downstream
Plow Rate (CFM)
1235 1919 2712 3320 4153 4704
Flow Rate (CFM)
1270 2714 4310 6012 7279 8690
(Re)eb -8600 1321
13400 2003 18900 2687 23100 5197 28900 4171 32800 5281
Center ot Single Battle
-8847 543
18900 824 30000 1135 41900 1442 50700 1733 60540 2001
(Nu)(Pr)-l3
1487 2255 3003 3600 4697 5946
(Nu)(Pr)-13
611 928
1278 1623 1951 2253
75
ABLE VIII
HEAT TRANSFER IN THE TEST SECTION WITHOUT ORIFICE
CFM Ute) 0b h Nu
1293 5-951 3 41 1942
33 09 15251 649 3746
5236 24193 827 4802
7387 34001 1111 6474
9433 43419 1346 7848
11496 52-914 1524 8883
76
TABLE IX
PRESSURE DROP FUNCTION
Orltlee Size Flow Rate incbea ~CFM (Re)eb X 10bull8
1 364 1011 7957 0808 1256 9885 1468 1480 11648 2765 1581 12443 4160 1689 1_3293 4 020
1 216 1257 9530 1327 1696 12858 2663 2117 16049 4615 2561 19415 7581 2990 22668 11560 3431 26011 16440
l 316 1322 9736 1819 2039 15016 4332 2845 20952 9275 3495 25739 15300 4377 32014 26800 5378 39607 50100
1 516 1011 7 957 oaos 1256 9885 1469 1480 11646 2765 1581 12443 4160 1689 13293 4020
77
TABLE X
EXPERIMENTAL DATA
Baffle Hole Diameter Run No
1 - 59
60 - 102
103 - 138
139 - 206
207 - 212
213 - 218
(Inches)
1 364
1 216
1 316
1 516
No Baffle
2nd - 1 516
TABLE X
EXPERIMENTAL DATA
Run Thermocouple Reading s (mv) No Position CFM I tc1 tc2 tc3 tc4 t c 5 tc6 tc7 tcair
1 c 1026 530 2055 1825 1768 1782 1802 1837 1965 1198 2 1290 612 2059 18 65 1809 18 32 1851 1880 1965 1160 3 1416 714 2151 1970 1931 1965 1988 2026 209 5 1130 4 1627 8 21 2235 2084 2 049 2093 2126 2173 2266 1130 5 1776 865 2203 2033 1970 2015 2084 2159 2 264 1121 6 12D 1109 542 1636 1507 1499 1499 1498 1498 1528 1218 7 1258 651 1670 1522 1503 1513 1513 1516 1548 1221 8 1433 750 1625 1480 1467 148 3 1487 1487 1516 1153 9 168 1 8 73 1656 1494 148 1 1511 1517 1517 1543 1159
10 1rtD 1102 485 1545 1450 1437 1446 1447 1442 1466 1220 11 13 08 6 10 1571 1470 1460 1476 1476 1469 1498 1194 12 1464 730 1 623 1509 1508 1528 1 5 32 1524 1548 1173 13 11 06 8 71 1663 1559 158 1 1606 160 6 1 583 1601 1190 14 1 12D 1115 520 1698 1579 1575 1 577 1580 1590 1615 1280 15 1275 6 10 1692 1567 1558 1 561 1570 1580 1601 1234 16 1498 770 1760 1619 1630 1 635 1642 1645 1661 1204 17 1695 912 1775 1635 1670 1689 1686 168 6 1701 1165 18 2D 1049 510 1736 15~2 1567 1558 1 553 1558 1620 1236 19 12 41 610 1655 1517 149 1 148 1 148 1 148 4 1546 1108 20 1 5 32 7 35 1720 1550 1530 1520 1519 1523 158 0 1104 21 16 74 8 8 0 1900 1 727 1714 1696 1691 1692 1753 1169 22 1U 1074 38 5 3 324 2740 2534 2478 2 465 2503 258 0 1210 23 1287 4 35 3510 2 870 2682 2 610 2599 2638 27 1 9 1190 24 1 5 08 470 3 618 2920 2690 2 637 2627 2 664 2747 1177 25 18 07 525 4 088 3235 2962 2905 2910 2988 3130 1169
z ())
TABLE X Continued
Run No Position CFM I tc1 tc 2
Thermocouple Readings te3 tc4 tc5
(mv) tc6 tc7 tcair
26 c 10~29 6 32 2340 2~092 2032 2060 2~097 2152 2~213 1211 27 12 66 679 2270 2 047 1993 2013 2069 2142 2 210 1 182 28 1430 723 2336 2097 2033 2080 2153 2~255 2 356 1 138 29 1729 8 52 2318 2070 1980 2061 2158 2279 2367 1121 30 12D 1054 570 1520 1 4 20 1402 1400 1396 1400 1 443 1159 31 1294 6 69 1599 1469 1444 1439 1433 1 442 1485 1168 32 1430 7 88 1720 1562 1536 1532 1528 1537 158 0 118 5 33 1770 8 81 1641 1488 1450 1~441 1 441 1_466 1518 1 163 34 1D 1058 548 1579 1498 1495 1526 1553 1_557 1 571 1 276 35 1263 640 1609 1509 1515 1570 1599 1598 1 598 1 266 36 18 36 8 47 1538 1452 1483 1553 1602 1 590 1 558 1195 37 1 12D 1029 5 41 1 578 1499 148 4 1473 1461 1465 1-512 1200 38 1315 6 30 159 1 1504 1493 1482 1470 1470 1505 118 5 39 1 4 26 743 1765 168 1666 1660 1645 1642 1678 1270 40 1757 8 54 1744 1648 1634 1620 1598 1 593 - 1612 1223 41 2D 1080 5 30 1734 1604 1570 1 570 1570 1 588 1 640 128 1 42 1305 6 40 1744 1622 1589 1 608 1593 1 609 1 661 1240 43 1434 750 1798 1687 1658 1 636 -1641 1 661 1 711 1_220 44 18 04 8 41 1 764 1666 1607 1605 1614 1 635 1 675 1205 45 12nu 1088 415 2614 2295 2195 2 169 2174 2217 2256 1171 46 1318 477 2805 2477 2371 2342 2364 2 401 2 438 1 163 47 1413 5 28 2930 2 646 2 555 2 526 2532 2570 2 577 1 199 48 1773 550 2740 2518 2450 2431 2448 2 479 2 480 1 170 49 1 11 U 1054 380 3175 2670 2505 2 461 2467 2 534 2 621 1 258 50 1240 420 3268 2738 2 546 2 510 2 508 258 2 2 649 1214 51 1419 451 3364 2B07 2 632 2590 2 590 2 651 2773 1 215 52 1 12U 1032 360 3 165 2 629 2 450 2402 2403 2 473 2 bull568 1 163
--I lt0
TABLE X Continued
Run No Position CFM I tc1 tc2
lhermocoup1e Reading s tc3 tc4 t c 5
(mv) tc6 tc7 tc a ir
5 3 1314 38 9 3178 2592 2411 2367 2361 2432 2555 1140 54 1448 403 3095 2544 238 1 2336 2336 2390 2476 1158 55 178 2 427 3006 2434 2286 2253 255 3 2299 2397 1154 56 2 11U 1061 360 3369 2814 2619 2567 2560 2650 2833 1220 57 1216 360 3044 2512 2338 2290 2288 2374 2566 1150 58 1322 387 3196 2614 2425 2383 2382 2472 2670 1138 59 1639 403 3020 2438 2272 2238 2238 2318 2502 1127
60 1D 1068 612 1552 1424 1400 1395 1396 1426 1745 0945 61 1399 612 1355 1246 1230 1229 1230 1250 1509 0872 62 1669 710 1436 1293 1272 1265 1266 1286 1551 0847 63 1959 900 159 5 1468 1444 14 38 1432 1446 1720 0851 64 2295 730 1169 1105 1098 1099 1108 1100 1298 0781 65 2636 8 80 1202 1129 1121 1126 1 138 1115 1342 0748 66 3390 9 35 1060 o 9s7 0999 1001 1017 0971 1154 0703 67 1nu 1190 370 2225 2188 2104 2080 2120 2209 2 7 15 0990 68 1559 368 2005 1950 1871 18 48 1876 1951 2408 0916 69 1904 368 1870 18 1 4 17 34 1711 1730 18 07 2238 0875 70 22 bull11 471 228 6 2 204 2099 2063 2092 218 $ 2732 0840 71 2289 471 2030 2000 1925 1895 18 96 19 5 2498 0785 72 2727 4 71 1854 18 23 1753 17 23 1716 3758 2241 0743 73 3210 471 1680 1651 158 6 1559 1551 158 1 1950 omiddot7o9 74 2uD 1210 404 1261 1212 1198 1197 1205 1222 139 1 0978 75 14 20 540 1321 1260 1242 1 240 1249 1268 148 7 0918 76 1692 7 18 1467 138 6 1364 1361 1376 1405 1678 0883 77 18 94 903 1708 1 591 1565 1560 1575 1603 1948 0 857 78 2301 903 1530 1432 1407 1402 1415 1432 1738 0815
ro 0
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc117 tcair
79 2621 6 50 1069 1 020 1009 1009 1009 1007 1~189 o739 80 3230 901 1200 1128 1113 1119 1119 1086 1341 0694 81 82
l2D 1155 1689
360 575
1191 1345
1142 1252
1122 1218
1118 1210
1118 1209
1132 1228
1292 1446
0916 0822
83 1244 430 1163 1134 1131 1130 1129 1132 1292 0877 84 2100 645 1175 1135 1147 1 142 1138 1122 1286 0757 85 2292 8 25 1 354 1310 1327 1330 1323 1285 148 6 0728 86 2907 8 23 1180 1138 1151 1158 1149 1107 1268 0687 87 3380 902 1113 1049 1025 1011 1006 1042 1178 0673 88 89
1 12D 1427 1875
480 615
118 2 1140
1140 1095
1124 1077
1125 1075
1129 1072
1137 1072
1290 1243
0880 0790
90 2259 8 41 1296 1231 1207 1206 1203 1182 1419 0757 91 2682 8 80 1231 1170 1149 1147 1142 1112 1350 0731 92 3417 940 1142 1092 1076 1076 1069 1021 1252 0693 93 c 15 17 431 1321 1298 1268 1249 1250 1273 1522 0841 94 2034 505 1285 1263 1235 1209 1205 1206 1464 0759 95 2348 6 10 1395 1379 1334 1302 1286 1268 1536 0732 96 2716 706 1486 1480 1427 1383 1358 1311 1572 0 700 97 3247 7 56 1417 1430 1375 1320 1284 1223 1450 0660 98 1135 400 1425 1388 1352 1329 1330 1 364 1651 0893 99 14 06 440 1379 1341 1304 128 2 1281 1305 1583 0 831
100 2311 680 1602 1593 1553 1514 1502 1480 1 7 27 0 802 101 2666 680 1471 1469 1428 1390 1372 1335 1564 0761 102 3392 798 1491 1 509 1449 1395 1372 1305 1534 0 719
103 1U 1235 410 2469 2295 2173 2165 2226 2361 3120 0 897 104 2010 410 2017 1848 1 737 1706 1747 1865 2582 0753 105 28 14 410 1682 1535 1457 1427 1437 1520 2109 0 660
00 t-
TABLE X Continued
Ru n Thermocouple Rea ding s (mv No Positi on CFM I tc1 tc2 tc3 tc4 tc5 tc6 tc7 tcair
106 3492 440 1649 1499 1420 1391 1390 1470 2042 0620 107 4395 550 18 33 1679 1597 1564 1570 1640 2223 0583 108 5075 588 1779 1642 1580 1550 1552 1 615 2 191 0548 109 c 1344 398 1464 1 399 1364 1353 1350 1380 1689 0 907 110 1936 459 1369 1290 1253 1242 1 237 1259 1574 078 2 111 2846 580 1347 128 5 1251 1232 1220 1215 1 5 23 0 683 112 34 8 4 700 1392 1369 1339 1317 1299 1259 1599 0 636 113 4066 8 13 1449 1458 1427 1391 1363 1270 1595 0 591 114 5012 930 1484 1530 1500 1453 1420 1272 1580 0 580 115 1D 1362 513 1269 1218 1 217 1214 1220 1238 1460 0 893 116 19 58 600 1187 1122 1121 1120 1124 1133 1352 0798 117 2812 705 1052 1008 1015 1010 1011 1001 1218 0691 118 34 32 913 1105 1075 1085 1081 1086 1047 1301 0645 119 4022 980 1038 1021 1026 1023 1029 0983 1211 0 609 120 5026 982 0 8 61 0839 0836 0836 0837 0791 0955 0570 121 2D 1244 475 1320 1246 1233 1240 1255 1275 1434 0925 122 1 9 60 5 50 1160 1088 1074 1079 1089 1100 1260 078 7 123 2817 6 80 1096 1024 1 013 1018 1029 1022 1201 0 700 124 3491 960 1248 1175 1163 1172 1192 1153 1435 0 658 125 4096 989 1141 1089 1078 108 9 1105 1051 1310 0629 126 50 37 989 0983 0933 0929 0 936 0949 0880 1090 0 602 127 128
12D 1278 1947
402 545
1270 1261
1 230 1216
1228 1216
1230 1 215
1235 1223
1242 1219
1483 1514
0 913 0778shy
129 2769 695 1273 1234 1237 1221 1251 1212 1525 0678 130 131 132
34 39 4103 4978
8 40 9 80 9 80
1336 1448 1271
1322 1458 1 288
1328 1 462 1286
1 259 1 356 1157
1353 1492 1311
1261 1329 1138
1 555 160 7 1343
0 629 0 600 0599
(l) l)
TABLE X Continued
Run No Position CFM I tel tc 2
Thermocouple Readings tc3 tc4 tc5
( mv) tc6 tc7 tcair
133 1 l2D 1299 5 16 1 28 1 1212 1196 1195 1205 1221 1478 0869 134 1973 6 15 1163 1098 1073 1071 1079 1083 1343 0751 135 136
27 88 34 73
802 9 -_78
1187 1214
1099 1131
1069 1104
1066 1101
1075 1~110
1l061 1066
1370 1360
0662 0618
137 4118 9 81 1084 1010 0983 0979 0982 o937 1209 0581 138 4973 98 1 0969 0897 0 868 0855 0860 0799 1041 0572
139 1D 1253 409 1371 1293 1298 1301 1309 1321 1578 0928 140 2366 480 1130 1 090 1 121 1130 1137 1132 1390 0744 141 34 61 6 38 1081 1086 1152 1161 1147 1069 1382 0644 142 143 144
4325 5677 6759
7 90 939 998
1110 1115 1034
1161 1208 1139
1253 1268 1180
1265 1302 1215
1228 1230 1123
1080 1056 0970
13$913r12 8
0601 0561 0542
145 84 08 989 0863 0961 0934 0895 0871 0 785 09 9 0530 146 86 54 9 80 0808 0901 0 872 0821 0809 0733 0891 0498 147 7376 9 80 0 927 1032 1027 1 040 0961 0889 1032 0511 148 2D 4254 776 1 050 0 981 0965 0961 0962 0922 1155 0579 149 5708 991 1102 1031 1014 1009 1010 0931 1227 0528 150 69 78 990 0914 0853 0839 0 839 0843 0759 0996 0521 151 1254 490 1 479 1352 1329 1334 1351 1379 1607 0930 152 2713 7 00 1310 1220 1201 1201 1211 1209 1516 0723 153 8730 991 0809 0756 0742 0745 0 748 0663 0874 0543 154 5811 966 1219 1108 108 6 1081 1079 1033 1330 0650 155 42 46 8 02 1248 1136 1114 1114 1118 1103 1376 0 699 156 c 1270 429 1671 1571 1551 1545 1563 1600 1933 0929 157 2714 488 1398 1285 1 267 1258 1262 1275 1628 0729 158 4310 642 1424 1318 1299 1282 1283 1261 1683 0617
co ~
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc7 tc a 1r
159 60 12 780 1461 1388 1370 1349 1343 1279 1700 0 573 160 72 79 8 60 1402 1344 1330 1312 1292 1189 1 566 0 520 161 8690 982 1472 1442 1437 1 422 1392 1224 1602 0 521 162 163
12D 4368 5833
6 30 8 30
1195 1368
1105 1270
1111 1283
1117 1294
1131 1313
1081 1194
1369 1553
0613 0 553
164 76 43 959 1428 1338 1348 1341 1371 1180 1488 0535 165 8739 984 1345 1272 1272 1208 129 3 1059 1361 0550 166 1268 459 1701 1548 1541 1547 1589 1 625 1976 0 973 167 2678 570 1485 1351 1349 1356 138 1 1 385 1795 0760 168 169
1 12D 128 3 2729
448 650
1664 1314
1501 1232
1425 1233
1428 1229
1491 1229
1527 1232
1869 1571
0 962 0767
170 4345 847 1245 1179 1187 1182 1172 1132 1476 0 650 171 6036 9 76 1139 1109 1117 1114 1095 1020 1332 0588 172 6578 9 72 0982 0949 0942 0938 0926 0 8 50 1079 0560 173 87 84 9 72 0880 0854 0 8 36 0822 0818 0 749 0941 0585 174 1278 480 1564 1416 1397 1403 1417 1445 1733 0998 175 2711 590 128 3 1175 4 1178 1182 1187 1195 1493 0796 176 4351 8 90 1331 1259 1266 1275 1272 1235 1592 0 682 177 5994 9 60 1228 1152 1150 1151 1143 1075 1 360 0644 178 lU 1223 408 2282 2140 2052 2052 2106 2188 2626 0 878 179 2351 408 178 1 1623 158 5 1519 1556 1634 2068 0717 180 3448 482 1888 1675 1570 1541 1572 1665 2199 0629 181 4513 563 2026 1797 168 4 1644 1670 1770 2385 0583 182 5714 589 1913 1700 1610 1568 1580 1 682 2382 0551 middot 183 6997 653 1903 1718 1643 1611 1612 1700 2326 0 549 184 8709 6 80 1738 158 3 1543 1510 1498 1519 1 912 0577 185 186
2 12D 4249 5737
660 9 74
1055 1221
0 979 1122
0960 1093
0 952 1088
0959 1090
0 956 1054
1147 1350
0661 0602
187 7432 9 8 1 1065 0981 0951 0942 0 939 0881 1135 0582 CD ~
TABLE X Continued
Run No Position CFM I t o1 to 2
188 87 23 9 83 0944 0 879 189 1435 585 18 26 1630 190 2718 690 1433 1298 191 7507 950 1070 0961 192 85 44 964 0982 0 881 193 1287 600 1806 1668 194 2717 7 80 1579 1444 195 4253 8 81 1371 1260 196 60 68 9 78 1252 1152 197 73 89 975 1100 1000 198 86 88 973 0953 0 871 199 58 64 9 81 1269 1155 200 2D 4 1 77 915 1362 1251 201 5712 975 1213 1111 202 7363 9 78 1036 0 951 203 8 604 973 0932 0861 204 1268 6 95 2015 18 20 205 2659 6 96 1405 1295 206 39 80 7 98 1261 1174
No 207 Orifice 114 96 509 1325 1148 208 94 33 509 1477 1243 209 7487 5 09 1686 1409 210 5236 505 2094 1691 211 3309 428 2188 1 778 212 1293 392 2976 2560
Thermo ooup1e Readin g s (mv) to 3 to4 to
5 to
6 to7 toair
0 851 0847 0 8 29 0759 0987 0592 158 4 1583 1611 1647 1993 0986 1270 1266 1 279 1298 1604 0 789 0916 0908 0900 0 858 1115 0602 08 39 0 823 0 818 0 770 1035 0602 1609 1602 1629 1676 2153 0979 139 1 1385 1400 1 430 1938 0776 1212 1201 1205 1201 1601 0669 1 105 1086 1086 1 052 1371 0621 0952 0936 0923 0870 1195 0582 0 8 20 0 801 078 1 0 729 1044 0569 1108 1090 108 2 1043 1407 0610 1218 1221 1241 1202 1582 0659 1081 1083 1084 1031 1 368 0622 0921 0924 0919 0 841 1111 0 610 08 34 0831 0 821 0 751 1003 0 630 1761 1761 1 809 1861 2399 0966 1271 1271 1295 1311 1650 0797 1150 1150 1161 1149 1440 0703
1083 1057 1053 1109 1566 0~530 1158 1125 1138 1217 1763 0 526 1291 1250 1278 1383 2038 0542 1518 1478 1519 1657 2420 0 589 1596 1557 1601 1737 2441 0688 2370 2344 2409 2561 3 297 0921
()) (11
TABLE X Continued
Run Thermocouple Readings (mv) No Position CFM I tc 1 tc2 tc3 tc4 tc tc tc tc i5 6 7 a r
C of 2nd 213 516 1235 4 63 1 432 1291 1265 1258 1 268 1 308 1550 0 971 214 1919 6 17 1357 1223 1196 1191 1199 1211 1461 0 851 215 27 12 8 35 1401 1259 1278 1220 1230 1218 1511 0 762 216 3320 981 1439 1305 1270 1259 1275 1238 1450 0719 217 41 53 980 1251 1142 1132 1094 1121 1088 1305 0 695 218 404 987 1102 1042 1030 1 bull006 1014 0960 1133 0681
Supplementary Equations
Calculating temperatures from thermocouple readings
t = -026tc)2 + 3512(tc) + 3201 (26)
where t is the temp in deg F and tc is the thermocouple reading in millishyvolts
Calculation of the thermal conductivity of air
k = 00000245ta + 0 0132 (27)
where k is the thermal conductivity in Btuhr rt2 degFft and ta is the air temp 1n OF
I I
bull co m
11
air left the test section through nine equally spaced 12
ineh holes placed around the side of the tube at the exit
end
Sensing Probe Assembly
The sensing probe was designed to measure the local
heat transfer coefficients at any point along the tube and
around the tube in the test section The tube was designed
so that it could be easily moved up- and downstream to
measure the heat transfer coefficients at various positions
in relation to the orifice
The sensing tube assembly consisted of the sensing
probe the thermoctmple lead s and selector switch the
power lines and the two aluminum tubes between which the
probe was centered
Imbedded in the sensing probe were seven iron-constanshy
tan thermocouples for measuring the temperatures around the
tube The lead wires from these thermocouples were conshy
nected to a seleotor switch at the downstream end or the
aluminum tube A layer of Saran wrap was placed around the
tube over the t hermocouple and three lengths of Trophet C
resistance ribbon were wrapped around the tube nd conshy
nected in series to the power leads
The heating surface of the probe was formed by these
three one inch wide strips of Trophet C resistance ribbons
The ribbons were 0002 inches thick and had a resistance of
12
0 271 ohms per foot and a thermal conductivity of 763
Btuhr ft 2 degFft They were held in position by four
copper bars placed in four parallel longitudinal slots
These copper bars served as connectors for the electrical
leads A photograph of the sensing probe is shown in
Figura 3 and a drawing of the assembled probe is given in
Figure 4
Power Source
Direct current was used to heat the resistance ribbon
on the sensing probe The current was regulated by a slide
wire resistor The po er source consisted of a Raytheon
Voltage Stabilizer to stabilize the city power source at
115 volts and an automatic selenium rectifier with an alshy
ternating current input of 115 volts at 60 cycles per
second and an output of 12 volts and 35 amperes direct
current
Temperature Measuring
The temperatures around the sensing probe were calcushy
lated from the emf readings of the ironbulloonstantan thermoshy
couples The emf measuring system consisted of the seven
probe thermocouples a separate thermocouple for measuring
the inlet air temperature a thermocouple selector switch
a cold junction and a Leeds and Northrup Type K Potentishy
ometer The potentiometer was placed on a Fischer
13
THERMOCOUPLE JUNCTIONS~ ~------- HOLES FOR THERMOCOUPLE LEADS
~----- SCREWS
~ff+--- CONNECTING BARS
END VIEW
POWER LEADS SOLDERED TO LOWER CONNECTING BAR
iER PLASTIC PIECE
RESISTANCE RIBBONS LOCATION OF THERMOCOUPLES
FIGURE 4 DRAWING OF ASSEMBLED SENSING PROBE
15
Vibradamp support to absorb the vibrations produced by the
air blower
Air Source
Air was used as the shell-side cooling fluid during
the study The air was pumped through the test section by
a Roots type air blower with a rating of 280 ofm at 3 12
psig outlet pressure The hot air leaving the blower was
passed tbxfugh two finned-tube box-type coolers and one
tubular edoler to oool it to approximately room temperature
The air flow rate was measured by passing it through a
flow measuring orifice in the line Two sharpbull edged orishy
ficas were used f or flow measurements The calibration
curves for these orifices were presented by Ambrose (1
p 166)
The pressure taps on each side of the orifice were
connected to two differential manometers containing 0 83
and 2 95 specific gravity fluids respectively The presshy
sure drop through the test section and test orifice was
measured by a pressure tap placed 13 inches upstream and
one placed 6 12 inches downstream from the orifice Two
pressure ga ges were used to measure the pressure at the
inlet to the flow orifice and to indicate the statio pres~
sure at the test section inlet
16
Pressure Probe
A probe was designed to measure the pressure drop
between the pressure tap 13 i nches upstream from the ori shy
fice baff le and any point downstream from the tap The
probe eonsisted of a l~in OD copper tube with six 132
i n ch holes even l y s paced around the tube The upstream
pressure tap and the pressure probe were connected to a
differential manometer so the pressure drop to various
points up- and downstream of the orifice could be measshy
ured
17
CHAPTER IV
EXPERIMENTAL PROGRAM
The experimental program was designed to measure the
heat transfer coefficients and pressure drops in the vicinshy
ity of annular orifices The four orifice sizes studied
were 1 364 1 216 l 316 and 1 516 inches~ The inner
tube used in each case was a 1-in OD alumintim tube
Hence tube to baffle clearances were respectively 3128
232 332 and 532 of an inch
Heat transfer coefficients were measured at poait~ons
1 i nch upstream at the orifice center and at 12 1
1 12 and 2 inches downstream for all orifices In addishy
middottion the heat transfer coefficient at a point 2 12
inches downstream from the 1 516 inch orifice was measured
and at the points 12 l 12 and 2 inches upstream from
the 1 364 inch orifice
The heat transfer coefficients at each point were
measured at five different flow rates for the 1 364 inch
orifice and at six different flow rates for the other orishy
fice sizes The high pressure drop through the small orishy
fice size limited the number of flow rates which could be
studied
The flow rate was calculated from the pressure drop
across the flow orifice This flow was corrected to cubic
feet per minute at 68degF and one atmosphere pressure by
18
using the orifice pressure and the test section pressure
which were measured by pressure gages
It was desired to determine a relationship between the
heat transfer coefficient and the total pressure drop for
each orifice size The pressure drop across each orifice
at various flow rates was measured by means of the presshy
sure probe described in Chapter III It was also desired
to obtain pressure profiles for each orifice size since
these might be similar to the heat transfer profiles The
pressure drop was measured from a point 13 inches upstream
of the orifice to points at 1 and 12 ineh upstream the
orifice center 12 1 1 12 and 2 inches downstream
The experimental program is summarized in Table I
TABLE I
SUla~RY OF EXPER IMENTAL PROGRAM
Position Investigated-Distance from Orifice-Inches
Orifice Range of Flow Rate Size Heat Transfer Pressure Drop CFM at 68degF amp 1 atm
1 364 2U 1 12U 1U 12U c 12U C 12D lD 10 - 18 l2D lD 1 12D 2D 1 12D 2D
1 216 1U c 12D lD 1 l2D 2D 12U c 12D lD 10 - 35
1 316 1U c 12D lD 1 l2D 2D l2U C 12D lD 12 - 50
1 516 1U c x2D lD 1 l2D 1U 12U C 12D 12 - 90 2D 2 1 2D l D 1 l2D 2D 2 12D
20
CHAPTER v
EXPERI MENTAL PROCEDURE
The experimental procedure for measuring the heat
transfer coefficients ~d corresponding flow rates reshy
quired the following procedure
(1) Install the orifice size to be studied in the
test section
(2) Place the heat transfer probe in the position up
or downstream from the orifice where the middot heat
transfer rate is to be studied
(3) Fill the cold junction thermos with cracked ice
(4) Measure the atmospheric pressure
(5 Open bypass line from blower and close line to
test section
(6) Turn on the cooling water for the exchangers used
to cool the air leaving the blower
(7) Start the automatic selen ium rectifier by turning
on the t 1mer bull
(8 ) Connect the voltage stabilizer to the wall outlet
(9) middot Set the slide wire resistor to the maximum re shy
s1atanee I
(10) Start the blower
(11 Open the line to the test section until the de shy
sired flow rate is obtained
(12) Switch on the probe direct current power source
21
(13) Adjust the slide wire resistor to obtain the
desired current
(14) After the thermocouples have reached equilibrium
values record the e m bullf across each of the
seven probe thermocouples and also the entering
air thermocouple
(15) Record the direct current amperage
(16) Record the gage pressure at the flow orifice and
the entrance to the test section
(17) Record the manometer measurement of the pressure
drop across the flow orifice and also the presshy
sure drop through the test section
22
CHAPTER VI
CALCULAT ION OF EXPERIMENTAL DATA
The local heat transfer coefficients were calculated
from the temperatures measured on the probe surface the
air temperature and the current input The results were
calculated by using the Alwae III-E computer
The general expression for calculation of the heat
transfer coefficients was derived by Ambrose (1 p 79)
The equation is derived by making an energy balance around
a small increment of the center resistance heating ribbon
The two ribbons tnstalled adjacent to the center ribbon
reduced the amount of logitudinal conduction and assured
little longitudinal temperature variation in the center
ribbon
A heat balan ce on this small increment of resistance
ribbon yields the following
(the heat conducted in) + (heat generated) = (heat
conducted out) +(Heat convected to the fluid) + (heat
radiated to the surroundings) + (Heat conducted into
the plastic center of the probe)
This gives the equation
kzw dtdS + 12RdS kzws [ t + (~) ds] + hwdS (t-ta )
+ ~Aad wd o middot+ qcAond 1 -~- wdS 5 )
23
Hence solving for h gi~ea
i2R kz d2t Qrad qcond w + -d$2 - ~- A
h = ( 6)t - ta
Since S = re where 9 equals the enclosed angle ~n radians
dS rd9 ( 7)
and
dt - dt (8)dS - rd9
Differentiating with respect to S
d2t (9)rd9dS
from which
(10)
Substitut1ng into the equation for heat transfer coeffishy
cient gives
h = i2R Qcond A (11)
w
The rate of radial heat conduction into the plastic
tube making up the probe was assumed to have negligible
effect on the heat transfer coefficient It was also
assumed that the heat loss by radiation from the ribbon
was negligible since all data were obtained with the ribbon
at a temperature less than 125degF
24
When t he rad iation and conduction terms are neglected
Eq (11) becomes
(12)
The following con stants are known
R = 0 271 ohmsft
w = 100 i n ches
k = 763 Btuhr rt2 degFft
z = 0 002 inches
r = 12 inch
Eq (12) putting 9 in degrees then reduces to
1110 12 + 2404 d 2t d92
( 15)h = ------~--~-------t - ta
Thi s equation was programed for the Alwac III- E comshy
puter and used to calculate the local heat transfer coefshy
ficients from the observed data
The average heat transfer coefficient around the tube
at a given position in the t est section was calculated by
averaging the local coefficients calculated from Eq (13 )
It was found 1n the course of the experimental work
that thermocouple numbers 1 and 7 were indicating higher
temperatures than would be expected This resulted in h1
and ~ being lower than the other local coefficients around
the tube Since the fluid was flowing parallel to the axis
of the probe the circumferential variation i n rate of heat
25
transfer should be small Hence in obtaining the average
coefficient around the tube the values of h1 and h7 were
not used even though they were calculated and are tabulated
1n Table I II in the Appendix
Then
(14
A Nusselt number as calculated from this aver age heat
transfer coefficient using the tube diameter as the characshy
teristic dimension
(15)
The air flow rates through the test section were calshy
culated by measuring the pressure drop across the flow orishy
fice the air temperature the pressure at the flow orifice
and the pressure at the entrance to the test section The
orifice calibration curves (1 p 166 ) were used to obtain
a value of the orifice coefficient f8e where Q equals
the flow in cubic feet per minute at 68deg F and one atmosmiddot
phere pressure and te is the density of air at the exchanger
and e the density of the air at the flow orifice The
den sity of the air can be expressed by
e = 2 703 p (16)T
where T equals the temperature in OR and P equals the absoshy
lUte pressure i n lb1n2 Using the value of e Qfo from
26
the calibration charts as A and Eq (16) solving for Q
gives
( 17
This equation was used to calculate the flow rate for
each flow studied
The Reynolds number used i n the correlation of the
data was the equivalent Reynolds number defined as
Re)eb ~ d2 - dl)Uf ( 18 ) lL
where d1 is the outside diameter of the inner tube and d2
is the orifice diameter U is the flow velocity through the
annular orifice e is the density of the air and U- is t he
viscosity of the air This equation can be transformed t o
(Re) b = 1611 Q (19) e dl + d2
where d1 and d2 are in inches
The pressure drop data were calculated i nto a dimenshy
sionless pressure drop function cent where
d1 )22( ~ P)gc f av(d2 shycent 2 bull (20
M-
For air this equation reduces to
where d2 and d1 are in i nches D P is expressed i n inches of
2 95 specific gravity fluid and P av is expressed as lbft3
27
CHAPTER VII
ANALYSIS OF DATA
In analyzing the heat transfer data an attempt was
made to correlate it 1n terms of the dimensionless groups
(Nusselt number Prandtl number and Reynolds number) which
appear in Eqs (3) and (4) Consequently all of the av~
erage heat transfer coefficients hav were brought into
the form ( Nu)( Pr)~3 bull The Nusselt number was based on the
tube diameter and the thermal conductivity of the air at
the flowing temperature The tube diameter was used in the
Nusselt number because comparison could then be made with
previous experimental work on heat exchangers which have
commonly used the Nusselt number defined as in Eq (15)
From the standpoint of dimensional analysis this is
equivalent to considering the tube diameter as the characshy
teristic length so far as the heat transfer is concerned
The Prandtl number of the air was taken as 0 7 in all
cases
Variation of Heat Transfer Rate with Distance from the Baffle
Considerable variation was observed in the rate of
heat transfer in the vicinity of the baffle In order to
obtain the variation with respect to position the term
(Nu)(Pr)-13 was plotted versus the flow rate Q for each
position and orifice studied Cros s plots were then made
28
at constant flow rates in order to obtain the variation of
(Nu)(Pr) -13 with position The resulting cross plots are
shown 1n Fi gures 5 6 and 7 for the four orifices studshy
ied
About one inch upstream from the orifice the heat
transfer coefficient begins to rise rapidly and continues
to do so until it reaches a maximum some distance downshy
stream After the maximum point the heat transfer coef fi shy
cient decreased slowly The heat transfer rate was found
to reach a maximum at a different position downstream for
each orifice size These figures also show that for a
given orifice size the maximum heat transfer rate occurs
a pproximately at the same point for all flow rates The
position of the maximum point f or each or ifice size is
shown in Table II
The region immediately downstream from the orifice is
one of h i gh turbulence due to the jetting action of the air
flowing through the orifice As the air flows t hrough the
orifice the streamlines continue to converge for some dis shy
tance downstream The point of maximum heat transfer is
probably at the point where the streamlines be gin to diverge
and a boundary layer begins to build up on the tube Tle
decreasing heat transfer coefficient beyond the maximum
point indicated the formation of a boundary layer
Since the position of the maximum point is independent
of flow rate middot it is possible to correlate it with respect
_ ct 11shyz-
100
0 136 ORIFICE
(
I 0
I )
~ 00
~p 0
I 0
--r--- ~
ISCFIII
-_ OCFM
rbull abull
~ middot~ a-1 z-
12fORIFICE
100
200
100
0 0 UPITRAM ORIFICE DISTANCE CENTER
CFM
h I DOWNSTREAM
DISTANCE
FIGURE 5 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLpound
30
too
700
800
100 ~ f gtf
400
z ~
100
100
100
0
13fORIFICE
~ -~ -- ---
)
~
~
-
I ~ ~OCFM
I vI~-~ OCFM
J ---
Iamp CFM
I 0 I I UPSTREAM ORIFICE DOWNSTREAM DIITANOE GENTER DIITANCI
FIGURE 6 VARIATION OF HEAT TRANSFER RATE WITH DISllNCE FROM BAFFLE
--
--- --
31
100
100
700
100
_ 100
f 9- 400 z-
100
tOO
100
0 - I 0 I I I UHTRIAM OAtfiCI DOWIIITMAM
+ I tyl6 ORIFICE
v I
~~ ~CFM
I v ~CFMI
v v 7
~~ v ~ iOCFM
- ~~ I-shy1-shy ~ICFM
DIITMCI OINTIR DIITANCI
FIGURE 7 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLE
32
TABLE II
POSITION OF MAXIMUM HEAT TRANSFER
Position of Maximum Orifice Size Heat Transfer
(inches) (inches downstream)
1 364 050
1 216 100
1 316 125
1 516 200
33
to orifice size Figure 8 shows the effect of the orifice
size on the position and value of the maximum heat transfer
at a constant flow rate of 15 cubic feet per minute It
can be seen that the larger the orifice size the further
downstream the point of maximum heat transfer occurs
Also as the orifice size increased the rate of heat
transfer decreased for a given flow rate The broken line
indicates the variation of the point of maximum heat transshy
fer with position and size The position of the point of
maximum heat transfer rate downstream from the orifice was
correlated with orifice size by means of the dimensionless
groups (Lde) and (d1de) where L is the distance downshy
stream from the orifice where the maximum rate of heat
transfer occurs d1 is the outside diameter of the inner
tube and de is the equivalent diameter of the orifice
ie de = d2-dlbull
Figure 9 shows a plot of Ld 6 versus d1d6 for the
four orifice sizes studied The four points on this logshy
log plot are approximately in a straight line and the
equation of this line is
Lde = 0 44 d1de)028 (22)
Although the above relationship represents a correlashy
tion of dimensionless groups it is based upon only one
tube diameter and needs to be substantiated further by
studying other tube diameters and other orifice sizes
34
aoo
400
aoo ~
-~ middot-CLshyJ z
200 -
100
0
ORIFICE CENTER
l~
l
t
I J~
1pound~
I
0 I I~
AT 15 CFM
-
bull ~ 1~6~
~ v~
~
~--~~6
~~~ ___ v v V -_
~ o q
~ I 16
v
~
ogWNSTREANI STANCE
FIGURE 8 EFFECT OF ORIFICE SIZE ON POSITION AND VALUE OF MAXIMUM HEAT TRANSFER
35
50
loshy____ -~
~ ~ -shylltl-shy~ r0
2 10 30
FIGURE 9 CORRELATION OF THE POINT OF MAXIMUM HEAT TRANSFER WITH
ORIFICE SIZE
36
Correlation of Data at the Baffle
The heat transfer data were correlated by obtaining a
relationship between the group (Nu)(Pr)-13 and a
Reynolds number based on twice the clearance (d2 - d1
between the tube and the baffle It was found that the
most satisfactory correlation could be obtained when the
term - d1 was used as the length term in the Reynoldsd2
number
Figure 10 shows the variation of the heat transfer
rate at the center of the orifice e xpressed as a function
of Reynolds number and the orifice size This shows that
for a given Reynolds number the heat transfer at the center
of the orifice is greatest for the smallest orifice size
In order to obtain a general correlation of the data
shown i n F1gure 10 the effect of the dimensionless ratio
d1de was considered This ratio considers all of the
geometric factor s needed to describe the annular orifice
The thiclaless of the orifice plate is also a factor but
was constant i n this i nvestigation
The data for the heat transfer at the baffle center
are shown in Figure 11 in which (Nu)( Pr)-13 is plotted
versus (Re)ebd1 de) 0 55 This data on a log-log plot
lies on a straight line for (Re)eb( dld8 )0 55 greater
than 3 x 104 The equation for cor relating the heat
37
4XI~middot~-r~------~--~~------~
Icf t--to_+--_c-c-________ SYMBOL SIZE
0 1~4
6 ~~
9 ~~ -o ~
(Re)eb
FIGURE 10 RATE OF HEAT TRANSFER AT BAFFLE CENTER
38
500
0
4 0 lcf
~ ~
~ ~iC-
~ ~
~IL 0~ 0 SYMBOL SIZE-
p 0 1364-
r 6 1~16 -~ -
9 1~16 --o 1~16
I I
FIGURE II CORRELATION OF HEAT TRANSFER DATA AT BAFFLE CENTER
39
transfer at the center bullOf the a nnular orifice was found by
the method of least s quares to be
(Nu)( Pr)-1 3 = 0018 ( Re)ebO Bl( dlde)04~ (23)
3 x 104 ltRe)eb(a1de)055 lt 105)
Rate of Heat Transfer at the Point of Maximum Heat Transfer-The heat transfer rate at the point of maximum heat
transfer is plotted in Figure 12 to show the variation with
Reynolds number and the size of the orifice It is shown
gives the h1gh st heat transfer ~ate at its point of maxibull
that for a given Reynolds number the smallest orifice size yen il
mum heat transfer
The data ~or the maximum poi~t could be correlated by
plotting (Nu) Pr)-13 versus (Re)eb(d1de)06 This plot
is shown 1n Figure 13 and the resulting eurve shows that
(Nu(Pr)-13 is not a simple p0wer function of the Reynolds
number as was the case for heat transfer at the baffle
center The reason for this is probably because other
factors such as intensity and scala of turbulence should
be considered At the orifice center the streamlines of
the flowing stream are converging_ and thus the flow is
quite stable Downstream from the orifice is a region of
large eddy currents and probably large scale turbulence
These factors could con ceivably cause the results which
were obtained for the point of maximum heat transfer
40
If)
~middotshy Q_-I z_
10~~~--------r----~~--~--
SYMBOL SIZE
0 13$4
6 1~8
Q 13-18
-o 1~8
7)(104
(Re)eb
FIGURE 12 RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
41
Ia ~
0 I
c ~ ~ c v
~ ~lt w ~
17
~ b
v ~ ( SYMBOL SIZE
-~ 0 f-64 -v ~ 6 t211e
~ Q I~~~
-o - l~rs I I
FIGURE 13 CORRELATION OF HEAT TRANSFER DATA AT THE POINT OF MAXIMUM HEAT TRANSFER
4 2
Effect of Upstream Baffles on Heat Transfer at the Orifice Center
The heat transfer rate at the orifice center using the
single orifice in a test section is a pproximately 13 of the
value that was obtained by Lee (7) using a model heat exshy
changer with orifice baffles Lee investigated the cent r al
baffles of the heat exchanger and thus the coeff icients he
obtained would be affected by the presence of a number of
upstream baffles To determine the effect of upstream
baffles an additional l 516 inch baffle was placed four
inches upstream 1n the test section The resulting data are
shown in Figure 14 where (Nu)(Prmiddot)-13 is plotted versus
(Re) eb for the case of a single baffle 1n the test section
and also the case of an additional baffle placed four inches
upstream Comparison is made with the results obtained by
Lee middot(7) using a four-baffle and a ten-baffle model heat exshy
changer Good a greement is obtained with Lees work and the
results show the marked effect that upstream baffles have on
the downstream heat transfer rate The additional up tream
ba ffle caused sufficient turbulence 1n the test section to
i n crease the heat transfer rate nearly three-fold at the
center of the next baffle
Heat Transfer i n the Test Section with No Orifice
In order to check the accuracy 6f the equipment the
orifice baffle was removed and the heat transfer mea sured
with the probe in the empty test section The data were
43
~~BAFFLES
0 l BAFFLE -shy
ll_9 2 BAFFLES
V 4 BAFFLES-LEE
4 10 BAFFLES- LEE lJf ~
~rv ~~ ~ v flvv ~~
I ~ J ~ L v
0
v
( V
40 3XIo 7XIa
(Re)eb
FIGURE 14 EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER AT BAFFLE CENTER
44
compared with heat transfe r coefficients predicted by the
equations for annuli which are recommended in the litera shy9
ture The two equa~ ions u sed tor comparison were
(hfe)=0 023 (rltGr e (~~ur4 (~r45 (24)
which was presente~ by Wiegant (10)
and ( h ) (cnM~5(M~l o14 o 023 CPG k j Mij - (de GJMb )0 2 ( 2 5)
which was presented by McAdams (8 p 242) The comparshy
i son is s hown in Figure 15 lq (25) gives a value which
is low by about ten percent while Eq (24) g ives values
which are high by as much as twenty -five percent when comshy
pared with the experimental data The se equations are gembull
erally considered to give coefficients with an accuracy of
about twenty percent Therefore the present experimental
data are within the accuracy of these equations Also the
plot indicate s that for a Reynold s number greater than 2 x
104 the slope of the line is the same for the experimental
data as for the equations
Pressure Drop Data
The total pressure drop across the orifice was measured
as a function of the flow rate and the orifice size The
pressure drop was expressed as a d1mens1onleas quantity r)
which ie plCltted ver sus the Reynolds number in Figure 18
The pressure drop function cent correlates for all or1f1oe
45
200
100
s z
10 5XI10 10
0 EXPERIMENTAL
--McADAMS
-WIEGAND L
V
~ ~ ~
P ~ ~
LL~ L
v~
~
v v
v 1 ~ ~ v
v -gt
~
~ ~
~
6Xid
FIGURE 15 HEAT TRANSFER WITH NO BAFFLE
46
0 1~4 -~ a 6 t216
Q t316 lJ J
-0 as a )t
A LEE I -shy SULLIVAN 8
p
10bull
BERGELIN
I _ll I
I ~
i I
~middot
lo II
f fl
J j
~middot
A)101
1q
I Ill
1 I3 X 10ao1
FIGURE 16 ORIFICE PRESSURE DROP FUNCTION VS REYNOLDS NUMBER
47
sizes- The present data extends the range covered by preshy
vious workers and agrees well with their work The preshy
vious work of Lee () for a heat exchanger containing 10
orifice baffles and also the data of Su livan and Bergelin
(9) for pressure drop in a model heat exchanger with a
single baffle is shown 1n Figure 16 long with the present
results~ This figure may be used to predict the preseure
drop from the equivalent Reynolds number of the annular
orifice
The pressure drop between individual points 1n the
vicinity of the orifice and an upstream pressure tap wa s
measured to obtain a pressure drop profile As might be
expected 1n all cases the profiles showed a rapid decrea e
in static pressure immediately upstream from the orifice
There was however little or no recovery of the pressure
loss downstream The 1 364 inch orifice did show a maxishy
mum point in the pressure drop but this maximum occurred at
the orifice center and total recovery was reached about 12
inch downstream
Heat Transfer at the Baffle and Maximum Point as a Function of Pressure Drop
In order to compare the effect of the total pressure
drop on the heat transfer at the baffle and the point of
maximum heat transfer Figure 17 was plotted showing
(Nu)(Pr)-13 as a function of the total pressure drop This
shows that for a given pressure drop the largest orifice
48
1200
1000
~ a -sshyz-
100
60 100 700
AT MAXIMUM POINT I 15116 2 13116 3 1~6 4 1364
AT ORIFICE CENTER
60
1
v
r ~ ~ ~
5
~
8 7
13116
8
~
1364
v
~
e6
1~6
v
~~ v ~ ~ -~ ~
~
~ v
l
~
vamp
I ~ ~
~
v L ~
v
I-
5
k= ~~
~ ~ ~
--I
v ~
FIGURE 17 HEAT TRANSFER AT THE BAFFLE AND MAXIMUM POINT AS A FUNCTION OF
ORIFICE PRESSURE DROP
49
size has the greatest heat transfer coefficient This is
true at both the orifice center and at the point of maxishy
mum heat transfer
Another comparison can be made by plotting the heat
transfer coefficient and the pressure drop versus the orishy
fice size at a constant flow rate Figure 18 shows this
plot This graph shows that at a constant flow rate the
pressure drop as well as the heat transfer coefficient
increases as the size of the orifice is decreased In
choosing an orifice size for maximum efficiency 1t would
be necessary to know the pumping power available as well
as the heat transfer desired
70 I I 700
AT 15 CFM 60 ---
~ aug
50 ---
NV
40 ~
~ ~ ~
~ _
MAXIMUM POINT ---- --- ~
1-----t---~ _
~00Qj ~
~t--- ORIFICE CENTER 10 1100
1---~ n
u0 01 02 03 Q35
a ltl
de inches
FIGURE 18 VARIATION OF HEAT TRANSFER RATE AND PRESSURE DROP WITH ORIFICE SIZE AT A CONSTANT FLOW RATE
cn 0
51
CHAPTER VI II
SUMMARY OF RESULTS
This study revealed several significant facts about
the heat transfer in the vicinity of annular orifices
Probably the most important contribution was the presshy
entation of the heat transfer profiles in the vicinity ot
the annular orifice ~ r s shown that t~ local heat
transfer coeffieient re~ches a maximum at a point downshy
stream from the orifice The distance downstream at which
this maximum oocurs is t1ven by the equation
22
The heat transfer coefficients at the center of the
orifice were correlated and found to follow the equation
(Nu)(Pr)-13 = 00176 (Re)eb08l(d 1de) 0 middot4~ (23)
3 x 104 lt( Re) 9 b( d1d6 )055 ltlo5 )
The heat transfer at the point of maximum heat trans
fer for each orifice size was correlated and presented in
Figure 13 as a plot of (Nu)(Pr)-l3 versus (Re)eb(d1de) 06
No simple po-orer relationship exists between the terms
Intensity and scale of turbulence downstream from the orishy
fice are probably important factors which affect the heat
transfer
The large effect of an upstream orifice on the heat
transfer rate at the second orifice was demonstrated by the
52
study of two 1 516 inch orifices in the test section The
added turbulence at the center of the second orifice was
found to raise the heat transfer rate almost three times
over that obtained for a single baffle
The pressure profiles in the vicinity of the orifice
indicate that nearly all the pressure drop occurs at the
orifice center~ Total pressure drop data were correlated
by a pressure drop function cent as a function of the Reynolds
number and good agreement obtained with the results of other
workers
The pressure drop and heat transfer data were correbull
lated by plotting the heat transfer as a function of the
pressure drop for each orifice size It was shown that for
a given pressure drop the largest orifice size gives the
greatest heat transfer coefficient
As a final presentation it was shown that the pressure
drop and the heat transfer coefficient both i ncrease i n
value at a constant flow rate as the orifice size is de shy
creased This is important in choosing the optimum clearshy
ance for orifice baffles
53
CHAPTER IX
RECOMMENDATIONS
A great deal of work remains to be done in the field of
evaluating shellmiddotside heat transfer coefficients This
study included only one tube size and air was the only f luid
used It is recommended that further studies be conducted
using other fluids and tube sizes It will also be necessary
to study several baffle types
The adde d turbulence due to a s e cond baffle placed upbull
s t ream would suggest that the heat transfer coef ficients at
a certain position i n relation to a baffle would increase as
the flow progressed through the exchanger It is recomshy
mended that an extensive s t udy should be made between baffles
the full length of a model heat exchanger
It is further recommended that the pressure drop study
be continued to include other fluids tube sizes and baffle
arrangements
Effects of turbulence downstream from the baff le should
be studied by i n vestigations with hot-wire anemometer equipshy
ment to determi ne t urbulence scale and i ntensity
54
NOMENCLATURE
Area of heat transfer
Heat capacity of the fluid
Outside diameter of the tube
Orifice diameter
Equivalent diameter of the orifice (d2 - dl)
Inside diameter of the test section
Inside diameter of the tube
Gravitational constant
G Mass velocity
h Local heat transfer coefficient
Coefficient of heat transfer from surface to fluid
i Direct current amperes
k Thermal conductivity of the fluid
L Distance downstream of the point of maximum heat transfer
p Absolute pressure
L P Total pressure drop across the orifice
Q Flow in cubio feet per minute at 1 atmosphere and 680 F
q Heat transferred
Thermal energy conducted into the sensing probe
Thermal energy radiated from the resistance ribbon
Resistivity of the resistance ribbon
s Length of the resistance ribbon
T Temperature oR
55
t Temperature of the resistance ribbon deg F
ta Temperature of the bulk stream oF
tw Wall temperature of the tube OF
U Veloc ity of the fluid
w Width of the resistance ribbon
z Thickness of the resistance ribbon
eeuro Density of the fluid in the test section
Density of the fluid at the flow orificef 0
AL Viscosity of the fluid
E9 Angle measured around the tube
Dimensionl ess groups
(Nu) Nusselt number hd1k
(Pr Prandtl number C~k
(Re)eb Equivalent Reynolds number at the baffle (d2 - d1 )uejt-Lshy
(Re)e Equivalent Reynolds number in the test section ( d 8 - d 1 )U fu
cent Orifice pressure drop function 2(~P ) gc~av(d2 - d1) 2
Al
56
BI BLIOGRAPHY
1 Ambrose Tommy W Local shell-side heat transfer coefshyficients in baffled tubular heat exchanger PhD thesis Corvallis Oregon State College 1957 183 numb leaves
2 Bell K J and o P Bergelin Flow through annular orif ices Transactions of the American Society of Mechanical Engineers 70593-601 1957
3 Colburn Allan P A method of correlating forced con shyvection heat transfer data and a comparison with fluid friction Transactions of the American Institute of Chemical Engineers 24 174-210 1933
4 Dittus F w and L M K Boelter Heat transfer 1n automobile radiators of the tubular type University of California Publications in Engineering 2443-461 1930
5 Gurushankariah M s Local shell-side heat transfer coefficients in the vicinity of baffles in tubular heat exchangers Masters thesis Corvallis Ore gon State Colle ge 1958 97 numb leaves
6 Knudsen James G and Donald L Katz Fluid dynamics and heat transfer New York McGraw-Hill 1958 576 p
7 Lee Kyu Sung Local shell-side heat transfer coeffishycients and pressure drop in a tubular heat exchanger with orifice baffles Masters thesis Corvallis Oregon State College 1959 118 numb leaves
8 McAdams William H Heat transmission 3d ed New York McGra ~-Hill 1954 532 p
9 Sullivan F W and 0 P Bergelin Heat transfer and fluid friction in a shell-andbulltube exchanger with a single baffle Chemica l Engineer ing Progress Symposium Series 52 ( 18) 85-94 1956
10 Wiegand J H Discussion on annular heat transfer coshyef f icients for turbulent flow Transactions of American Institut e of Chemical Eng i n eers 41147-153 1945
AP PENDIX
57
TABLE III
CALCULATED HEAT TRANSFER DATA
Baffle Hole Diameter Run No (inches)
1 - 59 1 364
60 - 102 1 216
103 - 138 1 316
139 - 206 1 516
207 - 212 No orifice
213 - 218 2nd - 1 516
TABLE III
CALCULATED HEAT TRANSFER DATA
Local Heat Transfer Coefficients Run
T0 bull Po s ition CFM hr h2 h3 h4 hs he ~ hav Nuav
1 c 1026 10 59 1476 16 09 1559 1510 1435 1203 1518 8511 2 1290 1369 1738 1878 18 05 1755 1689 1515 1773 9964 3 1416 1636 198 1 2068 1977 1924 1845 1715 1959 11030 4 1627 1991 2301 2382 2268 2194 20 ~98 1929 2249 12664 5 1776 2252 2669 2863 2713 2517 2338 2126 2620 14759 6 l2ttD 1109 2311 3317 3386 3373 3387 3394 3071 3371 18888 7 1258 3089 4583 4866 4683 4701 4643 4194 4695 26301 8 1433 38 8 5 55 83 5791 5495 5430 5436 5008 5547 31192 9 1681 4992 7378 7649 6980 6864 6870 64 28 7148 40180
10 1 D 1102 2371 3332 3511 3356 3342 3427 3102 3394 19012 11 1308 3218 4379 45 24 42 53 4255 4373 3965 43 57 24446 12 14 64 38 58 5146 5142 4839 4787 4903 4597 4963 278 79 13 1706 5218 6664 6269 58 81 5884 6237 5973 61 87 34718 14 15
1 l2D 1115 1275
2131 2661
2955 3638
2972 3720
2941 3675
2913 3576
28 22 34 74
2613 3278
2921 36 17
163 09 20246
16 1498 34 87 4644 4503 4441 4371 4343 4194 4460 25010 17 1695 4449 5743 5324 5222 5154 5157 5015 5320 298 97 18 2D 1049 1715 23 90 2550 2610 2656 2624 2208 2566 14363 19 1241 2117 2964 3145 3218 3221 3203 2759 3150 17757 20 1532 28 67 3936 4100 4188 4201 4167 3676 4118 23224 21 1674 3459 4508 4598 4746 4795 4792 4299 4688 26337 22 lU 1074 253 340 380 3 86 388 377 354 374 2097 23 1287 292 392 433 440 441 429 406 427 2394 24 1508 322 439 492 498 499 487 461 48 3 2713 25 18 07 3 38 464 519 5 24 520 499 463 5 05 28 40
~~ (]I agt
TABLE III Continued
Run No Position CFM h 1 h2 ~3 h4 h5 h6 ~ h
av Nu
av 26 c 1029 1171 1491 1589 15 28 1 4 62 1377 1293 1489 83 44 27 1266 1395 1746 1853 18 02 1685 1556 1453 1728 9704 28 1430 1637 2037 2175 2060 1909 1735 1591 1983 11159 29 1729 1982 24 96 2751 2507 2268 2030 1886 2410 13579 30 12D 1054 2934 4041 4321 4326 4423 4359 3706 4298 24160 31 1294 3385 4 8 26 52 42 5326 5450 5277 4566 52 24 293 50 32 1431 3784 5347 5721 57 bull75 58 44 5700 5084 5677 31870 33 1770 52 75 7 7 33 87 35 9005 9007 8267 7059 85 49 48050 34 lD 1058 3235 4401 4444 3877 3496 3451 3294 3934 21973 35 1263 38 98 5484 5330 4347 3964 3981 3987 4621 25823 36 18 36 6701 89 17 7855 6369 5597 5769 6283 69 01 38718 37 1 12D 1029 2404 31 8 2 3333 3459 3624 3577 3045 3435 19264 38 1315 3182 4033 4162 4310 4496 4502 4015 4301 24142 39 1426 3628 4389 4510 4573 4760 4804 43 8 5 4607 25678 40 1757 4547 5559 5(35 5931 6282 63 70 6060 5975 33471 41 2 11D 1080 2034 28 38 3155 3144 3145 2966 2540 3050 17027 42 1305 2650 3 4 87 3aoz 3595 3751 3595 3153 36 46 20405 43 1434 3167 39 07 4156 4371 4320 4126 3709 4176 23395 44 1804 4096 4 9 66 5691 5714 5586 53 15 48 65 5454 30582 45 12U 1088 409 516 557 564 5 60 535 513 5 46 30 67 46 1318 470 579 6 22 631 6 17 5 97 579 6 09 3422 47 14 13 540 640 676 6 86 681 6 60 6 54 6 69 3754 48 1773 641 740 774 782 7 69 749 746 763 42 87 49 l 11 U 1054 270 356 391 397 393 3 71 346 38 2 2133 50 1240 303 399 446 449 447 4 21 398 432 2420 51 1419 361 476 522 530 528 507 467 493 2760 52 1 1(2U 1032 236 311 342 347 344 325 301 334 18 78 53 1314 270 366 403 407 408 386 351 394 2217
(Tt tO
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ h av Nu av
54 1448 301 408 447 454 452 431 403 438 24 61 55 1782 353 494 548 544 415 529 531 506 2843 56 2U 10 61 220 287 316 320 322 303 268 310 1735 57 1216 249 335 370 377 378 353 307 363 2044 58 1322 263 356 394 398 399 374 327 384 2159 59 1639 310 433 478 481 482 452 393 465 2617
60 1D 10 68 2011 2536 2657 2681 2694 2560 15 62 2625 14938 61 1399 2520 3239 3369 3371 33r82 32 39 1946 3320 18968 62 1669 2781 3655 3820 38 76 3883 3738 2355 3794 21712 63 1959 3524 42 37 4399 4438 4497 4417 3047 4397 25156 64 2295 4426 5288 5396 5372 5240 5410 3369 5341 30680 65 2636 5490 6531 6662 6565 6379 6820 4249 6591 37938 66 3390 7869 9538 9462 9387 8924 10508 62 91 9564 59601 67 1U 1190 352 368 401 413 407 395 293 397 2256 68 1559 397 422 462 475 471 456 331 4 57 2603 69 1904 434 465 5 13 529 528 504 358 508 2901 70 2211 493 526 573 5 92 588 564 4 15 569 3257 71 2289 569 587 6 30 649 6 61 6 49 460 635 36 44 72 2727 637 6 60 7 09 733 751 743 521 719 4140 73 3210 728 755 8 15 8 43 8 62 8 54 616 826 4765 74 2nD 1210 181 2256 2393 2399 2333 2206 1325 2317 13158 75 1420 2340 2752 2899 2913 2850 2728 1701 2828 16121 76 1692 2853 3306 3452 3471 3379 3217 2134 3365 19217 77 1894 3102 3588 3713 3736 3670 3557 2455 3653 20892 78 2301 3682 4259 4433 4467 43 83 4289 2892 4366 250 30 79 2621 4117 4828 5017 5012 5030 5109 3071 4999 28785
m 0
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ hav Nuav
80 3230 5158 6006 62 13 61 18 6134 6695 4094 6233 359 87 8 1 12nD 1155 15 27 1854 2028 2064 20 85 1987 1164 1968 118 31 82 1689 2046 24 8 2 2688 2739 2760 2658 1749 2665 152 73 83 1244 2088 2317 2339 2345 2373 2381 1487 2351 13432 84 2100 3211 3539 34 21 3462 3512 3696 2575 3526 20284 85 2292 3 5 05 3761 3648 36 25 36 79 3957 2933 3734 21517 86 2907 4420 48 22 4679 46 04 4705 5206 3792 48 03 27741 87 33 80 59 35 69 38 7404 77 10 7 8 36 7 0 86 5190 7394 427 44 88 1 12D 1 4 27 2 4 58 28 31 3037 3021 2987 2927 18 57 2 9 61 16913 89 18 75 34 75 3 9 87 4230 4255 4317 4337 2734 4225 24258 90 22 59 4221 4796 5046 5052 51 01 5389 3491 5077 29206 91 2682 4978 5664 5943 5966 6054 6573 408 1 60 40 34795 92 3417 63 16 71 02 7 3 93 7385 75 40 8 6 95 51 45 7623 44017 93 c 1 5 17 1240 1305 1399 1467 1479 1429 9 26 1423 8251 94 20 34 1554 1623 1720 18 21 18 53 18 72 1215 1778 10229 95 2 3 48 1795 1843 198 5 2097 2171 2274 1540 2074 11947 96 2716 2028 2048 22 01 2 3 44 2444 2661 18 90 2340 13505 97 3247 2410 2375 2663 2778 2949 3298 2378 2793 1615 98 11 35 967 1040 1124 1186 1200 1142 728 1138 6496 99 14 06 1135 1220 1318 1384 1403 1 3 61 8 77 1336 7656
100 2311 1 8 54 18 78 1980 20 90 2136 2227 1653 2062 118 31 10 1 2666 2085 2094 2227 2 3 62 2438 2626 1902 2349 13508 102 3392 2635 2582 28 01 3026 3141 3529 2567 3016 17390
103 1 U 1235 349 395 434 436 4 28 411 286 423 2416 104 20 10 434 5 02 559 577 569 5 37 345 552 3177 105 28 14 538 626 685 711 7 21 682 424 6 8 6 3966
Q) j-J
TABIE III Continued
Run No Position CFM h1 h2 h3 h4 h5 hu h7 hav Nuav
106 3492 614 7 1 6 7 84 8 13 8 33 7 85 4 88 7 87 4562 107 4395 7 86 894 964 996 1005 9 64 640 9 65 56 06 108 50 75 9 11 10 22 1081 1112 1125 1085 7 24 1085 63 16 109 G 1344 9 22 1042 1120 1 1 46 1173 1131 7 04 1120 63 87 110 1936 1162 1340 1442 1474 1509 14 7 3 9 09 1441 82 77 111 2846 1631 1797 1902 1966 2027 2079 1342 19 2 3 11108 112 3484 207e 2144 2236 2307 2385 2574 1694 2268 13138 113 4066 24 65 24 42 2535 2648 2757 31 71 2178 2 5 96 15078 114 50 12 3059 2916 30 1 5 3176 3312 4059 2849 3105 180 46 115 1D 1362 2268 26 13 2613 26 35 2605 2503 15 46 2617 14934 116 1958 2993 3580 3580 3586 3539 3 5 02 2144 3571 20492 117 2812 4430 50 32 4913 4 9 86 4991 5196 3088 4981 287 66 118 3432 58 16 62 13 6067 61 18 60 66 6698 4143 61 16 354 16 119 40 22 71 71 7 4 62 7369 7419 7329 82 74 51 8 1 7395 42909 120 5026 105 95 11456 115 81 11574 11548 14010 80 91 11540 671 15 121 2D 1244 18 57 2277 2363 2305 2210 2107 1466 2289 13038 122 1960 2622 3240 3388 33 23 3226 31 40 2)99 3294 18919 123 2817 3762 45 87 4739 46 56 45 14 4 6 47 30 15 4624 26689 124 3491 50 22 5723 58 53 57 44 5542 60 18 3871 57 16 330 73 125 4096 61 29 68 16 69 79 6805 65 90 74 79 4677 67 98 39400 126 5037 82 27 94 60 95 69 93 57 9023 11324 65 05 93 52 542 83 127 12D 1278 14 70 1 6 48 1652 1638 1 6 34 1641 9 73 1 6 43 9369 128 1947 19 63 2155 2149 2151 2131 2190 1347 2147 12342 129 2769 2615 2791 2773 28 52 2716 2954 18 96 2783 1 60 82 130 3439 3208 3265 3239 3593 3133 3624 2515 3308 19174 131 4103 3637 35 88 3577 4077 3459 42 66 3138 3676 21343 132 49 78 45 82 44 60 44 8 1 55 17 43 25 5749 4227 4700 27288
Q) tlgt
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
133 1 12D 1299 2094 2507 2622 2625 2567 2489 1465 2578 14736 134 1973 29 56 3505 3772 3790 3718 3718 2115 3700 21290 135 2788 3941 4727 5069 5099 5 0 07 5231 2984 4976 28781 136 3473 5155 59 81 6308 6339 62 39 68 96 4204 6217 36052 137 4118 6135 71 8 6 7662 7731 76 91 87 16 49 8 5 7568 43985 138 4973 7765 94 75 10396 10861 10694 13646 66 64 10357 602 25
139 1ttn 1253 1242 1493 1460 1442 1431 1424 8 84 1457 83 01 140 2366 1942 2150 1961 1910 1897 19 62 1206 1980 11400 141 3461 3007 2957 2562 2513 2606 3143 18 51 2660 15400 142 4325 3942 3571 3060 2999 3198 4248 2631 3207 18618 143 5677 508 6 4359 39 88 3800 42 29 57 78 36 26 4094 23824 144 67 59 64 55 5330 4988 47 25 5494 2517 48 09 5134 29906 145 84 08 9326 72 26 7726 85 56 9172 12319 7733 8170 47626 146 86 54 9831 7582 818 9 94 90 9869 13116 78 97 8783 512 96 147 7376 7335 58 7 6 5941 5796 68 29 81 65 5954 6111 35662 148 2 11 D 4254 4106 48 02 4994 5038 5042 56 78 3419 4969 28881 149 5708 5487 6253 6466 6524 6527 78 63 45 8 2 64 43 37566 150 69 7 8 7983 9440 9848 98 34 97 32 13249 6701 9714 566 59 151 1254 1434 18 53 1947 1915 1850 1760 1186 1891 10772 152 2713 2696 3175 32 94 3288 3237 3288 20 44 3249 18728 153 87 30 118 07 14733 15758 15504 15305 26297 9617 15325 892 71 154 5811 5278 6543 6861 69 30 69 82 7 8 74 4478 68 29 39531 155 4246 3780 4736 4975 49 66 4936 5162 3113 4903 28301 156 (v 1270 8 15 935 959 966 9 51 9 23 6 35 953 5430 157 2714 1164 1390 1427 1447 1454 1455 9 08 1430 8242 158 4310 1655 18 96 1942 1988 2002 2111 1305 1957 11349
(j) ~
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 fry hav Nuav
159 6012 2208 2400 2450 2513 2548 28 20 18 00 2478 14416 160 7279 2696 2881 2927 2989 3081 3599 2340 2970 17326 161 86 90 3257 3360 3 3 76 34 26 3558 4455 2943 3430 2000 162 12D 4368 2209 2600 2558 2518 2466 2774 1753 2536 14713 163 5833 2730 3092 3028 2974 2913 3501 2287 3002 174 78 164 7643 3320 3681 3630 3651 3530 4623 3181 3623 21116 165 87 39 3920 4303 4300 4708 4178 61 60 3937 4372 25456 166 1268 962 1203 1205 1186 1118 1084 725 1178 6693 167 2678 14 67 1785 1779 1752 1698 1726 10 70 1754 88 49 168 1 12D 12 83 936 1217 1414 1397 1239 1190 7 65 1317 7484 169 2729 2502 2930 2914 2934 2956 2979 17 52 2934 16866 170 4345 3884 4357 4283 4318 4421 4836 28 59 4345 25151 171 6036 5546 5858 5764 5791 6028 7129 4184 5860 34045 172 6578 7167 7769 7907 79 82 8263 10492 5915 7980 46437 173 87 84 10237 112 23 120 26 12727 12968 185 19 85 98 12236 71103 174 1278 1344 1803 18 72 1835 1790 1712 1063 1825 10355 175 2711 2328 2972 2932 2893 28 78 2863 1667 2919 167 51 176 4351 3934 4414 4353 4281 4321 4654 28 63 4342 25088 177 5994 5076 5824 5838 5818 59 29 6914 4205 5852 33885 178 1 11 U 1223 388 432 465 464 449 435 338 453 2585 179 2351 521 602 6 22 675 6 57 619 436 639 3687 180 34 48 6 05 1725 803 8 27 8 11 760 518 792 4593 181 4513 718 850 934 9 68 9 57 8 99 609 9 27 5386 18 2 5714 8 32 981 1060 1102 11 06 1034 6 59 1062 61 82 183 6997 1025 1182 1258 1295 1309 1234 8 18 1261 7 3 44 184 8709 1295 1487 1 5 42 1594 1626 1612 1156 1562 9080
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
185 2 12D 4249 3560 4400 4670 4791 4695 47 81 2931 4639 268 37 186 5737 4926 58 54 61 92 6248 62 38 67 78 4134 6131 35590 187 7432 6390 7726 83 46 85 44 86 34 10371 5658 8313 48310 188 8723 7718 107 88 11933 12099 13046 186 22 79 39 119 67 69505 189 1 4 35 1340 1735 18 57 18 52 17 81 1711 1144 18 06 10256 190 2718 2399 3023 3187 3207 3138 30 53 1931 3139 18025 191 7 5 07 6189 80 11 9200 9427 9703 11364 5720 9085 527 38 192 8544 78 42 10666 125 42 13312 13775 178 20 6976 125 74 729 86 193 1287 1417 16 97 18 7 18 69 18 08 1720 1046 1800 10223 194 27 17 2450 2940 3187 3214 3157 3054 1749 3125 17954 195 42 53 3560 4222 45 90 4679 46 63 4743 2741 4539 26247 196 6068 48 69 57 79 6335 65 8 6 66 04 7172 4338 63 26 366 78 197 7389 58 86 72 8 6 82 23 8584 8936 10658 50 60 8257 4798 6 198 86 88 78 91 100 27 120 56 130 29 14299 190 81 6492 12353 71850 199 5864 4694 5 6 67 61 94 6419 65 48 7192 3950 6207 360 14 200 2 D 4177 38 36 4547 48 09 4775 4628 5006 2715 46 90 261 30 201 5712 5170 62 39 66 38 6599 6604 7518 4167 65 20 378 00 202 73 63 7201 8986 98 43 9733 9914 13353 6219 9619 55810 203 8604 10043 13118 148 41 150 42 158 66 25206 82 5 3 14717 85290 204 12 68 1506 18 41 1971 1966 1868 1799 11 42 1913 10880 205 2659 2571 3127 3276 32 50 3130 3069 18 80 3196 18 350 206 39 80 36 76 4347 4573 45~67 4473 46 34 28 37 4490 25910
o 207 Orifice 11496 10 64 1360 15 39 1 5 80 1 6 15 1496 8 58 15 24 88 83 208 9433 8 95 11 78 13 26 1394 1386 1263 727 1346 78 48 209 7387 746 9 77 1123 1184 1159 1048 6 11 1111 64 74 210 52 36 566 7 66 900 934 909 8 21 499 8 27 48 02
0) CJ1
TABLE III Continued
Run No Position CFM h 1 h2 hs h4 h5 h6 h7 hav Nuav
211 212
3309 1293
414 257
563 3 19
6 68 3 57
6 91 3 37
6 72 351
7 37 337
38 4 2 46
4 40 341
3748 1942
213 214 215 216 217 218
c of 2nd 1 516 1235
1919 2712 3320 4153 4704
1532 2447 35 46 4312 5567 74 29
2 1 87 3312 4225 52 86 6902 8 6 50
2360 3555 4340 56 12 7 0 49 8 9 40
2409 3598 4 8 85 5718 7713 9593
2347 2101 35 33 3453 48 00 49 62 5562 59 86 72~6 7 8 79 93 76 11237
1243 20 64 3054 4 2 8 1 5114 6983
2326 35 00 4638 5545 7225 91 40
132 13 200 27 26672 31968 41711 52811
bull
67
TABLE IV
PRESSURE PROFILE DATA
Baffle Flow Qpening Rate ~p
(Inches) Position (CFM) (Inches 295 S G Fluid)
1 364 l2 11 U 1012 0 254 1248 0197 1493 0 141 1718 0112
c 1000 9 80 1210 1710 1436 28 75 1746 4320 1011 1080 1277 2050 1393 3020 1 6 28 4450
12D 1011 9 75 1236 1520 1450 2510 1603 3450
1 D 1011 975 1256 1700 1480 2690 158 1 4070
1 12D 1010 950 1259 1750 1462 2650 1631 3710
2 11 D 1124 1315 1360 2130 1505 2850 1689 4125
1 216 12U 1294 045 1949 0324 2374 0282 2704 0225 3367 0169
c 1326 265 18 81 5 90 2313 990 2731 1480 3439 2660
12D 1272 2 49 1957 661
68
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Pos ition (CPM) Inches 2 95 S G Fluid)
2559 1275 3033 1940 3639 3025
1 216 1nD 1257 242 16 96 476 2117 8 05 2561 1280 2990 1895 3431 26 bull00
1 316 12U 1309 0 479 2004 0422 28 28 0 352 3526 0281 42 28 0225 5199 0225
c 1308 1 43 1998 272 28 14 5 10 3478 795 4248 1235 5048 1885
l2D 1286 140 2005 3 45 2831 725 3495 1180 4194 1805 5046 2945
1 11D 1322 150 2039 352 2841 735 43 77 1980 5378 3440
1 516 12U 1278 0493 2732 0493 4315 0408 5744 0352 7494 0352 8932 0422
c 1300 0 506 2731 1985 4310 348 6080 6 45
69
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Position (CPM) (Inches 295 SG Fluid)
7607 1090 8830 1585
l2D 1343 0549 2738 225 4566 583 6112 1195 7536 2055 9043 3415
1 516 1uD 1249 0464 2713 224 4155 579 5620 1150 7428 2115 90 70 3405
1 12D 1301 0493 2735 220 4501 616 61 50 1235 7440 2065 8862 3445
2D 1265 0 478 2750 226 4366 594 6578 1270 7678 2240 8945 5280
2 12D 1295 0493 2725 222 4293 600 5807 1120 7568 2200 9070 3615
TABLE V
RATE OF HEAT TR AN SFER Ar THE BAFFL~~ CID-TT ER
Orifice Size
(Inches)
Flow Rate
( CFM)
Re d e G tU
R~) 055 Nuav NuPr-l3
1 364 10 26 12 90
8 075 10015
43400 54 600
85 11 99 64
95 83 112 19
1416 11 140 59 900 110 30 124 20 16 27 12 800 68 900 126 64 142 60 17 29 13 610 73 200 135 79 152 90 17 76 13980 75 200 147 59 166 19
1 216 11 35 14 06
8 600 10 660
27000 33500
6 4 96 76 56
73 14 8 6 12
1517 11500 36100 82 51 9291 20 34 15400 48400 10229 115 18 23 11 17500 55000 118 31 13322 2348 17 800 55900 11947 13452 2666 20 200 63400 13508 15210 27 16 20 600 64700 135 05 152 07 32 47 24600 77200 161 57 18 193 3392 25 700 80700 17390 195 8 1
1 316 1344 19 36
9898 14 260
24800 35 700
63 8 7 8 2 77
71 92 93 20
28 46 20 9 60 52 500 111 08 125 08 34 84 25 660 64200 131 38 147 93 40 66 50 12
29900 36900
74800 92400
150 78 18046
169 78 203 20
~ 0
TABLE V Continued
Orifice Flow Re Size Rate d e G R~rmiddot55 NuPr-13(Inches) (CFM) U Nuav
1 516 12 70 8 847 16800 54 ~0 61 14 2 14 18 900 35800 82 42 92 80 43 10 30 000 56900 11349 127 79 60 12 41900 79400 14416 16232 7279 50700 96100 17326 19509 86 90 60540 115000 20098 22529
TABLE VI
RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
Orifice Size
(Inches)
1 364
1 216
1 316
Flow Rate
(CFM)
1054 1294 1431 1681 1770
1068 1399 1669 1959 2295 2636 3390
1299 1973 2788 34 73 4118 4973
Re deG Mshy
8 300 9870
11260 13200 13 930
8100 10600 12650 14850 17400 19980 25700
9 570 14500 20500 25600 30300 36600
R~r-6 51900 61700 70500 82 500 87 100
28200 36900 44000 51700 60 600 69500 89400
26100 39600 56000 69900 82700 99 900
Nuav
2416 293 5 3187 4018 4805
14938 18968 21712 25156 30680 37938 59601
14736 21290 28781 36052 439 85 60225
Uu Pr-1 3
27204 33050 3589 4524 541 0
16820 21358 24448 28326 34546 427 18 67111
16593 23973 32407 40595 495 1 678 13
TABLE VI Continued
Orifice Flow Re Size Rate deG R~rmiddot6 NuPr-13(Inches) (CFM ) M- Nuav
1 516 1268 88 30 17700 108 8 1225 2689 18700 37400 1835 2066 3980 27700 55700 2591 2917 4177 29100 58 500 2713 3055 5712 39800 80000 378 0 425 6 7362 51300 103000 5581 6284 8 604 59 900 120000 8529 9604
74
TABLE VII
EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER
l 516 Inch Orifice
Center ot 2nd Baffle 4 Downstream
Plow Rate (CFM)
1235 1919 2712 3320 4153 4704
Flow Rate (CFM)
1270 2714 4310 6012 7279 8690
(Re)eb -8600 1321
13400 2003 18900 2687 23100 5197 28900 4171 32800 5281
Center ot Single Battle
-8847 543
18900 824 30000 1135 41900 1442 50700 1733 60540 2001
(Nu)(Pr)-l3
1487 2255 3003 3600 4697 5946
(Nu)(Pr)-13
611 928
1278 1623 1951 2253
75
ABLE VIII
HEAT TRANSFER IN THE TEST SECTION WITHOUT ORIFICE
CFM Ute) 0b h Nu
1293 5-951 3 41 1942
33 09 15251 649 3746
5236 24193 827 4802
7387 34001 1111 6474
9433 43419 1346 7848
11496 52-914 1524 8883
76
TABLE IX
PRESSURE DROP FUNCTION
Orltlee Size Flow Rate incbea ~CFM (Re)eb X 10bull8
1 364 1011 7957 0808 1256 9885 1468 1480 11648 2765 1581 12443 4160 1689 1_3293 4 020
1 216 1257 9530 1327 1696 12858 2663 2117 16049 4615 2561 19415 7581 2990 22668 11560 3431 26011 16440
l 316 1322 9736 1819 2039 15016 4332 2845 20952 9275 3495 25739 15300 4377 32014 26800 5378 39607 50100
1 516 1011 7 957 oaos 1256 9885 1469 1480 11646 2765 1581 12443 4160 1689 13293 4020
77
TABLE X
EXPERIMENTAL DATA
Baffle Hole Diameter Run No
1 - 59
60 - 102
103 - 138
139 - 206
207 - 212
213 - 218
(Inches)
1 364
1 216
1 316
1 516
No Baffle
2nd - 1 516
TABLE X
EXPERIMENTAL DATA
Run Thermocouple Reading s (mv) No Position CFM I tc1 tc2 tc3 tc4 t c 5 tc6 tc7 tcair
1 c 1026 530 2055 1825 1768 1782 1802 1837 1965 1198 2 1290 612 2059 18 65 1809 18 32 1851 1880 1965 1160 3 1416 714 2151 1970 1931 1965 1988 2026 209 5 1130 4 1627 8 21 2235 2084 2 049 2093 2126 2173 2266 1130 5 1776 865 2203 2033 1970 2015 2084 2159 2 264 1121 6 12D 1109 542 1636 1507 1499 1499 1498 1498 1528 1218 7 1258 651 1670 1522 1503 1513 1513 1516 1548 1221 8 1433 750 1625 1480 1467 148 3 1487 1487 1516 1153 9 168 1 8 73 1656 1494 148 1 1511 1517 1517 1543 1159
10 1rtD 1102 485 1545 1450 1437 1446 1447 1442 1466 1220 11 13 08 6 10 1571 1470 1460 1476 1476 1469 1498 1194 12 1464 730 1 623 1509 1508 1528 1 5 32 1524 1548 1173 13 11 06 8 71 1663 1559 158 1 1606 160 6 1 583 1601 1190 14 1 12D 1115 520 1698 1579 1575 1 577 1580 1590 1615 1280 15 1275 6 10 1692 1567 1558 1 561 1570 1580 1601 1234 16 1498 770 1760 1619 1630 1 635 1642 1645 1661 1204 17 1695 912 1775 1635 1670 1689 1686 168 6 1701 1165 18 2D 1049 510 1736 15~2 1567 1558 1 553 1558 1620 1236 19 12 41 610 1655 1517 149 1 148 1 148 1 148 4 1546 1108 20 1 5 32 7 35 1720 1550 1530 1520 1519 1523 158 0 1104 21 16 74 8 8 0 1900 1 727 1714 1696 1691 1692 1753 1169 22 1U 1074 38 5 3 324 2740 2534 2478 2 465 2503 258 0 1210 23 1287 4 35 3510 2 870 2682 2 610 2599 2638 27 1 9 1190 24 1 5 08 470 3 618 2920 2690 2 637 2627 2 664 2747 1177 25 18 07 525 4 088 3235 2962 2905 2910 2988 3130 1169
z ())
TABLE X Continued
Run No Position CFM I tc1 tc 2
Thermocouple Readings te3 tc4 tc5
(mv) tc6 tc7 tcair
26 c 10~29 6 32 2340 2~092 2032 2060 2~097 2152 2~213 1211 27 12 66 679 2270 2 047 1993 2013 2069 2142 2 210 1 182 28 1430 723 2336 2097 2033 2080 2153 2~255 2 356 1 138 29 1729 8 52 2318 2070 1980 2061 2158 2279 2367 1121 30 12D 1054 570 1520 1 4 20 1402 1400 1396 1400 1 443 1159 31 1294 6 69 1599 1469 1444 1439 1433 1 442 1485 1168 32 1430 7 88 1720 1562 1536 1532 1528 1537 158 0 118 5 33 1770 8 81 1641 1488 1450 1~441 1 441 1_466 1518 1 163 34 1D 1058 548 1579 1498 1495 1526 1553 1_557 1 571 1 276 35 1263 640 1609 1509 1515 1570 1599 1598 1 598 1 266 36 18 36 8 47 1538 1452 1483 1553 1602 1 590 1 558 1195 37 1 12D 1029 5 41 1 578 1499 148 4 1473 1461 1465 1-512 1200 38 1315 6 30 159 1 1504 1493 1482 1470 1470 1505 118 5 39 1 4 26 743 1765 168 1666 1660 1645 1642 1678 1270 40 1757 8 54 1744 1648 1634 1620 1598 1 593 - 1612 1223 41 2D 1080 5 30 1734 1604 1570 1 570 1570 1 588 1 640 128 1 42 1305 6 40 1744 1622 1589 1 608 1593 1 609 1 661 1240 43 1434 750 1798 1687 1658 1 636 -1641 1 661 1 711 1_220 44 18 04 8 41 1 764 1666 1607 1605 1614 1 635 1 675 1205 45 12nu 1088 415 2614 2295 2195 2 169 2174 2217 2256 1171 46 1318 477 2805 2477 2371 2342 2364 2 401 2 438 1 163 47 1413 5 28 2930 2 646 2 555 2 526 2532 2570 2 577 1 199 48 1773 550 2740 2518 2450 2431 2448 2 479 2 480 1 170 49 1 11 U 1054 380 3175 2670 2505 2 461 2467 2 534 2 621 1 258 50 1240 420 3268 2738 2 546 2 510 2 508 258 2 2 649 1214 51 1419 451 3364 2B07 2 632 2590 2 590 2 651 2773 1 215 52 1 12U 1032 360 3 165 2 629 2 450 2402 2403 2 473 2 bull568 1 163
--I lt0
TABLE X Continued
Run No Position CFM I tc1 tc2
lhermocoup1e Reading s tc3 tc4 t c 5
(mv) tc6 tc7 tc a ir
5 3 1314 38 9 3178 2592 2411 2367 2361 2432 2555 1140 54 1448 403 3095 2544 238 1 2336 2336 2390 2476 1158 55 178 2 427 3006 2434 2286 2253 255 3 2299 2397 1154 56 2 11U 1061 360 3369 2814 2619 2567 2560 2650 2833 1220 57 1216 360 3044 2512 2338 2290 2288 2374 2566 1150 58 1322 387 3196 2614 2425 2383 2382 2472 2670 1138 59 1639 403 3020 2438 2272 2238 2238 2318 2502 1127
60 1D 1068 612 1552 1424 1400 1395 1396 1426 1745 0945 61 1399 612 1355 1246 1230 1229 1230 1250 1509 0872 62 1669 710 1436 1293 1272 1265 1266 1286 1551 0847 63 1959 900 159 5 1468 1444 14 38 1432 1446 1720 0851 64 2295 730 1169 1105 1098 1099 1108 1100 1298 0781 65 2636 8 80 1202 1129 1121 1126 1 138 1115 1342 0748 66 3390 9 35 1060 o 9s7 0999 1001 1017 0971 1154 0703 67 1nu 1190 370 2225 2188 2104 2080 2120 2209 2 7 15 0990 68 1559 368 2005 1950 1871 18 48 1876 1951 2408 0916 69 1904 368 1870 18 1 4 17 34 1711 1730 18 07 2238 0875 70 22 bull11 471 228 6 2 204 2099 2063 2092 218 $ 2732 0840 71 2289 471 2030 2000 1925 1895 18 96 19 5 2498 0785 72 2727 4 71 1854 18 23 1753 17 23 1716 3758 2241 0743 73 3210 471 1680 1651 158 6 1559 1551 158 1 1950 omiddot7o9 74 2uD 1210 404 1261 1212 1198 1197 1205 1222 139 1 0978 75 14 20 540 1321 1260 1242 1 240 1249 1268 148 7 0918 76 1692 7 18 1467 138 6 1364 1361 1376 1405 1678 0883 77 18 94 903 1708 1 591 1565 1560 1575 1603 1948 0 857 78 2301 903 1530 1432 1407 1402 1415 1432 1738 0815
ro 0
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc117 tcair
79 2621 6 50 1069 1 020 1009 1009 1009 1007 1~189 o739 80 3230 901 1200 1128 1113 1119 1119 1086 1341 0694 81 82
l2D 1155 1689
360 575
1191 1345
1142 1252
1122 1218
1118 1210
1118 1209
1132 1228
1292 1446
0916 0822
83 1244 430 1163 1134 1131 1130 1129 1132 1292 0877 84 2100 645 1175 1135 1147 1 142 1138 1122 1286 0757 85 2292 8 25 1 354 1310 1327 1330 1323 1285 148 6 0728 86 2907 8 23 1180 1138 1151 1158 1149 1107 1268 0687 87 3380 902 1113 1049 1025 1011 1006 1042 1178 0673 88 89
1 12D 1427 1875
480 615
118 2 1140
1140 1095
1124 1077
1125 1075
1129 1072
1137 1072
1290 1243
0880 0790
90 2259 8 41 1296 1231 1207 1206 1203 1182 1419 0757 91 2682 8 80 1231 1170 1149 1147 1142 1112 1350 0731 92 3417 940 1142 1092 1076 1076 1069 1021 1252 0693 93 c 15 17 431 1321 1298 1268 1249 1250 1273 1522 0841 94 2034 505 1285 1263 1235 1209 1205 1206 1464 0759 95 2348 6 10 1395 1379 1334 1302 1286 1268 1536 0732 96 2716 706 1486 1480 1427 1383 1358 1311 1572 0 700 97 3247 7 56 1417 1430 1375 1320 1284 1223 1450 0660 98 1135 400 1425 1388 1352 1329 1330 1 364 1651 0893 99 14 06 440 1379 1341 1304 128 2 1281 1305 1583 0 831
100 2311 680 1602 1593 1553 1514 1502 1480 1 7 27 0 802 101 2666 680 1471 1469 1428 1390 1372 1335 1564 0761 102 3392 798 1491 1 509 1449 1395 1372 1305 1534 0 719
103 1U 1235 410 2469 2295 2173 2165 2226 2361 3120 0 897 104 2010 410 2017 1848 1 737 1706 1747 1865 2582 0753 105 28 14 410 1682 1535 1457 1427 1437 1520 2109 0 660
00 t-
TABLE X Continued
Ru n Thermocouple Rea ding s (mv No Positi on CFM I tc1 tc2 tc3 tc4 tc5 tc6 tc7 tcair
106 3492 440 1649 1499 1420 1391 1390 1470 2042 0620 107 4395 550 18 33 1679 1597 1564 1570 1640 2223 0583 108 5075 588 1779 1642 1580 1550 1552 1 615 2 191 0548 109 c 1344 398 1464 1 399 1364 1353 1350 1380 1689 0 907 110 1936 459 1369 1290 1253 1242 1 237 1259 1574 078 2 111 2846 580 1347 128 5 1251 1232 1220 1215 1 5 23 0 683 112 34 8 4 700 1392 1369 1339 1317 1299 1259 1599 0 636 113 4066 8 13 1449 1458 1427 1391 1363 1270 1595 0 591 114 5012 930 1484 1530 1500 1453 1420 1272 1580 0 580 115 1D 1362 513 1269 1218 1 217 1214 1220 1238 1460 0 893 116 19 58 600 1187 1122 1121 1120 1124 1133 1352 0798 117 2812 705 1052 1008 1015 1010 1011 1001 1218 0691 118 34 32 913 1105 1075 1085 1081 1086 1047 1301 0645 119 4022 980 1038 1021 1026 1023 1029 0983 1211 0 609 120 5026 982 0 8 61 0839 0836 0836 0837 0791 0955 0570 121 2D 1244 475 1320 1246 1233 1240 1255 1275 1434 0925 122 1 9 60 5 50 1160 1088 1074 1079 1089 1100 1260 078 7 123 2817 6 80 1096 1024 1 013 1018 1029 1022 1201 0 700 124 3491 960 1248 1175 1163 1172 1192 1153 1435 0 658 125 4096 989 1141 1089 1078 108 9 1105 1051 1310 0629 126 50 37 989 0983 0933 0929 0 936 0949 0880 1090 0 602 127 128
12D 1278 1947
402 545
1270 1261
1 230 1216
1228 1216
1230 1 215
1235 1223
1242 1219
1483 1514
0 913 0778shy
129 2769 695 1273 1234 1237 1221 1251 1212 1525 0678 130 131 132
34 39 4103 4978
8 40 9 80 9 80
1336 1448 1271
1322 1458 1 288
1328 1 462 1286
1 259 1 356 1157
1353 1492 1311
1261 1329 1138
1 555 160 7 1343
0 629 0 600 0599
(l) l)
TABLE X Continued
Run No Position CFM I tel tc 2
Thermocouple Readings tc3 tc4 tc5
( mv) tc6 tc7 tcair
133 1 l2D 1299 5 16 1 28 1 1212 1196 1195 1205 1221 1478 0869 134 1973 6 15 1163 1098 1073 1071 1079 1083 1343 0751 135 136
27 88 34 73
802 9 -_78
1187 1214
1099 1131
1069 1104
1066 1101
1075 1~110
1l061 1066
1370 1360
0662 0618
137 4118 9 81 1084 1010 0983 0979 0982 o937 1209 0581 138 4973 98 1 0969 0897 0 868 0855 0860 0799 1041 0572
139 1D 1253 409 1371 1293 1298 1301 1309 1321 1578 0928 140 2366 480 1130 1 090 1 121 1130 1137 1132 1390 0744 141 34 61 6 38 1081 1086 1152 1161 1147 1069 1382 0644 142 143 144
4325 5677 6759
7 90 939 998
1110 1115 1034
1161 1208 1139
1253 1268 1180
1265 1302 1215
1228 1230 1123
1080 1056 0970
13$913r12 8
0601 0561 0542
145 84 08 989 0863 0961 0934 0895 0871 0 785 09 9 0530 146 86 54 9 80 0808 0901 0 872 0821 0809 0733 0891 0498 147 7376 9 80 0 927 1032 1027 1 040 0961 0889 1032 0511 148 2D 4254 776 1 050 0 981 0965 0961 0962 0922 1155 0579 149 5708 991 1102 1031 1014 1009 1010 0931 1227 0528 150 69 78 990 0914 0853 0839 0 839 0843 0759 0996 0521 151 1254 490 1 479 1352 1329 1334 1351 1379 1607 0930 152 2713 7 00 1310 1220 1201 1201 1211 1209 1516 0723 153 8730 991 0809 0756 0742 0745 0 748 0663 0874 0543 154 5811 966 1219 1108 108 6 1081 1079 1033 1330 0650 155 42 46 8 02 1248 1136 1114 1114 1118 1103 1376 0 699 156 c 1270 429 1671 1571 1551 1545 1563 1600 1933 0929 157 2714 488 1398 1285 1 267 1258 1262 1275 1628 0729 158 4310 642 1424 1318 1299 1282 1283 1261 1683 0617
co ~
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc7 tc a 1r
159 60 12 780 1461 1388 1370 1349 1343 1279 1700 0 573 160 72 79 8 60 1402 1344 1330 1312 1292 1189 1 566 0 520 161 8690 982 1472 1442 1437 1 422 1392 1224 1602 0 521 162 163
12D 4368 5833
6 30 8 30
1195 1368
1105 1270
1111 1283
1117 1294
1131 1313
1081 1194
1369 1553
0613 0 553
164 76 43 959 1428 1338 1348 1341 1371 1180 1488 0535 165 8739 984 1345 1272 1272 1208 129 3 1059 1361 0550 166 1268 459 1701 1548 1541 1547 1589 1 625 1976 0 973 167 2678 570 1485 1351 1349 1356 138 1 1 385 1795 0760 168 169
1 12D 128 3 2729
448 650
1664 1314
1501 1232
1425 1233
1428 1229
1491 1229
1527 1232
1869 1571
0 962 0767
170 4345 847 1245 1179 1187 1182 1172 1132 1476 0 650 171 6036 9 76 1139 1109 1117 1114 1095 1020 1332 0588 172 6578 9 72 0982 0949 0942 0938 0926 0 8 50 1079 0560 173 87 84 9 72 0880 0854 0 8 36 0822 0818 0 749 0941 0585 174 1278 480 1564 1416 1397 1403 1417 1445 1733 0998 175 2711 590 128 3 1175 4 1178 1182 1187 1195 1493 0796 176 4351 8 90 1331 1259 1266 1275 1272 1235 1592 0 682 177 5994 9 60 1228 1152 1150 1151 1143 1075 1 360 0644 178 lU 1223 408 2282 2140 2052 2052 2106 2188 2626 0 878 179 2351 408 178 1 1623 158 5 1519 1556 1634 2068 0717 180 3448 482 1888 1675 1570 1541 1572 1665 2199 0629 181 4513 563 2026 1797 168 4 1644 1670 1770 2385 0583 182 5714 589 1913 1700 1610 1568 1580 1 682 2382 0551 middot 183 6997 653 1903 1718 1643 1611 1612 1700 2326 0 549 184 8709 6 80 1738 158 3 1543 1510 1498 1519 1 912 0577 185 186
2 12D 4249 5737
660 9 74
1055 1221
0 979 1122
0960 1093
0 952 1088
0959 1090
0 956 1054
1147 1350
0661 0602
187 7432 9 8 1 1065 0981 0951 0942 0 939 0881 1135 0582 CD ~
TABLE X Continued
Run No Position CFM I t o1 to 2
188 87 23 9 83 0944 0 879 189 1435 585 18 26 1630 190 2718 690 1433 1298 191 7507 950 1070 0961 192 85 44 964 0982 0 881 193 1287 600 1806 1668 194 2717 7 80 1579 1444 195 4253 8 81 1371 1260 196 60 68 9 78 1252 1152 197 73 89 975 1100 1000 198 86 88 973 0953 0 871 199 58 64 9 81 1269 1155 200 2D 4 1 77 915 1362 1251 201 5712 975 1213 1111 202 7363 9 78 1036 0 951 203 8 604 973 0932 0861 204 1268 6 95 2015 18 20 205 2659 6 96 1405 1295 206 39 80 7 98 1261 1174
No 207 Orifice 114 96 509 1325 1148 208 94 33 509 1477 1243 209 7487 5 09 1686 1409 210 5236 505 2094 1691 211 3309 428 2188 1 778 212 1293 392 2976 2560
Thermo ooup1e Readin g s (mv) to 3 to4 to
5 to
6 to7 toair
0 851 0847 0 8 29 0759 0987 0592 158 4 1583 1611 1647 1993 0986 1270 1266 1 279 1298 1604 0 789 0916 0908 0900 0 858 1115 0602 08 39 0 823 0 818 0 770 1035 0602 1609 1602 1629 1676 2153 0979 139 1 1385 1400 1 430 1938 0776 1212 1201 1205 1201 1601 0669 1 105 1086 1086 1 052 1371 0621 0952 0936 0923 0870 1195 0582 0 8 20 0 801 078 1 0 729 1044 0569 1108 1090 108 2 1043 1407 0610 1218 1221 1241 1202 1582 0659 1081 1083 1084 1031 1 368 0622 0921 0924 0919 0 841 1111 0 610 08 34 0831 0 821 0 751 1003 0 630 1761 1761 1 809 1861 2399 0966 1271 1271 1295 1311 1650 0797 1150 1150 1161 1149 1440 0703
1083 1057 1053 1109 1566 0~530 1158 1125 1138 1217 1763 0 526 1291 1250 1278 1383 2038 0542 1518 1478 1519 1657 2420 0 589 1596 1557 1601 1737 2441 0688 2370 2344 2409 2561 3 297 0921
()) (11
TABLE X Continued
Run Thermocouple Readings (mv) No Position CFM I tc 1 tc2 tc3 tc4 tc tc tc tc i5 6 7 a r
C of 2nd 213 516 1235 4 63 1 432 1291 1265 1258 1 268 1 308 1550 0 971 214 1919 6 17 1357 1223 1196 1191 1199 1211 1461 0 851 215 27 12 8 35 1401 1259 1278 1220 1230 1218 1511 0 762 216 3320 981 1439 1305 1270 1259 1275 1238 1450 0719 217 41 53 980 1251 1142 1132 1094 1121 1088 1305 0 695 218 404 987 1102 1042 1030 1 bull006 1014 0960 1133 0681
Supplementary Equations
Calculating temperatures from thermocouple readings
t = -026tc)2 + 3512(tc) + 3201 (26)
where t is the temp in deg F and tc is the thermocouple reading in millishyvolts
Calculation of the thermal conductivity of air
k = 00000245ta + 0 0132 (27)
where k is the thermal conductivity in Btuhr rt2 degFft and ta is the air temp 1n OF
I I
bull co m
12
0 271 ohms per foot and a thermal conductivity of 763
Btuhr ft 2 degFft They were held in position by four
copper bars placed in four parallel longitudinal slots
These copper bars served as connectors for the electrical
leads A photograph of the sensing probe is shown in
Figura 3 and a drawing of the assembled probe is given in
Figure 4
Power Source
Direct current was used to heat the resistance ribbon
on the sensing probe The current was regulated by a slide
wire resistor The po er source consisted of a Raytheon
Voltage Stabilizer to stabilize the city power source at
115 volts and an automatic selenium rectifier with an alshy
ternating current input of 115 volts at 60 cycles per
second and an output of 12 volts and 35 amperes direct
current
Temperature Measuring
The temperatures around the sensing probe were calcushy
lated from the emf readings of the ironbulloonstantan thermoshy
couples The emf measuring system consisted of the seven
probe thermocouples a separate thermocouple for measuring
the inlet air temperature a thermocouple selector switch
a cold junction and a Leeds and Northrup Type K Potentishy
ometer The potentiometer was placed on a Fischer
13
THERMOCOUPLE JUNCTIONS~ ~------- HOLES FOR THERMOCOUPLE LEADS
~----- SCREWS
~ff+--- CONNECTING BARS
END VIEW
POWER LEADS SOLDERED TO LOWER CONNECTING BAR
iER PLASTIC PIECE
RESISTANCE RIBBONS LOCATION OF THERMOCOUPLES
FIGURE 4 DRAWING OF ASSEMBLED SENSING PROBE
15
Vibradamp support to absorb the vibrations produced by the
air blower
Air Source
Air was used as the shell-side cooling fluid during
the study The air was pumped through the test section by
a Roots type air blower with a rating of 280 ofm at 3 12
psig outlet pressure The hot air leaving the blower was
passed tbxfugh two finned-tube box-type coolers and one
tubular edoler to oool it to approximately room temperature
The air flow rate was measured by passing it through a
flow measuring orifice in the line Two sharpbull edged orishy
ficas were used f or flow measurements The calibration
curves for these orifices were presented by Ambrose (1
p 166)
The pressure taps on each side of the orifice were
connected to two differential manometers containing 0 83
and 2 95 specific gravity fluids respectively The presshy
sure drop through the test section and test orifice was
measured by a pressure tap placed 13 inches upstream and
one placed 6 12 inches downstream from the orifice Two
pressure ga ges were used to measure the pressure at the
inlet to the flow orifice and to indicate the statio pres~
sure at the test section inlet
16
Pressure Probe
A probe was designed to measure the pressure drop
between the pressure tap 13 i nches upstream from the ori shy
fice baff le and any point downstream from the tap The
probe eonsisted of a l~in OD copper tube with six 132
i n ch holes even l y s paced around the tube The upstream
pressure tap and the pressure probe were connected to a
differential manometer so the pressure drop to various
points up- and downstream of the orifice could be measshy
ured
17
CHAPTER IV
EXPERIMENTAL PROGRAM
The experimental program was designed to measure the
heat transfer coefficients and pressure drops in the vicinshy
ity of annular orifices The four orifice sizes studied
were 1 364 1 216 l 316 and 1 516 inches~ The inner
tube used in each case was a 1-in OD alumintim tube
Hence tube to baffle clearances were respectively 3128
232 332 and 532 of an inch
Heat transfer coefficients were measured at poait~ons
1 i nch upstream at the orifice center and at 12 1
1 12 and 2 inches downstream for all orifices In addishy
middottion the heat transfer coefficient at a point 2 12
inches downstream from the 1 516 inch orifice was measured
and at the points 12 l 12 and 2 inches upstream from
the 1 364 inch orifice
The heat transfer coefficients at each point were
measured at five different flow rates for the 1 364 inch
orifice and at six different flow rates for the other orishy
fice sizes The high pressure drop through the small orishy
fice size limited the number of flow rates which could be
studied
The flow rate was calculated from the pressure drop
across the flow orifice This flow was corrected to cubic
feet per minute at 68degF and one atmosphere pressure by
18
using the orifice pressure and the test section pressure
which were measured by pressure gages
It was desired to determine a relationship between the
heat transfer coefficient and the total pressure drop for
each orifice size The pressure drop across each orifice
at various flow rates was measured by means of the presshy
sure probe described in Chapter III It was also desired
to obtain pressure profiles for each orifice size since
these might be similar to the heat transfer profiles The
pressure drop was measured from a point 13 inches upstream
of the orifice to points at 1 and 12 ineh upstream the
orifice center 12 1 1 12 and 2 inches downstream
The experimental program is summarized in Table I
TABLE I
SUla~RY OF EXPER IMENTAL PROGRAM
Position Investigated-Distance from Orifice-Inches
Orifice Range of Flow Rate Size Heat Transfer Pressure Drop CFM at 68degF amp 1 atm
1 364 2U 1 12U 1U 12U c 12U C 12D lD 10 - 18 l2D lD 1 12D 2D 1 12D 2D
1 216 1U c 12D lD 1 l2D 2D 12U c 12D lD 10 - 35
1 316 1U c 12D lD 1 l2D 2D l2U C 12D lD 12 - 50
1 516 1U c x2D lD 1 l2D 1U 12U C 12D 12 - 90 2D 2 1 2D l D 1 l2D 2D 2 12D
20
CHAPTER v
EXPERI MENTAL PROCEDURE
The experimental procedure for measuring the heat
transfer coefficients ~d corresponding flow rates reshy
quired the following procedure
(1) Install the orifice size to be studied in the
test section
(2) Place the heat transfer probe in the position up
or downstream from the orifice where the middot heat
transfer rate is to be studied
(3) Fill the cold junction thermos with cracked ice
(4) Measure the atmospheric pressure
(5 Open bypass line from blower and close line to
test section
(6) Turn on the cooling water for the exchangers used
to cool the air leaving the blower
(7) Start the automatic selen ium rectifier by turning
on the t 1mer bull
(8 ) Connect the voltage stabilizer to the wall outlet
(9) middot Set the slide wire resistor to the maximum re shy
s1atanee I
(10) Start the blower
(11 Open the line to the test section until the de shy
sired flow rate is obtained
(12) Switch on the probe direct current power source
21
(13) Adjust the slide wire resistor to obtain the
desired current
(14) After the thermocouples have reached equilibrium
values record the e m bullf across each of the
seven probe thermocouples and also the entering
air thermocouple
(15) Record the direct current amperage
(16) Record the gage pressure at the flow orifice and
the entrance to the test section
(17) Record the manometer measurement of the pressure
drop across the flow orifice and also the presshy
sure drop through the test section
22
CHAPTER VI
CALCULAT ION OF EXPERIMENTAL DATA
The local heat transfer coefficients were calculated
from the temperatures measured on the probe surface the
air temperature and the current input The results were
calculated by using the Alwae III-E computer
The general expression for calculation of the heat
transfer coefficients was derived by Ambrose (1 p 79)
The equation is derived by making an energy balance around
a small increment of the center resistance heating ribbon
The two ribbons tnstalled adjacent to the center ribbon
reduced the amount of logitudinal conduction and assured
little longitudinal temperature variation in the center
ribbon
A heat balan ce on this small increment of resistance
ribbon yields the following
(the heat conducted in) + (heat generated) = (heat
conducted out) +(Heat convected to the fluid) + (heat
radiated to the surroundings) + (Heat conducted into
the plastic center of the probe)
This gives the equation
kzw dtdS + 12RdS kzws [ t + (~) ds] + hwdS (t-ta )
+ ~Aad wd o middot+ qcAond 1 -~- wdS 5 )
23
Hence solving for h gi~ea
i2R kz d2t Qrad qcond w + -d$2 - ~- A
h = ( 6)t - ta
Since S = re where 9 equals the enclosed angle ~n radians
dS rd9 ( 7)
and
dt - dt (8)dS - rd9
Differentiating with respect to S
d2t (9)rd9dS
from which
(10)
Substitut1ng into the equation for heat transfer coeffishy
cient gives
h = i2R Qcond A (11)
w
The rate of radial heat conduction into the plastic
tube making up the probe was assumed to have negligible
effect on the heat transfer coefficient It was also
assumed that the heat loss by radiation from the ribbon
was negligible since all data were obtained with the ribbon
at a temperature less than 125degF
24
When t he rad iation and conduction terms are neglected
Eq (11) becomes
(12)
The following con stants are known
R = 0 271 ohmsft
w = 100 i n ches
k = 763 Btuhr rt2 degFft
z = 0 002 inches
r = 12 inch
Eq (12) putting 9 in degrees then reduces to
1110 12 + 2404 d 2t d92
( 15)h = ------~--~-------t - ta
Thi s equation was programed for the Alwac III- E comshy
puter and used to calculate the local heat transfer coefshy
ficients from the observed data
The average heat transfer coefficient around the tube
at a given position in the t est section was calculated by
averaging the local coefficients calculated from Eq (13 )
It was found 1n the course of the experimental work
that thermocouple numbers 1 and 7 were indicating higher
temperatures than would be expected This resulted in h1
and ~ being lower than the other local coefficients around
the tube Since the fluid was flowing parallel to the axis
of the probe the circumferential variation i n rate of heat
25
transfer should be small Hence in obtaining the average
coefficient around the tube the values of h1 and h7 were
not used even though they were calculated and are tabulated
1n Table I II in the Appendix
Then
(14
A Nusselt number as calculated from this aver age heat
transfer coefficient using the tube diameter as the characshy
teristic dimension
(15)
The air flow rates through the test section were calshy
culated by measuring the pressure drop across the flow orishy
fice the air temperature the pressure at the flow orifice
and the pressure at the entrance to the test section The
orifice calibration curves (1 p 166 ) were used to obtain
a value of the orifice coefficient f8e where Q equals
the flow in cubic feet per minute at 68deg F and one atmosmiddot
phere pressure and te is the density of air at the exchanger
and e the density of the air at the flow orifice The
den sity of the air can be expressed by
e = 2 703 p (16)T
where T equals the temperature in OR and P equals the absoshy
lUte pressure i n lb1n2 Using the value of e Qfo from
26
the calibration charts as A and Eq (16) solving for Q
gives
( 17
This equation was used to calculate the flow rate for
each flow studied
The Reynolds number used i n the correlation of the
data was the equivalent Reynolds number defined as
Re)eb ~ d2 - dl)Uf ( 18 ) lL
where d1 is the outside diameter of the inner tube and d2
is the orifice diameter U is the flow velocity through the
annular orifice e is the density of the air and U- is t he
viscosity of the air This equation can be transformed t o
(Re) b = 1611 Q (19) e dl + d2
where d1 and d2 are in inches
The pressure drop data were calculated i nto a dimenshy
sionless pressure drop function cent where
d1 )22( ~ P)gc f av(d2 shycent 2 bull (20
M-
For air this equation reduces to
where d2 and d1 are in i nches D P is expressed i n inches of
2 95 specific gravity fluid and P av is expressed as lbft3
27
CHAPTER VII
ANALYSIS OF DATA
In analyzing the heat transfer data an attempt was
made to correlate it 1n terms of the dimensionless groups
(Nusselt number Prandtl number and Reynolds number) which
appear in Eqs (3) and (4) Consequently all of the av~
erage heat transfer coefficients hav were brought into
the form ( Nu)( Pr)~3 bull The Nusselt number was based on the
tube diameter and the thermal conductivity of the air at
the flowing temperature The tube diameter was used in the
Nusselt number because comparison could then be made with
previous experimental work on heat exchangers which have
commonly used the Nusselt number defined as in Eq (15)
From the standpoint of dimensional analysis this is
equivalent to considering the tube diameter as the characshy
teristic length so far as the heat transfer is concerned
The Prandtl number of the air was taken as 0 7 in all
cases
Variation of Heat Transfer Rate with Distance from the Baffle
Considerable variation was observed in the rate of
heat transfer in the vicinity of the baffle In order to
obtain the variation with respect to position the term
(Nu)(Pr)-13 was plotted versus the flow rate Q for each
position and orifice studied Cros s plots were then made
28
at constant flow rates in order to obtain the variation of
(Nu)(Pr) -13 with position The resulting cross plots are
shown 1n Fi gures 5 6 and 7 for the four orifices studshy
ied
About one inch upstream from the orifice the heat
transfer coefficient begins to rise rapidly and continues
to do so until it reaches a maximum some distance downshy
stream After the maximum point the heat transfer coef fi shy
cient decreased slowly The heat transfer rate was found
to reach a maximum at a different position downstream for
each orifice size These figures also show that for a
given orifice size the maximum heat transfer rate occurs
a pproximately at the same point for all flow rates The
position of the maximum point f or each or ifice size is
shown in Table II
The region immediately downstream from the orifice is
one of h i gh turbulence due to the jetting action of the air
flowing through the orifice As the air flows t hrough the
orifice the streamlines continue to converge for some dis shy
tance downstream The point of maximum heat transfer is
probably at the point where the streamlines be gin to diverge
and a boundary layer begins to build up on the tube Tle
decreasing heat transfer coefficient beyond the maximum
point indicated the formation of a boundary layer
Since the position of the maximum point is independent
of flow rate middot it is possible to correlate it with respect
_ ct 11shyz-
100
0 136 ORIFICE
(
I 0
I )
~ 00
~p 0
I 0
--r--- ~
ISCFIII
-_ OCFM
rbull abull
~ middot~ a-1 z-
12fORIFICE
100
200
100
0 0 UPITRAM ORIFICE DISTANCE CENTER
CFM
h I DOWNSTREAM
DISTANCE
FIGURE 5 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLpound
30
too
700
800
100 ~ f gtf
400
z ~
100
100
100
0
13fORIFICE
~ -~ -- ---
)
~
~
-
I ~ ~OCFM
I vI~-~ OCFM
J ---
Iamp CFM
I 0 I I UPSTREAM ORIFICE DOWNSTREAM DIITANOE GENTER DIITANCI
FIGURE 6 VARIATION OF HEAT TRANSFER RATE WITH DISllNCE FROM BAFFLE
--
--- --
31
100
100
700
100
_ 100
f 9- 400 z-
100
tOO
100
0 - I 0 I I I UHTRIAM OAtfiCI DOWIIITMAM
+ I tyl6 ORIFICE
v I
~~ ~CFM
I v ~CFMI
v v 7
~~ v ~ iOCFM
- ~~ I-shy1-shy ~ICFM
DIITMCI OINTIR DIITANCI
FIGURE 7 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLE
32
TABLE II
POSITION OF MAXIMUM HEAT TRANSFER
Position of Maximum Orifice Size Heat Transfer
(inches) (inches downstream)
1 364 050
1 216 100
1 316 125
1 516 200
33
to orifice size Figure 8 shows the effect of the orifice
size on the position and value of the maximum heat transfer
at a constant flow rate of 15 cubic feet per minute It
can be seen that the larger the orifice size the further
downstream the point of maximum heat transfer occurs
Also as the orifice size increased the rate of heat
transfer decreased for a given flow rate The broken line
indicates the variation of the point of maximum heat transshy
fer with position and size The position of the point of
maximum heat transfer rate downstream from the orifice was
correlated with orifice size by means of the dimensionless
groups (Lde) and (d1de) where L is the distance downshy
stream from the orifice where the maximum rate of heat
transfer occurs d1 is the outside diameter of the inner
tube and de is the equivalent diameter of the orifice
ie de = d2-dlbull
Figure 9 shows a plot of Ld 6 versus d1d6 for the
four orifice sizes studied The four points on this logshy
log plot are approximately in a straight line and the
equation of this line is
Lde = 0 44 d1de)028 (22)
Although the above relationship represents a correlashy
tion of dimensionless groups it is based upon only one
tube diameter and needs to be substantiated further by
studying other tube diameters and other orifice sizes
34
aoo
400
aoo ~
-~ middot-CLshyJ z
200 -
100
0
ORIFICE CENTER
l~
l
t
I J~
1pound~
I
0 I I~
AT 15 CFM
-
bull ~ 1~6~
~ v~
~
~--~~6
~~~ ___ v v V -_
~ o q
~ I 16
v
~
ogWNSTREANI STANCE
FIGURE 8 EFFECT OF ORIFICE SIZE ON POSITION AND VALUE OF MAXIMUM HEAT TRANSFER
35
50
loshy____ -~
~ ~ -shylltl-shy~ r0
2 10 30
FIGURE 9 CORRELATION OF THE POINT OF MAXIMUM HEAT TRANSFER WITH
ORIFICE SIZE
36
Correlation of Data at the Baffle
The heat transfer data were correlated by obtaining a
relationship between the group (Nu)(Pr)-13 and a
Reynolds number based on twice the clearance (d2 - d1
between the tube and the baffle It was found that the
most satisfactory correlation could be obtained when the
term - d1 was used as the length term in the Reynoldsd2
number
Figure 10 shows the variation of the heat transfer
rate at the center of the orifice e xpressed as a function
of Reynolds number and the orifice size This shows that
for a given Reynolds number the heat transfer at the center
of the orifice is greatest for the smallest orifice size
In order to obtain a general correlation of the data
shown i n F1gure 10 the effect of the dimensionless ratio
d1de was considered This ratio considers all of the
geometric factor s needed to describe the annular orifice
The thiclaless of the orifice plate is also a factor but
was constant i n this i nvestigation
The data for the heat transfer at the baffle center
are shown in Figure 11 in which (Nu)( Pr)-13 is plotted
versus (Re)ebd1 de) 0 55 This data on a log-log plot
lies on a straight line for (Re)eb( dld8 )0 55 greater
than 3 x 104 The equation for cor relating the heat
37
4XI~middot~-r~------~--~~------~
Icf t--to_+--_c-c-________ SYMBOL SIZE
0 1~4
6 ~~
9 ~~ -o ~
(Re)eb
FIGURE 10 RATE OF HEAT TRANSFER AT BAFFLE CENTER
38
500
0
4 0 lcf
~ ~
~ ~iC-
~ ~
~IL 0~ 0 SYMBOL SIZE-
p 0 1364-
r 6 1~16 -~ -
9 1~16 --o 1~16
I I
FIGURE II CORRELATION OF HEAT TRANSFER DATA AT BAFFLE CENTER
39
transfer at the center bullOf the a nnular orifice was found by
the method of least s quares to be
(Nu)( Pr)-1 3 = 0018 ( Re)ebO Bl( dlde)04~ (23)
3 x 104 ltRe)eb(a1de)055 lt 105)
Rate of Heat Transfer at the Point of Maximum Heat Transfer-The heat transfer rate at the point of maximum heat
transfer is plotted in Figure 12 to show the variation with
Reynolds number and the size of the orifice It is shown
gives the h1gh st heat transfer ~ate at its point of maxibull
that for a given Reynolds number the smallest orifice size yen il
mum heat transfer
The data ~or the maximum poi~t could be correlated by
plotting (Nu) Pr)-13 versus (Re)eb(d1de)06 This plot
is shown 1n Figure 13 and the resulting eurve shows that
(Nu(Pr)-13 is not a simple p0wer function of the Reynolds
number as was the case for heat transfer at the baffle
center The reason for this is probably because other
factors such as intensity and scala of turbulence should
be considered At the orifice center the streamlines of
the flowing stream are converging_ and thus the flow is
quite stable Downstream from the orifice is a region of
large eddy currents and probably large scale turbulence
These factors could con ceivably cause the results which
were obtained for the point of maximum heat transfer
40
If)
~middotshy Q_-I z_
10~~~--------r----~~--~--
SYMBOL SIZE
0 13$4
6 1~8
Q 13-18
-o 1~8
7)(104
(Re)eb
FIGURE 12 RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
41
Ia ~
0 I
c ~ ~ c v
~ ~lt w ~
17
~ b
v ~ ( SYMBOL SIZE
-~ 0 f-64 -v ~ 6 t211e
~ Q I~~~
-o - l~rs I I
FIGURE 13 CORRELATION OF HEAT TRANSFER DATA AT THE POINT OF MAXIMUM HEAT TRANSFER
4 2
Effect of Upstream Baffles on Heat Transfer at the Orifice Center
The heat transfer rate at the orifice center using the
single orifice in a test section is a pproximately 13 of the
value that was obtained by Lee (7) using a model heat exshy
changer with orifice baffles Lee investigated the cent r al
baffles of the heat exchanger and thus the coeff icients he
obtained would be affected by the presence of a number of
upstream baffles To determine the effect of upstream
baffles an additional l 516 inch baffle was placed four
inches upstream 1n the test section The resulting data are
shown in Figure 14 where (Nu)(Prmiddot)-13 is plotted versus
(Re) eb for the case of a single baffle 1n the test section
and also the case of an additional baffle placed four inches
upstream Comparison is made with the results obtained by
Lee middot(7) using a four-baffle and a ten-baffle model heat exshy
changer Good a greement is obtained with Lees work and the
results show the marked effect that upstream baffles have on
the downstream heat transfer rate The additional up tream
ba ffle caused sufficient turbulence 1n the test section to
i n crease the heat transfer rate nearly three-fold at the
center of the next baffle
Heat Transfer i n the Test Section with No Orifice
In order to check the accuracy 6f the equipment the
orifice baffle was removed and the heat transfer mea sured
with the probe in the empty test section The data were
43
~~BAFFLES
0 l BAFFLE -shy
ll_9 2 BAFFLES
V 4 BAFFLES-LEE
4 10 BAFFLES- LEE lJf ~
~rv ~~ ~ v flvv ~~
I ~ J ~ L v
0
v
( V
40 3XIo 7XIa
(Re)eb
FIGURE 14 EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER AT BAFFLE CENTER
44
compared with heat transfe r coefficients predicted by the
equations for annuli which are recommended in the litera shy9
ture The two equa~ ions u sed tor comparison were
(hfe)=0 023 (rltGr e (~~ur4 (~r45 (24)
which was presente~ by Wiegant (10)
and ( h ) (cnM~5(M~l o14 o 023 CPG k j Mij - (de GJMb )0 2 ( 2 5)
which was presented by McAdams (8 p 242) The comparshy
i son is s hown in Figure 15 lq (25) gives a value which
is low by about ten percent while Eq (24) g ives values
which are high by as much as twenty -five percent when comshy
pared with the experimental data The se equations are gembull
erally considered to give coefficients with an accuracy of
about twenty percent Therefore the present experimental
data are within the accuracy of these equations Also the
plot indicate s that for a Reynold s number greater than 2 x
104 the slope of the line is the same for the experimental
data as for the equations
Pressure Drop Data
The total pressure drop across the orifice was measured
as a function of the flow rate and the orifice size The
pressure drop was expressed as a d1mens1onleas quantity r)
which ie plCltted ver sus the Reynolds number in Figure 18
The pressure drop function cent correlates for all or1f1oe
45
200
100
s z
10 5XI10 10
0 EXPERIMENTAL
--McADAMS
-WIEGAND L
V
~ ~ ~
P ~ ~
LL~ L
v~
~
v v
v 1 ~ ~ v
v -gt
~
~ ~
~
6Xid
FIGURE 15 HEAT TRANSFER WITH NO BAFFLE
46
0 1~4 -~ a 6 t216
Q t316 lJ J
-0 as a )t
A LEE I -shy SULLIVAN 8
p
10bull
BERGELIN
I _ll I
I ~
i I
~middot
lo II
f fl
J j
~middot
A)101
1q
I Ill
1 I3 X 10ao1
FIGURE 16 ORIFICE PRESSURE DROP FUNCTION VS REYNOLDS NUMBER
47
sizes- The present data extends the range covered by preshy
vious workers and agrees well with their work The preshy
vious work of Lee () for a heat exchanger containing 10
orifice baffles and also the data of Su livan and Bergelin
(9) for pressure drop in a model heat exchanger with a
single baffle is shown 1n Figure 16 long with the present
results~ This figure may be used to predict the preseure
drop from the equivalent Reynolds number of the annular
orifice
The pressure drop between individual points 1n the
vicinity of the orifice and an upstream pressure tap wa s
measured to obtain a pressure drop profile As might be
expected 1n all cases the profiles showed a rapid decrea e
in static pressure immediately upstream from the orifice
There was however little or no recovery of the pressure
loss downstream The 1 364 inch orifice did show a maxishy
mum point in the pressure drop but this maximum occurred at
the orifice center and total recovery was reached about 12
inch downstream
Heat Transfer at the Baffle and Maximum Point as a Function of Pressure Drop
In order to compare the effect of the total pressure
drop on the heat transfer at the baffle and the point of
maximum heat transfer Figure 17 was plotted showing
(Nu)(Pr)-13 as a function of the total pressure drop This
shows that for a given pressure drop the largest orifice
48
1200
1000
~ a -sshyz-
100
60 100 700
AT MAXIMUM POINT I 15116 2 13116 3 1~6 4 1364
AT ORIFICE CENTER
60
1
v
r ~ ~ ~
5
~
8 7
13116
8
~
1364
v
~
e6
1~6
v
~~ v ~ ~ -~ ~
~
~ v
l
~
vamp
I ~ ~
~
v L ~
v
I-
5
k= ~~
~ ~ ~
--I
v ~
FIGURE 17 HEAT TRANSFER AT THE BAFFLE AND MAXIMUM POINT AS A FUNCTION OF
ORIFICE PRESSURE DROP
49
size has the greatest heat transfer coefficient This is
true at both the orifice center and at the point of maxishy
mum heat transfer
Another comparison can be made by plotting the heat
transfer coefficient and the pressure drop versus the orishy
fice size at a constant flow rate Figure 18 shows this
plot This graph shows that at a constant flow rate the
pressure drop as well as the heat transfer coefficient
increases as the size of the orifice is decreased In
choosing an orifice size for maximum efficiency 1t would
be necessary to know the pumping power available as well
as the heat transfer desired
70 I I 700
AT 15 CFM 60 ---
~ aug
50 ---
NV
40 ~
~ ~ ~
~ _
MAXIMUM POINT ---- --- ~
1-----t---~ _
~00Qj ~
~t--- ORIFICE CENTER 10 1100
1---~ n
u0 01 02 03 Q35
a ltl
de inches
FIGURE 18 VARIATION OF HEAT TRANSFER RATE AND PRESSURE DROP WITH ORIFICE SIZE AT A CONSTANT FLOW RATE
cn 0
51
CHAPTER VI II
SUMMARY OF RESULTS
This study revealed several significant facts about
the heat transfer in the vicinity of annular orifices
Probably the most important contribution was the presshy
entation of the heat transfer profiles in the vicinity ot
the annular orifice ~ r s shown that t~ local heat
transfer coeffieient re~ches a maximum at a point downshy
stream from the orifice The distance downstream at which
this maximum oocurs is t1ven by the equation
22
The heat transfer coefficients at the center of the
orifice were correlated and found to follow the equation
(Nu)(Pr)-13 = 00176 (Re)eb08l(d 1de) 0 middot4~ (23)
3 x 104 lt( Re) 9 b( d1d6 )055 ltlo5 )
The heat transfer at the point of maximum heat trans
fer for each orifice size was correlated and presented in
Figure 13 as a plot of (Nu)(Pr)-l3 versus (Re)eb(d1de) 06
No simple po-orer relationship exists between the terms
Intensity and scale of turbulence downstream from the orishy
fice are probably important factors which affect the heat
transfer
The large effect of an upstream orifice on the heat
transfer rate at the second orifice was demonstrated by the
52
study of two 1 516 inch orifices in the test section The
added turbulence at the center of the second orifice was
found to raise the heat transfer rate almost three times
over that obtained for a single baffle
The pressure profiles in the vicinity of the orifice
indicate that nearly all the pressure drop occurs at the
orifice center~ Total pressure drop data were correlated
by a pressure drop function cent as a function of the Reynolds
number and good agreement obtained with the results of other
workers
The pressure drop and heat transfer data were correbull
lated by plotting the heat transfer as a function of the
pressure drop for each orifice size It was shown that for
a given pressure drop the largest orifice size gives the
greatest heat transfer coefficient
As a final presentation it was shown that the pressure
drop and the heat transfer coefficient both i ncrease i n
value at a constant flow rate as the orifice size is de shy
creased This is important in choosing the optimum clearshy
ance for orifice baffles
53
CHAPTER IX
RECOMMENDATIONS
A great deal of work remains to be done in the field of
evaluating shellmiddotside heat transfer coefficients This
study included only one tube size and air was the only f luid
used It is recommended that further studies be conducted
using other fluids and tube sizes It will also be necessary
to study several baffle types
The adde d turbulence due to a s e cond baffle placed upbull
s t ream would suggest that the heat transfer coef ficients at
a certain position i n relation to a baffle would increase as
the flow progressed through the exchanger It is recomshy
mended that an extensive s t udy should be made between baffles
the full length of a model heat exchanger
It is further recommended that the pressure drop study
be continued to include other fluids tube sizes and baffle
arrangements
Effects of turbulence downstream from the baff le should
be studied by i n vestigations with hot-wire anemometer equipshy
ment to determi ne t urbulence scale and i ntensity
54
NOMENCLATURE
Area of heat transfer
Heat capacity of the fluid
Outside diameter of the tube
Orifice diameter
Equivalent diameter of the orifice (d2 - dl)
Inside diameter of the test section
Inside diameter of the tube
Gravitational constant
G Mass velocity
h Local heat transfer coefficient
Coefficient of heat transfer from surface to fluid
i Direct current amperes
k Thermal conductivity of the fluid
L Distance downstream of the point of maximum heat transfer
p Absolute pressure
L P Total pressure drop across the orifice
Q Flow in cubio feet per minute at 1 atmosphere and 680 F
q Heat transferred
Thermal energy conducted into the sensing probe
Thermal energy radiated from the resistance ribbon
Resistivity of the resistance ribbon
s Length of the resistance ribbon
T Temperature oR
55
t Temperature of the resistance ribbon deg F
ta Temperature of the bulk stream oF
tw Wall temperature of the tube OF
U Veloc ity of the fluid
w Width of the resistance ribbon
z Thickness of the resistance ribbon
eeuro Density of the fluid in the test section
Density of the fluid at the flow orificef 0
AL Viscosity of the fluid
E9 Angle measured around the tube
Dimensionl ess groups
(Nu) Nusselt number hd1k
(Pr Prandtl number C~k
(Re)eb Equivalent Reynolds number at the baffle (d2 - d1 )uejt-Lshy
(Re)e Equivalent Reynolds number in the test section ( d 8 - d 1 )U fu
cent Orifice pressure drop function 2(~P ) gc~av(d2 - d1) 2
Al
56
BI BLIOGRAPHY
1 Ambrose Tommy W Local shell-side heat transfer coefshyficients in baffled tubular heat exchanger PhD thesis Corvallis Oregon State College 1957 183 numb leaves
2 Bell K J and o P Bergelin Flow through annular orif ices Transactions of the American Society of Mechanical Engineers 70593-601 1957
3 Colburn Allan P A method of correlating forced con shyvection heat transfer data and a comparison with fluid friction Transactions of the American Institute of Chemical Engineers 24 174-210 1933
4 Dittus F w and L M K Boelter Heat transfer 1n automobile radiators of the tubular type University of California Publications in Engineering 2443-461 1930
5 Gurushankariah M s Local shell-side heat transfer coefficients in the vicinity of baffles in tubular heat exchangers Masters thesis Corvallis Ore gon State Colle ge 1958 97 numb leaves
6 Knudsen James G and Donald L Katz Fluid dynamics and heat transfer New York McGraw-Hill 1958 576 p
7 Lee Kyu Sung Local shell-side heat transfer coeffishycients and pressure drop in a tubular heat exchanger with orifice baffles Masters thesis Corvallis Oregon State College 1959 118 numb leaves
8 McAdams William H Heat transmission 3d ed New York McGra ~-Hill 1954 532 p
9 Sullivan F W and 0 P Bergelin Heat transfer and fluid friction in a shell-andbulltube exchanger with a single baffle Chemica l Engineer ing Progress Symposium Series 52 ( 18) 85-94 1956
10 Wiegand J H Discussion on annular heat transfer coshyef f icients for turbulent flow Transactions of American Institut e of Chemical Eng i n eers 41147-153 1945
AP PENDIX
57
TABLE III
CALCULATED HEAT TRANSFER DATA
Baffle Hole Diameter Run No (inches)
1 - 59 1 364
60 - 102 1 216
103 - 138 1 316
139 - 206 1 516
207 - 212 No orifice
213 - 218 2nd - 1 516
TABLE III
CALCULATED HEAT TRANSFER DATA
Local Heat Transfer Coefficients Run
T0 bull Po s ition CFM hr h2 h3 h4 hs he ~ hav Nuav
1 c 1026 10 59 1476 16 09 1559 1510 1435 1203 1518 8511 2 1290 1369 1738 1878 18 05 1755 1689 1515 1773 9964 3 1416 1636 198 1 2068 1977 1924 1845 1715 1959 11030 4 1627 1991 2301 2382 2268 2194 20 ~98 1929 2249 12664 5 1776 2252 2669 2863 2713 2517 2338 2126 2620 14759 6 l2ttD 1109 2311 3317 3386 3373 3387 3394 3071 3371 18888 7 1258 3089 4583 4866 4683 4701 4643 4194 4695 26301 8 1433 38 8 5 55 83 5791 5495 5430 5436 5008 5547 31192 9 1681 4992 7378 7649 6980 6864 6870 64 28 7148 40180
10 1 D 1102 2371 3332 3511 3356 3342 3427 3102 3394 19012 11 1308 3218 4379 45 24 42 53 4255 4373 3965 43 57 24446 12 14 64 38 58 5146 5142 4839 4787 4903 4597 4963 278 79 13 1706 5218 6664 6269 58 81 5884 6237 5973 61 87 34718 14 15
1 l2D 1115 1275
2131 2661
2955 3638
2972 3720
2941 3675
2913 3576
28 22 34 74
2613 3278
2921 36 17
163 09 20246
16 1498 34 87 4644 4503 4441 4371 4343 4194 4460 25010 17 1695 4449 5743 5324 5222 5154 5157 5015 5320 298 97 18 2D 1049 1715 23 90 2550 2610 2656 2624 2208 2566 14363 19 1241 2117 2964 3145 3218 3221 3203 2759 3150 17757 20 1532 28 67 3936 4100 4188 4201 4167 3676 4118 23224 21 1674 3459 4508 4598 4746 4795 4792 4299 4688 26337 22 lU 1074 253 340 380 3 86 388 377 354 374 2097 23 1287 292 392 433 440 441 429 406 427 2394 24 1508 322 439 492 498 499 487 461 48 3 2713 25 18 07 3 38 464 519 5 24 520 499 463 5 05 28 40
~~ (]I agt
TABLE III Continued
Run No Position CFM h 1 h2 ~3 h4 h5 h6 ~ h
av Nu
av 26 c 1029 1171 1491 1589 15 28 1 4 62 1377 1293 1489 83 44 27 1266 1395 1746 1853 18 02 1685 1556 1453 1728 9704 28 1430 1637 2037 2175 2060 1909 1735 1591 1983 11159 29 1729 1982 24 96 2751 2507 2268 2030 1886 2410 13579 30 12D 1054 2934 4041 4321 4326 4423 4359 3706 4298 24160 31 1294 3385 4 8 26 52 42 5326 5450 5277 4566 52 24 293 50 32 1431 3784 5347 5721 57 bull75 58 44 5700 5084 5677 31870 33 1770 52 75 7 7 33 87 35 9005 9007 8267 7059 85 49 48050 34 lD 1058 3235 4401 4444 3877 3496 3451 3294 3934 21973 35 1263 38 98 5484 5330 4347 3964 3981 3987 4621 25823 36 18 36 6701 89 17 7855 6369 5597 5769 6283 69 01 38718 37 1 12D 1029 2404 31 8 2 3333 3459 3624 3577 3045 3435 19264 38 1315 3182 4033 4162 4310 4496 4502 4015 4301 24142 39 1426 3628 4389 4510 4573 4760 4804 43 8 5 4607 25678 40 1757 4547 5559 5(35 5931 6282 63 70 6060 5975 33471 41 2 11D 1080 2034 28 38 3155 3144 3145 2966 2540 3050 17027 42 1305 2650 3 4 87 3aoz 3595 3751 3595 3153 36 46 20405 43 1434 3167 39 07 4156 4371 4320 4126 3709 4176 23395 44 1804 4096 4 9 66 5691 5714 5586 53 15 48 65 5454 30582 45 12U 1088 409 516 557 564 5 60 535 513 5 46 30 67 46 1318 470 579 6 22 631 6 17 5 97 579 6 09 3422 47 14 13 540 640 676 6 86 681 6 60 6 54 6 69 3754 48 1773 641 740 774 782 7 69 749 746 763 42 87 49 l 11 U 1054 270 356 391 397 393 3 71 346 38 2 2133 50 1240 303 399 446 449 447 4 21 398 432 2420 51 1419 361 476 522 530 528 507 467 493 2760 52 1 1(2U 1032 236 311 342 347 344 325 301 334 18 78 53 1314 270 366 403 407 408 386 351 394 2217
(Tt tO
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ h av Nu av
54 1448 301 408 447 454 452 431 403 438 24 61 55 1782 353 494 548 544 415 529 531 506 2843 56 2U 10 61 220 287 316 320 322 303 268 310 1735 57 1216 249 335 370 377 378 353 307 363 2044 58 1322 263 356 394 398 399 374 327 384 2159 59 1639 310 433 478 481 482 452 393 465 2617
60 1D 10 68 2011 2536 2657 2681 2694 2560 15 62 2625 14938 61 1399 2520 3239 3369 3371 33r82 32 39 1946 3320 18968 62 1669 2781 3655 3820 38 76 3883 3738 2355 3794 21712 63 1959 3524 42 37 4399 4438 4497 4417 3047 4397 25156 64 2295 4426 5288 5396 5372 5240 5410 3369 5341 30680 65 2636 5490 6531 6662 6565 6379 6820 4249 6591 37938 66 3390 7869 9538 9462 9387 8924 10508 62 91 9564 59601 67 1U 1190 352 368 401 413 407 395 293 397 2256 68 1559 397 422 462 475 471 456 331 4 57 2603 69 1904 434 465 5 13 529 528 504 358 508 2901 70 2211 493 526 573 5 92 588 564 4 15 569 3257 71 2289 569 587 6 30 649 6 61 6 49 460 635 36 44 72 2727 637 6 60 7 09 733 751 743 521 719 4140 73 3210 728 755 8 15 8 43 8 62 8 54 616 826 4765 74 2nD 1210 181 2256 2393 2399 2333 2206 1325 2317 13158 75 1420 2340 2752 2899 2913 2850 2728 1701 2828 16121 76 1692 2853 3306 3452 3471 3379 3217 2134 3365 19217 77 1894 3102 3588 3713 3736 3670 3557 2455 3653 20892 78 2301 3682 4259 4433 4467 43 83 4289 2892 4366 250 30 79 2621 4117 4828 5017 5012 5030 5109 3071 4999 28785
m 0
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ hav Nuav
80 3230 5158 6006 62 13 61 18 6134 6695 4094 6233 359 87 8 1 12nD 1155 15 27 1854 2028 2064 20 85 1987 1164 1968 118 31 82 1689 2046 24 8 2 2688 2739 2760 2658 1749 2665 152 73 83 1244 2088 2317 2339 2345 2373 2381 1487 2351 13432 84 2100 3211 3539 34 21 3462 3512 3696 2575 3526 20284 85 2292 3 5 05 3761 3648 36 25 36 79 3957 2933 3734 21517 86 2907 4420 48 22 4679 46 04 4705 5206 3792 48 03 27741 87 33 80 59 35 69 38 7404 77 10 7 8 36 7 0 86 5190 7394 427 44 88 1 12D 1 4 27 2 4 58 28 31 3037 3021 2987 2927 18 57 2 9 61 16913 89 18 75 34 75 3 9 87 4230 4255 4317 4337 2734 4225 24258 90 22 59 4221 4796 5046 5052 51 01 5389 3491 5077 29206 91 2682 4978 5664 5943 5966 6054 6573 408 1 60 40 34795 92 3417 63 16 71 02 7 3 93 7385 75 40 8 6 95 51 45 7623 44017 93 c 1 5 17 1240 1305 1399 1467 1479 1429 9 26 1423 8251 94 20 34 1554 1623 1720 18 21 18 53 18 72 1215 1778 10229 95 2 3 48 1795 1843 198 5 2097 2171 2274 1540 2074 11947 96 2716 2028 2048 22 01 2 3 44 2444 2661 18 90 2340 13505 97 3247 2410 2375 2663 2778 2949 3298 2378 2793 1615 98 11 35 967 1040 1124 1186 1200 1142 728 1138 6496 99 14 06 1135 1220 1318 1384 1403 1 3 61 8 77 1336 7656
100 2311 1 8 54 18 78 1980 20 90 2136 2227 1653 2062 118 31 10 1 2666 2085 2094 2227 2 3 62 2438 2626 1902 2349 13508 102 3392 2635 2582 28 01 3026 3141 3529 2567 3016 17390
103 1 U 1235 349 395 434 436 4 28 411 286 423 2416 104 20 10 434 5 02 559 577 569 5 37 345 552 3177 105 28 14 538 626 685 711 7 21 682 424 6 8 6 3966
Q) j-J
TABIE III Continued
Run No Position CFM h1 h2 h3 h4 h5 hu h7 hav Nuav
106 3492 614 7 1 6 7 84 8 13 8 33 7 85 4 88 7 87 4562 107 4395 7 86 894 964 996 1005 9 64 640 9 65 56 06 108 50 75 9 11 10 22 1081 1112 1125 1085 7 24 1085 63 16 109 G 1344 9 22 1042 1120 1 1 46 1173 1131 7 04 1120 63 87 110 1936 1162 1340 1442 1474 1509 14 7 3 9 09 1441 82 77 111 2846 1631 1797 1902 1966 2027 2079 1342 19 2 3 11108 112 3484 207e 2144 2236 2307 2385 2574 1694 2268 13138 113 4066 24 65 24 42 2535 2648 2757 31 71 2178 2 5 96 15078 114 50 12 3059 2916 30 1 5 3176 3312 4059 2849 3105 180 46 115 1D 1362 2268 26 13 2613 26 35 2605 2503 15 46 2617 14934 116 1958 2993 3580 3580 3586 3539 3 5 02 2144 3571 20492 117 2812 4430 50 32 4913 4 9 86 4991 5196 3088 4981 287 66 118 3432 58 16 62 13 6067 61 18 60 66 6698 4143 61 16 354 16 119 40 22 71 71 7 4 62 7369 7419 7329 82 74 51 8 1 7395 42909 120 5026 105 95 11456 115 81 11574 11548 14010 80 91 11540 671 15 121 2D 1244 18 57 2277 2363 2305 2210 2107 1466 2289 13038 122 1960 2622 3240 3388 33 23 3226 31 40 2)99 3294 18919 123 2817 3762 45 87 4739 46 56 45 14 4 6 47 30 15 4624 26689 124 3491 50 22 5723 58 53 57 44 5542 60 18 3871 57 16 330 73 125 4096 61 29 68 16 69 79 6805 65 90 74 79 4677 67 98 39400 126 5037 82 27 94 60 95 69 93 57 9023 11324 65 05 93 52 542 83 127 12D 1278 14 70 1 6 48 1652 1638 1 6 34 1641 9 73 1 6 43 9369 128 1947 19 63 2155 2149 2151 2131 2190 1347 2147 12342 129 2769 2615 2791 2773 28 52 2716 2954 18 96 2783 1 60 82 130 3439 3208 3265 3239 3593 3133 3624 2515 3308 19174 131 4103 3637 35 88 3577 4077 3459 42 66 3138 3676 21343 132 49 78 45 82 44 60 44 8 1 55 17 43 25 5749 4227 4700 27288
Q) tlgt
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
133 1 12D 1299 2094 2507 2622 2625 2567 2489 1465 2578 14736 134 1973 29 56 3505 3772 3790 3718 3718 2115 3700 21290 135 2788 3941 4727 5069 5099 5 0 07 5231 2984 4976 28781 136 3473 5155 59 81 6308 6339 62 39 68 96 4204 6217 36052 137 4118 6135 71 8 6 7662 7731 76 91 87 16 49 8 5 7568 43985 138 4973 7765 94 75 10396 10861 10694 13646 66 64 10357 602 25
139 1ttn 1253 1242 1493 1460 1442 1431 1424 8 84 1457 83 01 140 2366 1942 2150 1961 1910 1897 19 62 1206 1980 11400 141 3461 3007 2957 2562 2513 2606 3143 18 51 2660 15400 142 4325 3942 3571 3060 2999 3198 4248 2631 3207 18618 143 5677 508 6 4359 39 88 3800 42 29 57 78 36 26 4094 23824 144 67 59 64 55 5330 4988 47 25 5494 2517 48 09 5134 29906 145 84 08 9326 72 26 7726 85 56 9172 12319 7733 8170 47626 146 86 54 9831 7582 818 9 94 90 9869 13116 78 97 8783 512 96 147 7376 7335 58 7 6 5941 5796 68 29 81 65 5954 6111 35662 148 2 11 D 4254 4106 48 02 4994 5038 5042 56 78 3419 4969 28881 149 5708 5487 6253 6466 6524 6527 78 63 45 8 2 64 43 37566 150 69 7 8 7983 9440 9848 98 34 97 32 13249 6701 9714 566 59 151 1254 1434 18 53 1947 1915 1850 1760 1186 1891 10772 152 2713 2696 3175 32 94 3288 3237 3288 20 44 3249 18728 153 87 30 118 07 14733 15758 15504 15305 26297 9617 15325 892 71 154 5811 5278 6543 6861 69 30 69 82 7 8 74 4478 68 29 39531 155 4246 3780 4736 4975 49 66 4936 5162 3113 4903 28301 156 (v 1270 8 15 935 959 966 9 51 9 23 6 35 953 5430 157 2714 1164 1390 1427 1447 1454 1455 9 08 1430 8242 158 4310 1655 18 96 1942 1988 2002 2111 1305 1957 11349
(j) ~
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 fry hav Nuav
159 6012 2208 2400 2450 2513 2548 28 20 18 00 2478 14416 160 7279 2696 2881 2927 2989 3081 3599 2340 2970 17326 161 86 90 3257 3360 3 3 76 34 26 3558 4455 2943 3430 2000 162 12D 4368 2209 2600 2558 2518 2466 2774 1753 2536 14713 163 5833 2730 3092 3028 2974 2913 3501 2287 3002 174 78 164 7643 3320 3681 3630 3651 3530 4623 3181 3623 21116 165 87 39 3920 4303 4300 4708 4178 61 60 3937 4372 25456 166 1268 962 1203 1205 1186 1118 1084 725 1178 6693 167 2678 14 67 1785 1779 1752 1698 1726 10 70 1754 88 49 168 1 12D 12 83 936 1217 1414 1397 1239 1190 7 65 1317 7484 169 2729 2502 2930 2914 2934 2956 2979 17 52 2934 16866 170 4345 3884 4357 4283 4318 4421 4836 28 59 4345 25151 171 6036 5546 5858 5764 5791 6028 7129 4184 5860 34045 172 6578 7167 7769 7907 79 82 8263 10492 5915 7980 46437 173 87 84 10237 112 23 120 26 12727 12968 185 19 85 98 12236 71103 174 1278 1344 1803 18 72 1835 1790 1712 1063 1825 10355 175 2711 2328 2972 2932 2893 28 78 2863 1667 2919 167 51 176 4351 3934 4414 4353 4281 4321 4654 28 63 4342 25088 177 5994 5076 5824 5838 5818 59 29 6914 4205 5852 33885 178 1 11 U 1223 388 432 465 464 449 435 338 453 2585 179 2351 521 602 6 22 675 6 57 619 436 639 3687 180 34 48 6 05 1725 803 8 27 8 11 760 518 792 4593 181 4513 718 850 934 9 68 9 57 8 99 609 9 27 5386 18 2 5714 8 32 981 1060 1102 11 06 1034 6 59 1062 61 82 183 6997 1025 1182 1258 1295 1309 1234 8 18 1261 7 3 44 184 8709 1295 1487 1 5 42 1594 1626 1612 1156 1562 9080
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
185 2 12D 4249 3560 4400 4670 4791 4695 47 81 2931 4639 268 37 186 5737 4926 58 54 61 92 6248 62 38 67 78 4134 6131 35590 187 7432 6390 7726 83 46 85 44 86 34 10371 5658 8313 48310 188 8723 7718 107 88 11933 12099 13046 186 22 79 39 119 67 69505 189 1 4 35 1340 1735 18 57 18 52 17 81 1711 1144 18 06 10256 190 2718 2399 3023 3187 3207 3138 30 53 1931 3139 18025 191 7 5 07 6189 80 11 9200 9427 9703 11364 5720 9085 527 38 192 8544 78 42 10666 125 42 13312 13775 178 20 6976 125 74 729 86 193 1287 1417 16 97 18 7 18 69 18 08 1720 1046 1800 10223 194 27 17 2450 2940 3187 3214 3157 3054 1749 3125 17954 195 42 53 3560 4222 45 90 4679 46 63 4743 2741 4539 26247 196 6068 48 69 57 79 6335 65 8 6 66 04 7172 4338 63 26 366 78 197 7389 58 86 72 8 6 82 23 8584 8936 10658 50 60 8257 4798 6 198 86 88 78 91 100 27 120 56 130 29 14299 190 81 6492 12353 71850 199 5864 4694 5 6 67 61 94 6419 65 48 7192 3950 6207 360 14 200 2 D 4177 38 36 4547 48 09 4775 4628 5006 2715 46 90 261 30 201 5712 5170 62 39 66 38 6599 6604 7518 4167 65 20 378 00 202 73 63 7201 8986 98 43 9733 9914 13353 6219 9619 55810 203 8604 10043 13118 148 41 150 42 158 66 25206 82 5 3 14717 85290 204 12 68 1506 18 41 1971 1966 1868 1799 11 42 1913 10880 205 2659 2571 3127 3276 32 50 3130 3069 18 80 3196 18 350 206 39 80 36 76 4347 4573 45~67 4473 46 34 28 37 4490 25910
o 207 Orifice 11496 10 64 1360 15 39 1 5 80 1 6 15 1496 8 58 15 24 88 83 208 9433 8 95 11 78 13 26 1394 1386 1263 727 1346 78 48 209 7387 746 9 77 1123 1184 1159 1048 6 11 1111 64 74 210 52 36 566 7 66 900 934 909 8 21 499 8 27 48 02
0) CJ1
TABLE III Continued
Run No Position CFM h 1 h2 hs h4 h5 h6 h7 hav Nuav
211 212
3309 1293
414 257
563 3 19
6 68 3 57
6 91 3 37
6 72 351
7 37 337
38 4 2 46
4 40 341
3748 1942
213 214 215 216 217 218
c of 2nd 1 516 1235
1919 2712 3320 4153 4704
1532 2447 35 46 4312 5567 74 29
2 1 87 3312 4225 52 86 6902 8 6 50
2360 3555 4340 56 12 7 0 49 8 9 40
2409 3598 4 8 85 5718 7713 9593
2347 2101 35 33 3453 48 00 49 62 5562 59 86 72~6 7 8 79 93 76 11237
1243 20 64 3054 4 2 8 1 5114 6983
2326 35 00 4638 5545 7225 91 40
132 13 200 27 26672 31968 41711 52811
bull
67
TABLE IV
PRESSURE PROFILE DATA
Baffle Flow Qpening Rate ~p
(Inches) Position (CFM) (Inches 295 S G Fluid)
1 364 l2 11 U 1012 0 254 1248 0197 1493 0 141 1718 0112
c 1000 9 80 1210 1710 1436 28 75 1746 4320 1011 1080 1277 2050 1393 3020 1 6 28 4450
12D 1011 9 75 1236 1520 1450 2510 1603 3450
1 D 1011 975 1256 1700 1480 2690 158 1 4070
1 12D 1010 950 1259 1750 1462 2650 1631 3710
2 11 D 1124 1315 1360 2130 1505 2850 1689 4125
1 216 12U 1294 045 1949 0324 2374 0282 2704 0225 3367 0169
c 1326 265 18 81 5 90 2313 990 2731 1480 3439 2660
12D 1272 2 49 1957 661
68
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Pos ition (CPM) Inches 2 95 S G Fluid)
2559 1275 3033 1940 3639 3025
1 216 1nD 1257 242 16 96 476 2117 8 05 2561 1280 2990 1895 3431 26 bull00
1 316 12U 1309 0 479 2004 0422 28 28 0 352 3526 0281 42 28 0225 5199 0225
c 1308 1 43 1998 272 28 14 5 10 3478 795 4248 1235 5048 1885
l2D 1286 140 2005 3 45 2831 725 3495 1180 4194 1805 5046 2945
1 11D 1322 150 2039 352 2841 735 43 77 1980 5378 3440
1 516 12U 1278 0493 2732 0493 4315 0408 5744 0352 7494 0352 8932 0422
c 1300 0 506 2731 1985 4310 348 6080 6 45
69
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Position (CPM) (Inches 295 SG Fluid)
7607 1090 8830 1585
l2D 1343 0549 2738 225 4566 583 6112 1195 7536 2055 9043 3415
1 516 1uD 1249 0464 2713 224 4155 579 5620 1150 7428 2115 90 70 3405
1 12D 1301 0493 2735 220 4501 616 61 50 1235 7440 2065 8862 3445
2D 1265 0 478 2750 226 4366 594 6578 1270 7678 2240 8945 5280
2 12D 1295 0493 2725 222 4293 600 5807 1120 7568 2200 9070 3615
TABLE V
RATE OF HEAT TR AN SFER Ar THE BAFFL~~ CID-TT ER
Orifice Size
(Inches)
Flow Rate
( CFM)
Re d e G tU
R~) 055 Nuav NuPr-l3
1 364 10 26 12 90
8 075 10015
43400 54 600
85 11 99 64
95 83 112 19
1416 11 140 59 900 110 30 124 20 16 27 12 800 68 900 126 64 142 60 17 29 13 610 73 200 135 79 152 90 17 76 13980 75 200 147 59 166 19
1 216 11 35 14 06
8 600 10 660
27000 33500
6 4 96 76 56
73 14 8 6 12
1517 11500 36100 82 51 9291 20 34 15400 48400 10229 115 18 23 11 17500 55000 118 31 13322 2348 17 800 55900 11947 13452 2666 20 200 63400 13508 15210 27 16 20 600 64700 135 05 152 07 32 47 24600 77200 161 57 18 193 3392 25 700 80700 17390 195 8 1
1 316 1344 19 36
9898 14 260
24800 35 700
63 8 7 8 2 77
71 92 93 20
28 46 20 9 60 52 500 111 08 125 08 34 84 25 660 64200 131 38 147 93 40 66 50 12
29900 36900
74800 92400
150 78 18046
169 78 203 20
~ 0
TABLE V Continued
Orifice Flow Re Size Rate d e G R~rmiddot55 NuPr-13(Inches) (CFM) U Nuav
1 516 12 70 8 847 16800 54 ~0 61 14 2 14 18 900 35800 82 42 92 80 43 10 30 000 56900 11349 127 79 60 12 41900 79400 14416 16232 7279 50700 96100 17326 19509 86 90 60540 115000 20098 22529
TABLE VI
RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
Orifice Size
(Inches)
1 364
1 216
1 316
Flow Rate
(CFM)
1054 1294 1431 1681 1770
1068 1399 1669 1959 2295 2636 3390
1299 1973 2788 34 73 4118 4973
Re deG Mshy
8 300 9870
11260 13200 13 930
8100 10600 12650 14850 17400 19980 25700
9 570 14500 20500 25600 30300 36600
R~r-6 51900 61700 70500 82 500 87 100
28200 36900 44000 51700 60 600 69500 89400
26100 39600 56000 69900 82700 99 900
Nuav
2416 293 5 3187 4018 4805
14938 18968 21712 25156 30680 37938 59601
14736 21290 28781 36052 439 85 60225
Uu Pr-1 3
27204 33050 3589 4524 541 0
16820 21358 24448 28326 34546 427 18 67111
16593 23973 32407 40595 495 1 678 13
TABLE VI Continued
Orifice Flow Re Size Rate deG R~rmiddot6 NuPr-13(Inches) (CFM ) M- Nuav
1 516 1268 88 30 17700 108 8 1225 2689 18700 37400 1835 2066 3980 27700 55700 2591 2917 4177 29100 58 500 2713 3055 5712 39800 80000 378 0 425 6 7362 51300 103000 5581 6284 8 604 59 900 120000 8529 9604
74
TABLE VII
EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER
l 516 Inch Orifice
Center ot 2nd Baffle 4 Downstream
Plow Rate (CFM)
1235 1919 2712 3320 4153 4704
Flow Rate (CFM)
1270 2714 4310 6012 7279 8690
(Re)eb -8600 1321
13400 2003 18900 2687 23100 5197 28900 4171 32800 5281
Center ot Single Battle
-8847 543
18900 824 30000 1135 41900 1442 50700 1733 60540 2001
(Nu)(Pr)-l3
1487 2255 3003 3600 4697 5946
(Nu)(Pr)-13
611 928
1278 1623 1951 2253
75
ABLE VIII
HEAT TRANSFER IN THE TEST SECTION WITHOUT ORIFICE
CFM Ute) 0b h Nu
1293 5-951 3 41 1942
33 09 15251 649 3746
5236 24193 827 4802
7387 34001 1111 6474
9433 43419 1346 7848
11496 52-914 1524 8883
76
TABLE IX
PRESSURE DROP FUNCTION
Orltlee Size Flow Rate incbea ~CFM (Re)eb X 10bull8
1 364 1011 7957 0808 1256 9885 1468 1480 11648 2765 1581 12443 4160 1689 1_3293 4 020
1 216 1257 9530 1327 1696 12858 2663 2117 16049 4615 2561 19415 7581 2990 22668 11560 3431 26011 16440
l 316 1322 9736 1819 2039 15016 4332 2845 20952 9275 3495 25739 15300 4377 32014 26800 5378 39607 50100
1 516 1011 7 957 oaos 1256 9885 1469 1480 11646 2765 1581 12443 4160 1689 13293 4020
77
TABLE X
EXPERIMENTAL DATA
Baffle Hole Diameter Run No
1 - 59
60 - 102
103 - 138
139 - 206
207 - 212
213 - 218
(Inches)
1 364
1 216
1 316
1 516
No Baffle
2nd - 1 516
TABLE X
EXPERIMENTAL DATA
Run Thermocouple Reading s (mv) No Position CFM I tc1 tc2 tc3 tc4 t c 5 tc6 tc7 tcair
1 c 1026 530 2055 1825 1768 1782 1802 1837 1965 1198 2 1290 612 2059 18 65 1809 18 32 1851 1880 1965 1160 3 1416 714 2151 1970 1931 1965 1988 2026 209 5 1130 4 1627 8 21 2235 2084 2 049 2093 2126 2173 2266 1130 5 1776 865 2203 2033 1970 2015 2084 2159 2 264 1121 6 12D 1109 542 1636 1507 1499 1499 1498 1498 1528 1218 7 1258 651 1670 1522 1503 1513 1513 1516 1548 1221 8 1433 750 1625 1480 1467 148 3 1487 1487 1516 1153 9 168 1 8 73 1656 1494 148 1 1511 1517 1517 1543 1159
10 1rtD 1102 485 1545 1450 1437 1446 1447 1442 1466 1220 11 13 08 6 10 1571 1470 1460 1476 1476 1469 1498 1194 12 1464 730 1 623 1509 1508 1528 1 5 32 1524 1548 1173 13 11 06 8 71 1663 1559 158 1 1606 160 6 1 583 1601 1190 14 1 12D 1115 520 1698 1579 1575 1 577 1580 1590 1615 1280 15 1275 6 10 1692 1567 1558 1 561 1570 1580 1601 1234 16 1498 770 1760 1619 1630 1 635 1642 1645 1661 1204 17 1695 912 1775 1635 1670 1689 1686 168 6 1701 1165 18 2D 1049 510 1736 15~2 1567 1558 1 553 1558 1620 1236 19 12 41 610 1655 1517 149 1 148 1 148 1 148 4 1546 1108 20 1 5 32 7 35 1720 1550 1530 1520 1519 1523 158 0 1104 21 16 74 8 8 0 1900 1 727 1714 1696 1691 1692 1753 1169 22 1U 1074 38 5 3 324 2740 2534 2478 2 465 2503 258 0 1210 23 1287 4 35 3510 2 870 2682 2 610 2599 2638 27 1 9 1190 24 1 5 08 470 3 618 2920 2690 2 637 2627 2 664 2747 1177 25 18 07 525 4 088 3235 2962 2905 2910 2988 3130 1169
z ())
TABLE X Continued
Run No Position CFM I tc1 tc 2
Thermocouple Readings te3 tc4 tc5
(mv) tc6 tc7 tcair
26 c 10~29 6 32 2340 2~092 2032 2060 2~097 2152 2~213 1211 27 12 66 679 2270 2 047 1993 2013 2069 2142 2 210 1 182 28 1430 723 2336 2097 2033 2080 2153 2~255 2 356 1 138 29 1729 8 52 2318 2070 1980 2061 2158 2279 2367 1121 30 12D 1054 570 1520 1 4 20 1402 1400 1396 1400 1 443 1159 31 1294 6 69 1599 1469 1444 1439 1433 1 442 1485 1168 32 1430 7 88 1720 1562 1536 1532 1528 1537 158 0 118 5 33 1770 8 81 1641 1488 1450 1~441 1 441 1_466 1518 1 163 34 1D 1058 548 1579 1498 1495 1526 1553 1_557 1 571 1 276 35 1263 640 1609 1509 1515 1570 1599 1598 1 598 1 266 36 18 36 8 47 1538 1452 1483 1553 1602 1 590 1 558 1195 37 1 12D 1029 5 41 1 578 1499 148 4 1473 1461 1465 1-512 1200 38 1315 6 30 159 1 1504 1493 1482 1470 1470 1505 118 5 39 1 4 26 743 1765 168 1666 1660 1645 1642 1678 1270 40 1757 8 54 1744 1648 1634 1620 1598 1 593 - 1612 1223 41 2D 1080 5 30 1734 1604 1570 1 570 1570 1 588 1 640 128 1 42 1305 6 40 1744 1622 1589 1 608 1593 1 609 1 661 1240 43 1434 750 1798 1687 1658 1 636 -1641 1 661 1 711 1_220 44 18 04 8 41 1 764 1666 1607 1605 1614 1 635 1 675 1205 45 12nu 1088 415 2614 2295 2195 2 169 2174 2217 2256 1171 46 1318 477 2805 2477 2371 2342 2364 2 401 2 438 1 163 47 1413 5 28 2930 2 646 2 555 2 526 2532 2570 2 577 1 199 48 1773 550 2740 2518 2450 2431 2448 2 479 2 480 1 170 49 1 11 U 1054 380 3175 2670 2505 2 461 2467 2 534 2 621 1 258 50 1240 420 3268 2738 2 546 2 510 2 508 258 2 2 649 1214 51 1419 451 3364 2B07 2 632 2590 2 590 2 651 2773 1 215 52 1 12U 1032 360 3 165 2 629 2 450 2402 2403 2 473 2 bull568 1 163
--I lt0
TABLE X Continued
Run No Position CFM I tc1 tc2
lhermocoup1e Reading s tc3 tc4 t c 5
(mv) tc6 tc7 tc a ir
5 3 1314 38 9 3178 2592 2411 2367 2361 2432 2555 1140 54 1448 403 3095 2544 238 1 2336 2336 2390 2476 1158 55 178 2 427 3006 2434 2286 2253 255 3 2299 2397 1154 56 2 11U 1061 360 3369 2814 2619 2567 2560 2650 2833 1220 57 1216 360 3044 2512 2338 2290 2288 2374 2566 1150 58 1322 387 3196 2614 2425 2383 2382 2472 2670 1138 59 1639 403 3020 2438 2272 2238 2238 2318 2502 1127
60 1D 1068 612 1552 1424 1400 1395 1396 1426 1745 0945 61 1399 612 1355 1246 1230 1229 1230 1250 1509 0872 62 1669 710 1436 1293 1272 1265 1266 1286 1551 0847 63 1959 900 159 5 1468 1444 14 38 1432 1446 1720 0851 64 2295 730 1169 1105 1098 1099 1108 1100 1298 0781 65 2636 8 80 1202 1129 1121 1126 1 138 1115 1342 0748 66 3390 9 35 1060 o 9s7 0999 1001 1017 0971 1154 0703 67 1nu 1190 370 2225 2188 2104 2080 2120 2209 2 7 15 0990 68 1559 368 2005 1950 1871 18 48 1876 1951 2408 0916 69 1904 368 1870 18 1 4 17 34 1711 1730 18 07 2238 0875 70 22 bull11 471 228 6 2 204 2099 2063 2092 218 $ 2732 0840 71 2289 471 2030 2000 1925 1895 18 96 19 5 2498 0785 72 2727 4 71 1854 18 23 1753 17 23 1716 3758 2241 0743 73 3210 471 1680 1651 158 6 1559 1551 158 1 1950 omiddot7o9 74 2uD 1210 404 1261 1212 1198 1197 1205 1222 139 1 0978 75 14 20 540 1321 1260 1242 1 240 1249 1268 148 7 0918 76 1692 7 18 1467 138 6 1364 1361 1376 1405 1678 0883 77 18 94 903 1708 1 591 1565 1560 1575 1603 1948 0 857 78 2301 903 1530 1432 1407 1402 1415 1432 1738 0815
ro 0
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc117 tcair
79 2621 6 50 1069 1 020 1009 1009 1009 1007 1~189 o739 80 3230 901 1200 1128 1113 1119 1119 1086 1341 0694 81 82
l2D 1155 1689
360 575
1191 1345
1142 1252
1122 1218
1118 1210
1118 1209
1132 1228
1292 1446
0916 0822
83 1244 430 1163 1134 1131 1130 1129 1132 1292 0877 84 2100 645 1175 1135 1147 1 142 1138 1122 1286 0757 85 2292 8 25 1 354 1310 1327 1330 1323 1285 148 6 0728 86 2907 8 23 1180 1138 1151 1158 1149 1107 1268 0687 87 3380 902 1113 1049 1025 1011 1006 1042 1178 0673 88 89
1 12D 1427 1875
480 615
118 2 1140
1140 1095
1124 1077
1125 1075
1129 1072
1137 1072
1290 1243
0880 0790
90 2259 8 41 1296 1231 1207 1206 1203 1182 1419 0757 91 2682 8 80 1231 1170 1149 1147 1142 1112 1350 0731 92 3417 940 1142 1092 1076 1076 1069 1021 1252 0693 93 c 15 17 431 1321 1298 1268 1249 1250 1273 1522 0841 94 2034 505 1285 1263 1235 1209 1205 1206 1464 0759 95 2348 6 10 1395 1379 1334 1302 1286 1268 1536 0732 96 2716 706 1486 1480 1427 1383 1358 1311 1572 0 700 97 3247 7 56 1417 1430 1375 1320 1284 1223 1450 0660 98 1135 400 1425 1388 1352 1329 1330 1 364 1651 0893 99 14 06 440 1379 1341 1304 128 2 1281 1305 1583 0 831
100 2311 680 1602 1593 1553 1514 1502 1480 1 7 27 0 802 101 2666 680 1471 1469 1428 1390 1372 1335 1564 0761 102 3392 798 1491 1 509 1449 1395 1372 1305 1534 0 719
103 1U 1235 410 2469 2295 2173 2165 2226 2361 3120 0 897 104 2010 410 2017 1848 1 737 1706 1747 1865 2582 0753 105 28 14 410 1682 1535 1457 1427 1437 1520 2109 0 660
00 t-
TABLE X Continued
Ru n Thermocouple Rea ding s (mv No Positi on CFM I tc1 tc2 tc3 tc4 tc5 tc6 tc7 tcair
106 3492 440 1649 1499 1420 1391 1390 1470 2042 0620 107 4395 550 18 33 1679 1597 1564 1570 1640 2223 0583 108 5075 588 1779 1642 1580 1550 1552 1 615 2 191 0548 109 c 1344 398 1464 1 399 1364 1353 1350 1380 1689 0 907 110 1936 459 1369 1290 1253 1242 1 237 1259 1574 078 2 111 2846 580 1347 128 5 1251 1232 1220 1215 1 5 23 0 683 112 34 8 4 700 1392 1369 1339 1317 1299 1259 1599 0 636 113 4066 8 13 1449 1458 1427 1391 1363 1270 1595 0 591 114 5012 930 1484 1530 1500 1453 1420 1272 1580 0 580 115 1D 1362 513 1269 1218 1 217 1214 1220 1238 1460 0 893 116 19 58 600 1187 1122 1121 1120 1124 1133 1352 0798 117 2812 705 1052 1008 1015 1010 1011 1001 1218 0691 118 34 32 913 1105 1075 1085 1081 1086 1047 1301 0645 119 4022 980 1038 1021 1026 1023 1029 0983 1211 0 609 120 5026 982 0 8 61 0839 0836 0836 0837 0791 0955 0570 121 2D 1244 475 1320 1246 1233 1240 1255 1275 1434 0925 122 1 9 60 5 50 1160 1088 1074 1079 1089 1100 1260 078 7 123 2817 6 80 1096 1024 1 013 1018 1029 1022 1201 0 700 124 3491 960 1248 1175 1163 1172 1192 1153 1435 0 658 125 4096 989 1141 1089 1078 108 9 1105 1051 1310 0629 126 50 37 989 0983 0933 0929 0 936 0949 0880 1090 0 602 127 128
12D 1278 1947
402 545
1270 1261
1 230 1216
1228 1216
1230 1 215
1235 1223
1242 1219
1483 1514
0 913 0778shy
129 2769 695 1273 1234 1237 1221 1251 1212 1525 0678 130 131 132
34 39 4103 4978
8 40 9 80 9 80
1336 1448 1271
1322 1458 1 288
1328 1 462 1286
1 259 1 356 1157
1353 1492 1311
1261 1329 1138
1 555 160 7 1343
0 629 0 600 0599
(l) l)
TABLE X Continued
Run No Position CFM I tel tc 2
Thermocouple Readings tc3 tc4 tc5
( mv) tc6 tc7 tcair
133 1 l2D 1299 5 16 1 28 1 1212 1196 1195 1205 1221 1478 0869 134 1973 6 15 1163 1098 1073 1071 1079 1083 1343 0751 135 136
27 88 34 73
802 9 -_78
1187 1214
1099 1131
1069 1104
1066 1101
1075 1~110
1l061 1066
1370 1360
0662 0618
137 4118 9 81 1084 1010 0983 0979 0982 o937 1209 0581 138 4973 98 1 0969 0897 0 868 0855 0860 0799 1041 0572
139 1D 1253 409 1371 1293 1298 1301 1309 1321 1578 0928 140 2366 480 1130 1 090 1 121 1130 1137 1132 1390 0744 141 34 61 6 38 1081 1086 1152 1161 1147 1069 1382 0644 142 143 144
4325 5677 6759
7 90 939 998
1110 1115 1034
1161 1208 1139
1253 1268 1180
1265 1302 1215
1228 1230 1123
1080 1056 0970
13$913r12 8
0601 0561 0542
145 84 08 989 0863 0961 0934 0895 0871 0 785 09 9 0530 146 86 54 9 80 0808 0901 0 872 0821 0809 0733 0891 0498 147 7376 9 80 0 927 1032 1027 1 040 0961 0889 1032 0511 148 2D 4254 776 1 050 0 981 0965 0961 0962 0922 1155 0579 149 5708 991 1102 1031 1014 1009 1010 0931 1227 0528 150 69 78 990 0914 0853 0839 0 839 0843 0759 0996 0521 151 1254 490 1 479 1352 1329 1334 1351 1379 1607 0930 152 2713 7 00 1310 1220 1201 1201 1211 1209 1516 0723 153 8730 991 0809 0756 0742 0745 0 748 0663 0874 0543 154 5811 966 1219 1108 108 6 1081 1079 1033 1330 0650 155 42 46 8 02 1248 1136 1114 1114 1118 1103 1376 0 699 156 c 1270 429 1671 1571 1551 1545 1563 1600 1933 0929 157 2714 488 1398 1285 1 267 1258 1262 1275 1628 0729 158 4310 642 1424 1318 1299 1282 1283 1261 1683 0617
co ~
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc7 tc a 1r
159 60 12 780 1461 1388 1370 1349 1343 1279 1700 0 573 160 72 79 8 60 1402 1344 1330 1312 1292 1189 1 566 0 520 161 8690 982 1472 1442 1437 1 422 1392 1224 1602 0 521 162 163
12D 4368 5833
6 30 8 30
1195 1368
1105 1270
1111 1283
1117 1294
1131 1313
1081 1194
1369 1553
0613 0 553
164 76 43 959 1428 1338 1348 1341 1371 1180 1488 0535 165 8739 984 1345 1272 1272 1208 129 3 1059 1361 0550 166 1268 459 1701 1548 1541 1547 1589 1 625 1976 0 973 167 2678 570 1485 1351 1349 1356 138 1 1 385 1795 0760 168 169
1 12D 128 3 2729
448 650
1664 1314
1501 1232
1425 1233
1428 1229
1491 1229
1527 1232
1869 1571
0 962 0767
170 4345 847 1245 1179 1187 1182 1172 1132 1476 0 650 171 6036 9 76 1139 1109 1117 1114 1095 1020 1332 0588 172 6578 9 72 0982 0949 0942 0938 0926 0 8 50 1079 0560 173 87 84 9 72 0880 0854 0 8 36 0822 0818 0 749 0941 0585 174 1278 480 1564 1416 1397 1403 1417 1445 1733 0998 175 2711 590 128 3 1175 4 1178 1182 1187 1195 1493 0796 176 4351 8 90 1331 1259 1266 1275 1272 1235 1592 0 682 177 5994 9 60 1228 1152 1150 1151 1143 1075 1 360 0644 178 lU 1223 408 2282 2140 2052 2052 2106 2188 2626 0 878 179 2351 408 178 1 1623 158 5 1519 1556 1634 2068 0717 180 3448 482 1888 1675 1570 1541 1572 1665 2199 0629 181 4513 563 2026 1797 168 4 1644 1670 1770 2385 0583 182 5714 589 1913 1700 1610 1568 1580 1 682 2382 0551 middot 183 6997 653 1903 1718 1643 1611 1612 1700 2326 0 549 184 8709 6 80 1738 158 3 1543 1510 1498 1519 1 912 0577 185 186
2 12D 4249 5737
660 9 74
1055 1221
0 979 1122
0960 1093
0 952 1088
0959 1090
0 956 1054
1147 1350
0661 0602
187 7432 9 8 1 1065 0981 0951 0942 0 939 0881 1135 0582 CD ~
TABLE X Continued
Run No Position CFM I t o1 to 2
188 87 23 9 83 0944 0 879 189 1435 585 18 26 1630 190 2718 690 1433 1298 191 7507 950 1070 0961 192 85 44 964 0982 0 881 193 1287 600 1806 1668 194 2717 7 80 1579 1444 195 4253 8 81 1371 1260 196 60 68 9 78 1252 1152 197 73 89 975 1100 1000 198 86 88 973 0953 0 871 199 58 64 9 81 1269 1155 200 2D 4 1 77 915 1362 1251 201 5712 975 1213 1111 202 7363 9 78 1036 0 951 203 8 604 973 0932 0861 204 1268 6 95 2015 18 20 205 2659 6 96 1405 1295 206 39 80 7 98 1261 1174
No 207 Orifice 114 96 509 1325 1148 208 94 33 509 1477 1243 209 7487 5 09 1686 1409 210 5236 505 2094 1691 211 3309 428 2188 1 778 212 1293 392 2976 2560
Thermo ooup1e Readin g s (mv) to 3 to4 to
5 to
6 to7 toair
0 851 0847 0 8 29 0759 0987 0592 158 4 1583 1611 1647 1993 0986 1270 1266 1 279 1298 1604 0 789 0916 0908 0900 0 858 1115 0602 08 39 0 823 0 818 0 770 1035 0602 1609 1602 1629 1676 2153 0979 139 1 1385 1400 1 430 1938 0776 1212 1201 1205 1201 1601 0669 1 105 1086 1086 1 052 1371 0621 0952 0936 0923 0870 1195 0582 0 8 20 0 801 078 1 0 729 1044 0569 1108 1090 108 2 1043 1407 0610 1218 1221 1241 1202 1582 0659 1081 1083 1084 1031 1 368 0622 0921 0924 0919 0 841 1111 0 610 08 34 0831 0 821 0 751 1003 0 630 1761 1761 1 809 1861 2399 0966 1271 1271 1295 1311 1650 0797 1150 1150 1161 1149 1440 0703
1083 1057 1053 1109 1566 0~530 1158 1125 1138 1217 1763 0 526 1291 1250 1278 1383 2038 0542 1518 1478 1519 1657 2420 0 589 1596 1557 1601 1737 2441 0688 2370 2344 2409 2561 3 297 0921
()) (11
TABLE X Continued
Run Thermocouple Readings (mv) No Position CFM I tc 1 tc2 tc3 tc4 tc tc tc tc i5 6 7 a r
C of 2nd 213 516 1235 4 63 1 432 1291 1265 1258 1 268 1 308 1550 0 971 214 1919 6 17 1357 1223 1196 1191 1199 1211 1461 0 851 215 27 12 8 35 1401 1259 1278 1220 1230 1218 1511 0 762 216 3320 981 1439 1305 1270 1259 1275 1238 1450 0719 217 41 53 980 1251 1142 1132 1094 1121 1088 1305 0 695 218 404 987 1102 1042 1030 1 bull006 1014 0960 1133 0681
Supplementary Equations
Calculating temperatures from thermocouple readings
t = -026tc)2 + 3512(tc) + 3201 (26)
where t is the temp in deg F and tc is the thermocouple reading in millishyvolts
Calculation of the thermal conductivity of air
k = 00000245ta + 0 0132 (27)
where k is the thermal conductivity in Btuhr rt2 degFft and ta is the air temp 1n OF
I I
bull co m
13
THERMOCOUPLE JUNCTIONS~ ~------- HOLES FOR THERMOCOUPLE LEADS
~----- SCREWS
~ff+--- CONNECTING BARS
END VIEW
POWER LEADS SOLDERED TO LOWER CONNECTING BAR
iER PLASTIC PIECE
RESISTANCE RIBBONS LOCATION OF THERMOCOUPLES
FIGURE 4 DRAWING OF ASSEMBLED SENSING PROBE
15
Vibradamp support to absorb the vibrations produced by the
air blower
Air Source
Air was used as the shell-side cooling fluid during
the study The air was pumped through the test section by
a Roots type air blower with a rating of 280 ofm at 3 12
psig outlet pressure The hot air leaving the blower was
passed tbxfugh two finned-tube box-type coolers and one
tubular edoler to oool it to approximately room temperature
The air flow rate was measured by passing it through a
flow measuring orifice in the line Two sharpbull edged orishy
ficas were used f or flow measurements The calibration
curves for these orifices were presented by Ambrose (1
p 166)
The pressure taps on each side of the orifice were
connected to two differential manometers containing 0 83
and 2 95 specific gravity fluids respectively The presshy
sure drop through the test section and test orifice was
measured by a pressure tap placed 13 inches upstream and
one placed 6 12 inches downstream from the orifice Two
pressure ga ges were used to measure the pressure at the
inlet to the flow orifice and to indicate the statio pres~
sure at the test section inlet
16
Pressure Probe
A probe was designed to measure the pressure drop
between the pressure tap 13 i nches upstream from the ori shy
fice baff le and any point downstream from the tap The
probe eonsisted of a l~in OD copper tube with six 132
i n ch holes even l y s paced around the tube The upstream
pressure tap and the pressure probe were connected to a
differential manometer so the pressure drop to various
points up- and downstream of the orifice could be measshy
ured
17
CHAPTER IV
EXPERIMENTAL PROGRAM
The experimental program was designed to measure the
heat transfer coefficients and pressure drops in the vicinshy
ity of annular orifices The four orifice sizes studied
were 1 364 1 216 l 316 and 1 516 inches~ The inner
tube used in each case was a 1-in OD alumintim tube
Hence tube to baffle clearances were respectively 3128
232 332 and 532 of an inch
Heat transfer coefficients were measured at poait~ons
1 i nch upstream at the orifice center and at 12 1
1 12 and 2 inches downstream for all orifices In addishy
middottion the heat transfer coefficient at a point 2 12
inches downstream from the 1 516 inch orifice was measured
and at the points 12 l 12 and 2 inches upstream from
the 1 364 inch orifice
The heat transfer coefficients at each point were
measured at five different flow rates for the 1 364 inch
orifice and at six different flow rates for the other orishy
fice sizes The high pressure drop through the small orishy
fice size limited the number of flow rates which could be
studied
The flow rate was calculated from the pressure drop
across the flow orifice This flow was corrected to cubic
feet per minute at 68degF and one atmosphere pressure by
18
using the orifice pressure and the test section pressure
which were measured by pressure gages
It was desired to determine a relationship between the
heat transfer coefficient and the total pressure drop for
each orifice size The pressure drop across each orifice
at various flow rates was measured by means of the presshy
sure probe described in Chapter III It was also desired
to obtain pressure profiles for each orifice size since
these might be similar to the heat transfer profiles The
pressure drop was measured from a point 13 inches upstream
of the orifice to points at 1 and 12 ineh upstream the
orifice center 12 1 1 12 and 2 inches downstream
The experimental program is summarized in Table I
TABLE I
SUla~RY OF EXPER IMENTAL PROGRAM
Position Investigated-Distance from Orifice-Inches
Orifice Range of Flow Rate Size Heat Transfer Pressure Drop CFM at 68degF amp 1 atm
1 364 2U 1 12U 1U 12U c 12U C 12D lD 10 - 18 l2D lD 1 12D 2D 1 12D 2D
1 216 1U c 12D lD 1 l2D 2D 12U c 12D lD 10 - 35
1 316 1U c 12D lD 1 l2D 2D l2U C 12D lD 12 - 50
1 516 1U c x2D lD 1 l2D 1U 12U C 12D 12 - 90 2D 2 1 2D l D 1 l2D 2D 2 12D
20
CHAPTER v
EXPERI MENTAL PROCEDURE
The experimental procedure for measuring the heat
transfer coefficients ~d corresponding flow rates reshy
quired the following procedure
(1) Install the orifice size to be studied in the
test section
(2) Place the heat transfer probe in the position up
or downstream from the orifice where the middot heat
transfer rate is to be studied
(3) Fill the cold junction thermos with cracked ice
(4) Measure the atmospheric pressure
(5 Open bypass line from blower and close line to
test section
(6) Turn on the cooling water for the exchangers used
to cool the air leaving the blower
(7) Start the automatic selen ium rectifier by turning
on the t 1mer bull
(8 ) Connect the voltage stabilizer to the wall outlet
(9) middot Set the slide wire resistor to the maximum re shy
s1atanee I
(10) Start the blower
(11 Open the line to the test section until the de shy
sired flow rate is obtained
(12) Switch on the probe direct current power source
21
(13) Adjust the slide wire resistor to obtain the
desired current
(14) After the thermocouples have reached equilibrium
values record the e m bullf across each of the
seven probe thermocouples and also the entering
air thermocouple
(15) Record the direct current amperage
(16) Record the gage pressure at the flow orifice and
the entrance to the test section
(17) Record the manometer measurement of the pressure
drop across the flow orifice and also the presshy
sure drop through the test section
22
CHAPTER VI
CALCULAT ION OF EXPERIMENTAL DATA
The local heat transfer coefficients were calculated
from the temperatures measured on the probe surface the
air temperature and the current input The results were
calculated by using the Alwae III-E computer
The general expression for calculation of the heat
transfer coefficients was derived by Ambrose (1 p 79)
The equation is derived by making an energy balance around
a small increment of the center resistance heating ribbon
The two ribbons tnstalled adjacent to the center ribbon
reduced the amount of logitudinal conduction and assured
little longitudinal temperature variation in the center
ribbon
A heat balan ce on this small increment of resistance
ribbon yields the following
(the heat conducted in) + (heat generated) = (heat
conducted out) +(Heat convected to the fluid) + (heat
radiated to the surroundings) + (Heat conducted into
the plastic center of the probe)
This gives the equation
kzw dtdS + 12RdS kzws [ t + (~) ds] + hwdS (t-ta )
+ ~Aad wd o middot+ qcAond 1 -~- wdS 5 )
23
Hence solving for h gi~ea
i2R kz d2t Qrad qcond w + -d$2 - ~- A
h = ( 6)t - ta
Since S = re where 9 equals the enclosed angle ~n radians
dS rd9 ( 7)
and
dt - dt (8)dS - rd9
Differentiating with respect to S
d2t (9)rd9dS
from which
(10)
Substitut1ng into the equation for heat transfer coeffishy
cient gives
h = i2R Qcond A (11)
w
The rate of radial heat conduction into the plastic
tube making up the probe was assumed to have negligible
effect on the heat transfer coefficient It was also
assumed that the heat loss by radiation from the ribbon
was negligible since all data were obtained with the ribbon
at a temperature less than 125degF
24
When t he rad iation and conduction terms are neglected
Eq (11) becomes
(12)
The following con stants are known
R = 0 271 ohmsft
w = 100 i n ches
k = 763 Btuhr rt2 degFft
z = 0 002 inches
r = 12 inch
Eq (12) putting 9 in degrees then reduces to
1110 12 + 2404 d 2t d92
( 15)h = ------~--~-------t - ta
Thi s equation was programed for the Alwac III- E comshy
puter and used to calculate the local heat transfer coefshy
ficients from the observed data
The average heat transfer coefficient around the tube
at a given position in the t est section was calculated by
averaging the local coefficients calculated from Eq (13 )
It was found 1n the course of the experimental work
that thermocouple numbers 1 and 7 were indicating higher
temperatures than would be expected This resulted in h1
and ~ being lower than the other local coefficients around
the tube Since the fluid was flowing parallel to the axis
of the probe the circumferential variation i n rate of heat
25
transfer should be small Hence in obtaining the average
coefficient around the tube the values of h1 and h7 were
not used even though they were calculated and are tabulated
1n Table I II in the Appendix
Then
(14
A Nusselt number as calculated from this aver age heat
transfer coefficient using the tube diameter as the characshy
teristic dimension
(15)
The air flow rates through the test section were calshy
culated by measuring the pressure drop across the flow orishy
fice the air temperature the pressure at the flow orifice
and the pressure at the entrance to the test section The
orifice calibration curves (1 p 166 ) were used to obtain
a value of the orifice coefficient f8e where Q equals
the flow in cubic feet per minute at 68deg F and one atmosmiddot
phere pressure and te is the density of air at the exchanger
and e the density of the air at the flow orifice The
den sity of the air can be expressed by
e = 2 703 p (16)T
where T equals the temperature in OR and P equals the absoshy
lUte pressure i n lb1n2 Using the value of e Qfo from
26
the calibration charts as A and Eq (16) solving for Q
gives
( 17
This equation was used to calculate the flow rate for
each flow studied
The Reynolds number used i n the correlation of the
data was the equivalent Reynolds number defined as
Re)eb ~ d2 - dl)Uf ( 18 ) lL
where d1 is the outside diameter of the inner tube and d2
is the orifice diameter U is the flow velocity through the
annular orifice e is the density of the air and U- is t he
viscosity of the air This equation can be transformed t o
(Re) b = 1611 Q (19) e dl + d2
where d1 and d2 are in inches
The pressure drop data were calculated i nto a dimenshy
sionless pressure drop function cent where
d1 )22( ~ P)gc f av(d2 shycent 2 bull (20
M-
For air this equation reduces to
where d2 and d1 are in i nches D P is expressed i n inches of
2 95 specific gravity fluid and P av is expressed as lbft3
27
CHAPTER VII
ANALYSIS OF DATA
In analyzing the heat transfer data an attempt was
made to correlate it 1n terms of the dimensionless groups
(Nusselt number Prandtl number and Reynolds number) which
appear in Eqs (3) and (4) Consequently all of the av~
erage heat transfer coefficients hav were brought into
the form ( Nu)( Pr)~3 bull The Nusselt number was based on the
tube diameter and the thermal conductivity of the air at
the flowing temperature The tube diameter was used in the
Nusselt number because comparison could then be made with
previous experimental work on heat exchangers which have
commonly used the Nusselt number defined as in Eq (15)
From the standpoint of dimensional analysis this is
equivalent to considering the tube diameter as the characshy
teristic length so far as the heat transfer is concerned
The Prandtl number of the air was taken as 0 7 in all
cases
Variation of Heat Transfer Rate with Distance from the Baffle
Considerable variation was observed in the rate of
heat transfer in the vicinity of the baffle In order to
obtain the variation with respect to position the term
(Nu)(Pr)-13 was plotted versus the flow rate Q for each
position and orifice studied Cros s plots were then made
28
at constant flow rates in order to obtain the variation of
(Nu)(Pr) -13 with position The resulting cross plots are
shown 1n Fi gures 5 6 and 7 for the four orifices studshy
ied
About one inch upstream from the orifice the heat
transfer coefficient begins to rise rapidly and continues
to do so until it reaches a maximum some distance downshy
stream After the maximum point the heat transfer coef fi shy
cient decreased slowly The heat transfer rate was found
to reach a maximum at a different position downstream for
each orifice size These figures also show that for a
given orifice size the maximum heat transfer rate occurs
a pproximately at the same point for all flow rates The
position of the maximum point f or each or ifice size is
shown in Table II
The region immediately downstream from the orifice is
one of h i gh turbulence due to the jetting action of the air
flowing through the orifice As the air flows t hrough the
orifice the streamlines continue to converge for some dis shy
tance downstream The point of maximum heat transfer is
probably at the point where the streamlines be gin to diverge
and a boundary layer begins to build up on the tube Tle
decreasing heat transfer coefficient beyond the maximum
point indicated the formation of a boundary layer
Since the position of the maximum point is independent
of flow rate middot it is possible to correlate it with respect
_ ct 11shyz-
100
0 136 ORIFICE
(
I 0
I )
~ 00
~p 0
I 0
--r--- ~
ISCFIII
-_ OCFM
rbull abull
~ middot~ a-1 z-
12fORIFICE
100
200
100
0 0 UPITRAM ORIFICE DISTANCE CENTER
CFM
h I DOWNSTREAM
DISTANCE
FIGURE 5 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLpound
30
too
700
800
100 ~ f gtf
400
z ~
100
100
100
0
13fORIFICE
~ -~ -- ---
)
~
~
-
I ~ ~OCFM
I vI~-~ OCFM
J ---
Iamp CFM
I 0 I I UPSTREAM ORIFICE DOWNSTREAM DIITANOE GENTER DIITANCI
FIGURE 6 VARIATION OF HEAT TRANSFER RATE WITH DISllNCE FROM BAFFLE
--
--- --
31
100
100
700
100
_ 100
f 9- 400 z-
100
tOO
100
0 - I 0 I I I UHTRIAM OAtfiCI DOWIIITMAM
+ I tyl6 ORIFICE
v I
~~ ~CFM
I v ~CFMI
v v 7
~~ v ~ iOCFM
- ~~ I-shy1-shy ~ICFM
DIITMCI OINTIR DIITANCI
FIGURE 7 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLE
32
TABLE II
POSITION OF MAXIMUM HEAT TRANSFER
Position of Maximum Orifice Size Heat Transfer
(inches) (inches downstream)
1 364 050
1 216 100
1 316 125
1 516 200
33
to orifice size Figure 8 shows the effect of the orifice
size on the position and value of the maximum heat transfer
at a constant flow rate of 15 cubic feet per minute It
can be seen that the larger the orifice size the further
downstream the point of maximum heat transfer occurs
Also as the orifice size increased the rate of heat
transfer decreased for a given flow rate The broken line
indicates the variation of the point of maximum heat transshy
fer with position and size The position of the point of
maximum heat transfer rate downstream from the orifice was
correlated with orifice size by means of the dimensionless
groups (Lde) and (d1de) where L is the distance downshy
stream from the orifice where the maximum rate of heat
transfer occurs d1 is the outside diameter of the inner
tube and de is the equivalent diameter of the orifice
ie de = d2-dlbull
Figure 9 shows a plot of Ld 6 versus d1d6 for the
four orifice sizes studied The four points on this logshy
log plot are approximately in a straight line and the
equation of this line is
Lde = 0 44 d1de)028 (22)
Although the above relationship represents a correlashy
tion of dimensionless groups it is based upon only one
tube diameter and needs to be substantiated further by
studying other tube diameters and other orifice sizes
34
aoo
400
aoo ~
-~ middot-CLshyJ z
200 -
100
0
ORIFICE CENTER
l~
l
t
I J~
1pound~
I
0 I I~
AT 15 CFM
-
bull ~ 1~6~
~ v~
~
~--~~6
~~~ ___ v v V -_
~ o q
~ I 16
v
~
ogWNSTREANI STANCE
FIGURE 8 EFFECT OF ORIFICE SIZE ON POSITION AND VALUE OF MAXIMUM HEAT TRANSFER
35
50
loshy____ -~
~ ~ -shylltl-shy~ r0
2 10 30
FIGURE 9 CORRELATION OF THE POINT OF MAXIMUM HEAT TRANSFER WITH
ORIFICE SIZE
36
Correlation of Data at the Baffle
The heat transfer data were correlated by obtaining a
relationship between the group (Nu)(Pr)-13 and a
Reynolds number based on twice the clearance (d2 - d1
between the tube and the baffle It was found that the
most satisfactory correlation could be obtained when the
term - d1 was used as the length term in the Reynoldsd2
number
Figure 10 shows the variation of the heat transfer
rate at the center of the orifice e xpressed as a function
of Reynolds number and the orifice size This shows that
for a given Reynolds number the heat transfer at the center
of the orifice is greatest for the smallest orifice size
In order to obtain a general correlation of the data
shown i n F1gure 10 the effect of the dimensionless ratio
d1de was considered This ratio considers all of the
geometric factor s needed to describe the annular orifice
The thiclaless of the orifice plate is also a factor but
was constant i n this i nvestigation
The data for the heat transfer at the baffle center
are shown in Figure 11 in which (Nu)( Pr)-13 is plotted
versus (Re)ebd1 de) 0 55 This data on a log-log plot
lies on a straight line for (Re)eb( dld8 )0 55 greater
than 3 x 104 The equation for cor relating the heat
37
4XI~middot~-r~------~--~~------~
Icf t--to_+--_c-c-________ SYMBOL SIZE
0 1~4
6 ~~
9 ~~ -o ~
(Re)eb
FIGURE 10 RATE OF HEAT TRANSFER AT BAFFLE CENTER
38
500
0
4 0 lcf
~ ~
~ ~iC-
~ ~
~IL 0~ 0 SYMBOL SIZE-
p 0 1364-
r 6 1~16 -~ -
9 1~16 --o 1~16
I I
FIGURE II CORRELATION OF HEAT TRANSFER DATA AT BAFFLE CENTER
39
transfer at the center bullOf the a nnular orifice was found by
the method of least s quares to be
(Nu)( Pr)-1 3 = 0018 ( Re)ebO Bl( dlde)04~ (23)
3 x 104 ltRe)eb(a1de)055 lt 105)
Rate of Heat Transfer at the Point of Maximum Heat Transfer-The heat transfer rate at the point of maximum heat
transfer is plotted in Figure 12 to show the variation with
Reynolds number and the size of the orifice It is shown
gives the h1gh st heat transfer ~ate at its point of maxibull
that for a given Reynolds number the smallest orifice size yen il
mum heat transfer
The data ~or the maximum poi~t could be correlated by
plotting (Nu) Pr)-13 versus (Re)eb(d1de)06 This plot
is shown 1n Figure 13 and the resulting eurve shows that
(Nu(Pr)-13 is not a simple p0wer function of the Reynolds
number as was the case for heat transfer at the baffle
center The reason for this is probably because other
factors such as intensity and scala of turbulence should
be considered At the orifice center the streamlines of
the flowing stream are converging_ and thus the flow is
quite stable Downstream from the orifice is a region of
large eddy currents and probably large scale turbulence
These factors could con ceivably cause the results which
were obtained for the point of maximum heat transfer
40
If)
~middotshy Q_-I z_
10~~~--------r----~~--~--
SYMBOL SIZE
0 13$4
6 1~8
Q 13-18
-o 1~8
7)(104
(Re)eb
FIGURE 12 RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
41
Ia ~
0 I
c ~ ~ c v
~ ~lt w ~
17
~ b
v ~ ( SYMBOL SIZE
-~ 0 f-64 -v ~ 6 t211e
~ Q I~~~
-o - l~rs I I
FIGURE 13 CORRELATION OF HEAT TRANSFER DATA AT THE POINT OF MAXIMUM HEAT TRANSFER
4 2
Effect of Upstream Baffles on Heat Transfer at the Orifice Center
The heat transfer rate at the orifice center using the
single orifice in a test section is a pproximately 13 of the
value that was obtained by Lee (7) using a model heat exshy
changer with orifice baffles Lee investigated the cent r al
baffles of the heat exchanger and thus the coeff icients he
obtained would be affected by the presence of a number of
upstream baffles To determine the effect of upstream
baffles an additional l 516 inch baffle was placed four
inches upstream 1n the test section The resulting data are
shown in Figure 14 where (Nu)(Prmiddot)-13 is plotted versus
(Re) eb for the case of a single baffle 1n the test section
and also the case of an additional baffle placed four inches
upstream Comparison is made with the results obtained by
Lee middot(7) using a four-baffle and a ten-baffle model heat exshy
changer Good a greement is obtained with Lees work and the
results show the marked effect that upstream baffles have on
the downstream heat transfer rate The additional up tream
ba ffle caused sufficient turbulence 1n the test section to
i n crease the heat transfer rate nearly three-fold at the
center of the next baffle
Heat Transfer i n the Test Section with No Orifice
In order to check the accuracy 6f the equipment the
orifice baffle was removed and the heat transfer mea sured
with the probe in the empty test section The data were
43
~~BAFFLES
0 l BAFFLE -shy
ll_9 2 BAFFLES
V 4 BAFFLES-LEE
4 10 BAFFLES- LEE lJf ~
~rv ~~ ~ v flvv ~~
I ~ J ~ L v
0
v
( V
40 3XIo 7XIa
(Re)eb
FIGURE 14 EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER AT BAFFLE CENTER
44
compared with heat transfe r coefficients predicted by the
equations for annuli which are recommended in the litera shy9
ture The two equa~ ions u sed tor comparison were
(hfe)=0 023 (rltGr e (~~ur4 (~r45 (24)
which was presente~ by Wiegant (10)
and ( h ) (cnM~5(M~l o14 o 023 CPG k j Mij - (de GJMb )0 2 ( 2 5)
which was presented by McAdams (8 p 242) The comparshy
i son is s hown in Figure 15 lq (25) gives a value which
is low by about ten percent while Eq (24) g ives values
which are high by as much as twenty -five percent when comshy
pared with the experimental data The se equations are gembull
erally considered to give coefficients with an accuracy of
about twenty percent Therefore the present experimental
data are within the accuracy of these equations Also the
plot indicate s that for a Reynold s number greater than 2 x
104 the slope of the line is the same for the experimental
data as for the equations
Pressure Drop Data
The total pressure drop across the orifice was measured
as a function of the flow rate and the orifice size The
pressure drop was expressed as a d1mens1onleas quantity r)
which ie plCltted ver sus the Reynolds number in Figure 18
The pressure drop function cent correlates for all or1f1oe
45
200
100
s z
10 5XI10 10
0 EXPERIMENTAL
--McADAMS
-WIEGAND L
V
~ ~ ~
P ~ ~
LL~ L
v~
~
v v
v 1 ~ ~ v
v -gt
~
~ ~
~
6Xid
FIGURE 15 HEAT TRANSFER WITH NO BAFFLE
46
0 1~4 -~ a 6 t216
Q t316 lJ J
-0 as a )t
A LEE I -shy SULLIVAN 8
p
10bull
BERGELIN
I _ll I
I ~
i I
~middot
lo II
f fl
J j
~middot
A)101
1q
I Ill
1 I3 X 10ao1
FIGURE 16 ORIFICE PRESSURE DROP FUNCTION VS REYNOLDS NUMBER
47
sizes- The present data extends the range covered by preshy
vious workers and agrees well with their work The preshy
vious work of Lee () for a heat exchanger containing 10
orifice baffles and also the data of Su livan and Bergelin
(9) for pressure drop in a model heat exchanger with a
single baffle is shown 1n Figure 16 long with the present
results~ This figure may be used to predict the preseure
drop from the equivalent Reynolds number of the annular
orifice
The pressure drop between individual points 1n the
vicinity of the orifice and an upstream pressure tap wa s
measured to obtain a pressure drop profile As might be
expected 1n all cases the profiles showed a rapid decrea e
in static pressure immediately upstream from the orifice
There was however little or no recovery of the pressure
loss downstream The 1 364 inch orifice did show a maxishy
mum point in the pressure drop but this maximum occurred at
the orifice center and total recovery was reached about 12
inch downstream
Heat Transfer at the Baffle and Maximum Point as a Function of Pressure Drop
In order to compare the effect of the total pressure
drop on the heat transfer at the baffle and the point of
maximum heat transfer Figure 17 was plotted showing
(Nu)(Pr)-13 as a function of the total pressure drop This
shows that for a given pressure drop the largest orifice
48
1200
1000
~ a -sshyz-
100
60 100 700
AT MAXIMUM POINT I 15116 2 13116 3 1~6 4 1364
AT ORIFICE CENTER
60
1
v
r ~ ~ ~
5
~
8 7
13116
8
~
1364
v
~
e6
1~6
v
~~ v ~ ~ -~ ~
~
~ v
l
~
vamp
I ~ ~
~
v L ~
v
I-
5
k= ~~
~ ~ ~
--I
v ~
FIGURE 17 HEAT TRANSFER AT THE BAFFLE AND MAXIMUM POINT AS A FUNCTION OF
ORIFICE PRESSURE DROP
49
size has the greatest heat transfer coefficient This is
true at both the orifice center and at the point of maxishy
mum heat transfer
Another comparison can be made by plotting the heat
transfer coefficient and the pressure drop versus the orishy
fice size at a constant flow rate Figure 18 shows this
plot This graph shows that at a constant flow rate the
pressure drop as well as the heat transfer coefficient
increases as the size of the orifice is decreased In
choosing an orifice size for maximum efficiency 1t would
be necessary to know the pumping power available as well
as the heat transfer desired
70 I I 700
AT 15 CFM 60 ---
~ aug
50 ---
NV
40 ~
~ ~ ~
~ _
MAXIMUM POINT ---- --- ~
1-----t---~ _
~00Qj ~
~t--- ORIFICE CENTER 10 1100
1---~ n
u0 01 02 03 Q35
a ltl
de inches
FIGURE 18 VARIATION OF HEAT TRANSFER RATE AND PRESSURE DROP WITH ORIFICE SIZE AT A CONSTANT FLOW RATE
cn 0
51
CHAPTER VI II
SUMMARY OF RESULTS
This study revealed several significant facts about
the heat transfer in the vicinity of annular orifices
Probably the most important contribution was the presshy
entation of the heat transfer profiles in the vicinity ot
the annular orifice ~ r s shown that t~ local heat
transfer coeffieient re~ches a maximum at a point downshy
stream from the orifice The distance downstream at which
this maximum oocurs is t1ven by the equation
22
The heat transfer coefficients at the center of the
orifice were correlated and found to follow the equation
(Nu)(Pr)-13 = 00176 (Re)eb08l(d 1de) 0 middot4~ (23)
3 x 104 lt( Re) 9 b( d1d6 )055 ltlo5 )
The heat transfer at the point of maximum heat trans
fer for each orifice size was correlated and presented in
Figure 13 as a plot of (Nu)(Pr)-l3 versus (Re)eb(d1de) 06
No simple po-orer relationship exists between the terms
Intensity and scale of turbulence downstream from the orishy
fice are probably important factors which affect the heat
transfer
The large effect of an upstream orifice on the heat
transfer rate at the second orifice was demonstrated by the
52
study of two 1 516 inch orifices in the test section The
added turbulence at the center of the second orifice was
found to raise the heat transfer rate almost three times
over that obtained for a single baffle
The pressure profiles in the vicinity of the orifice
indicate that nearly all the pressure drop occurs at the
orifice center~ Total pressure drop data were correlated
by a pressure drop function cent as a function of the Reynolds
number and good agreement obtained with the results of other
workers
The pressure drop and heat transfer data were correbull
lated by plotting the heat transfer as a function of the
pressure drop for each orifice size It was shown that for
a given pressure drop the largest orifice size gives the
greatest heat transfer coefficient
As a final presentation it was shown that the pressure
drop and the heat transfer coefficient both i ncrease i n
value at a constant flow rate as the orifice size is de shy
creased This is important in choosing the optimum clearshy
ance for orifice baffles
53
CHAPTER IX
RECOMMENDATIONS
A great deal of work remains to be done in the field of
evaluating shellmiddotside heat transfer coefficients This
study included only one tube size and air was the only f luid
used It is recommended that further studies be conducted
using other fluids and tube sizes It will also be necessary
to study several baffle types
The adde d turbulence due to a s e cond baffle placed upbull
s t ream would suggest that the heat transfer coef ficients at
a certain position i n relation to a baffle would increase as
the flow progressed through the exchanger It is recomshy
mended that an extensive s t udy should be made between baffles
the full length of a model heat exchanger
It is further recommended that the pressure drop study
be continued to include other fluids tube sizes and baffle
arrangements
Effects of turbulence downstream from the baff le should
be studied by i n vestigations with hot-wire anemometer equipshy
ment to determi ne t urbulence scale and i ntensity
54
NOMENCLATURE
Area of heat transfer
Heat capacity of the fluid
Outside diameter of the tube
Orifice diameter
Equivalent diameter of the orifice (d2 - dl)
Inside diameter of the test section
Inside diameter of the tube
Gravitational constant
G Mass velocity
h Local heat transfer coefficient
Coefficient of heat transfer from surface to fluid
i Direct current amperes
k Thermal conductivity of the fluid
L Distance downstream of the point of maximum heat transfer
p Absolute pressure
L P Total pressure drop across the orifice
Q Flow in cubio feet per minute at 1 atmosphere and 680 F
q Heat transferred
Thermal energy conducted into the sensing probe
Thermal energy radiated from the resistance ribbon
Resistivity of the resistance ribbon
s Length of the resistance ribbon
T Temperature oR
55
t Temperature of the resistance ribbon deg F
ta Temperature of the bulk stream oF
tw Wall temperature of the tube OF
U Veloc ity of the fluid
w Width of the resistance ribbon
z Thickness of the resistance ribbon
eeuro Density of the fluid in the test section
Density of the fluid at the flow orificef 0
AL Viscosity of the fluid
E9 Angle measured around the tube
Dimensionl ess groups
(Nu) Nusselt number hd1k
(Pr Prandtl number C~k
(Re)eb Equivalent Reynolds number at the baffle (d2 - d1 )uejt-Lshy
(Re)e Equivalent Reynolds number in the test section ( d 8 - d 1 )U fu
cent Orifice pressure drop function 2(~P ) gc~av(d2 - d1) 2
Al
56
BI BLIOGRAPHY
1 Ambrose Tommy W Local shell-side heat transfer coefshyficients in baffled tubular heat exchanger PhD thesis Corvallis Oregon State College 1957 183 numb leaves
2 Bell K J and o P Bergelin Flow through annular orif ices Transactions of the American Society of Mechanical Engineers 70593-601 1957
3 Colburn Allan P A method of correlating forced con shyvection heat transfer data and a comparison with fluid friction Transactions of the American Institute of Chemical Engineers 24 174-210 1933
4 Dittus F w and L M K Boelter Heat transfer 1n automobile radiators of the tubular type University of California Publications in Engineering 2443-461 1930
5 Gurushankariah M s Local shell-side heat transfer coefficients in the vicinity of baffles in tubular heat exchangers Masters thesis Corvallis Ore gon State Colle ge 1958 97 numb leaves
6 Knudsen James G and Donald L Katz Fluid dynamics and heat transfer New York McGraw-Hill 1958 576 p
7 Lee Kyu Sung Local shell-side heat transfer coeffishycients and pressure drop in a tubular heat exchanger with orifice baffles Masters thesis Corvallis Oregon State College 1959 118 numb leaves
8 McAdams William H Heat transmission 3d ed New York McGra ~-Hill 1954 532 p
9 Sullivan F W and 0 P Bergelin Heat transfer and fluid friction in a shell-andbulltube exchanger with a single baffle Chemica l Engineer ing Progress Symposium Series 52 ( 18) 85-94 1956
10 Wiegand J H Discussion on annular heat transfer coshyef f icients for turbulent flow Transactions of American Institut e of Chemical Eng i n eers 41147-153 1945
AP PENDIX
57
TABLE III
CALCULATED HEAT TRANSFER DATA
Baffle Hole Diameter Run No (inches)
1 - 59 1 364
60 - 102 1 216
103 - 138 1 316
139 - 206 1 516
207 - 212 No orifice
213 - 218 2nd - 1 516
TABLE III
CALCULATED HEAT TRANSFER DATA
Local Heat Transfer Coefficients Run
T0 bull Po s ition CFM hr h2 h3 h4 hs he ~ hav Nuav
1 c 1026 10 59 1476 16 09 1559 1510 1435 1203 1518 8511 2 1290 1369 1738 1878 18 05 1755 1689 1515 1773 9964 3 1416 1636 198 1 2068 1977 1924 1845 1715 1959 11030 4 1627 1991 2301 2382 2268 2194 20 ~98 1929 2249 12664 5 1776 2252 2669 2863 2713 2517 2338 2126 2620 14759 6 l2ttD 1109 2311 3317 3386 3373 3387 3394 3071 3371 18888 7 1258 3089 4583 4866 4683 4701 4643 4194 4695 26301 8 1433 38 8 5 55 83 5791 5495 5430 5436 5008 5547 31192 9 1681 4992 7378 7649 6980 6864 6870 64 28 7148 40180
10 1 D 1102 2371 3332 3511 3356 3342 3427 3102 3394 19012 11 1308 3218 4379 45 24 42 53 4255 4373 3965 43 57 24446 12 14 64 38 58 5146 5142 4839 4787 4903 4597 4963 278 79 13 1706 5218 6664 6269 58 81 5884 6237 5973 61 87 34718 14 15
1 l2D 1115 1275
2131 2661
2955 3638
2972 3720
2941 3675
2913 3576
28 22 34 74
2613 3278
2921 36 17
163 09 20246
16 1498 34 87 4644 4503 4441 4371 4343 4194 4460 25010 17 1695 4449 5743 5324 5222 5154 5157 5015 5320 298 97 18 2D 1049 1715 23 90 2550 2610 2656 2624 2208 2566 14363 19 1241 2117 2964 3145 3218 3221 3203 2759 3150 17757 20 1532 28 67 3936 4100 4188 4201 4167 3676 4118 23224 21 1674 3459 4508 4598 4746 4795 4792 4299 4688 26337 22 lU 1074 253 340 380 3 86 388 377 354 374 2097 23 1287 292 392 433 440 441 429 406 427 2394 24 1508 322 439 492 498 499 487 461 48 3 2713 25 18 07 3 38 464 519 5 24 520 499 463 5 05 28 40
~~ (]I agt
TABLE III Continued
Run No Position CFM h 1 h2 ~3 h4 h5 h6 ~ h
av Nu
av 26 c 1029 1171 1491 1589 15 28 1 4 62 1377 1293 1489 83 44 27 1266 1395 1746 1853 18 02 1685 1556 1453 1728 9704 28 1430 1637 2037 2175 2060 1909 1735 1591 1983 11159 29 1729 1982 24 96 2751 2507 2268 2030 1886 2410 13579 30 12D 1054 2934 4041 4321 4326 4423 4359 3706 4298 24160 31 1294 3385 4 8 26 52 42 5326 5450 5277 4566 52 24 293 50 32 1431 3784 5347 5721 57 bull75 58 44 5700 5084 5677 31870 33 1770 52 75 7 7 33 87 35 9005 9007 8267 7059 85 49 48050 34 lD 1058 3235 4401 4444 3877 3496 3451 3294 3934 21973 35 1263 38 98 5484 5330 4347 3964 3981 3987 4621 25823 36 18 36 6701 89 17 7855 6369 5597 5769 6283 69 01 38718 37 1 12D 1029 2404 31 8 2 3333 3459 3624 3577 3045 3435 19264 38 1315 3182 4033 4162 4310 4496 4502 4015 4301 24142 39 1426 3628 4389 4510 4573 4760 4804 43 8 5 4607 25678 40 1757 4547 5559 5(35 5931 6282 63 70 6060 5975 33471 41 2 11D 1080 2034 28 38 3155 3144 3145 2966 2540 3050 17027 42 1305 2650 3 4 87 3aoz 3595 3751 3595 3153 36 46 20405 43 1434 3167 39 07 4156 4371 4320 4126 3709 4176 23395 44 1804 4096 4 9 66 5691 5714 5586 53 15 48 65 5454 30582 45 12U 1088 409 516 557 564 5 60 535 513 5 46 30 67 46 1318 470 579 6 22 631 6 17 5 97 579 6 09 3422 47 14 13 540 640 676 6 86 681 6 60 6 54 6 69 3754 48 1773 641 740 774 782 7 69 749 746 763 42 87 49 l 11 U 1054 270 356 391 397 393 3 71 346 38 2 2133 50 1240 303 399 446 449 447 4 21 398 432 2420 51 1419 361 476 522 530 528 507 467 493 2760 52 1 1(2U 1032 236 311 342 347 344 325 301 334 18 78 53 1314 270 366 403 407 408 386 351 394 2217
(Tt tO
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ h av Nu av
54 1448 301 408 447 454 452 431 403 438 24 61 55 1782 353 494 548 544 415 529 531 506 2843 56 2U 10 61 220 287 316 320 322 303 268 310 1735 57 1216 249 335 370 377 378 353 307 363 2044 58 1322 263 356 394 398 399 374 327 384 2159 59 1639 310 433 478 481 482 452 393 465 2617
60 1D 10 68 2011 2536 2657 2681 2694 2560 15 62 2625 14938 61 1399 2520 3239 3369 3371 33r82 32 39 1946 3320 18968 62 1669 2781 3655 3820 38 76 3883 3738 2355 3794 21712 63 1959 3524 42 37 4399 4438 4497 4417 3047 4397 25156 64 2295 4426 5288 5396 5372 5240 5410 3369 5341 30680 65 2636 5490 6531 6662 6565 6379 6820 4249 6591 37938 66 3390 7869 9538 9462 9387 8924 10508 62 91 9564 59601 67 1U 1190 352 368 401 413 407 395 293 397 2256 68 1559 397 422 462 475 471 456 331 4 57 2603 69 1904 434 465 5 13 529 528 504 358 508 2901 70 2211 493 526 573 5 92 588 564 4 15 569 3257 71 2289 569 587 6 30 649 6 61 6 49 460 635 36 44 72 2727 637 6 60 7 09 733 751 743 521 719 4140 73 3210 728 755 8 15 8 43 8 62 8 54 616 826 4765 74 2nD 1210 181 2256 2393 2399 2333 2206 1325 2317 13158 75 1420 2340 2752 2899 2913 2850 2728 1701 2828 16121 76 1692 2853 3306 3452 3471 3379 3217 2134 3365 19217 77 1894 3102 3588 3713 3736 3670 3557 2455 3653 20892 78 2301 3682 4259 4433 4467 43 83 4289 2892 4366 250 30 79 2621 4117 4828 5017 5012 5030 5109 3071 4999 28785
m 0
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ hav Nuav
80 3230 5158 6006 62 13 61 18 6134 6695 4094 6233 359 87 8 1 12nD 1155 15 27 1854 2028 2064 20 85 1987 1164 1968 118 31 82 1689 2046 24 8 2 2688 2739 2760 2658 1749 2665 152 73 83 1244 2088 2317 2339 2345 2373 2381 1487 2351 13432 84 2100 3211 3539 34 21 3462 3512 3696 2575 3526 20284 85 2292 3 5 05 3761 3648 36 25 36 79 3957 2933 3734 21517 86 2907 4420 48 22 4679 46 04 4705 5206 3792 48 03 27741 87 33 80 59 35 69 38 7404 77 10 7 8 36 7 0 86 5190 7394 427 44 88 1 12D 1 4 27 2 4 58 28 31 3037 3021 2987 2927 18 57 2 9 61 16913 89 18 75 34 75 3 9 87 4230 4255 4317 4337 2734 4225 24258 90 22 59 4221 4796 5046 5052 51 01 5389 3491 5077 29206 91 2682 4978 5664 5943 5966 6054 6573 408 1 60 40 34795 92 3417 63 16 71 02 7 3 93 7385 75 40 8 6 95 51 45 7623 44017 93 c 1 5 17 1240 1305 1399 1467 1479 1429 9 26 1423 8251 94 20 34 1554 1623 1720 18 21 18 53 18 72 1215 1778 10229 95 2 3 48 1795 1843 198 5 2097 2171 2274 1540 2074 11947 96 2716 2028 2048 22 01 2 3 44 2444 2661 18 90 2340 13505 97 3247 2410 2375 2663 2778 2949 3298 2378 2793 1615 98 11 35 967 1040 1124 1186 1200 1142 728 1138 6496 99 14 06 1135 1220 1318 1384 1403 1 3 61 8 77 1336 7656
100 2311 1 8 54 18 78 1980 20 90 2136 2227 1653 2062 118 31 10 1 2666 2085 2094 2227 2 3 62 2438 2626 1902 2349 13508 102 3392 2635 2582 28 01 3026 3141 3529 2567 3016 17390
103 1 U 1235 349 395 434 436 4 28 411 286 423 2416 104 20 10 434 5 02 559 577 569 5 37 345 552 3177 105 28 14 538 626 685 711 7 21 682 424 6 8 6 3966
Q) j-J
TABIE III Continued
Run No Position CFM h1 h2 h3 h4 h5 hu h7 hav Nuav
106 3492 614 7 1 6 7 84 8 13 8 33 7 85 4 88 7 87 4562 107 4395 7 86 894 964 996 1005 9 64 640 9 65 56 06 108 50 75 9 11 10 22 1081 1112 1125 1085 7 24 1085 63 16 109 G 1344 9 22 1042 1120 1 1 46 1173 1131 7 04 1120 63 87 110 1936 1162 1340 1442 1474 1509 14 7 3 9 09 1441 82 77 111 2846 1631 1797 1902 1966 2027 2079 1342 19 2 3 11108 112 3484 207e 2144 2236 2307 2385 2574 1694 2268 13138 113 4066 24 65 24 42 2535 2648 2757 31 71 2178 2 5 96 15078 114 50 12 3059 2916 30 1 5 3176 3312 4059 2849 3105 180 46 115 1D 1362 2268 26 13 2613 26 35 2605 2503 15 46 2617 14934 116 1958 2993 3580 3580 3586 3539 3 5 02 2144 3571 20492 117 2812 4430 50 32 4913 4 9 86 4991 5196 3088 4981 287 66 118 3432 58 16 62 13 6067 61 18 60 66 6698 4143 61 16 354 16 119 40 22 71 71 7 4 62 7369 7419 7329 82 74 51 8 1 7395 42909 120 5026 105 95 11456 115 81 11574 11548 14010 80 91 11540 671 15 121 2D 1244 18 57 2277 2363 2305 2210 2107 1466 2289 13038 122 1960 2622 3240 3388 33 23 3226 31 40 2)99 3294 18919 123 2817 3762 45 87 4739 46 56 45 14 4 6 47 30 15 4624 26689 124 3491 50 22 5723 58 53 57 44 5542 60 18 3871 57 16 330 73 125 4096 61 29 68 16 69 79 6805 65 90 74 79 4677 67 98 39400 126 5037 82 27 94 60 95 69 93 57 9023 11324 65 05 93 52 542 83 127 12D 1278 14 70 1 6 48 1652 1638 1 6 34 1641 9 73 1 6 43 9369 128 1947 19 63 2155 2149 2151 2131 2190 1347 2147 12342 129 2769 2615 2791 2773 28 52 2716 2954 18 96 2783 1 60 82 130 3439 3208 3265 3239 3593 3133 3624 2515 3308 19174 131 4103 3637 35 88 3577 4077 3459 42 66 3138 3676 21343 132 49 78 45 82 44 60 44 8 1 55 17 43 25 5749 4227 4700 27288
Q) tlgt
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
133 1 12D 1299 2094 2507 2622 2625 2567 2489 1465 2578 14736 134 1973 29 56 3505 3772 3790 3718 3718 2115 3700 21290 135 2788 3941 4727 5069 5099 5 0 07 5231 2984 4976 28781 136 3473 5155 59 81 6308 6339 62 39 68 96 4204 6217 36052 137 4118 6135 71 8 6 7662 7731 76 91 87 16 49 8 5 7568 43985 138 4973 7765 94 75 10396 10861 10694 13646 66 64 10357 602 25
139 1ttn 1253 1242 1493 1460 1442 1431 1424 8 84 1457 83 01 140 2366 1942 2150 1961 1910 1897 19 62 1206 1980 11400 141 3461 3007 2957 2562 2513 2606 3143 18 51 2660 15400 142 4325 3942 3571 3060 2999 3198 4248 2631 3207 18618 143 5677 508 6 4359 39 88 3800 42 29 57 78 36 26 4094 23824 144 67 59 64 55 5330 4988 47 25 5494 2517 48 09 5134 29906 145 84 08 9326 72 26 7726 85 56 9172 12319 7733 8170 47626 146 86 54 9831 7582 818 9 94 90 9869 13116 78 97 8783 512 96 147 7376 7335 58 7 6 5941 5796 68 29 81 65 5954 6111 35662 148 2 11 D 4254 4106 48 02 4994 5038 5042 56 78 3419 4969 28881 149 5708 5487 6253 6466 6524 6527 78 63 45 8 2 64 43 37566 150 69 7 8 7983 9440 9848 98 34 97 32 13249 6701 9714 566 59 151 1254 1434 18 53 1947 1915 1850 1760 1186 1891 10772 152 2713 2696 3175 32 94 3288 3237 3288 20 44 3249 18728 153 87 30 118 07 14733 15758 15504 15305 26297 9617 15325 892 71 154 5811 5278 6543 6861 69 30 69 82 7 8 74 4478 68 29 39531 155 4246 3780 4736 4975 49 66 4936 5162 3113 4903 28301 156 (v 1270 8 15 935 959 966 9 51 9 23 6 35 953 5430 157 2714 1164 1390 1427 1447 1454 1455 9 08 1430 8242 158 4310 1655 18 96 1942 1988 2002 2111 1305 1957 11349
(j) ~
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 fry hav Nuav
159 6012 2208 2400 2450 2513 2548 28 20 18 00 2478 14416 160 7279 2696 2881 2927 2989 3081 3599 2340 2970 17326 161 86 90 3257 3360 3 3 76 34 26 3558 4455 2943 3430 2000 162 12D 4368 2209 2600 2558 2518 2466 2774 1753 2536 14713 163 5833 2730 3092 3028 2974 2913 3501 2287 3002 174 78 164 7643 3320 3681 3630 3651 3530 4623 3181 3623 21116 165 87 39 3920 4303 4300 4708 4178 61 60 3937 4372 25456 166 1268 962 1203 1205 1186 1118 1084 725 1178 6693 167 2678 14 67 1785 1779 1752 1698 1726 10 70 1754 88 49 168 1 12D 12 83 936 1217 1414 1397 1239 1190 7 65 1317 7484 169 2729 2502 2930 2914 2934 2956 2979 17 52 2934 16866 170 4345 3884 4357 4283 4318 4421 4836 28 59 4345 25151 171 6036 5546 5858 5764 5791 6028 7129 4184 5860 34045 172 6578 7167 7769 7907 79 82 8263 10492 5915 7980 46437 173 87 84 10237 112 23 120 26 12727 12968 185 19 85 98 12236 71103 174 1278 1344 1803 18 72 1835 1790 1712 1063 1825 10355 175 2711 2328 2972 2932 2893 28 78 2863 1667 2919 167 51 176 4351 3934 4414 4353 4281 4321 4654 28 63 4342 25088 177 5994 5076 5824 5838 5818 59 29 6914 4205 5852 33885 178 1 11 U 1223 388 432 465 464 449 435 338 453 2585 179 2351 521 602 6 22 675 6 57 619 436 639 3687 180 34 48 6 05 1725 803 8 27 8 11 760 518 792 4593 181 4513 718 850 934 9 68 9 57 8 99 609 9 27 5386 18 2 5714 8 32 981 1060 1102 11 06 1034 6 59 1062 61 82 183 6997 1025 1182 1258 1295 1309 1234 8 18 1261 7 3 44 184 8709 1295 1487 1 5 42 1594 1626 1612 1156 1562 9080
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
185 2 12D 4249 3560 4400 4670 4791 4695 47 81 2931 4639 268 37 186 5737 4926 58 54 61 92 6248 62 38 67 78 4134 6131 35590 187 7432 6390 7726 83 46 85 44 86 34 10371 5658 8313 48310 188 8723 7718 107 88 11933 12099 13046 186 22 79 39 119 67 69505 189 1 4 35 1340 1735 18 57 18 52 17 81 1711 1144 18 06 10256 190 2718 2399 3023 3187 3207 3138 30 53 1931 3139 18025 191 7 5 07 6189 80 11 9200 9427 9703 11364 5720 9085 527 38 192 8544 78 42 10666 125 42 13312 13775 178 20 6976 125 74 729 86 193 1287 1417 16 97 18 7 18 69 18 08 1720 1046 1800 10223 194 27 17 2450 2940 3187 3214 3157 3054 1749 3125 17954 195 42 53 3560 4222 45 90 4679 46 63 4743 2741 4539 26247 196 6068 48 69 57 79 6335 65 8 6 66 04 7172 4338 63 26 366 78 197 7389 58 86 72 8 6 82 23 8584 8936 10658 50 60 8257 4798 6 198 86 88 78 91 100 27 120 56 130 29 14299 190 81 6492 12353 71850 199 5864 4694 5 6 67 61 94 6419 65 48 7192 3950 6207 360 14 200 2 D 4177 38 36 4547 48 09 4775 4628 5006 2715 46 90 261 30 201 5712 5170 62 39 66 38 6599 6604 7518 4167 65 20 378 00 202 73 63 7201 8986 98 43 9733 9914 13353 6219 9619 55810 203 8604 10043 13118 148 41 150 42 158 66 25206 82 5 3 14717 85290 204 12 68 1506 18 41 1971 1966 1868 1799 11 42 1913 10880 205 2659 2571 3127 3276 32 50 3130 3069 18 80 3196 18 350 206 39 80 36 76 4347 4573 45~67 4473 46 34 28 37 4490 25910
o 207 Orifice 11496 10 64 1360 15 39 1 5 80 1 6 15 1496 8 58 15 24 88 83 208 9433 8 95 11 78 13 26 1394 1386 1263 727 1346 78 48 209 7387 746 9 77 1123 1184 1159 1048 6 11 1111 64 74 210 52 36 566 7 66 900 934 909 8 21 499 8 27 48 02
0) CJ1
TABLE III Continued
Run No Position CFM h 1 h2 hs h4 h5 h6 h7 hav Nuav
211 212
3309 1293
414 257
563 3 19
6 68 3 57
6 91 3 37
6 72 351
7 37 337
38 4 2 46
4 40 341
3748 1942
213 214 215 216 217 218
c of 2nd 1 516 1235
1919 2712 3320 4153 4704
1532 2447 35 46 4312 5567 74 29
2 1 87 3312 4225 52 86 6902 8 6 50
2360 3555 4340 56 12 7 0 49 8 9 40
2409 3598 4 8 85 5718 7713 9593
2347 2101 35 33 3453 48 00 49 62 5562 59 86 72~6 7 8 79 93 76 11237
1243 20 64 3054 4 2 8 1 5114 6983
2326 35 00 4638 5545 7225 91 40
132 13 200 27 26672 31968 41711 52811
bull
67
TABLE IV
PRESSURE PROFILE DATA
Baffle Flow Qpening Rate ~p
(Inches) Position (CFM) (Inches 295 S G Fluid)
1 364 l2 11 U 1012 0 254 1248 0197 1493 0 141 1718 0112
c 1000 9 80 1210 1710 1436 28 75 1746 4320 1011 1080 1277 2050 1393 3020 1 6 28 4450
12D 1011 9 75 1236 1520 1450 2510 1603 3450
1 D 1011 975 1256 1700 1480 2690 158 1 4070
1 12D 1010 950 1259 1750 1462 2650 1631 3710
2 11 D 1124 1315 1360 2130 1505 2850 1689 4125
1 216 12U 1294 045 1949 0324 2374 0282 2704 0225 3367 0169
c 1326 265 18 81 5 90 2313 990 2731 1480 3439 2660
12D 1272 2 49 1957 661
68
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Pos ition (CPM) Inches 2 95 S G Fluid)
2559 1275 3033 1940 3639 3025
1 216 1nD 1257 242 16 96 476 2117 8 05 2561 1280 2990 1895 3431 26 bull00
1 316 12U 1309 0 479 2004 0422 28 28 0 352 3526 0281 42 28 0225 5199 0225
c 1308 1 43 1998 272 28 14 5 10 3478 795 4248 1235 5048 1885
l2D 1286 140 2005 3 45 2831 725 3495 1180 4194 1805 5046 2945
1 11D 1322 150 2039 352 2841 735 43 77 1980 5378 3440
1 516 12U 1278 0493 2732 0493 4315 0408 5744 0352 7494 0352 8932 0422
c 1300 0 506 2731 1985 4310 348 6080 6 45
69
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Position (CPM) (Inches 295 SG Fluid)
7607 1090 8830 1585
l2D 1343 0549 2738 225 4566 583 6112 1195 7536 2055 9043 3415
1 516 1uD 1249 0464 2713 224 4155 579 5620 1150 7428 2115 90 70 3405
1 12D 1301 0493 2735 220 4501 616 61 50 1235 7440 2065 8862 3445
2D 1265 0 478 2750 226 4366 594 6578 1270 7678 2240 8945 5280
2 12D 1295 0493 2725 222 4293 600 5807 1120 7568 2200 9070 3615
TABLE V
RATE OF HEAT TR AN SFER Ar THE BAFFL~~ CID-TT ER
Orifice Size
(Inches)
Flow Rate
( CFM)
Re d e G tU
R~) 055 Nuav NuPr-l3
1 364 10 26 12 90
8 075 10015
43400 54 600
85 11 99 64
95 83 112 19
1416 11 140 59 900 110 30 124 20 16 27 12 800 68 900 126 64 142 60 17 29 13 610 73 200 135 79 152 90 17 76 13980 75 200 147 59 166 19
1 216 11 35 14 06
8 600 10 660
27000 33500
6 4 96 76 56
73 14 8 6 12
1517 11500 36100 82 51 9291 20 34 15400 48400 10229 115 18 23 11 17500 55000 118 31 13322 2348 17 800 55900 11947 13452 2666 20 200 63400 13508 15210 27 16 20 600 64700 135 05 152 07 32 47 24600 77200 161 57 18 193 3392 25 700 80700 17390 195 8 1
1 316 1344 19 36
9898 14 260
24800 35 700
63 8 7 8 2 77
71 92 93 20
28 46 20 9 60 52 500 111 08 125 08 34 84 25 660 64200 131 38 147 93 40 66 50 12
29900 36900
74800 92400
150 78 18046
169 78 203 20
~ 0
TABLE V Continued
Orifice Flow Re Size Rate d e G R~rmiddot55 NuPr-13(Inches) (CFM) U Nuav
1 516 12 70 8 847 16800 54 ~0 61 14 2 14 18 900 35800 82 42 92 80 43 10 30 000 56900 11349 127 79 60 12 41900 79400 14416 16232 7279 50700 96100 17326 19509 86 90 60540 115000 20098 22529
TABLE VI
RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
Orifice Size
(Inches)
1 364
1 216
1 316
Flow Rate
(CFM)
1054 1294 1431 1681 1770
1068 1399 1669 1959 2295 2636 3390
1299 1973 2788 34 73 4118 4973
Re deG Mshy
8 300 9870
11260 13200 13 930
8100 10600 12650 14850 17400 19980 25700
9 570 14500 20500 25600 30300 36600
R~r-6 51900 61700 70500 82 500 87 100
28200 36900 44000 51700 60 600 69500 89400
26100 39600 56000 69900 82700 99 900
Nuav
2416 293 5 3187 4018 4805
14938 18968 21712 25156 30680 37938 59601
14736 21290 28781 36052 439 85 60225
Uu Pr-1 3
27204 33050 3589 4524 541 0
16820 21358 24448 28326 34546 427 18 67111
16593 23973 32407 40595 495 1 678 13
TABLE VI Continued
Orifice Flow Re Size Rate deG R~rmiddot6 NuPr-13(Inches) (CFM ) M- Nuav
1 516 1268 88 30 17700 108 8 1225 2689 18700 37400 1835 2066 3980 27700 55700 2591 2917 4177 29100 58 500 2713 3055 5712 39800 80000 378 0 425 6 7362 51300 103000 5581 6284 8 604 59 900 120000 8529 9604
74
TABLE VII
EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER
l 516 Inch Orifice
Center ot 2nd Baffle 4 Downstream
Plow Rate (CFM)
1235 1919 2712 3320 4153 4704
Flow Rate (CFM)
1270 2714 4310 6012 7279 8690
(Re)eb -8600 1321
13400 2003 18900 2687 23100 5197 28900 4171 32800 5281
Center ot Single Battle
-8847 543
18900 824 30000 1135 41900 1442 50700 1733 60540 2001
(Nu)(Pr)-l3
1487 2255 3003 3600 4697 5946
(Nu)(Pr)-13
611 928
1278 1623 1951 2253
75
ABLE VIII
HEAT TRANSFER IN THE TEST SECTION WITHOUT ORIFICE
CFM Ute) 0b h Nu
1293 5-951 3 41 1942
33 09 15251 649 3746
5236 24193 827 4802
7387 34001 1111 6474
9433 43419 1346 7848
11496 52-914 1524 8883
76
TABLE IX
PRESSURE DROP FUNCTION
Orltlee Size Flow Rate incbea ~CFM (Re)eb X 10bull8
1 364 1011 7957 0808 1256 9885 1468 1480 11648 2765 1581 12443 4160 1689 1_3293 4 020
1 216 1257 9530 1327 1696 12858 2663 2117 16049 4615 2561 19415 7581 2990 22668 11560 3431 26011 16440
l 316 1322 9736 1819 2039 15016 4332 2845 20952 9275 3495 25739 15300 4377 32014 26800 5378 39607 50100
1 516 1011 7 957 oaos 1256 9885 1469 1480 11646 2765 1581 12443 4160 1689 13293 4020
77
TABLE X
EXPERIMENTAL DATA
Baffle Hole Diameter Run No
1 - 59
60 - 102
103 - 138
139 - 206
207 - 212
213 - 218
(Inches)
1 364
1 216
1 316
1 516
No Baffle
2nd - 1 516
TABLE X
EXPERIMENTAL DATA
Run Thermocouple Reading s (mv) No Position CFM I tc1 tc2 tc3 tc4 t c 5 tc6 tc7 tcair
1 c 1026 530 2055 1825 1768 1782 1802 1837 1965 1198 2 1290 612 2059 18 65 1809 18 32 1851 1880 1965 1160 3 1416 714 2151 1970 1931 1965 1988 2026 209 5 1130 4 1627 8 21 2235 2084 2 049 2093 2126 2173 2266 1130 5 1776 865 2203 2033 1970 2015 2084 2159 2 264 1121 6 12D 1109 542 1636 1507 1499 1499 1498 1498 1528 1218 7 1258 651 1670 1522 1503 1513 1513 1516 1548 1221 8 1433 750 1625 1480 1467 148 3 1487 1487 1516 1153 9 168 1 8 73 1656 1494 148 1 1511 1517 1517 1543 1159
10 1rtD 1102 485 1545 1450 1437 1446 1447 1442 1466 1220 11 13 08 6 10 1571 1470 1460 1476 1476 1469 1498 1194 12 1464 730 1 623 1509 1508 1528 1 5 32 1524 1548 1173 13 11 06 8 71 1663 1559 158 1 1606 160 6 1 583 1601 1190 14 1 12D 1115 520 1698 1579 1575 1 577 1580 1590 1615 1280 15 1275 6 10 1692 1567 1558 1 561 1570 1580 1601 1234 16 1498 770 1760 1619 1630 1 635 1642 1645 1661 1204 17 1695 912 1775 1635 1670 1689 1686 168 6 1701 1165 18 2D 1049 510 1736 15~2 1567 1558 1 553 1558 1620 1236 19 12 41 610 1655 1517 149 1 148 1 148 1 148 4 1546 1108 20 1 5 32 7 35 1720 1550 1530 1520 1519 1523 158 0 1104 21 16 74 8 8 0 1900 1 727 1714 1696 1691 1692 1753 1169 22 1U 1074 38 5 3 324 2740 2534 2478 2 465 2503 258 0 1210 23 1287 4 35 3510 2 870 2682 2 610 2599 2638 27 1 9 1190 24 1 5 08 470 3 618 2920 2690 2 637 2627 2 664 2747 1177 25 18 07 525 4 088 3235 2962 2905 2910 2988 3130 1169
z ())
TABLE X Continued
Run No Position CFM I tc1 tc 2
Thermocouple Readings te3 tc4 tc5
(mv) tc6 tc7 tcair
26 c 10~29 6 32 2340 2~092 2032 2060 2~097 2152 2~213 1211 27 12 66 679 2270 2 047 1993 2013 2069 2142 2 210 1 182 28 1430 723 2336 2097 2033 2080 2153 2~255 2 356 1 138 29 1729 8 52 2318 2070 1980 2061 2158 2279 2367 1121 30 12D 1054 570 1520 1 4 20 1402 1400 1396 1400 1 443 1159 31 1294 6 69 1599 1469 1444 1439 1433 1 442 1485 1168 32 1430 7 88 1720 1562 1536 1532 1528 1537 158 0 118 5 33 1770 8 81 1641 1488 1450 1~441 1 441 1_466 1518 1 163 34 1D 1058 548 1579 1498 1495 1526 1553 1_557 1 571 1 276 35 1263 640 1609 1509 1515 1570 1599 1598 1 598 1 266 36 18 36 8 47 1538 1452 1483 1553 1602 1 590 1 558 1195 37 1 12D 1029 5 41 1 578 1499 148 4 1473 1461 1465 1-512 1200 38 1315 6 30 159 1 1504 1493 1482 1470 1470 1505 118 5 39 1 4 26 743 1765 168 1666 1660 1645 1642 1678 1270 40 1757 8 54 1744 1648 1634 1620 1598 1 593 - 1612 1223 41 2D 1080 5 30 1734 1604 1570 1 570 1570 1 588 1 640 128 1 42 1305 6 40 1744 1622 1589 1 608 1593 1 609 1 661 1240 43 1434 750 1798 1687 1658 1 636 -1641 1 661 1 711 1_220 44 18 04 8 41 1 764 1666 1607 1605 1614 1 635 1 675 1205 45 12nu 1088 415 2614 2295 2195 2 169 2174 2217 2256 1171 46 1318 477 2805 2477 2371 2342 2364 2 401 2 438 1 163 47 1413 5 28 2930 2 646 2 555 2 526 2532 2570 2 577 1 199 48 1773 550 2740 2518 2450 2431 2448 2 479 2 480 1 170 49 1 11 U 1054 380 3175 2670 2505 2 461 2467 2 534 2 621 1 258 50 1240 420 3268 2738 2 546 2 510 2 508 258 2 2 649 1214 51 1419 451 3364 2B07 2 632 2590 2 590 2 651 2773 1 215 52 1 12U 1032 360 3 165 2 629 2 450 2402 2403 2 473 2 bull568 1 163
--I lt0
TABLE X Continued
Run No Position CFM I tc1 tc2
lhermocoup1e Reading s tc3 tc4 t c 5
(mv) tc6 tc7 tc a ir
5 3 1314 38 9 3178 2592 2411 2367 2361 2432 2555 1140 54 1448 403 3095 2544 238 1 2336 2336 2390 2476 1158 55 178 2 427 3006 2434 2286 2253 255 3 2299 2397 1154 56 2 11U 1061 360 3369 2814 2619 2567 2560 2650 2833 1220 57 1216 360 3044 2512 2338 2290 2288 2374 2566 1150 58 1322 387 3196 2614 2425 2383 2382 2472 2670 1138 59 1639 403 3020 2438 2272 2238 2238 2318 2502 1127
60 1D 1068 612 1552 1424 1400 1395 1396 1426 1745 0945 61 1399 612 1355 1246 1230 1229 1230 1250 1509 0872 62 1669 710 1436 1293 1272 1265 1266 1286 1551 0847 63 1959 900 159 5 1468 1444 14 38 1432 1446 1720 0851 64 2295 730 1169 1105 1098 1099 1108 1100 1298 0781 65 2636 8 80 1202 1129 1121 1126 1 138 1115 1342 0748 66 3390 9 35 1060 o 9s7 0999 1001 1017 0971 1154 0703 67 1nu 1190 370 2225 2188 2104 2080 2120 2209 2 7 15 0990 68 1559 368 2005 1950 1871 18 48 1876 1951 2408 0916 69 1904 368 1870 18 1 4 17 34 1711 1730 18 07 2238 0875 70 22 bull11 471 228 6 2 204 2099 2063 2092 218 $ 2732 0840 71 2289 471 2030 2000 1925 1895 18 96 19 5 2498 0785 72 2727 4 71 1854 18 23 1753 17 23 1716 3758 2241 0743 73 3210 471 1680 1651 158 6 1559 1551 158 1 1950 omiddot7o9 74 2uD 1210 404 1261 1212 1198 1197 1205 1222 139 1 0978 75 14 20 540 1321 1260 1242 1 240 1249 1268 148 7 0918 76 1692 7 18 1467 138 6 1364 1361 1376 1405 1678 0883 77 18 94 903 1708 1 591 1565 1560 1575 1603 1948 0 857 78 2301 903 1530 1432 1407 1402 1415 1432 1738 0815
ro 0
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc117 tcair
79 2621 6 50 1069 1 020 1009 1009 1009 1007 1~189 o739 80 3230 901 1200 1128 1113 1119 1119 1086 1341 0694 81 82
l2D 1155 1689
360 575
1191 1345
1142 1252
1122 1218
1118 1210
1118 1209
1132 1228
1292 1446
0916 0822
83 1244 430 1163 1134 1131 1130 1129 1132 1292 0877 84 2100 645 1175 1135 1147 1 142 1138 1122 1286 0757 85 2292 8 25 1 354 1310 1327 1330 1323 1285 148 6 0728 86 2907 8 23 1180 1138 1151 1158 1149 1107 1268 0687 87 3380 902 1113 1049 1025 1011 1006 1042 1178 0673 88 89
1 12D 1427 1875
480 615
118 2 1140
1140 1095
1124 1077
1125 1075
1129 1072
1137 1072
1290 1243
0880 0790
90 2259 8 41 1296 1231 1207 1206 1203 1182 1419 0757 91 2682 8 80 1231 1170 1149 1147 1142 1112 1350 0731 92 3417 940 1142 1092 1076 1076 1069 1021 1252 0693 93 c 15 17 431 1321 1298 1268 1249 1250 1273 1522 0841 94 2034 505 1285 1263 1235 1209 1205 1206 1464 0759 95 2348 6 10 1395 1379 1334 1302 1286 1268 1536 0732 96 2716 706 1486 1480 1427 1383 1358 1311 1572 0 700 97 3247 7 56 1417 1430 1375 1320 1284 1223 1450 0660 98 1135 400 1425 1388 1352 1329 1330 1 364 1651 0893 99 14 06 440 1379 1341 1304 128 2 1281 1305 1583 0 831
100 2311 680 1602 1593 1553 1514 1502 1480 1 7 27 0 802 101 2666 680 1471 1469 1428 1390 1372 1335 1564 0761 102 3392 798 1491 1 509 1449 1395 1372 1305 1534 0 719
103 1U 1235 410 2469 2295 2173 2165 2226 2361 3120 0 897 104 2010 410 2017 1848 1 737 1706 1747 1865 2582 0753 105 28 14 410 1682 1535 1457 1427 1437 1520 2109 0 660
00 t-
TABLE X Continued
Ru n Thermocouple Rea ding s (mv No Positi on CFM I tc1 tc2 tc3 tc4 tc5 tc6 tc7 tcair
106 3492 440 1649 1499 1420 1391 1390 1470 2042 0620 107 4395 550 18 33 1679 1597 1564 1570 1640 2223 0583 108 5075 588 1779 1642 1580 1550 1552 1 615 2 191 0548 109 c 1344 398 1464 1 399 1364 1353 1350 1380 1689 0 907 110 1936 459 1369 1290 1253 1242 1 237 1259 1574 078 2 111 2846 580 1347 128 5 1251 1232 1220 1215 1 5 23 0 683 112 34 8 4 700 1392 1369 1339 1317 1299 1259 1599 0 636 113 4066 8 13 1449 1458 1427 1391 1363 1270 1595 0 591 114 5012 930 1484 1530 1500 1453 1420 1272 1580 0 580 115 1D 1362 513 1269 1218 1 217 1214 1220 1238 1460 0 893 116 19 58 600 1187 1122 1121 1120 1124 1133 1352 0798 117 2812 705 1052 1008 1015 1010 1011 1001 1218 0691 118 34 32 913 1105 1075 1085 1081 1086 1047 1301 0645 119 4022 980 1038 1021 1026 1023 1029 0983 1211 0 609 120 5026 982 0 8 61 0839 0836 0836 0837 0791 0955 0570 121 2D 1244 475 1320 1246 1233 1240 1255 1275 1434 0925 122 1 9 60 5 50 1160 1088 1074 1079 1089 1100 1260 078 7 123 2817 6 80 1096 1024 1 013 1018 1029 1022 1201 0 700 124 3491 960 1248 1175 1163 1172 1192 1153 1435 0 658 125 4096 989 1141 1089 1078 108 9 1105 1051 1310 0629 126 50 37 989 0983 0933 0929 0 936 0949 0880 1090 0 602 127 128
12D 1278 1947
402 545
1270 1261
1 230 1216
1228 1216
1230 1 215
1235 1223
1242 1219
1483 1514
0 913 0778shy
129 2769 695 1273 1234 1237 1221 1251 1212 1525 0678 130 131 132
34 39 4103 4978
8 40 9 80 9 80
1336 1448 1271
1322 1458 1 288
1328 1 462 1286
1 259 1 356 1157
1353 1492 1311
1261 1329 1138
1 555 160 7 1343
0 629 0 600 0599
(l) l)
TABLE X Continued
Run No Position CFM I tel tc 2
Thermocouple Readings tc3 tc4 tc5
( mv) tc6 tc7 tcair
133 1 l2D 1299 5 16 1 28 1 1212 1196 1195 1205 1221 1478 0869 134 1973 6 15 1163 1098 1073 1071 1079 1083 1343 0751 135 136
27 88 34 73
802 9 -_78
1187 1214
1099 1131
1069 1104
1066 1101
1075 1~110
1l061 1066
1370 1360
0662 0618
137 4118 9 81 1084 1010 0983 0979 0982 o937 1209 0581 138 4973 98 1 0969 0897 0 868 0855 0860 0799 1041 0572
139 1D 1253 409 1371 1293 1298 1301 1309 1321 1578 0928 140 2366 480 1130 1 090 1 121 1130 1137 1132 1390 0744 141 34 61 6 38 1081 1086 1152 1161 1147 1069 1382 0644 142 143 144
4325 5677 6759
7 90 939 998
1110 1115 1034
1161 1208 1139
1253 1268 1180
1265 1302 1215
1228 1230 1123
1080 1056 0970
13$913r12 8
0601 0561 0542
145 84 08 989 0863 0961 0934 0895 0871 0 785 09 9 0530 146 86 54 9 80 0808 0901 0 872 0821 0809 0733 0891 0498 147 7376 9 80 0 927 1032 1027 1 040 0961 0889 1032 0511 148 2D 4254 776 1 050 0 981 0965 0961 0962 0922 1155 0579 149 5708 991 1102 1031 1014 1009 1010 0931 1227 0528 150 69 78 990 0914 0853 0839 0 839 0843 0759 0996 0521 151 1254 490 1 479 1352 1329 1334 1351 1379 1607 0930 152 2713 7 00 1310 1220 1201 1201 1211 1209 1516 0723 153 8730 991 0809 0756 0742 0745 0 748 0663 0874 0543 154 5811 966 1219 1108 108 6 1081 1079 1033 1330 0650 155 42 46 8 02 1248 1136 1114 1114 1118 1103 1376 0 699 156 c 1270 429 1671 1571 1551 1545 1563 1600 1933 0929 157 2714 488 1398 1285 1 267 1258 1262 1275 1628 0729 158 4310 642 1424 1318 1299 1282 1283 1261 1683 0617
co ~
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc7 tc a 1r
159 60 12 780 1461 1388 1370 1349 1343 1279 1700 0 573 160 72 79 8 60 1402 1344 1330 1312 1292 1189 1 566 0 520 161 8690 982 1472 1442 1437 1 422 1392 1224 1602 0 521 162 163
12D 4368 5833
6 30 8 30
1195 1368
1105 1270
1111 1283
1117 1294
1131 1313
1081 1194
1369 1553
0613 0 553
164 76 43 959 1428 1338 1348 1341 1371 1180 1488 0535 165 8739 984 1345 1272 1272 1208 129 3 1059 1361 0550 166 1268 459 1701 1548 1541 1547 1589 1 625 1976 0 973 167 2678 570 1485 1351 1349 1356 138 1 1 385 1795 0760 168 169
1 12D 128 3 2729
448 650
1664 1314
1501 1232
1425 1233
1428 1229
1491 1229
1527 1232
1869 1571
0 962 0767
170 4345 847 1245 1179 1187 1182 1172 1132 1476 0 650 171 6036 9 76 1139 1109 1117 1114 1095 1020 1332 0588 172 6578 9 72 0982 0949 0942 0938 0926 0 8 50 1079 0560 173 87 84 9 72 0880 0854 0 8 36 0822 0818 0 749 0941 0585 174 1278 480 1564 1416 1397 1403 1417 1445 1733 0998 175 2711 590 128 3 1175 4 1178 1182 1187 1195 1493 0796 176 4351 8 90 1331 1259 1266 1275 1272 1235 1592 0 682 177 5994 9 60 1228 1152 1150 1151 1143 1075 1 360 0644 178 lU 1223 408 2282 2140 2052 2052 2106 2188 2626 0 878 179 2351 408 178 1 1623 158 5 1519 1556 1634 2068 0717 180 3448 482 1888 1675 1570 1541 1572 1665 2199 0629 181 4513 563 2026 1797 168 4 1644 1670 1770 2385 0583 182 5714 589 1913 1700 1610 1568 1580 1 682 2382 0551 middot 183 6997 653 1903 1718 1643 1611 1612 1700 2326 0 549 184 8709 6 80 1738 158 3 1543 1510 1498 1519 1 912 0577 185 186
2 12D 4249 5737
660 9 74
1055 1221
0 979 1122
0960 1093
0 952 1088
0959 1090
0 956 1054
1147 1350
0661 0602
187 7432 9 8 1 1065 0981 0951 0942 0 939 0881 1135 0582 CD ~
TABLE X Continued
Run No Position CFM I t o1 to 2
188 87 23 9 83 0944 0 879 189 1435 585 18 26 1630 190 2718 690 1433 1298 191 7507 950 1070 0961 192 85 44 964 0982 0 881 193 1287 600 1806 1668 194 2717 7 80 1579 1444 195 4253 8 81 1371 1260 196 60 68 9 78 1252 1152 197 73 89 975 1100 1000 198 86 88 973 0953 0 871 199 58 64 9 81 1269 1155 200 2D 4 1 77 915 1362 1251 201 5712 975 1213 1111 202 7363 9 78 1036 0 951 203 8 604 973 0932 0861 204 1268 6 95 2015 18 20 205 2659 6 96 1405 1295 206 39 80 7 98 1261 1174
No 207 Orifice 114 96 509 1325 1148 208 94 33 509 1477 1243 209 7487 5 09 1686 1409 210 5236 505 2094 1691 211 3309 428 2188 1 778 212 1293 392 2976 2560
Thermo ooup1e Readin g s (mv) to 3 to4 to
5 to
6 to7 toair
0 851 0847 0 8 29 0759 0987 0592 158 4 1583 1611 1647 1993 0986 1270 1266 1 279 1298 1604 0 789 0916 0908 0900 0 858 1115 0602 08 39 0 823 0 818 0 770 1035 0602 1609 1602 1629 1676 2153 0979 139 1 1385 1400 1 430 1938 0776 1212 1201 1205 1201 1601 0669 1 105 1086 1086 1 052 1371 0621 0952 0936 0923 0870 1195 0582 0 8 20 0 801 078 1 0 729 1044 0569 1108 1090 108 2 1043 1407 0610 1218 1221 1241 1202 1582 0659 1081 1083 1084 1031 1 368 0622 0921 0924 0919 0 841 1111 0 610 08 34 0831 0 821 0 751 1003 0 630 1761 1761 1 809 1861 2399 0966 1271 1271 1295 1311 1650 0797 1150 1150 1161 1149 1440 0703
1083 1057 1053 1109 1566 0~530 1158 1125 1138 1217 1763 0 526 1291 1250 1278 1383 2038 0542 1518 1478 1519 1657 2420 0 589 1596 1557 1601 1737 2441 0688 2370 2344 2409 2561 3 297 0921
()) (11
TABLE X Continued
Run Thermocouple Readings (mv) No Position CFM I tc 1 tc2 tc3 tc4 tc tc tc tc i5 6 7 a r
C of 2nd 213 516 1235 4 63 1 432 1291 1265 1258 1 268 1 308 1550 0 971 214 1919 6 17 1357 1223 1196 1191 1199 1211 1461 0 851 215 27 12 8 35 1401 1259 1278 1220 1230 1218 1511 0 762 216 3320 981 1439 1305 1270 1259 1275 1238 1450 0719 217 41 53 980 1251 1142 1132 1094 1121 1088 1305 0 695 218 404 987 1102 1042 1030 1 bull006 1014 0960 1133 0681
Supplementary Equations
Calculating temperatures from thermocouple readings
t = -026tc)2 + 3512(tc) + 3201 (26)
where t is the temp in deg F and tc is the thermocouple reading in millishyvolts
Calculation of the thermal conductivity of air
k = 00000245ta + 0 0132 (27)
where k is the thermal conductivity in Btuhr rt2 degFft and ta is the air temp 1n OF
I I
bull co m
THERMOCOUPLE JUNCTIONS~ ~------- HOLES FOR THERMOCOUPLE LEADS
~----- SCREWS
~ff+--- CONNECTING BARS
END VIEW
POWER LEADS SOLDERED TO LOWER CONNECTING BAR
iER PLASTIC PIECE
RESISTANCE RIBBONS LOCATION OF THERMOCOUPLES
FIGURE 4 DRAWING OF ASSEMBLED SENSING PROBE
15
Vibradamp support to absorb the vibrations produced by the
air blower
Air Source
Air was used as the shell-side cooling fluid during
the study The air was pumped through the test section by
a Roots type air blower with a rating of 280 ofm at 3 12
psig outlet pressure The hot air leaving the blower was
passed tbxfugh two finned-tube box-type coolers and one
tubular edoler to oool it to approximately room temperature
The air flow rate was measured by passing it through a
flow measuring orifice in the line Two sharpbull edged orishy
ficas were used f or flow measurements The calibration
curves for these orifices were presented by Ambrose (1
p 166)
The pressure taps on each side of the orifice were
connected to two differential manometers containing 0 83
and 2 95 specific gravity fluids respectively The presshy
sure drop through the test section and test orifice was
measured by a pressure tap placed 13 inches upstream and
one placed 6 12 inches downstream from the orifice Two
pressure ga ges were used to measure the pressure at the
inlet to the flow orifice and to indicate the statio pres~
sure at the test section inlet
16
Pressure Probe
A probe was designed to measure the pressure drop
between the pressure tap 13 i nches upstream from the ori shy
fice baff le and any point downstream from the tap The
probe eonsisted of a l~in OD copper tube with six 132
i n ch holes even l y s paced around the tube The upstream
pressure tap and the pressure probe were connected to a
differential manometer so the pressure drop to various
points up- and downstream of the orifice could be measshy
ured
17
CHAPTER IV
EXPERIMENTAL PROGRAM
The experimental program was designed to measure the
heat transfer coefficients and pressure drops in the vicinshy
ity of annular orifices The four orifice sizes studied
were 1 364 1 216 l 316 and 1 516 inches~ The inner
tube used in each case was a 1-in OD alumintim tube
Hence tube to baffle clearances were respectively 3128
232 332 and 532 of an inch
Heat transfer coefficients were measured at poait~ons
1 i nch upstream at the orifice center and at 12 1
1 12 and 2 inches downstream for all orifices In addishy
middottion the heat transfer coefficient at a point 2 12
inches downstream from the 1 516 inch orifice was measured
and at the points 12 l 12 and 2 inches upstream from
the 1 364 inch orifice
The heat transfer coefficients at each point were
measured at five different flow rates for the 1 364 inch
orifice and at six different flow rates for the other orishy
fice sizes The high pressure drop through the small orishy
fice size limited the number of flow rates which could be
studied
The flow rate was calculated from the pressure drop
across the flow orifice This flow was corrected to cubic
feet per minute at 68degF and one atmosphere pressure by
18
using the orifice pressure and the test section pressure
which were measured by pressure gages
It was desired to determine a relationship between the
heat transfer coefficient and the total pressure drop for
each orifice size The pressure drop across each orifice
at various flow rates was measured by means of the presshy
sure probe described in Chapter III It was also desired
to obtain pressure profiles for each orifice size since
these might be similar to the heat transfer profiles The
pressure drop was measured from a point 13 inches upstream
of the orifice to points at 1 and 12 ineh upstream the
orifice center 12 1 1 12 and 2 inches downstream
The experimental program is summarized in Table I
TABLE I
SUla~RY OF EXPER IMENTAL PROGRAM
Position Investigated-Distance from Orifice-Inches
Orifice Range of Flow Rate Size Heat Transfer Pressure Drop CFM at 68degF amp 1 atm
1 364 2U 1 12U 1U 12U c 12U C 12D lD 10 - 18 l2D lD 1 12D 2D 1 12D 2D
1 216 1U c 12D lD 1 l2D 2D 12U c 12D lD 10 - 35
1 316 1U c 12D lD 1 l2D 2D l2U C 12D lD 12 - 50
1 516 1U c x2D lD 1 l2D 1U 12U C 12D 12 - 90 2D 2 1 2D l D 1 l2D 2D 2 12D
20
CHAPTER v
EXPERI MENTAL PROCEDURE
The experimental procedure for measuring the heat
transfer coefficients ~d corresponding flow rates reshy
quired the following procedure
(1) Install the orifice size to be studied in the
test section
(2) Place the heat transfer probe in the position up
or downstream from the orifice where the middot heat
transfer rate is to be studied
(3) Fill the cold junction thermos with cracked ice
(4) Measure the atmospheric pressure
(5 Open bypass line from blower and close line to
test section
(6) Turn on the cooling water for the exchangers used
to cool the air leaving the blower
(7) Start the automatic selen ium rectifier by turning
on the t 1mer bull
(8 ) Connect the voltage stabilizer to the wall outlet
(9) middot Set the slide wire resistor to the maximum re shy
s1atanee I
(10) Start the blower
(11 Open the line to the test section until the de shy
sired flow rate is obtained
(12) Switch on the probe direct current power source
21
(13) Adjust the slide wire resistor to obtain the
desired current
(14) After the thermocouples have reached equilibrium
values record the e m bullf across each of the
seven probe thermocouples and also the entering
air thermocouple
(15) Record the direct current amperage
(16) Record the gage pressure at the flow orifice and
the entrance to the test section
(17) Record the manometer measurement of the pressure
drop across the flow orifice and also the presshy
sure drop through the test section
22
CHAPTER VI
CALCULAT ION OF EXPERIMENTAL DATA
The local heat transfer coefficients were calculated
from the temperatures measured on the probe surface the
air temperature and the current input The results were
calculated by using the Alwae III-E computer
The general expression for calculation of the heat
transfer coefficients was derived by Ambrose (1 p 79)
The equation is derived by making an energy balance around
a small increment of the center resistance heating ribbon
The two ribbons tnstalled adjacent to the center ribbon
reduced the amount of logitudinal conduction and assured
little longitudinal temperature variation in the center
ribbon
A heat balan ce on this small increment of resistance
ribbon yields the following
(the heat conducted in) + (heat generated) = (heat
conducted out) +(Heat convected to the fluid) + (heat
radiated to the surroundings) + (Heat conducted into
the plastic center of the probe)
This gives the equation
kzw dtdS + 12RdS kzws [ t + (~) ds] + hwdS (t-ta )
+ ~Aad wd o middot+ qcAond 1 -~- wdS 5 )
23
Hence solving for h gi~ea
i2R kz d2t Qrad qcond w + -d$2 - ~- A
h = ( 6)t - ta
Since S = re where 9 equals the enclosed angle ~n radians
dS rd9 ( 7)
and
dt - dt (8)dS - rd9
Differentiating with respect to S
d2t (9)rd9dS
from which
(10)
Substitut1ng into the equation for heat transfer coeffishy
cient gives
h = i2R Qcond A (11)
w
The rate of radial heat conduction into the plastic
tube making up the probe was assumed to have negligible
effect on the heat transfer coefficient It was also
assumed that the heat loss by radiation from the ribbon
was negligible since all data were obtained with the ribbon
at a temperature less than 125degF
24
When t he rad iation and conduction terms are neglected
Eq (11) becomes
(12)
The following con stants are known
R = 0 271 ohmsft
w = 100 i n ches
k = 763 Btuhr rt2 degFft
z = 0 002 inches
r = 12 inch
Eq (12) putting 9 in degrees then reduces to
1110 12 + 2404 d 2t d92
( 15)h = ------~--~-------t - ta
Thi s equation was programed for the Alwac III- E comshy
puter and used to calculate the local heat transfer coefshy
ficients from the observed data
The average heat transfer coefficient around the tube
at a given position in the t est section was calculated by
averaging the local coefficients calculated from Eq (13 )
It was found 1n the course of the experimental work
that thermocouple numbers 1 and 7 were indicating higher
temperatures than would be expected This resulted in h1
and ~ being lower than the other local coefficients around
the tube Since the fluid was flowing parallel to the axis
of the probe the circumferential variation i n rate of heat
25
transfer should be small Hence in obtaining the average
coefficient around the tube the values of h1 and h7 were
not used even though they were calculated and are tabulated
1n Table I II in the Appendix
Then
(14
A Nusselt number as calculated from this aver age heat
transfer coefficient using the tube diameter as the characshy
teristic dimension
(15)
The air flow rates through the test section were calshy
culated by measuring the pressure drop across the flow orishy
fice the air temperature the pressure at the flow orifice
and the pressure at the entrance to the test section The
orifice calibration curves (1 p 166 ) were used to obtain
a value of the orifice coefficient f8e where Q equals
the flow in cubic feet per minute at 68deg F and one atmosmiddot
phere pressure and te is the density of air at the exchanger
and e the density of the air at the flow orifice The
den sity of the air can be expressed by
e = 2 703 p (16)T
where T equals the temperature in OR and P equals the absoshy
lUte pressure i n lb1n2 Using the value of e Qfo from
26
the calibration charts as A and Eq (16) solving for Q
gives
( 17
This equation was used to calculate the flow rate for
each flow studied
The Reynolds number used i n the correlation of the
data was the equivalent Reynolds number defined as
Re)eb ~ d2 - dl)Uf ( 18 ) lL
where d1 is the outside diameter of the inner tube and d2
is the orifice diameter U is the flow velocity through the
annular orifice e is the density of the air and U- is t he
viscosity of the air This equation can be transformed t o
(Re) b = 1611 Q (19) e dl + d2
where d1 and d2 are in inches
The pressure drop data were calculated i nto a dimenshy
sionless pressure drop function cent where
d1 )22( ~ P)gc f av(d2 shycent 2 bull (20
M-
For air this equation reduces to
where d2 and d1 are in i nches D P is expressed i n inches of
2 95 specific gravity fluid and P av is expressed as lbft3
27
CHAPTER VII
ANALYSIS OF DATA
In analyzing the heat transfer data an attempt was
made to correlate it 1n terms of the dimensionless groups
(Nusselt number Prandtl number and Reynolds number) which
appear in Eqs (3) and (4) Consequently all of the av~
erage heat transfer coefficients hav were brought into
the form ( Nu)( Pr)~3 bull The Nusselt number was based on the
tube diameter and the thermal conductivity of the air at
the flowing temperature The tube diameter was used in the
Nusselt number because comparison could then be made with
previous experimental work on heat exchangers which have
commonly used the Nusselt number defined as in Eq (15)
From the standpoint of dimensional analysis this is
equivalent to considering the tube diameter as the characshy
teristic length so far as the heat transfer is concerned
The Prandtl number of the air was taken as 0 7 in all
cases
Variation of Heat Transfer Rate with Distance from the Baffle
Considerable variation was observed in the rate of
heat transfer in the vicinity of the baffle In order to
obtain the variation with respect to position the term
(Nu)(Pr)-13 was plotted versus the flow rate Q for each
position and orifice studied Cros s plots were then made
28
at constant flow rates in order to obtain the variation of
(Nu)(Pr) -13 with position The resulting cross plots are
shown 1n Fi gures 5 6 and 7 for the four orifices studshy
ied
About one inch upstream from the orifice the heat
transfer coefficient begins to rise rapidly and continues
to do so until it reaches a maximum some distance downshy
stream After the maximum point the heat transfer coef fi shy
cient decreased slowly The heat transfer rate was found
to reach a maximum at a different position downstream for
each orifice size These figures also show that for a
given orifice size the maximum heat transfer rate occurs
a pproximately at the same point for all flow rates The
position of the maximum point f or each or ifice size is
shown in Table II
The region immediately downstream from the orifice is
one of h i gh turbulence due to the jetting action of the air
flowing through the orifice As the air flows t hrough the
orifice the streamlines continue to converge for some dis shy
tance downstream The point of maximum heat transfer is
probably at the point where the streamlines be gin to diverge
and a boundary layer begins to build up on the tube Tle
decreasing heat transfer coefficient beyond the maximum
point indicated the formation of a boundary layer
Since the position of the maximum point is independent
of flow rate middot it is possible to correlate it with respect
_ ct 11shyz-
100
0 136 ORIFICE
(
I 0
I )
~ 00
~p 0
I 0
--r--- ~
ISCFIII
-_ OCFM
rbull abull
~ middot~ a-1 z-
12fORIFICE
100
200
100
0 0 UPITRAM ORIFICE DISTANCE CENTER
CFM
h I DOWNSTREAM
DISTANCE
FIGURE 5 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLpound
30
too
700
800
100 ~ f gtf
400
z ~
100
100
100
0
13fORIFICE
~ -~ -- ---
)
~
~
-
I ~ ~OCFM
I vI~-~ OCFM
J ---
Iamp CFM
I 0 I I UPSTREAM ORIFICE DOWNSTREAM DIITANOE GENTER DIITANCI
FIGURE 6 VARIATION OF HEAT TRANSFER RATE WITH DISllNCE FROM BAFFLE
--
--- --
31
100
100
700
100
_ 100
f 9- 400 z-
100
tOO
100
0 - I 0 I I I UHTRIAM OAtfiCI DOWIIITMAM
+ I tyl6 ORIFICE
v I
~~ ~CFM
I v ~CFMI
v v 7
~~ v ~ iOCFM
- ~~ I-shy1-shy ~ICFM
DIITMCI OINTIR DIITANCI
FIGURE 7 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLE
32
TABLE II
POSITION OF MAXIMUM HEAT TRANSFER
Position of Maximum Orifice Size Heat Transfer
(inches) (inches downstream)
1 364 050
1 216 100
1 316 125
1 516 200
33
to orifice size Figure 8 shows the effect of the orifice
size on the position and value of the maximum heat transfer
at a constant flow rate of 15 cubic feet per minute It
can be seen that the larger the orifice size the further
downstream the point of maximum heat transfer occurs
Also as the orifice size increased the rate of heat
transfer decreased for a given flow rate The broken line
indicates the variation of the point of maximum heat transshy
fer with position and size The position of the point of
maximum heat transfer rate downstream from the orifice was
correlated with orifice size by means of the dimensionless
groups (Lde) and (d1de) where L is the distance downshy
stream from the orifice where the maximum rate of heat
transfer occurs d1 is the outside diameter of the inner
tube and de is the equivalent diameter of the orifice
ie de = d2-dlbull
Figure 9 shows a plot of Ld 6 versus d1d6 for the
four orifice sizes studied The four points on this logshy
log plot are approximately in a straight line and the
equation of this line is
Lde = 0 44 d1de)028 (22)
Although the above relationship represents a correlashy
tion of dimensionless groups it is based upon only one
tube diameter and needs to be substantiated further by
studying other tube diameters and other orifice sizes
34
aoo
400
aoo ~
-~ middot-CLshyJ z
200 -
100
0
ORIFICE CENTER
l~
l
t
I J~
1pound~
I
0 I I~
AT 15 CFM
-
bull ~ 1~6~
~ v~
~
~--~~6
~~~ ___ v v V -_
~ o q
~ I 16
v
~
ogWNSTREANI STANCE
FIGURE 8 EFFECT OF ORIFICE SIZE ON POSITION AND VALUE OF MAXIMUM HEAT TRANSFER
35
50
loshy____ -~
~ ~ -shylltl-shy~ r0
2 10 30
FIGURE 9 CORRELATION OF THE POINT OF MAXIMUM HEAT TRANSFER WITH
ORIFICE SIZE
36
Correlation of Data at the Baffle
The heat transfer data were correlated by obtaining a
relationship between the group (Nu)(Pr)-13 and a
Reynolds number based on twice the clearance (d2 - d1
between the tube and the baffle It was found that the
most satisfactory correlation could be obtained when the
term - d1 was used as the length term in the Reynoldsd2
number
Figure 10 shows the variation of the heat transfer
rate at the center of the orifice e xpressed as a function
of Reynolds number and the orifice size This shows that
for a given Reynolds number the heat transfer at the center
of the orifice is greatest for the smallest orifice size
In order to obtain a general correlation of the data
shown i n F1gure 10 the effect of the dimensionless ratio
d1de was considered This ratio considers all of the
geometric factor s needed to describe the annular orifice
The thiclaless of the orifice plate is also a factor but
was constant i n this i nvestigation
The data for the heat transfer at the baffle center
are shown in Figure 11 in which (Nu)( Pr)-13 is plotted
versus (Re)ebd1 de) 0 55 This data on a log-log plot
lies on a straight line for (Re)eb( dld8 )0 55 greater
than 3 x 104 The equation for cor relating the heat
37
4XI~middot~-r~------~--~~------~
Icf t--to_+--_c-c-________ SYMBOL SIZE
0 1~4
6 ~~
9 ~~ -o ~
(Re)eb
FIGURE 10 RATE OF HEAT TRANSFER AT BAFFLE CENTER
38
500
0
4 0 lcf
~ ~
~ ~iC-
~ ~
~IL 0~ 0 SYMBOL SIZE-
p 0 1364-
r 6 1~16 -~ -
9 1~16 --o 1~16
I I
FIGURE II CORRELATION OF HEAT TRANSFER DATA AT BAFFLE CENTER
39
transfer at the center bullOf the a nnular orifice was found by
the method of least s quares to be
(Nu)( Pr)-1 3 = 0018 ( Re)ebO Bl( dlde)04~ (23)
3 x 104 ltRe)eb(a1de)055 lt 105)
Rate of Heat Transfer at the Point of Maximum Heat Transfer-The heat transfer rate at the point of maximum heat
transfer is plotted in Figure 12 to show the variation with
Reynolds number and the size of the orifice It is shown
gives the h1gh st heat transfer ~ate at its point of maxibull
that for a given Reynolds number the smallest orifice size yen il
mum heat transfer
The data ~or the maximum poi~t could be correlated by
plotting (Nu) Pr)-13 versus (Re)eb(d1de)06 This plot
is shown 1n Figure 13 and the resulting eurve shows that
(Nu(Pr)-13 is not a simple p0wer function of the Reynolds
number as was the case for heat transfer at the baffle
center The reason for this is probably because other
factors such as intensity and scala of turbulence should
be considered At the orifice center the streamlines of
the flowing stream are converging_ and thus the flow is
quite stable Downstream from the orifice is a region of
large eddy currents and probably large scale turbulence
These factors could con ceivably cause the results which
were obtained for the point of maximum heat transfer
40
If)
~middotshy Q_-I z_
10~~~--------r----~~--~--
SYMBOL SIZE
0 13$4
6 1~8
Q 13-18
-o 1~8
7)(104
(Re)eb
FIGURE 12 RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
41
Ia ~
0 I
c ~ ~ c v
~ ~lt w ~
17
~ b
v ~ ( SYMBOL SIZE
-~ 0 f-64 -v ~ 6 t211e
~ Q I~~~
-o - l~rs I I
FIGURE 13 CORRELATION OF HEAT TRANSFER DATA AT THE POINT OF MAXIMUM HEAT TRANSFER
4 2
Effect of Upstream Baffles on Heat Transfer at the Orifice Center
The heat transfer rate at the orifice center using the
single orifice in a test section is a pproximately 13 of the
value that was obtained by Lee (7) using a model heat exshy
changer with orifice baffles Lee investigated the cent r al
baffles of the heat exchanger and thus the coeff icients he
obtained would be affected by the presence of a number of
upstream baffles To determine the effect of upstream
baffles an additional l 516 inch baffle was placed four
inches upstream 1n the test section The resulting data are
shown in Figure 14 where (Nu)(Prmiddot)-13 is plotted versus
(Re) eb for the case of a single baffle 1n the test section
and also the case of an additional baffle placed four inches
upstream Comparison is made with the results obtained by
Lee middot(7) using a four-baffle and a ten-baffle model heat exshy
changer Good a greement is obtained with Lees work and the
results show the marked effect that upstream baffles have on
the downstream heat transfer rate The additional up tream
ba ffle caused sufficient turbulence 1n the test section to
i n crease the heat transfer rate nearly three-fold at the
center of the next baffle
Heat Transfer i n the Test Section with No Orifice
In order to check the accuracy 6f the equipment the
orifice baffle was removed and the heat transfer mea sured
with the probe in the empty test section The data were
43
~~BAFFLES
0 l BAFFLE -shy
ll_9 2 BAFFLES
V 4 BAFFLES-LEE
4 10 BAFFLES- LEE lJf ~
~rv ~~ ~ v flvv ~~
I ~ J ~ L v
0
v
( V
40 3XIo 7XIa
(Re)eb
FIGURE 14 EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER AT BAFFLE CENTER
44
compared with heat transfe r coefficients predicted by the
equations for annuli which are recommended in the litera shy9
ture The two equa~ ions u sed tor comparison were
(hfe)=0 023 (rltGr e (~~ur4 (~r45 (24)
which was presente~ by Wiegant (10)
and ( h ) (cnM~5(M~l o14 o 023 CPG k j Mij - (de GJMb )0 2 ( 2 5)
which was presented by McAdams (8 p 242) The comparshy
i son is s hown in Figure 15 lq (25) gives a value which
is low by about ten percent while Eq (24) g ives values
which are high by as much as twenty -five percent when comshy
pared with the experimental data The se equations are gembull
erally considered to give coefficients with an accuracy of
about twenty percent Therefore the present experimental
data are within the accuracy of these equations Also the
plot indicate s that for a Reynold s number greater than 2 x
104 the slope of the line is the same for the experimental
data as for the equations
Pressure Drop Data
The total pressure drop across the orifice was measured
as a function of the flow rate and the orifice size The
pressure drop was expressed as a d1mens1onleas quantity r)
which ie plCltted ver sus the Reynolds number in Figure 18
The pressure drop function cent correlates for all or1f1oe
45
200
100
s z
10 5XI10 10
0 EXPERIMENTAL
--McADAMS
-WIEGAND L
V
~ ~ ~
P ~ ~
LL~ L
v~
~
v v
v 1 ~ ~ v
v -gt
~
~ ~
~
6Xid
FIGURE 15 HEAT TRANSFER WITH NO BAFFLE
46
0 1~4 -~ a 6 t216
Q t316 lJ J
-0 as a )t
A LEE I -shy SULLIVAN 8
p
10bull
BERGELIN
I _ll I
I ~
i I
~middot
lo II
f fl
J j
~middot
A)101
1q
I Ill
1 I3 X 10ao1
FIGURE 16 ORIFICE PRESSURE DROP FUNCTION VS REYNOLDS NUMBER
47
sizes- The present data extends the range covered by preshy
vious workers and agrees well with their work The preshy
vious work of Lee () for a heat exchanger containing 10
orifice baffles and also the data of Su livan and Bergelin
(9) for pressure drop in a model heat exchanger with a
single baffle is shown 1n Figure 16 long with the present
results~ This figure may be used to predict the preseure
drop from the equivalent Reynolds number of the annular
orifice
The pressure drop between individual points 1n the
vicinity of the orifice and an upstream pressure tap wa s
measured to obtain a pressure drop profile As might be
expected 1n all cases the profiles showed a rapid decrea e
in static pressure immediately upstream from the orifice
There was however little or no recovery of the pressure
loss downstream The 1 364 inch orifice did show a maxishy
mum point in the pressure drop but this maximum occurred at
the orifice center and total recovery was reached about 12
inch downstream
Heat Transfer at the Baffle and Maximum Point as a Function of Pressure Drop
In order to compare the effect of the total pressure
drop on the heat transfer at the baffle and the point of
maximum heat transfer Figure 17 was plotted showing
(Nu)(Pr)-13 as a function of the total pressure drop This
shows that for a given pressure drop the largest orifice
48
1200
1000
~ a -sshyz-
100
60 100 700
AT MAXIMUM POINT I 15116 2 13116 3 1~6 4 1364
AT ORIFICE CENTER
60
1
v
r ~ ~ ~
5
~
8 7
13116
8
~
1364
v
~
e6
1~6
v
~~ v ~ ~ -~ ~
~
~ v
l
~
vamp
I ~ ~
~
v L ~
v
I-
5
k= ~~
~ ~ ~
--I
v ~
FIGURE 17 HEAT TRANSFER AT THE BAFFLE AND MAXIMUM POINT AS A FUNCTION OF
ORIFICE PRESSURE DROP
49
size has the greatest heat transfer coefficient This is
true at both the orifice center and at the point of maxishy
mum heat transfer
Another comparison can be made by plotting the heat
transfer coefficient and the pressure drop versus the orishy
fice size at a constant flow rate Figure 18 shows this
plot This graph shows that at a constant flow rate the
pressure drop as well as the heat transfer coefficient
increases as the size of the orifice is decreased In
choosing an orifice size for maximum efficiency 1t would
be necessary to know the pumping power available as well
as the heat transfer desired
70 I I 700
AT 15 CFM 60 ---
~ aug
50 ---
NV
40 ~
~ ~ ~
~ _
MAXIMUM POINT ---- --- ~
1-----t---~ _
~00Qj ~
~t--- ORIFICE CENTER 10 1100
1---~ n
u0 01 02 03 Q35
a ltl
de inches
FIGURE 18 VARIATION OF HEAT TRANSFER RATE AND PRESSURE DROP WITH ORIFICE SIZE AT A CONSTANT FLOW RATE
cn 0
51
CHAPTER VI II
SUMMARY OF RESULTS
This study revealed several significant facts about
the heat transfer in the vicinity of annular orifices
Probably the most important contribution was the presshy
entation of the heat transfer profiles in the vicinity ot
the annular orifice ~ r s shown that t~ local heat
transfer coeffieient re~ches a maximum at a point downshy
stream from the orifice The distance downstream at which
this maximum oocurs is t1ven by the equation
22
The heat transfer coefficients at the center of the
orifice were correlated and found to follow the equation
(Nu)(Pr)-13 = 00176 (Re)eb08l(d 1de) 0 middot4~ (23)
3 x 104 lt( Re) 9 b( d1d6 )055 ltlo5 )
The heat transfer at the point of maximum heat trans
fer for each orifice size was correlated and presented in
Figure 13 as a plot of (Nu)(Pr)-l3 versus (Re)eb(d1de) 06
No simple po-orer relationship exists between the terms
Intensity and scale of turbulence downstream from the orishy
fice are probably important factors which affect the heat
transfer
The large effect of an upstream orifice on the heat
transfer rate at the second orifice was demonstrated by the
52
study of two 1 516 inch orifices in the test section The
added turbulence at the center of the second orifice was
found to raise the heat transfer rate almost three times
over that obtained for a single baffle
The pressure profiles in the vicinity of the orifice
indicate that nearly all the pressure drop occurs at the
orifice center~ Total pressure drop data were correlated
by a pressure drop function cent as a function of the Reynolds
number and good agreement obtained with the results of other
workers
The pressure drop and heat transfer data were correbull
lated by plotting the heat transfer as a function of the
pressure drop for each orifice size It was shown that for
a given pressure drop the largest orifice size gives the
greatest heat transfer coefficient
As a final presentation it was shown that the pressure
drop and the heat transfer coefficient both i ncrease i n
value at a constant flow rate as the orifice size is de shy
creased This is important in choosing the optimum clearshy
ance for orifice baffles
53
CHAPTER IX
RECOMMENDATIONS
A great deal of work remains to be done in the field of
evaluating shellmiddotside heat transfer coefficients This
study included only one tube size and air was the only f luid
used It is recommended that further studies be conducted
using other fluids and tube sizes It will also be necessary
to study several baffle types
The adde d turbulence due to a s e cond baffle placed upbull
s t ream would suggest that the heat transfer coef ficients at
a certain position i n relation to a baffle would increase as
the flow progressed through the exchanger It is recomshy
mended that an extensive s t udy should be made between baffles
the full length of a model heat exchanger
It is further recommended that the pressure drop study
be continued to include other fluids tube sizes and baffle
arrangements
Effects of turbulence downstream from the baff le should
be studied by i n vestigations with hot-wire anemometer equipshy
ment to determi ne t urbulence scale and i ntensity
54
NOMENCLATURE
Area of heat transfer
Heat capacity of the fluid
Outside diameter of the tube
Orifice diameter
Equivalent diameter of the orifice (d2 - dl)
Inside diameter of the test section
Inside diameter of the tube
Gravitational constant
G Mass velocity
h Local heat transfer coefficient
Coefficient of heat transfer from surface to fluid
i Direct current amperes
k Thermal conductivity of the fluid
L Distance downstream of the point of maximum heat transfer
p Absolute pressure
L P Total pressure drop across the orifice
Q Flow in cubio feet per minute at 1 atmosphere and 680 F
q Heat transferred
Thermal energy conducted into the sensing probe
Thermal energy radiated from the resistance ribbon
Resistivity of the resistance ribbon
s Length of the resistance ribbon
T Temperature oR
55
t Temperature of the resistance ribbon deg F
ta Temperature of the bulk stream oF
tw Wall temperature of the tube OF
U Veloc ity of the fluid
w Width of the resistance ribbon
z Thickness of the resistance ribbon
eeuro Density of the fluid in the test section
Density of the fluid at the flow orificef 0
AL Viscosity of the fluid
E9 Angle measured around the tube
Dimensionl ess groups
(Nu) Nusselt number hd1k
(Pr Prandtl number C~k
(Re)eb Equivalent Reynolds number at the baffle (d2 - d1 )uejt-Lshy
(Re)e Equivalent Reynolds number in the test section ( d 8 - d 1 )U fu
cent Orifice pressure drop function 2(~P ) gc~av(d2 - d1) 2
Al
56
BI BLIOGRAPHY
1 Ambrose Tommy W Local shell-side heat transfer coefshyficients in baffled tubular heat exchanger PhD thesis Corvallis Oregon State College 1957 183 numb leaves
2 Bell K J and o P Bergelin Flow through annular orif ices Transactions of the American Society of Mechanical Engineers 70593-601 1957
3 Colburn Allan P A method of correlating forced con shyvection heat transfer data and a comparison with fluid friction Transactions of the American Institute of Chemical Engineers 24 174-210 1933
4 Dittus F w and L M K Boelter Heat transfer 1n automobile radiators of the tubular type University of California Publications in Engineering 2443-461 1930
5 Gurushankariah M s Local shell-side heat transfer coefficients in the vicinity of baffles in tubular heat exchangers Masters thesis Corvallis Ore gon State Colle ge 1958 97 numb leaves
6 Knudsen James G and Donald L Katz Fluid dynamics and heat transfer New York McGraw-Hill 1958 576 p
7 Lee Kyu Sung Local shell-side heat transfer coeffishycients and pressure drop in a tubular heat exchanger with orifice baffles Masters thesis Corvallis Oregon State College 1959 118 numb leaves
8 McAdams William H Heat transmission 3d ed New York McGra ~-Hill 1954 532 p
9 Sullivan F W and 0 P Bergelin Heat transfer and fluid friction in a shell-andbulltube exchanger with a single baffle Chemica l Engineer ing Progress Symposium Series 52 ( 18) 85-94 1956
10 Wiegand J H Discussion on annular heat transfer coshyef f icients for turbulent flow Transactions of American Institut e of Chemical Eng i n eers 41147-153 1945
AP PENDIX
57
TABLE III
CALCULATED HEAT TRANSFER DATA
Baffle Hole Diameter Run No (inches)
1 - 59 1 364
60 - 102 1 216
103 - 138 1 316
139 - 206 1 516
207 - 212 No orifice
213 - 218 2nd - 1 516
TABLE III
CALCULATED HEAT TRANSFER DATA
Local Heat Transfer Coefficients Run
T0 bull Po s ition CFM hr h2 h3 h4 hs he ~ hav Nuav
1 c 1026 10 59 1476 16 09 1559 1510 1435 1203 1518 8511 2 1290 1369 1738 1878 18 05 1755 1689 1515 1773 9964 3 1416 1636 198 1 2068 1977 1924 1845 1715 1959 11030 4 1627 1991 2301 2382 2268 2194 20 ~98 1929 2249 12664 5 1776 2252 2669 2863 2713 2517 2338 2126 2620 14759 6 l2ttD 1109 2311 3317 3386 3373 3387 3394 3071 3371 18888 7 1258 3089 4583 4866 4683 4701 4643 4194 4695 26301 8 1433 38 8 5 55 83 5791 5495 5430 5436 5008 5547 31192 9 1681 4992 7378 7649 6980 6864 6870 64 28 7148 40180
10 1 D 1102 2371 3332 3511 3356 3342 3427 3102 3394 19012 11 1308 3218 4379 45 24 42 53 4255 4373 3965 43 57 24446 12 14 64 38 58 5146 5142 4839 4787 4903 4597 4963 278 79 13 1706 5218 6664 6269 58 81 5884 6237 5973 61 87 34718 14 15
1 l2D 1115 1275
2131 2661
2955 3638
2972 3720
2941 3675
2913 3576
28 22 34 74
2613 3278
2921 36 17
163 09 20246
16 1498 34 87 4644 4503 4441 4371 4343 4194 4460 25010 17 1695 4449 5743 5324 5222 5154 5157 5015 5320 298 97 18 2D 1049 1715 23 90 2550 2610 2656 2624 2208 2566 14363 19 1241 2117 2964 3145 3218 3221 3203 2759 3150 17757 20 1532 28 67 3936 4100 4188 4201 4167 3676 4118 23224 21 1674 3459 4508 4598 4746 4795 4792 4299 4688 26337 22 lU 1074 253 340 380 3 86 388 377 354 374 2097 23 1287 292 392 433 440 441 429 406 427 2394 24 1508 322 439 492 498 499 487 461 48 3 2713 25 18 07 3 38 464 519 5 24 520 499 463 5 05 28 40
~~ (]I agt
TABLE III Continued
Run No Position CFM h 1 h2 ~3 h4 h5 h6 ~ h
av Nu
av 26 c 1029 1171 1491 1589 15 28 1 4 62 1377 1293 1489 83 44 27 1266 1395 1746 1853 18 02 1685 1556 1453 1728 9704 28 1430 1637 2037 2175 2060 1909 1735 1591 1983 11159 29 1729 1982 24 96 2751 2507 2268 2030 1886 2410 13579 30 12D 1054 2934 4041 4321 4326 4423 4359 3706 4298 24160 31 1294 3385 4 8 26 52 42 5326 5450 5277 4566 52 24 293 50 32 1431 3784 5347 5721 57 bull75 58 44 5700 5084 5677 31870 33 1770 52 75 7 7 33 87 35 9005 9007 8267 7059 85 49 48050 34 lD 1058 3235 4401 4444 3877 3496 3451 3294 3934 21973 35 1263 38 98 5484 5330 4347 3964 3981 3987 4621 25823 36 18 36 6701 89 17 7855 6369 5597 5769 6283 69 01 38718 37 1 12D 1029 2404 31 8 2 3333 3459 3624 3577 3045 3435 19264 38 1315 3182 4033 4162 4310 4496 4502 4015 4301 24142 39 1426 3628 4389 4510 4573 4760 4804 43 8 5 4607 25678 40 1757 4547 5559 5(35 5931 6282 63 70 6060 5975 33471 41 2 11D 1080 2034 28 38 3155 3144 3145 2966 2540 3050 17027 42 1305 2650 3 4 87 3aoz 3595 3751 3595 3153 36 46 20405 43 1434 3167 39 07 4156 4371 4320 4126 3709 4176 23395 44 1804 4096 4 9 66 5691 5714 5586 53 15 48 65 5454 30582 45 12U 1088 409 516 557 564 5 60 535 513 5 46 30 67 46 1318 470 579 6 22 631 6 17 5 97 579 6 09 3422 47 14 13 540 640 676 6 86 681 6 60 6 54 6 69 3754 48 1773 641 740 774 782 7 69 749 746 763 42 87 49 l 11 U 1054 270 356 391 397 393 3 71 346 38 2 2133 50 1240 303 399 446 449 447 4 21 398 432 2420 51 1419 361 476 522 530 528 507 467 493 2760 52 1 1(2U 1032 236 311 342 347 344 325 301 334 18 78 53 1314 270 366 403 407 408 386 351 394 2217
(Tt tO
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ h av Nu av
54 1448 301 408 447 454 452 431 403 438 24 61 55 1782 353 494 548 544 415 529 531 506 2843 56 2U 10 61 220 287 316 320 322 303 268 310 1735 57 1216 249 335 370 377 378 353 307 363 2044 58 1322 263 356 394 398 399 374 327 384 2159 59 1639 310 433 478 481 482 452 393 465 2617
60 1D 10 68 2011 2536 2657 2681 2694 2560 15 62 2625 14938 61 1399 2520 3239 3369 3371 33r82 32 39 1946 3320 18968 62 1669 2781 3655 3820 38 76 3883 3738 2355 3794 21712 63 1959 3524 42 37 4399 4438 4497 4417 3047 4397 25156 64 2295 4426 5288 5396 5372 5240 5410 3369 5341 30680 65 2636 5490 6531 6662 6565 6379 6820 4249 6591 37938 66 3390 7869 9538 9462 9387 8924 10508 62 91 9564 59601 67 1U 1190 352 368 401 413 407 395 293 397 2256 68 1559 397 422 462 475 471 456 331 4 57 2603 69 1904 434 465 5 13 529 528 504 358 508 2901 70 2211 493 526 573 5 92 588 564 4 15 569 3257 71 2289 569 587 6 30 649 6 61 6 49 460 635 36 44 72 2727 637 6 60 7 09 733 751 743 521 719 4140 73 3210 728 755 8 15 8 43 8 62 8 54 616 826 4765 74 2nD 1210 181 2256 2393 2399 2333 2206 1325 2317 13158 75 1420 2340 2752 2899 2913 2850 2728 1701 2828 16121 76 1692 2853 3306 3452 3471 3379 3217 2134 3365 19217 77 1894 3102 3588 3713 3736 3670 3557 2455 3653 20892 78 2301 3682 4259 4433 4467 43 83 4289 2892 4366 250 30 79 2621 4117 4828 5017 5012 5030 5109 3071 4999 28785
m 0
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ hav Nuav
80 3230 5158 6006 62 13 61 18 6134 6695 4094 6233 359 87 8 1 12nD 1155 15 27 1854 2028 2064 20 85 1987 1164 1968 118 31 82 1689 2046 24 8 2 2688 2739 2760 2658 1749 2665 152 73 83 1244 2088 2317 2339 2345 2373 2381 1487 2351 13432 84 2100 3211 3539 34 21 3462 3512 3696 2575 3526 20284 85 2292 3 5 05 3761 3648 36 25 36 79 3957 2933 3734 21517 86 2907 4420 48 22 4679 46 04 4705 5206 3792 48 03 27741 87 33 80 59 35 69 38 7404 77 10 7 8 36 7 0 86 5190 7394 427 44 88 1 12D 1 4 27 2 4 58 28 31 3037 3021 2987 2927 18 57 2 9 61 16913 89 18 75 34 75 3 9 87 4230 4255 4317 4337 2734 4225 24258 90 22 59 4221 4796 5046 5052 51 01 5389 3491 5077 29206 91 2682 4978 5664 5943 5966 6054 6573 408 1 60 40 34795 92 3417 63 16 71 02 7 3 93 7385 75 40 8 6 95 51 45 7623 44017 93 c 1 5 17 1240 1305 1399 1467 1479 1429 9 26 1423 8251 94 20 34 1554 1623 1720 18 21 18 53 18 72 1215 1778 10229 95 2 3 48 1795 1843 198 5 2097 2171 2274 1540 2074 11947 96 2716 2028 2048 22 01 2 3 44 2444 2661 18 90 2340 13505 97 3247 2410 2375 2663 2778 2949 3298 2378 2793 1615 98 11 35 967 1040 1124 1186 1200 1142 728 1138 6496 99 14 06 1135 1220 1318 1384 1403 1 3 61 8 77 1336 7656
100 2311 1 8 54 18 78 1980 20 90 2136 2227 1653 2062 118 31 10 1 2666 2085 2094 2227 2 3 62 2438 2626 1902 2349 13508 102 3392 2635 2582 28 01 3026 3141 3529 2567 3016 17390
103 1 U 1235 349 395 434 436 4 28 411 286 423 2416 104 20 10 434 5 02 559 577 569 5 37 345 552 3177 105 28 14 538 626 685 711 7 21 682 424 6 8 6 3966
Q) j-J
TABIE III Continued
Run No Position CFM h1 h2 h3 h4 h5 hu h7 hav Nuav
106 3492 614 7 1 6 7 84 8 13 8 33 7 85 4 88 7 87 4562 107 4395 7 86 894 964 996 1005 9 64 640 9 65 56 06 108 50 75 9 11 10 22 1081 1112 1125 1085 7 24 1085 63 16 109 G 1344 9 22 1042 1120 1 1 46 1173 1131 7 04 1120 63 87 110 1936 1162 1340 1442 1474 1509 14 7 3 9 09 1441 82 77 111 2846 1631 1797 1902 1966 2027 2079 1342 19 2 3 11108 112 3484 207e 2144 2236 2307 2385 2574 1694 2268 13138 113 4066 24 65 24 42 2535 2648 2757 31 71 2178 2 5 96 15078 114 50 12 3059 2916 30 1 5 3176 3312 4059 2849 3105 180 46 115 1D 1362 2268 26 13 2613 26 35 2605 2503 15 46 2617 14934 116 1958 2993 3580 3580 3586 3539 3 5 02 2144 3571 20492 117 2812 4430 50 32 4913 4 9 86 4991 5196 3088 4981 287 66 118 3432 58 16 62 13 6067 61 18 60 66 6698 4143 61 16 354 16 119 40 22 71 71 7 4 62 7369 7419 7329 82 74 51 8 1 7395 42909 120 5026 105 95 11456 115 81 11574 11548 14010 80 91 11540 671 15 121 2D 1244 18 57 2277 2363 2305 2210 2107 1466 2289 13038 122 1960 2622 3240 3388 33 23 3226 31 40 2)99 3294 18919 123 2817 3762 45 87 4739 46 56 45 14 4 6 47 30 15 4624 26689 124 3491 50 22 5723 58 53 57 44 5542 60 18 3871 57 16 330 73 125 4096 61 29 68 16 69 79 6805 65 90 74 79 4677 67 98 39400 126 5037 82 27 94 60 95 69 93 57 9023 11324 65 05 93 52 542 83 127 12D 1278 14 70 1 6 48 1652 1638 1 6 34 1641 9 73 1 6 43 9369 128 1947 19 63 2155 2149 2151 2131 2190 1347 2147 12342 129 2769 2615 2791 2773 28 52 2716 2954 18 96 2783 1 60 82 130 3439 3208 3265 3239 3593 3133 3624 2515 3308 19174 131 4103 3637 35 88 3577 4077 3459 42 66 3138 3676 21343 132 49 78 45 82 44 60 44 8 1 55 17 43 25 5749 4227 4700 27288
Q) tlgt
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
133 1 12D 1299 2094 2507 2622 2625 2567 2489 1465 2578 14736 134 1973 29 56 3505 3772 3790 3718 3718 2115 3700 21290 135 2788 3941 4727 5069 5099 5 0 07 5231 2984 4976 28781 136 3473 5155 59 81 6308 6339 62 39 68 96 4204 6217 36052 137 4118 6135 71 8 6 7662 7731 76 91 87 16 49 8 5 7568 43985 138 4973 7765 94 75 10396 10861 10694 13646 66 64 10357 602 25
139 1ttn 1253 1242 1493 1460 1442 1431 1424 8 84 1457 83 01 140 2366 1942 2150 1961 1910 1897 19 62 1206 1980 11400 141 3461 3007 2957 2562 2513 2606 3143 18 51 2660 15400 142 4325 3942 3571 3060 2999 3198 4248 2631 3207 18618 143 5677 508 6 4359 39 88 3800 42 29 57 78 36 26 4094 23824 144 67 59 64 55 5330 4988 47 25 5494 2517 48 09 5134 29906 145 84 08 9326 72 26 7726 85 56 9172 12319 7733 8170 47626 146 86 54 9831 7582 818 9 94 90 9869 13116 78 97 8783 512 96 147 7376 7335 58 7 6 5941 5796 68 29 81 65 5954 6111 35662 148 2 11 D 4254 4106 48 02 4994 5038 5042 56 78 3419 4969 28881 149 5708 5487 6253 6466 6524 6527 78 63 45 8 2 64 43 37566 150 69 7 8 7983 9440 9848 98 34 97 32 13249 6701 9714 566 59 151 1254 1434 18 53 1947 1915 1850 1760 1186 1891 10772 152 2713 2696 3175 32 94 3288 3237 3288 20 44 3249 18728 153 87 30 118 07 14733 15758 15504 15305 26297 9617 15325 892 71 154 5811 5278 6543 6861 69 30 69 82 7 8 74 4478 68 29 39531 155 4246 3780 4736 4975 49 66 4936 5162 3113 4903 28301 156 (v 1270 8 15 935 959 966 9 51 9 23 6 35 953 5430 157 2714 1164 1390 1427 1447 1454 1455 9 08 1430 8242 158 4310 1655 18 96 1942 1988 2002 2111 1305 1957 11349
(j) ~
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 fry hav Nuav
159 6012 2208 2400 2450 2513 2548 28 20 18 00 2478 14416 160 7279 2696 2881 2927 2989 3081 3599 2340 2970 17326 161 86 90 3257 3360 3 3 76 34 26 3558 4455 2943 3430 2000 162 12D 4368 2209 2600 2558 2518 2466 2774 1753 2536 14713 163 5833 2730 3092 3028 2974 2913 3501 2287 3002 174 78 164 7643 3320 3681 3630 3651 3530 4623 3181 3623 21116 165 87 39 3920 4303 4300 4708 4178 61 60 3937 4372 25456 166 1268 962 1203 1205 1186 1118 1084 725 1178 6693 167 2678 14 67 1785 1779 1752 1698 1726 10 70 1754 88 49 168 1 12D 12 83 936 1217 1414 1397 1239 1190 7 65 1317 7484 169 2729 2502 2930 2914 2934 2956 2979 17 52 2934 16866 170 4345 3884 4357 4283 4318 4421 4836 28 59 4345 25151 171 6036 5546 5858 5764 5791 6028 7129 4184 5860 34045 172 6578 7167 7769 7907 79 82 8263 10492 5915 7980 46437 173 87 84 10237 112 23 120 26 12727 12968 185 19 85 98 12236 71103 174 1278 1344 1803 18 72 1835 1790 1712 1063 1825 10355 175 2711 2328 2972 2932 2893 28 78 2863 1667 2919 167 51 176 4351 3934 4414 4353 4281 4321 4654 28 63 4342 25088 177 5994 5076 5824 5838 5818 59 29 6914 4205 5852 33885 178 1 11 U 1223 388 432 465 464 449 435 338 453 2585 179 2351 521 602 6 22 675 6 57 619 436 639 3687 180 34 48 6 05 1725 803 8 27 8 11 760 518 792 4593 181 4513 718 850 934 9 68 9 57 8 99 609 9 27 5386 18 2 5714 8 32 981 1060 1102 11 06 1034 6 59 1062 61 82 183 6997 1025 1182 1258 1295 1309 1234 8 18 1261 7 3 44 184 8709 1295 1487 1 5 42 1594 1626 1612 1156 1562 9080
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
185 2 12D 4249 3560 4400 4670 4791 4695 47 81 2931 4639 268 37 186 5737 4926 58 54 61 92 6248 62 38 67 78 4134 6131 35590 187 7432 6390 7726 83 46 85 44 86 34 10371 5658 8313 48310 188 8723 7718 107 88 11933 12099 13046 186 22 79 39 119 67 69505 189 1 4 35 1340 1735 18 57 18 52 17 81 1711 1144 18 06 10256 190 2718 2399 3023 3187 3207 3138 30 53 1931 3139 18025 191 7 5 07 6189 80 11 9200 9427 9703 11364 5720 9085 527 38 192 8544 78 42 10666 125 42 13312 13775 178 20 6976 125 74 729 86 193 1287 1417 16 97 18 7 18 69 18 08 1720 1046 1800 10223 194 27 17 2450 2940 3187 3214 3157 3054 1749 3125 17954 195 42 53 3560 4222 45 90 4679 46 63 4743 2741 4539 26247 196 6068 48 69 57 79 6335 65 8 6 66 04 7172 4338 63 26 366 78 197 7389 58 86 72 8 6 82 23 8584 8936 10658 50 60 8257 4798 6 198 86 88 78 91 100 27 120 56 130 29 14299 190 81 6492 12353 71850 199 5864 4694 5 6 67 61 94 6419 65 48 7192 3950 6207 360 14 200 2 D 4177 38 36 4547 48 09 4775 4628 5006 2715 46 90 261 30 201 5712 5170 62 39 66 38 6599 6604 7518 4167 65 20 378 00 202 73 63 7201 8986 98 43 9733 9914 13353 6219 9619 55810 203 8604 10043 13118 148 41 150 42 158 66 25206 82 5 3 14717 85290 204 12 68 1506 18 41 1971 1966 1868 1799 11 42 1913 10880 205 2659 2571 3127 3276 32 50 3130 3069 18 80 3196 18 350 206 39 80 36 76 4347 4573 45~67 4473 46 34 28 37 4490 25910
o 207 Orifice 11496 10 64 1360 15 39 1 5 80 1 6 15 1496 8 58 15 24 88 83 208 9433 8 95 11 78 13 26 1394 1386 1263 727 1346 78 48 209 7387 746 9 77 1123 1184 1159 1048 6 11 1111 64 74 210 52 36 566 7 66 900 934 909 8 21 499 8 27 48 02
0) CJ1
TABLE III Continued
Run No Position CFM h 1 h2 hs h4 h5 h6 h7 hav Nuav
211 212
3309 1293
414 257
563 3 19
6 68 3 57
6 91 3 37
6 72 351
7 37 337
38 4 2 46
4 40 341
3748 1942
213 214 215 216 217 218
c of 2nd 1 516 1235
1919 2712 3320 4153 4704
1532 2447 35 46 4312 5567 74 29
2 1 87 3312 4225 52 86 6902 8 6 50
2360 3555 4340 56 12 7 0 49 8 9 40
2409 3598 4 8 85 5718 7713 9593
2347 2101 35 33 3453 48 00 49 62 5562 59 86 72~6 7 8 79 93 76 11237
1243 20 64 3054 4 2 8 1 5114 6983
2326 35 00 4638 5545 7225 91 40
132 13 200 27 26672 31968 41711 52811
bull
67
TABLE IV
PRESSURE PROFILE DATA
Baffle Flow Qpening Rate ~p
(Inches) Position (CFM) (Inches 295 S G Fluid)
1 364 l2 11 U 1012 0 254 1248 0197 1493 0 141 1718 0112
c 1000 9 80 1210 1710 1436 28 75 1746 4320 1011 1080 1277 2050 1393 3020 1 6 28 4450
12D 1011 9 75 1236 1520 1450 2510 1603 3450
1 D 1011 975 1256 1700 1480 2690 158 1 4070
1 12D 1010 950 1259 1750 1462 2650 1631 3710
2 11 D 1124 1315 1360 2130 1505 2850 1689 4125
1 216 12U 1294 045 1949 0324 2374 0282 2704 0225 3367 0169
c 1326 265 18 81 5 90 2313 990 2731 1480 3439 2660
12D 1272 2 49 1957 661
68
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Pos ition (CPM) Inches 2 95 S G Fluid)
2559 1275 3033 1940 3639 3025
1 216 1nD 1257 242 16 96 476 2117 8 05 2561 1280 2990 1895 3431 26 bull00
1 316 12U 1309 0 479 2004 0422 28 28 0 352 3526 0281 42 28 0225 5199 0225
c 1308 1 43 1998 272 28 14 5 10 3478 795 4248 1235 5048 1885
l2D 1286 140 2005 3 45 2831 725 3495 1180 4194 1805 5046 2945
1 11D 1322 150 2039 352 2841 735 43 77 1980 5378 3440
1 516 12U 1278 0493 2732 0493 4315 0408 5744 0352 7494 0352 8932 0422
c 1300 0 506 2731 1985 4310 348 6080 6 45
69
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Position (CPM) (Inches 295 SG Fluid)
7607 1090 8830 1585
l2D 1343 0549 2738 225 4566 583 6112 1195 7536 2055 9043 3415
1 516 1uD 1249 0464 2713 224 4155 579 5620 1150 7428 2115 90 70 3405
1 12D 1301 0493 2735 220 4501 616 61 50 1235 7440 2065 8862 3445
2D 1265 0 478 2750 226 4366 594 6578 1270 7678 2240 8945 5280
2 12D 1295 0493 2725 222 4293 600 5807 1120 7568 2200 9070 3615
TABLE V
RATE OF HEAT TR AN SFER Ar THE BAFFL~~ CID-TT ER
Orifice Size
(Inches)
Flow Rate
( CFM)
Re d e G tU
R~) 055 Nuav NuPr-l3
1 364 10 26 12 90
8 075 10015
43400 54 600
85 11 99 64
95 83 112 19
1416 11 140 59 900 110 30 124 20 16 27 12 800 68 900 126 64 142 60 17 29 13 610 73 200 135 79 152 90 17 76 13980 75 200 147 59 166 19
1 216 11 35 14 06
8 600 10 660
27000 33500
6 4 96 76 56
73 14 8 6 12
1517 11500 36100 82 51 9291 20 34 15400 48400 10229 115 18 23 11 17500 55000 118 31 13322 2348 17 800 55900 11947 13452 2666 20 200 63400 13508 15210 27 16 20 600 64700 135 05 152 07 32 47 24600 77200 161 57 18 193 3392 25 700 80700 17390 195 8 1
1 316 1344 19 36
9898 14 260
24800 35 700
63 8 7 8 2 77
71 92 93 20
28 46 20 9 60 52 500 111 08 125 08 34 84 25 660 64200 131 38 147 93 40 66 50 12
29900 36900
74800 92400
150 78 18046
169 78 203 20
~ 0
TABLE V Continued
Orifice Flow Re Size Rate d e G R~rmiddot55 NuPr-13(Inches) (CFM) U Nuav
1 516 12 70 8 847 16800 54 ~0 61 14 2 14 18 900 35800 82 42 92 80 43 10 30 000 56900 11349 127 79 60 12 41900 79400 14416 16232 7279 50700 96100 17326 19509 86 90 60540 115000 20098 22529
TABLE VI
RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
Orifice Size
(Inches)
1 364
1 216
1 316
Flow Rate
(CFM)
1054 1294 1431 1681 1770
1068 1399 1669 1959 2295 2636 3390
1299 1973 2788 34 73 4118 4973
Re deG Mshy
8 300 9870
11260 13200 13 930
8100 10600 12650 14850 17400 19980 25700
9 570 14500 20500 25600 30300 36600
R~r-6 51900 61700 70500 82 500 87 100
28200 36900 44000 51700 60 600 69500 89400
26100 39600 56000 69900 82700 99 900
Nuav
2416 293 5 3187 4018 4805
14938 18968 21712 25156 30680 37938 59601
14736 21290 28781 36052 439 85 60225
Uu Pr-1 3
27204 33050 3589 4524 541 0
16820 21358 24448 28326 34546 427 18 67111
16593 23973 32407 40595 495 1 678 13
TABLE VI Continued
Orifice Flow Re Size Rate deG R~rmiddot6 NuPr-13(Inches) (CFM ) M- Nuav
1 516 1268 88 30 17700 108 8 1225 2689 18700 37400 1835 2066 3980 27700 55700 2591 2917 4177 29100 58 500 2713 3055 5712 39800 80000 378 0 425 6 7362 51300 103000 5581 6284 8 604 59 900 120000 8529 9604
74
TABLE VII
EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER
l 516 Inch Orifice
Center ot 2nd Baffle 4 Downstream
Plow Rate (CFM)
1235 1919 2712 3320 4153 4704
Flow Rate (CFM)
1270 2714 4310 6012 7279 8690
(Re)eb -8600 1321
13400 2003 18900 2687 23100 5197 28900 4171 32800 5281
Center ot Single Battle
-8847 543
18900 824 30000 1135 41900 1442 50700 1733 60540 2001
(Nu)(Pr)-l3
1487 2255 3003 3600 4697 5946
(Nu)(Pr)-13
611 928
1278 1623 1951 2253
75
ABLE VIII
HEAT TRANSFER IN THE TEST SECTION WITHOUT ORIFICE
CFM Ute) 0b h Nu
1293 5-951 3 41 1942
33 09 15251 649 3746
5236 24193 827 4802
7387 34001 1111 6474
9433 43419 1346 7848
11496 52-914 1524 8883
76
TABLE IX
PRESSURE DROP FUNCTION
Orltlee Size Flow Rate incbea ~CFM (Re)eb X 10bull8
1 364 1011 7957 0808 1256 9885 1468 1480 11648 2765 1581 12443 4160 1689 1_3293 4 020
1 216 1257 9530 1327 1696 12858 2663 2117 16049 4615 2561 19415 7581 2990 22668 11560 3431 26011 16440
l 316 1322 9736 1819 2039 15016 4332 2845 20952 9275 3495 25739 15300 4377 32014 26800 5378 39607 50100
1 516 1011 7 957 oaos 1256 9885 1469 1480 11646 2765 1581 12443 4160 1689 13293 4020
77
TABLE X
EXPERIMENTAL DATA
Baffle Hole Diameter Run No
1 - 59
60 - 102
103 - 138
139 - 206
207 - 212
213 - 218
(Inches)
1 364
1 216
1 316
1 516
No Baffle
2nd - 1 516
TABLE X
EXPERIMENTAL DATA
Run Thermocouple Reading s (mv) No Position CFM I tc1 tc2 tc3 tc4 t c 5 tc6 tc7 tcair
1 c 1026 530 2055 1825 1768 1782 1802 1837 1965 1198 2 1290 612 2059 18 65 1809 18 32 1851 1880 1965 1160 3 1416 714 2151 1970 1931 1965 1988 2026 209 5 1130 4 1627 8 21 2235 2084 2 049 2093 2126 2173 2266 1130 5 1776 865 2203 2033 1970 2015 2084 2159 2 264 1121 6 12D 1109 542 1636 1507 1499 1499 1498 1498 1528 1218 7 1258 651 1670 1522 1503 1513 1513 1516 1548 1221 8 1433 750 1625 1480 1467 148 3 1487 1487 1516 1153 9 168 1 8 73 1656 1494 148 1 1511 1517 1517 1543 1159
10 1rtD 1102 485 1545 1450 1437 1446 1447 1442 1466 1220 11 13 08 6 10 1571 1470 1460 1476 1476 1469 1498 1194 12 1464 730 1 623 1509 1508 1528 1 5 32 1524 1548 1173 13 11 06 8 71 1663 1559 158 1 1606 160 6 1 583 1601 1190 14 1 12D 1115 520 1698 1579 1575 1 577 1580 1590 1615 1280 15 1275 6 10 1692 1567 1558 1 561 1570 1580 1601 1234 16 1498 770 1760 1619 1630 1 635 1642 1645 1661 1204 17 1695 912 1775 1635 1670 1689 1686 168 6 1701 1165 18 2D 1049 510 1736 15~2 1567 1558 1 553 1558 1620 1236 19 12 41 610 1655 1517 149 1 148 1 148 1 148 4 1546 1108 20 1 5 32 7 35 1720 1550 1530 1520 1519 1523 158 0 1104 21 16 74 8 8 0 1900 1 727 1714 1696 1691 1692 1753 1169 22 1U 1074 38 5 3 324 2740 2534 2478 2 465 2503 258 0 1210 23 1287 4 35 3510 2 870 2682 2 610 2599 2638 27 1 9 1190 24 1 5 08 470 3 618 2920 2690 2 637 2627 2 664 2747 1177 25 18 07 525 4 088 3235 2962 2905 2910 2988 3130 1169
z ())
TABLE X Continued
Run No Position CFM I tc1 tc 2
Thermocouple Readings te3 tc4 tc5
(mv) tc6 tc7 tcair
26 c 10~29 6 32 2340 2~092 2032 2060 2~097 2152 2~213 1211 27 12 66 679 2270 2 047 1993 2013 2069 2142 2 210 1 182 28 1430 723 2336 2097 2033 2080 2153 2~255 2 356 1 138 29 1729 8 52 2318 2070 1980 2061 2158 2279 2367 1121 30 12D 1054 570 1520 1 4 20 1402 1400 1396 1400 1 443 1159 31 1294 6 69 1599 1469 1444 1439 1433 1 442 1485 1168 32 1430 7 88 1720 1562 1536 1532 1528 1537 158 0 118 5 33 1770 8 81 1641 1488 1450 1~441 1 441 1_466 1518 1 163 34 1D 1058 548 1579 1498 1495 1526 1553 1_557 1 571 1 276 35 1263 640 1609 1509 1515 1570 1599 1598 1 598 1 266 36 18 36 8 47 1538 1452 1483 1553 1602 1 590 1 558 1195 37 1 12D 1029 5 41 1 578 1499 148 4 1473 1461 1465 1-512 1200 38 1315 6 30 159 1 1504 1493 1482 1470 1470 1505 118 5 39 1 4 26 743 1765 168 1666 1660 1645 1642 1678 1270 40 1757 8 54 1744 1648 1634 1620 1598 1 593 - 1612 1223 41 2D 1080 5 30 1734 1604 1570 1 570 1570 1 588 1 640 128 1 42 1305 6 40 1744 1622 1589 1 608 1593 1 609 1 661 1240 43 1434 750 1798 1687 1658 1 636 -1641 1 661 1 711 1_220 44 18 04 8 41 1 764 1666 1607 1605 1614 1 635 1 675 1205 45 12nu 1088 415 2614 2295 2195 2 169 2174 2217 2256 1171 46 1318 477 2805 2477 2371 2342 2364 2 401 2 438 1 163 47 1413 5 28 2930 2 646 2 555 2 526 2532 2570 2 577 1 199 48 1773 550 2740 2518 2450 2431 2448 2 479 2 480 1 170 49 1 11 U 1054 380 3175 2670 2505 2 461 2467 2 534 2 621 1 258 50 1240 420 3268 2738 2 546 2 510 2 508 258 2 2 649 1214 51 1419 451 3364 2B07 2 632 2590 2 590 2 651 2773 1 215 52 1 12U 1032 360 3 165 2 629 2 450 2402 2403 2 473 2 bull568 1 163
--I lt0
TABLE X Continued
Run No Position CFM I tc1 tc2
lhermocoup1e Reading s tc3 tc4 t c 5
(mv) tc6 tc7 tc a ir
5 3 1314 38 9 3178 2592 2411 2367 2361 2432 2555 1140 54 1448 403 3095 2544 238 1 2336 2336 2390 2476 1158 55 178 2 427 3006 2434 2286 2253 255 3 2299 2397 1154 56 2 11U 1061 360 3369 2814 2619 2567 2560 2650 2833 1220 57 1216 360 3044 2512 2338 2290 2288 2374 2566 1150 58 1322 387 3196 2614 2425 2383 2382 2472 2670 1138 59 1639 403 3020 2438 2272 2238 2238 2318 2502 1127
60 1D 1068 612 1552 1424 1400 1395 1396 1426 1745 0945 61 1399 612 1355 1246 1230 1229 1230 1250 1509 0872 62 1669 710 1436 1293 1272 1265 1266 1286 1551 0847 63 1959 900 159 5 1468 1444 14 38 1432 1446 1720 0851 64 2295 730 1169 1105 1098 1099 1108 1100 1298 0781 65 2636 8 80 1202 1129 1121 1126 1 138 1115 1342 0748 66 3390 9 35 1060 o 9s7 0999 1001 1017 0971 1154 0703 67 1nu 1190 370 2225 2188 2104 2080 2120 2209 2 7 15 0990 68 1559 368 2005 1950 1871 18 48 1876 1951 2408 0916 69 1904 368 1870 18 1 4 17 34 1711 1730 18 07 2238 0875 70 22 bull11 471 228 6 2 204 2099 2063 2092 218 $ 2732 0840 71 2289 471 2030 2000 1925 1895 18 96 19 5 2498 0785 72 2727 4 71 1854 18 23 1753 17 23 1716 3758 2241 0743 73 3210 471 1680 1651 158 6 1559 1551 158 1 1950 omiddot7o9 74 2uD 1210 404 1261 1212 1198 1197 1205 1222 139 1 0978 75 14 20 540 1321 1260 1242 1 240 1249 1268 148 7 0918 76 1692 7 18 1467 138 6 1364 1361 1376 1405 1678 0883 77 18 94 903 1708 1 591 1565 1560 1575 1603 1948 0 857 78 2301 903 1530 1432 1407 1402 1415 1432 1738 0815
ro 0
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc117 tcair
79 2621 6 50 1069 1 020 1009 1009 1009 1007 1~189 o739 80 3230 901 1200 1128 1113 1119 1119 1086 1341 0694 81 82
l2D 1155 1689
360 575
1191 1345
1142 1252
1122 1218
1118 1210
1118 1209
1132 1228
1292 1446
0916 0822
83 1244 430 1163 1134 1131 1130 1129 1132 1292 0877 84 2100 645 1175 1135 1147 1 142 1138 1122 1286 0757 85 2292 8 25 1 354 1310 1327 1330 1323 1285 148 6 0728 86 2907 8 23 1180 1138 1151 1158 1149 1107 1268 0687 87 3380 902 1113 1049 1025 1011 1006 1042 1178 0673 88 89
1 12D 1427 1875
480 615
118 2 1140
1140 1095
1124 1077
1125 1075
1129 1072
1137 1072
1290 1243
0880 0790
90 2259 8 41 1296 1231 1207 1206 1203 1182 1419 0757 91 2682 8 80 1231 1170 1149 1147 1142 1112 1350 0731 92 3417 940 1142 1092 1076 1076 1069 1021 1252 0693 93 c 15 17 431 1321 1298 1268 1249 1250 1273 1522 0841 94 2034 505 1285 1263 1235 1209 1205 1206 1464 0759 95 2348 6 10 1395 1379 1334 1302 1286 1268 1536 0732 96 2716 706 1486 1480 1427 1383 1358 1311 1572 0 700 97 3247 7 56 1417 1430 1375 1320 1284 1223 1450 0660 98 1135 400 1425 1388 1352 1329 1330 1 364 1651 0893 99 14 06 440 1379 1341 1304 128 2 1281 1305 1583 0 831
100 2311 680 1602 1593 1553 1514 1502 1480 1 7 27 0 802 101 2666 680 1471 1469 1428 1390 1372 1335 1564 0761 102 3392 798 1491 1 509 1449 1395 1372 1305 1534 0 719
103 1U 1235 410 2469 2295 2173 2165 2226 2361 3120 0 897 104 2010 410 2017 1848 1 737 1706 1747 1865 2582 0753 105 28 14 410 1682 1535 1457 1427 1437 1520 2109 0 660
00 t-
TABLE X Continued
Ru n Thermocouple Rea ding s (mv No Positi on CFM I tc1 tc2 tc3 tc4 tc5 tc6 tc7 tcair
106 3492 440 1649 1499 1420 1391 1390 1470 2042 0620 107 4395 550 18 33 1679 1597 1564 1570 1640 2223 0583 108 5075 588 1779 1642 1580 1550 1552 1 615 2 191 0548 109 c 1344 398 1464 1 399 1364 1353 1350 1380 1689 0 907 110 1936 459 1369 1290 1253 1242 1 237 1259 1574 078 2 111 2846 580 1347 128 5 1251 1232 1220 1215 1 5 23 0 683 112 34 8 4 700 1392 1369 1339 1317 1299 1259 1599 0 636 113 4066 8 13 1449 1458 1427 1391 1363 1270 1595 0 591 114 5012 930 1484 1530 1500 1453 1420 1272 1580 0 580 115 1D 1362 513 1269 1218 1 217 1214 1220 1238 1460 0 893 116 19 58 600 1187 1122 1121 1120 1124 1133 1352 0798 117 2812 705 1052 1008 1015 1010 1011 1001 1218 0691 118 34 32 913 1105 1075 1085 1081 1086 1047 1301 0645 119 4022 980 1038 1021 1026 1023 1029 0983 1211 0 609 120 5026 982 0 8 61 0839 0836 0836 0837 0791 0955 0570 121 2D 1244 475 1320 1246 1233 1240 1255 1275 1434 0925 122 1 9 60 5 50 1160 1088 1074 1079 1089 1100 1260 078 7 123 2817 6 80 1096 1024 1 013 1018 1029 1022 1201 0 700 124 3491 960 1248 1175 1163 1172 1192 1153 1435 0 658 125 4096 989 1141 1089 1078 108 9 1105 1051 1310 0629 126 50 37 989 0983 0933 0929 0 936 0949 0880 1090 0 602 127 128
12D 1278 1947
402 545
1270 1261
1 230 1216
1228 1216
1230 1 215
1235 1223
1242 1219
1483 1514
0 913 0778shy
129 2769 695 1273 1234 1237 1221 1251 1212 1525 0678 130 131 132
34 39 4103 4978
8 40 9 80 9 80
1336 1448 1271
1322 1458 1 288
1328 1 462 1286
1 259 1 356 1157
1353 1492 1311
1261 1329 1138
1 555 160 7 1343
0 629 0 600 0599
(l) l)
TABLE X Continued
Run No Position CFM I tel tc 2
Thermocouple Readings tc3 tc4 tc5
( mv) tc6 tc7 tcair
133 1 l2D 1299 5 16 1 28 1 1212 1196 1195 1205 1221 1478 0869 134 1973 6 15 1163 1098 1073 1071 1079 1083 1343 0751 135 136
27 88 34 73
802 9 -_78
1187 1214
1099 1131
1069 1104
1066 1101
1075 1~110
1l061 1066
1370 1360
0662 0618
137 4118 9 81 1084 1010 0983 0979 0982 o937 1209 0581 138 4973 98 1 0969 0897 0 868 0855 0860 0799 1041 0572
139 1D 1253 409 1371 1293 1298 1301 1309 1321 1578 0928 140 2366 480 1130 1 090 1 121 1130 1137 1132 1390 0744 141 34 61 6 38 1081 1086 1152 1161 1147 1069 1382 0644 142 143 144
4325 5677 6759
7 90 939 998
1110 1115 1034
1161 1208 1139
1253 1268 1180
1265 1302 1215
1228 1230 1123
1080 1056 0970
13$913r12 8
0601 0561 0542
145 84 08 989 0863 0961 0934 0895 0871 0 785 09 9 0530 146 86 54 9 80 0808 0901 0 872 0821 0809 0733 0891 0498 147 7376 9 80 0 927 1032 1027 1 040 0961 0889 1032 0511 148 2D 4254 776 1 050 0 981 0965 0961 0962 0922 1155 0579 149 5708 991 1102 1031 1014 1009 1010 0931 1227 0528 150 69 78 990 0914 0853 0839 0 839 0843 0759 0996 0521 151 1254 490 1 479 1352 1329 1334 1351 1379 1607 0930 152 2713 7 00 1310 1220 1201 1201 1211 1209 1516 0723 153 8730 991 0809 0756 0742 0745 0 748 0663 0874 0543 154 5811 966 1219 1108 108 6 1081 1079 1033 1330 0650 155 42 46 8 02 1248 1136 1114 1114 1118 1103 1376 0 699 156 c 1270 429 1671 1571 1551 1545 1563 1600 1933 0929 157 2714 488 1398 1285 1 267 1258 1262 1275 1628 0729 158 4310 642 1424 1318 1299 1282 1283 1261 1683 0617
co ~
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc7 tc a 1r
159 60 12 780 1461 1388 1370 1349 1343 1279 1700 0 573 160 72 79 8 60 1402 1344 1330 1312 1292 1189 1 566 0 520 161 8690 982 1472 1442 1437 1 422 1392 1224 1602 0 521 162 163
12D 4368 5833
6 30 8 30
1195 1368
1105 1270
1111 1283
1117 1294
1131 1313
1081 1194
1369 1553
0613 0 553
164 76 43 959 1428 1338 1348 1341 1371 1180 1488 0535 165 8739 984 1345 1272 1272 1208 129 3 1059 1361 0550 166 1268 459 1701 1548 1541 1547 1589 1 625 1976 0 973 167 2678 570 1485 1351 1349 1356 138 1 1 385 1795 0760 168 169
1 12D 128 3 2729
448 650
1664 1314
1501 1232
1425 1233
1428 1229
1491 1229
1527 1232
1869 1571
0 962 0767
170 4345 847 1245 1179 1187 1182 1172 1132 1476 0 650 171 6036 9 76 1139 1109 1117 1114 1095 1020 1332 0588 172 6578 9 72 0982 0949 0942 0938 0926 0 8 50 1079 0560 173 87 84 9 72 0880 0854 0 8 36 0822 0818 0 749 0941 0585 174 1278 480 1564 1416 1397 1403 1417 1445 1733 0998 175 2711 590 128 3 1175 4 1178 1182 1187 1195 1493 0796 176 4351 8 90 1331 1259 1266 1275 1272 1235 1592 0 682 177 5994 9 60 1228 1152 1150 1151 1143 1075 1 360 0644 178 lU 1223 408 2282 2140 2052 2052 2106 2188 2626 0 878 179 2351 408 178 1 1623 158 5 1519 1556 1634 2068 0717 180 3448 482 1888 1675 1570 1541 1572 1665 2199 0629 181 4513 563 2026 1797 168 4 1644 1670 1770 2385 0583 182 5714 589 1913 1700 1610 1568 1580 1 682 2382 0551 middot 183 6997 653 1903 1718 1643 1611 1612 1700 2326 0 549 184 8709 6 80 1738 158 3 1543 1510 1498 1519 1 912 0577 185 186
2 12D 4249 5737
660 9 74
1055 1221
0 979 1122
0960 1093
0 952 1088
0959 1090
0 956 1054
1147 1350
0661 0602
187 7432 9 8 1 1065 0981 0951 0942 0 939 0881 1135 0582 CD ~
TABLE X Continued
Run No Position CFM I t o1 to 2
188 87 23 9 83 0944 0 879 189 1435 585 18 26 1630 190 2718 690 1433 1298 191 7507 950 1070 0961 192 85 44 964 0982 0 881 193 1287 600 1806 1668 194 2717 7 80 1579 1444 195 4253 8 81 1371 1260 196 60 68 9 78 1252 1152 197 73 89 975 1100 1000 198 86 88 973 0953 0 871 199 58 64 9 81 1269 1155 200 2D 4 1 77 915 1362 1251 201 5712 975 1213 1111 202 7363 9 78 1036 0 951 203 8 604 973 0932 0861 204 1268 6 95 2015 18 20 205 2659 6 96 1405 1295 206 39 80 7 98 1261 1174
No 207 Orifice 114 96 509 1325 1148 208 94 33 509 1477 1243 209 7487 5 09 1686 1409 210 5236 505 2094 1691 211 3309 428 2188 1 778 212 1293 392 2976 2560
Thermo ooup1e Readin g s (mv) to 3 to4 to
5 to
6 to7 toair
0 851 0847 0 8 29 0759 0987 0592 158 4 1583 1611 1647 1993 0986 1270 1266 1 279 1298 1604 0 789 0916 0908 0900 0 858 1115 0602 08 39 0 823 0 818 0 770 1035 0602 1609 1602 1629 1676 2153 0979 139 1 1385 1400 1 430 1938 0776 1212 1201 1205 1201 1601 0669 1 105 1086 1086 1 052 1371 0621 0952 0936 0923 0870 1195 0582 0 8 20 0 801 078 1 0 729 1044 0569 1108 1090 108 2 1043 1407 0610 1218 1221 1241 1202 1582 0659 1081 1083 1084 1031 1 368 0622 0921 0924 0919 0 841 1111 0 610 08 34 0831 0 821 0 751 1003 0 630 1761 1761 1 809 1861 2399 0966 1271 1271 1295 1311 1650 0797 1150 1150 1161 1149 1440 0703
1083 1057 1053 1109 1566 0~530 1158 1125 1138 1217 1763 0 526 1291 1250 1278 1383 2038 0542 1518 1478 1519 1657 2420 0 589 1596 1557 1601 1737 2441 0688 2370 2344 2409 2561 3 297 0921
()) (11
TABLE X Continued
Run Thermocouple Readings (mv) No Position CFM I tc 1 tc2 tc3 tc4 tc tc tc tc i5 6 7 a r
C of 2nd 213 516 1235 4 63 1 432 1291 1265 1258 1 268 1 308 1550 0 971 214 1919 6 17 1357 1223 1196 1191 1199 1211 1461 0 851 215 27 12 8 35 1401 1259 1278 1220 1230 1218 1511 0 762 216 3320 981 1439 1305 1270 1259 1275 1238 1450 0719 217 41 53 980 1251 1142 1132 1094 1121 1088 1305 0 695 218 404 987 1102 1042 1030 1 bull006 1014 0960 1133 0681
Supplementary Equations
Calculating temperatures from thermocouple readings
t = -026tc)2 + 3512(tc) + 3201 (26)
where t is the temp in deg F and tc is the thermocouple reading in millishyvolts
Calculation of the thermal conductivity of air
k = 00000245ta + 0 0132 (27)
where k is the thermal conductivity in Btuhr rt2 degFft and ta is the air temp 1n OF
I I
bull co m
15
Vibradamp support to absorb the vibrations produced by the
air blower
Air Source
Air was used as the shell-side cooling fluid during
the study The air was pumped through the test section by
a Roots type air blower with a rating of 280 ofm at 3 12
psig outlet pressure The hot air leaving the blower was
passed tbxfugh two finned-tube box-type coolers and one
tubular edoler to oool it to approximately room temperature
The air flow rate was measured by passing it through a
flow measuring orifice in the line Two sharpbull edged orishy
ficas were used f or flow measurements The calibration
curves for these orifices were presented by Ambrose (1
p 166)
The pressure taps on each side of the orifice were
connected to two differential manometers containing 0 83
and 2 95 specific gravity fluids respectively The presshy
sure drop through the test section and test orifice was
measured by a pressure tap placed 13 inches upstream and
one placed 6 12 inches downstream from the orifice Two
pressure ga ges were used to measure the pressure at the
inlet to the flow orifice and to indicate the statio pres~
sure at the test section inlet
16
Pressure Probe
A probe was designed to measure the pressure drop
between the pressure tap 13 i nches upstream from the ori shy
fice baff le and any point downstream from the tap The
probe eonsisted of a l~in OD copper tube with six 132
i n ch holes even l y s paced around the tube The upstream
pressure tap and the pressure probe were connected to a
differential manometer so the pressure drop to various
points up- and downstream of the orifice could be measshy
ured
17
CHAPTER IV
EXPERIMENTAL PROGRAM
The experimental program was designed to measure the
heat transfer coefficients and pressure drops in the vicinshy
ity of annular orifices The four orifice sizes studied
were 1 364 1 216 l 316 and 1 516 inches~ The inner
tube used in each case was a 1-in OD alumintim tube
Hence tube to baffle clearances were respectively 3128
232 332 and 532 of an inch
Heat transfer coefficients were measured at poait~ons
1 i nch upstream at the orifice center and at 12 1
1 12 and 2 inches downstream for all orifices In addishy
middottion the heat transfer coefficient at a point 2 12
inches downstream from the 1 516 inch orifice was measured
and at the points 12 l 12 and 2 inches upstream from
the 1 364 inch orifice
The heat transfer coefficients at each point were
measured at five different flow rates for the 1 364 inch
orifice and at six different flow rates for the other orishy
fice sizes The high pressure drop through the small orishy
fice size limited the number of flow rates which could be
studied
The flow rate was calculated from the pressure drop
across the flow orifice This flow was corrected to cubic
feet per minute at 68degF and one atmosphere pressure by
18
using the orifice pressure and the test section pressure
which were measured by pressure gages
It was desired to determine a relationship between the
heat transfer coefficient and the total pressure drop for
each orifice size The pressure drop across each orifice
at various flow rates was measured by means of the presshy
sure probe described in Chapter III It was also desired
to obtain pressure profiles for each orifice size since
these might be similar to the heat transfer profiles The
pressure drop was measured from a point 13 inches upstream
of the orifice to points at 1 and 12 ineh upstream the
orifice center 12 1 1 12 and 2 inches downstream
The experimental program is summarized in Table I
TABLE I
SUla~RY OF EXPER IMENTAL PROGRAM
Position Investigated-Distance from Orifice-Inches
Orifice Range of Flow Rate Size Heat Transfer Pressure Drop CFM at 68degF amp 1 atm
1 364 2U 1 12U 1U 12U c 12U C 12D lD 10 - 18 l2D lD 1 12D 2D 1 12D 2D
1 216 1U c 12D lD 1 l2D 2D 12U c 12D lD 10 - 35
1 316 1U c 12D lD 1 l2D 2D l2U C 12D lD 12 - 50
1 516 1U c x2D lD 1 l2D 1U 12U C 12D 12 - 90 2D 2 1 2D l D 1 l2D 2D 2 12D
20
CHAPTER v
EXPERI MENTAL PROCEDURE
The experimental procedure for measuring the heat
transfer coefficients ~d corresponding flow rates reshy
quired the following procedure
(1) Install the orifice size to be studied in the
test section
(2) Place the heat transfer probe in the position up
or downstream from the orifice where the middot heat
transfer rate is to be studied
(3) Fill the cold junction thermos with cracked ice
(4) Measure the atmospheric pressure
(5 Open bypass line from blower and close line to
test section
(6) Turn on the cooling water for the exchangers used
to cool the air leaving the blower
(7) Start the automatic selen ium rectifier by turning
on the t 1mer bull
(8 ) Connect the voltage stabilizer to the wall outlet
(9) middot Set the slide wire resistor to the maximum re shy
s1atanee I
(10) Start the blower
(11 Open the line to the test section until the de shy
sired flow rate is obtained
(12) Switch on the probe direct current power source
21
(13) Adjust the slide wire resistor to obtain the
desired current
(14) After the thermocouples have reached equilibrium
values record the e m bullf across each of the
seven probe thermocouples and also the entering
air thermocouple
(15) Record the direct current amperage
(16) Record the gage pressure at the flow orifice and
the entrance to the test section
(17) Record the manometer measurement of the pressure
drop across the flow orifice and also the presshy
sure drop through the test section
22
CHAPTER VI
CALCULAT ION OF EXPERIMENTAL DATA
The local heat transfer coefficients were calculated
from the temperatures measured on the probe surface the
air temperature and the current input The results were
calculated by using the Alwae III-E computer
The general expression for calculation of the heat
transfer coefficients was derived by Ambrose (1 p 79)
The equation is derived by making an energy balance around
a small increment of the center resistance heating ribbon
The two ribbons tnstalled adjacent to the center ribbon
reduced the amount of logitudinal conduction and assured
little longitudinal temperature variation in the center
ribbon
A heat balan ce on this small increment of resistance
ribbon yields the following
(the heat conducted in) + (heat generated) = (heat
conducted out) +(Heat convected to the fluid) + (heat
radiated to the surroundings) + (Heat conducted into
the plastic center of the probe)
This gives the equation
kzw dtdS + 12RdS kzws [ t + (~) ds] + hwdS (t-ta )
+ ~Aad wd o middot+ qcAond 1 -~- wdS 5 )
23
Hence solving for h gi~ea
i2R kz d2t Qrad qcond w + -d$2 - ~- A
h = ( 6)t - ta
Since S = re where 9 equals the enclosed angle ~n radians
dS rd9 ( 7)
and
dt - dt (8)dS - rd9
Differentiating with respect to S
d2t (9)rd9dS
from which
(10)
Substitut1ng into the equation for heat transfer coeffishy
cient gives
h = i2R Qcond A (11)
w
The rate of radial heat conduction into the plastic
tube making up the probe was assumed to have negligible
effect on the heat transfer coefficient It was also
assumed that the heat loss by radiation from the ribbon
was negligible since all data were obtained with the ribbon
at a temperature less than 125degF
24
When t he rad iation and conduction terms are neglected
Eq (11) becomes
(12)
The following con stants are known
R = 0 271 ohmsft
w = 100 i n ches
k = 763 Btuhr rt2 degFft
z = 0 002 inches
r = 12 inch
Eq (12) putting 9 in degrees then reduces to
1110 12 + 2404 d 2t d92
( 15)h = ------~--~-------t - ta
Thi s equation was programed for the Alwac III- E comshy
puter and used to calculate the local heat transfer coefshy
ficients from the observed data
The average heat transfer coefficient around the tube
at a given position in the t est section was calculated by
averaging the local coefficients calculated from Eq (13 )
It was found 1n the course of the experimental work
that thermocouple numbers 1 and 7 were indicating higher
temperatures than would be expected This resulted in h1
and ~ being lower than the other local coefficients around
the tube Since the fluid was flowing parallel to the axis
of the probe the circumferential variation i n rate of heat
25
transfer should be small Hence in obtaining the average
coefficient around the tube the values of h1 and h7 were
not used even though they were calculated and are tabulated
1n Table I II in the Appendix
Then
(14
A Nusselt number as calculated from this aver age heat
transfer coefficient using the tube diameter as the characshy
teristic dimension
(15)
The air flow rates through the test section were calshy
culated by measuring the pressure drop across the flow orishy
fice the air temperature the pressure at the flow orifice
and the pressure at the entrance to the test section The
orifice calibration curves (1 p 166 ) were used to obtain
a value of the orifice coefficient f8e where Q equals
the flow in cubic feet per minute at 68deg F and one atmosmiddot
phere pressure and te is the density of air at the exchanger
and e the density of the air at the flow orifice The
den sity of the air can be expressed by
e = 2 703 p (16)T
where T equals the temperature in OR and P equals the absoshy
lUte pressure i n lb1n2 Using the value of e Qfo from
26
the calibration charts as A and Eq (16) solving for Q
gives
( 17
This equation was used to calculate the flow rate for
each flow studied
The Reynolds number used i n the correlation of the
data was the equivalent Reynolds number defined as
Re)eb ~ d2 - dl)Uf ( 18 ) lL
where d1 is the outside diameter of the inner tube and d2
is the orifice diameter U is the flow velocity through the
annular orifice e is the density of the air and U- is t he
viscosity of the air This equation can be transformed t o
(Re) b = 1611 Q (19) e dl + d2
where d1 and d2 are in inches
The pressure drop data were calculated i nto a dimenshy
sionless pressure drop function cent where
d1 )22( ~ P)gc f av(d2 shycent 2 bull (20
M-
For air this equation reduces to
where d2 and d1 are in i nches D P is expressed i n inches of
2 95 specific gravity fluid and P av is expressed as lbft3
27
CHAPTER VII
ANALYSIS OF DATA
In analyzing the heat transfer data an attempt was
made to correlate it 1n terms of the dimensionless groups
(Nusselt number Prandtl number and Reynolds number) which
appear in Eqs (3) and (4) Consequently all of the av~
erage heat transfer coefficients hav were brought into
the form ( Nu)( Pr)~3 bull The Nusselt number was based on the
tube diameter and the thermal conductivity of the air at
the flowing temperature The tube diameter was used in the
Nusselt number because comparison could then be made with
previous experimental work on heat exchangers which have
commonly used the Nusselt number defined as in Eq (15)
From the standpoint of dimensional analysis this is
equivalent to considering the tube diameter as the characshy
teristic length so far as the heat transfer is concerned
The Prandtl number of the air was taken as 0 7 in all
cases
Variation of Heat Transfer Rate with Distance from the Baffle
Considerable variation was observed in the rate of
heat transfer in the vicinity of the baffle In order to
obtain the variation with respect to position the term
(Nu)(Pr)-13 was plotted versus the flow rate Q for each
position and orifice studied Cros s plots were then made
28
at constant flow rates in order to obtain the variation of
(Nu)(Pr) -13 with position The resulting cross plots are
shown 1n Fi gures 5 6 and 7 for the four orifices studshy
ied
About one inch upstream from the orifice the heat
transfer coefficient begins to rise rapidly and continues
to do so until it reaches a maximum some distance downshy
stream After the maximum point the heat transfer coef fi shy
cient decreased slowly The heat transfer rate was found
to reach a maximum at a different position downstream for
each orifice size These figures also show that for a
given orifice size the maximum heat transfer rate occurs
a pproximately at the same point for all flow rates The
position of the maximum point f or each or ifice size is
shown in Table II
The region immediately downstream from the orifice is
one of h i gh turbulence due to the jetting action of the air
flowing through the orifice As the air flows t hrough the
orifice the streamlines continue to converge for some dis shy
tance downstream The point of maximum heat transfer is
probably at the point where the streamlines be gin to diverge
and a boundary layer begins to build up on the tube Tle
decreasing heat transfer coefficient beyond the maximum
point indicated the formation of a boundary layer
Since the position of the maximum point is independent
of flow rate middot it is possible to correlate it with respect
_ ct 11shyz-
100
0 136 ORIFICE
(
I 0
I )
~ 00
~p 0
I 0
--r--- ~
ISCFIII
-_ OCFM
rbull abull
~ middot~ a-1 z-
12fORIFICE
100
200
100
0 0 UPITRAM ORIFICE DISTANCE CENTER
CFM
h I DOWNSTREAM
DISTANCE
FIGURE 5 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLpound
30
too
700
800
100 ~ f gtf
400
z ~
100
100
100
0
13fORIFICE
~ -~ -- ---
)
~
~
-
I ~ ~OCFM
I vI~-~ OCFM
J ---
Iamp CFM
I 0 I I UPSTREAM ORIFICE DOWNSTREAM DIITANOE GENTER DIITANCI
FIGURE 6 VARIATION OF HEAT TRANSFER RATE WITH DISllNCE FROM BAFFLE
--
--- --
31
100
100
700
100
_ 100
f 9- 400 z-
100
tOO
100
0 - I 0 I I I UHTRIAM OAtfiCI DOWIIITMAM
+ I tyl6 ORIFICE
v I
~~ ~CFM
I v ~CFMI
v v 7
~~ v ~ iOCFM
- ~~ I-shy1-shy ~ICFM
DIITMCI OINTIR DIITANCI
FIGURE 7 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLE
32
TABLE II
POSITION OF MAXIMUM HEAT TRANSFER
Position of Maximum Orifice Size Heat Transfer
(inches) (inches downstream)
1 364 050
1 216 100
1 316 125
1 516 200
33
to orifice size Figure 8 shows the effect of the orifice
size on the position and value of the maximum heat transfer
at a constant flow rate of 15 cubic feet per minute It
can be seen that the larger the orifice size the further
downstream the point of maximum heat transfer occurs
Also as the orifice size increased the rate of heat
transfer decreased for a given flow rate The broken line
indicates the variation of the point of maximum heat transshy
fer with position and size The position of the point of
maximum heat transfer rate downstream from the orifice was
correlated with orifice size by means of the dimensionless
groups (Lde) and (d1de) where L is the distance downshy
stream from the orifice where the maximum rate of heat
transfer occurs d1 is the outside diameter of the inner
tube and de is the equivalent diameter of the orifice
ie de = d2-dlbull
Figure 9 shows a plot of Ld 6 versus d1d6 for the
four orifice sizes studied The four points on this logshy
log plot are approximately in a straight line and the
equation of this line is
Lde = 0 44 d1de)028 (22)
Although the above relationship represents a correlashy
tion of dimensionless groups it is based upon only one
tube diameter and needs to be substantiated further by
studying other tube diameters and other orifice sizes
34
aoo
400
aoo ~
-~ middot-CLshyJ z
200 -
100
0
ORIFICE CENTER
l~
l
t
I J~
1pound~
I
0 I I~
AT 15 CFM
-
bull ~ 1~6~
~ v~
~
~--~~6
~~~ ___ v v V -_
~ o q
~ I 16
v
~
ogWNSTREANI STANCE
FIGURE 8 EFFECT OF ORIFICE SIZE ON POSITION AND VALUE OF MAXIMUM HEAT TRANSFER
35
50
loshy____ -~
~ ~ -shylltl-shy~ r0
2 10 30
FIGURE 9 CORRELATION OF THE POINT OF MAXIMUM HEAT TRANSFER WITH
ORIFICE SIZE
36
Correlation of Data at the Baffle
The heat transfer data were correlated by obtaining a
relationship between the group (Nu)(Pr)-13 and a
Reynolds number based on twice the clearance (d2 - d1
between the tube and the baffle It was found that the
most satisfactory correlation could be obtained when the
term - d1 was used as the length term in the Reynoldsd2
number
Figure 10 shows the variation of the heat transfer
rate at the center of the orifice e xpressed as a function
of Reynolds number and the orifice size This shows that
for a given Reynolds number the heat transfer at the center
of the orifice is greatest for the smallest orifice size
In order to obtain a general correlation of the data
shown i n F1gure 10 the effect of the dimensionless ratio
d1de was considered This ratio considers all of the
geometric factor s needed to describe the annular orifice
The thiclaless of the orifice plate is also a factor but
was constant i n this i nvestigation
The data for the heat transfer at the baffle center
are shown in Figure 11 in which (Nu)( Pr)-13 is plotted
versus (Re)ebd1 de) 0 55 This data on a log-log plot
lies on a straight line for (Re)eb( dld8 )0 55 greater
than 3 x 104 The equation for cor relating the heat
37
4XI~middot~-r~------~--~~------~
Icf t--to_+--_c-c-________ SYMBOL SIZE
0 1~4
6 ~~
9 ~~ -o ~
(Re)eb
FIGURE 10 RATE OF HEAT TRANSFER AT BAFFLE CENTER
38
500
0
4 0 lcf
~ ~
~ ~iC-
~ ~
~IL 0~ 0 SYMBOL SIZE-
p 0 1364-
r 6 1~16 -~ -
9 1~16 --o 1~16
I I
FIGURE II CORRELATION OF HEAT TRANSFER DATA AT BAFFLE CENTER
39
transfer at the center bullOf the a nnular orifice was found by
the method of least s quares to be
(Nu)( Pr)-1 3 = 0018 ( Re)ebO Bl( dlde)04~ (23)
3 x 104 ltRe)eb(a1de)055 lt 105)
Rate of Heat Transfer at the Point of Maximum Heat Transfer-The heat transfer rate at the point of maximum heat
transfer is plotted in Figure 12 to show the variation with
Reynolds number and the size of the orifice It is shown
gives the h1gh st heat transfer ~ate at its point of maxibull
that for a given Reynolds number the smallest orifice size yen il
mum heat transfer
The data ~or the maximum poi~t could be correlated by
plotting (Nu) Pr)-13 versus (Re)eb(d1de)06 This plot
is shown 1n Figure 13 and the resulting eurve shows that
(Nu(Pr)-13 is not a simple p0wer function of the Reynolds
number as was the case for heat transfer at the baffle
center The reason for this is probably because other
factors such as intensity and scala of turbulence should
be considered At the orifice center the streamlines of
the flowing stream are converging_ and thus the flow is
quite stable Downstream from the orifice is a region of
large eddy currents and probably large scale turbulence
These factors could con ceivably cause the results which
were obtained for the point of maximum heat transfer
40
If)
~middotshy Q_-I z_
10~~~--------r----~~--~--
SYMBOL SIZE
0 13$4
6 1~8
Q 13-18
-o 1~8
7)(104
(Re)eb
FIGURE 12 RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
41
Ia ~
0 I
c ~ ~ c v
~ ~lt w ~
17
~ b
v ~ ( SYMBOL SIZE
-~ 0 f-64 -v ~ 6 t211e
~ Q I~~~
-o - l~rs I I
FIGURE 13 CORRELATION OF HEAT TRANSFER DATA AT THE POINT OF MAXIMUM HEAT TRANSFER
4 2
Effect of Upstream Baffles on Heat Transfer at the Orifice Center
The heat transfer rate at the orifice center using the
single orifice in a test section is a pproximately 13 of the
value that was obtained by Lee (7) using a model heat exshy
changer with orifice baffles Lee investigated the cent r al
baffles of the heat exchanger and thus the coeff icients he
obtained would be affected by the presence of a number of
upstream baffles To determine the effect of upstream
baffles an additional l 516 inch baffle was placed four
inches upstream 1n the test section The resulting data are
shown in Figure 14 where (Nu)(Prmiddot)-13 is plotted versus
(Re) eb for the case of a single baffle 1n the test section
and also the case of an additional baffle placed four inches
upstream Comparison is made with the results obtained by
Lee middot(7) using a four-baffle and a ten-baffle model heat exshy
changer Good a greement is obtained with Lees work and the
results show the marked effect that upstream baffles have on
the downstream heat transfer rate The additional up tream
ba ffle caused sufficient turbulence 1n the test section to
i n crease the heat transfer rate nearly three-fold at the
center of the next baffle
Heat Transfer i n the Test Section with No Orifice
In order to check the accuracy 6f the equipment the
orifice baffle was removed and the heat transfer mea sured
with the probe in the empty test section The data were
43
~~BAFFLES
0 l BAFFLE -shy
ll_9 2 BAFFLES
V 4 BAFFLES-LEE
4 10 BAFFLES- LEE lJf ~
~rv ~~ ~ v flvv ~~
I ~ J ~ L v
0
v
( V
40 3XIo 7XIa
(Re)eb
FIGURE 14 EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER AT BAFFLE CENTER
44
compared with heat transfe r coefficients predicted by the
equations for annuli which are recommended in the litera shy9
ture The two equa~ ions u sed tor comparison were
(hfe)=0 023 (rltGr e (~~ur4 (~r45 (24)
which was presente~ by Wiegant (10)
and ( h ) (cnM~5(M~l o14 o 023 CPG k j Mij - (de GJMb )0 2 ( 2 5)
which was presented by McAdams (8 p 242) The comparshy
i son is s hown in Figure 15 lq (25) gives a value which
is low by about ten percent while Eq (24) g ives values
which are high by as much as twenty -five percent when comshy
pared with the experimental data The se equations are gembull
erally considered to give coefficients with an accuracy of
about twenty percent Therefore the present experimental
data are within the accuracy of these equations Also the
plot indicate s that for a Reynold s number greater than 2 x
104 the slope of the line is the same for the experimental
data as for the equations
Pressure Drop Data
The total pressure drop across the orifice was measured
as a function of the flow rate and the orifice size The
pressure drop was expressed as a d1mens1onleas quantity r)
which ie plCltted ver sus the Reynolds number in Figure 18
The pressure drop function cent correlates for all or1f1oe
45
200
100
s z
10 5XI10 10
0 EXPERIMENTAL
--McADAMS
-WIEGAND L
V
~ ~ ~
P ~ ~
LL~ L
v~
~
v v
v 1 ~ ~ v
v -gt
~
~ ~
~
6Xid
FIGURE 15 HEAT TRANSFER WITH NO BAFFLE
46
0 1~4 -~ a 6 t216
Q t316 lJ J
-0 as a )t
A LEE I -shy SULLIVAN 8
p
10bull
BERGELIN
I _ll I
I ~
i I
~middot
lo II
f fl
J j
~middot
A)101
1q
I Ill
1 I3 X 10ao1
FIGURE 16 ORIFICE PRESSURE DROP FUNCTION VS REYNOLDS NUMBER
47
sizes- The present data extends the range covered by preshy
vious workers and agrees well with their work The preshy
vious work of Lee () for a heat exchanger containing 10
orifice baffles and also the data of Su livan and Bergelin
(9) for pressure drop in a model heat exchanger with a
single baffle is shown 1n Figure 16 long with the present
results~ This figure may be used to predict the preseure
drop from the equivalent Reynolds number of the annular
orifice
The pressure drop between individual points 1n the
vicinity of the orifice and an upstream pressure tap wa s
measured to obtain a pressure drop profile As might be
expected 1n all cases the profiles showed a rapid decrea e
in static pressure immediately upstream from the orifice
There was however little or no recovery of the pressure
loss downstream The 1 364 inch orifice did show a maxishy
mum point in the pressure drop but this maximum occurred at
the orifice center and total recovery was reached about 12
inch downstream
Heat Transfer at the Baffle and Maximum Point as a Function of Pressure Drop
In order to compare the effect of the total pressure
drop on the heat transfer at the baffle and the point of
maximum heat transfer Figure 17 was plotted showing
(Nu)(Pr)-13 as a function of the total pressure drop This
shows that for a given pressure drop the largest orifice
48
1200
1000
~ a -sshyz-
100
60 100 700
AT MAXIMUM POINT I 15116 2 13116 3 1~6 4 1364
AT ORIFICE CENTER
60
1
v
r ~ ~ ~
5
~
8 7
13116
8
~
1364
v
~
e6
1~6
v
~~ v ~ ~ -~ ~
~
~ v
l
~
vamp
I ~ ~
~
v L ~
v
I-
5
k= ~~
~ ~ ~
--I
v ~
FIGURE 17 HEAT TRANSFER AT THE BAFFLE AND MAXIMUM POINT AS A FUNCTION OF
ORIFICE PRESSURE DROP
49
size has the greatest heat transfer coefficient This is
true at both the orifice center and at the point of maxishy
mum heat transfer
Another comparison can be made by plotting the heat
transfer coefficient and the pressure drop versus the orishy
fice size at a constant flow rate Figure 18 shows this
plot This graph shows that at a constant flow rate the
pressure drop as well as the heat transfer coefficient
increases as the size of the orifice is decreased In
choosing an orifice size for maximum efficiency 1t would
be necessary to know the pumping power available as well
as the heat transfer desired
70 I I 700
AT 15 CFM 60 ---
~ aug
50 ---
NV
40 ~
~ ~ ~
~ _
MAXIMUM POINT ---- --- ~
1-----t---~ _
~00Qj ~
~t--- ORIFICE CENTER 10 1100
1---~ n
u0 01 02 03 Q35
a ltl
de inches
FIGURE 18 VARIATION OF HEAT TRANSFER RATE AND PRESSURE DROP WITH ORIFICE SIZE AT A CONSTANT FLOW RATE
cn 0
51
CHAPTER VI II
SUMMARY OF RESULTS
This study revealed several significant facts about
the heat transfer in the vicinity of annular orifices
Probably the most important contribution was the presshy
entation of the heat transfer profiles in the vicinity ot
the annular orifice ~ r s shown that t~ local heat
transfer coeffieient re~ches a maximum at a point downshy
stream from the orifice The distance downstream at which
this maximum oocurs is t1ven by the equation
22
The heat transfer coefficients at the center of the
orifice were correlated and found to follow the equation
(Nu)(Pr)-13 = 00176 (Re)eb08l(d 1de) 0 middot4~ (23)
3 x 104 lt( Re) 9 b( d1d6 )055 ltlo5 )
The heat transfer at the point of maximum heat trans
fer for each orifice size was correlated and presented in
Figure 13 as a plot of (Nu)(Pr)-l3 versus (Re)eb(d1de) 06
No simple po-orer relationship exists between the terms
Intensity and scale of turbulence downstream from the orishy
fice are probably important factors which affect the heat
transfer
The large effect of an upstream orifice on the heat
transfer rate at the second orifice was demonstrated by the
52
study of two 1 516 inch orifices in the test section The
added turbulence at the center of the second orifice was
found to raise the heat transfer rate almost three times
over that obtained for a single baffle
The pressure profiles in the vicinity of the orifice
indicate that nearly all the pressure drop occurs at the
orifice center~ Total pressure drop data were correlated
by a pressure drop function cent as a function of the Reynolds
number and good agreement obtained with the results of other
workers
The pressure drop and heat transfer data were correbull
lated by plotting the heat transfer as a function of the
pressure drop for each orifice size It was shown that for
a given pressure drop the largest orifice size gives the
greatest heat transfer coefficient
As a final presentation it was shown that the pressure
drop and the heat transfer coefficient both i ncrease i n
value at a constant flow rate as the orifice size is de shy
creased This is important in choosing the optimum clearshy
ance for orifice baffles
53
CHAPTER IX
RECOMMENDATIONS
A great deal of work remains to be done in the field of
evaluating shellmiddotside heat transfer coefficients This
study included only one tube size and air was the only f luid
used It is recommended that further studies be conducted
using other fluids and tube sizes It will also be necessary
to study several baffle types
The adde d turbulence due to a s e cond baffle placed upbull
s t ream would suggest that the heat transfer coef ficients at
a certain position i n relation to a baffle would increase as
the flow progressed through the exchanger It is recomshy
mended that an extensive s t udy should be made between baffles
the full length of a model heat exchanger
It is further recommended that the pressure drop study
be continued to include other fluids tube sizes and baffle
arrangements
Effects of turbulence downstream from the baff le should
be studied by i n vestigations with hot-wire anemometer equipshy
ment to determi ne t urbulence scale and i ntensity
54
NOMENCLATURE
Area of heat transfer
Heat capacity of the fluid
Outside diameter of the tube
Orifice diameter
Equivalent diameter of the orifice (d2 - dl)
Inside diameter of the test section
Inside diameter of the tube
Gravitational constant
G Mass velocity
h Local heat transfer coefficient
Coefficient of heat transfer from surface to fluid
i Direct current amperes
k Thermal conductivity of the fluid
L Distance downstream of the point of maximum heat transfer
p Absolute pressure
L P Total pressure drop across the orifice
Q Flow in cubio feet per minute at 1 atmosphere and 680 F
q Heat transferred
Thermal energy conducted into the sensing probe
Thermal energy radiated from the resistance ribbon
Resistivity of the resistance ribbon
s Length of the resistance ribbon
T Temperature oR
55
t Temperature of the resistance ribbon deg F
ta Temperature of the bulk stream oF
tw Wall temperature of the tube OF
U Veloc ity of the fluid
w Width of the resistance ribbon
z Thickness of the resistance ribbon
eeuro Density of the fluid in the test section
Density of the fluid at the flow orificef 0
AL Viscosity of the fluid
E9 Angle measured around the tube
Dimensionl ess groups
(Nu) Nusselt number hd1k
(Pr Prandtl number C~k
(Re)eb Equivalent Reynolds number at the baffle (d2 - d1 )uejt-Lshy
(Re)e Equivalent Reynolds number in the test section ( d 8 - d 1 )U fu
cent Orifice pressure drop function 2(~P ) gc~av(d2 - d1) 2
Al
56
BI BLIOGRAPHY
1 Ambrose Tommy W Local shell-side heat transfer coefshyficients in baffled tubular heat exchanger PhD thesis Corvallis Oregon State College 1957 183 numb leaves
2 Bell K J and o P Bergelin Flow through annular orif ices Transactions of the American Society of Mechanical Engineers 70593-601 1957
3 Colburn Allan P A method of correlating forced con shyvection heat transfer data and a comparison with fluid friction Transactions of the American Institute of Chemical Engineers 24 174-210 1933
4 Dittus F w and L M K Boelter Heat transfer 1n automobile radiators of the tubular type University of California Publications in Engineering 2443-461 1930
5 Gurushankariah M s Local shell-side heat transfer coefficients in the vicinity of baffles in tubular heat exchangers Masters thesis Corvallis Ore gon State Colle ge 1958 97 numb leaves
6 Knudsen James G and Donald L Katz Fluid dynamics and heat transfer New York McGraw-Hill 1958 576 p
7 Lee Kyu Sung Local shell-side heat transfer coeffishycients and pressure drop in a tubular heat exchanger with orifice baffles Masters thesis Corvallis Oregon State College 1959 118 numb leaves
8 McAdams William H Heat transmission 3d ed New York McGra ~-Hill 1954 532 p
9 Sullivan F W and 0 P Bergelin Heat transfer and fluid friction in a shell-andbulltube exchanger with a single baffle Chemica l Engineer ing Progress Symposium Series 52 ( 18) 85-94 1956
10 Wiegand J H Discussion on annular heat transfer coshyef f icients for turbulent flow Transactions of American Institut e of Chemical Eng i n eers 41147-153 1945
AP PENDIX
57
TABLE III
CALCULATED HEAT TRANSFER DATA
Baffle Hole Diameter Run No (inches)
1 - 59 1 364
60 - 102 1 216
103 - 138 1 316
139 - 206 1 516
207 - 212 No orifice
213 - 218 2nd - 1 516
TABLE III
CALCULATED HEAT TRANSFER DATA
Local Heat Transfer Coefficients Run
T0 bull Po s ition CFM hr h2 h3 h4 hs he ~ hav Nuav
1 c 1026 10 59 1476 16 09 1559 1510 1435 1203 1518 8511 2 1290 1369 1738 1878 18 05 1755 1689 1515 1773 9964 3 1416 1636 198 1 2068 1977 1924 1845 1715 1959 11030 4 1627 1991 2301 2382 2268 2194 20 ~98 1929 2249 12664 5 1776 2252 2669 2863 2713 2517 2338 2126 2620 14759 6 l2ttD 1109 2311 3317 3386 3373 3387 3394 3071 3371 18888 7 1258 3089 4583 4866 4683 4701 4643 4194 4695 26301 8 1433 38 8 5 55 83 5791 5495 5430 5436 5008 5547 31192 9 1681 4992 7378 7649 6980 6864 6870 64 28 7148 40180
10 1 D 1102 2371 3332 3511 3356 3342 3427 3102 3394 19012 11 1308 3218 4379 45 24 42 53 4255 4373 3965 43 57 24446 12 14 64 38 58 5146 5142 4839 4787 4903 4597 4963 278 79 13 1706 5218 6664 6269 58 81 5884 6237 5973 61 87 34718 14 15
1 l2D 1115 1275
2131 2661
2955 3638
2972 3720
2941 3675
2913 3576
28 22 34 74
2613 3278
2921 36 17
163 09 20246
16 1498 34 87 4644 4503 4441 4371 4343 4194 4460 25010 17 1695 4449 5743 5324 5222 5154 5157 5015 5320 298 97 18 2D 1049 1715 23 90 2550 2610 2656 2624 2208 2566 14363 19 1241 2117 2964 3145 3218 3221 3203 2759 3150 17757 20 1532 28 67 3936 4100 4188 4201 4167 3676 4118 23224 21 1674 3459 4508 4598 4746 4795 4792 4299 4688 26337 22 lU 1074 253 340 380 3 86 388 377 354 374 2097 23 1287 292 392 433 440 441 429 406 427 2394 24 1508 322 439 492 498 499 487 461 48 3 2713 25 18 07 3 38 464 519 5 24 520 499 463 5 05 28 40
~~ (]I agt
TABLE III Continued
Run No Position CFM h 1 h2 ~3 h4 h5 h6 ~ h
av Nu
av 26 c 1029 1171 1491 1589 15 28 1 4 62 1377 1293 1489 83 44 27 1266 1395 1746 1853 18 02 1685 1556 1453 1728 9704 28 1430 1637 2037 2175 2060 1909 1735 1591 1983 11159 29 1729 1982 24 96 2751 2507 2268 2030 1886 2410 13579 30 12D 1054 2934 4041 4321 4326 4423 4359 3706 4298 24160 31 1294 3385 4 8 26 52 42 5326 5450 5277 4566 52 24 293 50 32 1431 3784 5347 5721 57 bull75 58 44 5700 5084 5677 31870 33 1770 52 75 7 7 33 87 35 9005 9007 8267 7059 85 49 48050 34 lD 1058 3235 4401 4444 3877 3496 3451 3294 3934 21973 35 1263 38 98 5484 5330 4347 3964 3981 3987 4621 25823 36 18 36 6701 89 17 7855 6369 5597 5769 6283 69 01 38718 37 1 12D 1029 2404 31 8 2 3333 3459 3624 3577 3045 3435 19264 38 1315 3182 4033 4162 4310 4496 4502 4015 4301 24142 39 1426 3628 4389 4510 4573 4760 4804 43 8 5 4607 25678 40 1757 4547 5559 5(35 5931 6282 63 70 6060 5975 33471 41 2 11D 1080 2034 28 38 3155 3144 3145 2966 2540 3050 17027 42 1305 2650 3 4 87 3aoz 3595 3751 3595 3153 36 46 20405 43 1434 3167 39 07 4156 4371 4320 4126 3709 4176 23395 44 1804 4096 4 9 66 5691 5714 5586 53 15 48 65 5454 30582 45 12U 1088 409 516 557 564 5 60 535 513 5 46 30 67 46 1318 470 579 6 22 631 6 17 5 97 579 6 09 3422 47 14 13 540 640 676 6 86 681 6 60 6 54 6 69 3754 48 1773 641 740 774 782 7 69 749 746 763 42 87 49 l 11 U 1054 270 356 391 397 393 3 71 346 38 2 2133 50 1240 303 399 446 449 447 4 21 398 432 2420 51 1419 361 476 522 530 528 507 467 493 2760 52 1 1(2U 1032 236 311 342 347 344 325 301 334 18 78 53 1314 270 366 403 407 408 386 351 394 2217
(Tt tO
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ h av Nu av
54 1448 301 408 447 454 452 431 403 438 24 61 55 1782 353 494 548 544 415 529 531 506 2843 56 2U 10 61 220 287 316 320 322 303 268 310 1735 57 1216 249 335 370 377 378 353 307 363 2044 58 1322 263 356 394 398 399 374 327 384 2159 59 1639 310 433 478 481 482 452 393 465 2617
60 1D 10 68 2011 2536 2657 2681 2694 2560 15 62 2625 14938 61 1399 2520 3239 3369 3371 33r82 32 39 1946 3320 18968 62 1669 2781 3655 3820 38 76 3883 3738 2355 3794 21712 63 1959 3524 42 37 4399 4438 4497 4417 3047 4397 25156 64 2295 4426 5288 5396 5372 5240 5410 3369 5341 30680 65 2636 5490 6531 6662 6565 6379 6820 4249 6591 37938 66 3390 7869 9538 9462 9387 8924 10508 62 91 9564 59601 67 1U 1190 352 368 401 413 407 395 293 397 2256 68 1559 397 422 462 475 471 456 331 4 57 2603 69 1904 434 465 5 13 529 528 504 358 508 2901 70 2211 493 526 573 5 92 588 564 4 15 569 3257 71 2289 569 587 6 30 649 6 61 6 49 460 635 36 44 72 2727 637 6 60 7 09 733 751 743 521 719 4140 73 3210 728 755 8 15 8 43 8 62 8 54 616 826 4765 74 2nD 1210 181 2256 2393 2399 2333 2206 1325 2317 13158 75 1420 2340 2752 2899 2913 2850 2728 1701 2828 16121 76 1692 2853 3306 3452 3471 3379 3217 2134 3365 19217 77 1894 3102 3588 3713 3736 3670 3557 2455 3653 20892 78 2301 3682 4259 4433 4467 43 83 4289 2892 4366 250 30 79 2621 4117 4828 5017 5012 5030 5109 3071 4999 28785
m 0
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ hav Nuav
80 3230 5158 6006 62 13 61 18 6134 6695 4094 6233 359 87 8 1 12nD 1155 15 27 1854 2028 2064 20 85 1987 1164 1968 118 31 82 1689 2046 24 8 2 2688 2739 2760 2658 1749 2665 152 73 83 1244 2088 2317 2339 2345 2373 2381 1487 2351 13432 84 2100 3211 3539 34 21 3462 3512 3696 2575 3526 20284 85 2292 3 5 05 3761 3648 36 25 36 79 3957 2933 3734 21517 86 2907 4420 48 22 4679 46 04 4705 5206 3792 48 03 27741 87 33 80 59 35 69 38 7404 77 10 7 8 36 7 0 86 5190 7394 427 44 88 1 12D 1 4 27 2 4 58 28 31 3037 3021 2987 2927 18 57 2 9 61 16913 89 18 75 34 75 3 9 87 4230 4255 4317 4337 2734 4225 24258 90 22 59 4221 4796 5046 5052 51 01 5389 3491 5077 29206 91 2682 4978 5664 5943 5966 6054 6573 408 1 60 40 34795 92 3417 63 16 71 02 7 3 93 7385 75 40 8 6 95 51 45 7623 44017 93 c 1 5 17 1240 1305 1399 1467 1479 1429 9 26 1423 8251 94 20 34 1554 1623 1720 18 21 18 53 18 72 1215 1778 10229 95 2 3 48 1795 1843 198 5 2097 2171 2274 1540 2074 11947 96 2716 2028 2048 22 01 2 3 44 2444 2661 18 90 2340 13505 97 3247 2410 2375 2663 2778 2949 3298 2378 2793 1615 98 11 35 967 1040 1124 1186 1200 1142 728 1138 6496 99 14 06 1135 1220 1318 1384 1403 1 3 61 8 77 1336 7656
100 2311 1 8 54 18 78 1980 20 90 2136 2227 1653 2062 118 31 10 1 2666 2085 2094 2227 2 3 62 2438 2626 1902 2349 13508 102 3392 2635 2582 28 01 3026 3141 3529 2567 3016 17390
103 1 U 1235 349 395 434 436 4 28 411 286 423 2416 104 20 10 434 5 02 559 577 569 5 37 345 552 3177 105 28 14 538 626 685 711 7 21 682 424 6 8 6 3966
Q) j-J
TABIE III Continued
Run No Position CFM h1 h2 h3 h4 h5 hu h7 hav Nuav
106 3492 614 7 1 6 7 84 8 13 8 33 7 85 4 88 7 87 4562 107 4395 7 86 894 964 996 1005 9 64 640 9 65 56 06 108 50 75 9 11 10 22 1081 1112 1125 1085 7 24 1085 63 16 109 G 1344 9 22 1042 1120 1 1 46 1173 1131 7 04 1120 63 87 110 1936 1162 1340 1442 1474 1509 14 7 3 9 09 1441 82 77 111 2846 1631 1797 1902 1966 2027 2079 1342 19 2 3 11108 112 3484 207e 2144 2236 2307 2385 2574 1694 2268 13138 113 4066 24 65 24 42 2535 2648 2757 31 71 2178 2 5 96 15078 114 50 12 3059 2916 30 1 5 3176 3312 4059 2849 3105 180 46 115 1D 1362 2268 26 13 2613 26 35 2605 2503 15 46 2617 14934 116 1958 2993 3580 3580 3586 3539 3 5 02 2144 3571 20492 117 2812 4430 50 32 4913 4 9 86 4991 5196 3088 4981 287 66 118 3432 58 16 62 13 6067 61 18 60 66 6698 4143 61 16 354 16 119 40 22 71 71 7 4 62 7369 7419 7329 82 74 51 8 1 7395 42909 120 5026 105 95 11456 115 81 11574 11548 14010 80 91 11540 671 15 121 2D 1244 18 57 2277 2363 2305 2210 2107 1466 2289 13038 122 1960 2622 3240 3388 33 23 3226 31 40 2)99 3294 18919 123 2817 3762 45 87 4739 46 56 45 14 4 6 47 30 15 4624 26689 124 3491 50 22 5723 58 53 57 44 5542 60 18 3871 57 16 330 73 125 4096 61 29 68 16 69 79 6805 65 90 74 79 4677 67 98 39400 126 5037 82 27 94 60 95 69 93 57 9023 11324 65 05 93 52 542 83 127 12D 1278 14 70 1 6 48 1652 1638 1 6 34 1641 9 73 1 6 43 9369 128 1947 19 63 2155 2149 2151 2131 2190 1347 2147 12342 129 2769 2615 2791 2773 28 52 2716 2954 18 96 2783 1 60 82 130 3439 3208 3265 3239 3593 3133 3624 2515 3308 19174 131 4103 3637 35 88 3577 4077 3459 42 66 3138 3676 21343 132 49 78 45 82 44 60 44 8 1 55 17 43 25 5749 4227 4700 27288
Q) tlgt
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
133 1 12D 1299 2094 2507 2622 2625 2567 2489 1465 2578 14736 134 1973 29 56 3505 3772 3790 3718 3718 2115 3700 21290 135 2788 3941 4727 5069 5099 5 0 07 5231 2984 4976 28781 136 3473 5155 59 81 6308 6339 62 39 68 96 4204 6217 36052 137 4118 6135 71 8 6 7662 7731 76 91 87 16 49 8 5 7568 43985 138 4973 7765 94 75 10396 10861 10694 13646 66 64 10357 602 25
139 1ttn 1253 1242 1493 1460 1442 1431 1424 8 84 1457 83 01 140 2366 1942 2150 1961 1910 1897 19 62 1206 1980 11400 141 3461 3007 2957 2562 2513 2606 3143 18 51 2660 15400 142 4325 3942 3571 3060 2999 3198 4248 2631 3207 18618 143 5677 508 6 4359 39 88 3800 42 29 57 78 36 26 4094 23824 144 67 59 64 55 5330 4988 47 25 5494 2517 48 09 5134 29906 145 84 08 9326 72 26 7726 85 56 9172 12319 7733 8170 47626 146 86 54 9831 7582 818 9 94 90 9869 13116 78 97 8783 512 96 147 7376 7335 58 7 6 5941 5796 68 29 81 65 5954 6111 35662 148 2 11 D 4254 4106 48 02 4994 5038 5042 56 78 3419 4969 28881 149 5708 5487 6253 6466 6524 6527 78 63 45 8 2 64 43 37566 150 69 7 8 7983 9440 9848 98 34 97 32 13249 6701 9714 566 59 151 1254 1434 18 53 1947 1915 1850 1760 1186 1891 10772 152 2713 2696 3175 32 94 3288 3237 3288 20 44 3249 18728 153 87 30 118 07 14733 15758 15504 15305 26297 9617 15325 892 71 154 5811 5278 6543 6861 69 30 69 82 7 8 74 4478 68 29 39531 155 4246 3780 4736 4975 49 66 4936 5162 3113 4903 28301 156 (v 1270 8 15 935 959 966 9 51 9 23 6 35 953 5430 157 2714 1164 1390 1427 1447 1454 1455 9 08 1430 8242 158 4310 1655 18 96 1942 1988 2002 2111 1305 1957 11349
(j) ~
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 fry hav Nuav
159 6012 2208 2400 2450 2513 2548 28 20 18 00 2478 14416 160 7279 2696 2881 2927 2989 3081 3599 2340 2970 17326 161 86 90 3257 3360 3 3 76 34 26 3558 4455 2943 3430 2000 162 12D 4368 2209 2600 2558 2518 2466 2774 1753 2536 14713 163 5833 2730 3092 3028 2974 2913 3501 2287 3002 174 78 164 7643 3320 3681 3630 3651 3530 4623 3181 3623 21116 165 87 39 3920 4303 4300 4708 4178 61 60 3937 4372 25456 166 1268 962 1203 1205 1186 1118 1084 725 1178 6693 167 2678 14 67 1785 1779 1752 1698 1726 10 70 1754 88 49 168 1 12D 12 83 936 1217 1414 1397 1239 1190 7 65 1317 7484 169 2729 2502 2930 2914 2934 2956 2979 17 52 2934 16866 170 4345 3884 4357 4283 4318 4421 4836 28 59 4345 25151 171 6036 5546 5858 5764 5791 6028 7129 4184 5860 34045 172 6578 7167 7769 7907 79 82 8263 10492 5915 7980 46437 173 87 84 10237 112 23 120 26 12727 12968 185 19 85 98 12236 71103 174 1278 1344 1803 18 72 1835 1790 1712 1063 1825 10355 175 2711 2328 2972 2932 2893 28 78 2863 1667 2919 167 51 176 4351 3934 4414 4353 4281 4321 4654 28 63 4342 25088 177 5994 5076 5824 5838 5818 59 29 6914 4205 5852 33885 178 1 11 U 1223 388 432 465 464 449 435 338 453 2585 179 2351 521 602 6 22 675 6 57 619 436 639 3687 180 34 48 6 05 1725 803 8 27 8 11 760 518 792 4593 181 4513 718 850 934 9 68 9 57 8 99 609 9 27 5386 18 2 5714 8 32 981 1060 1102 11 06 1034 6 59 1062 61 82 183 6997 1025 1182 1258 1295 1309 1234 8 18 1261 7 3 44 184 8709 1295 1487 1 5 42 1594 1626 1612 1156 1562 9080
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
185 2 12D 4249 3560 4400 4670 4791 4695 47 81 2931 4639 268 37 186 5737 4926 58 54 61 92 6248 62 38 67 78 4134 6131 35590 187 7432 6390 7726 83 46 85 44 86 34 10371 5658 8313 48310 188 8723 7718 107 88 11933 12099 13046 186 22 79 39 119 67 69505 189 1 4 35 1340 1735 18 57 18 52 17 81 1711 1144 18 06 10256 190 2718 2399 3023 3187 3207 3138 30 53 1931 3139 18025 191 7 5 07 6189 80 11 9200 9427 9703 11364 5720 9085 527 38 192 8544 78 42 10666 125 42 13312 13775 178 20 6976 125 74 729 86 193 1287 1417 16 97 18 7 18 69 18 08 1720 1046 1800 10223 194 27 17 2450 2940 3187 3214 3157 3054 1749 3125 17954 195 42 53 3560 4222 45 90 4679 46 63 4743 2741 4539 26247 196 6068 48 69 57 79 6335 65 8 6 66 04 7172 4338 63 26 366 78 197 7389 58 86 72 8 6 82 23 8584 8936 10658 50 60 8257 4798 6 198 86 88 78 91 100 27 120 56 130 29 14299 190 81 6492 12353 71850 199 5864 4694 5 6 67 61 94 6419 65 48 7192 3950 6207 360 14 200 2 D 4177 38 36 4547 48 09 4775 4628 5006 2715 46 90 261 30 201 5712 5170 62 39 66 38 6599 6604 7518 4167 65 20 378 00 202 73 63 7201 8986 98 43 9733 9914 13353 6219 9619 55810 203 8604 10043 13118 148 41 150 42 158 66 25206 82 5 3 14717 85290 204 12 68 1506 18 41 1971 1966 1868 1799 11 42 1913 10880 205 2659 2571 3127 3276 32 50 3130 3069 18 80 3196 18 350 206 39 80 36 76 4347 4573 45~67 4473 46 34 28 37 4490 25910
o 207 Orifice 11496 10 64 1360 15 39 1 5 80 1 6 15 1496 8 58 15 24 88 83 208 9433 8 95 11 78 13 26 1394 1386 1263 727 1346 78 48 209 7387 746 9 77 1123 1184 1159 1048 6 11 1111 64 74 210 52 36 566 7 66 900 934 909 8 21 499 8 27 48 02
0) CJ1
TABLE III Continued
Run No Position CFM h 1 h2 hs h4 h5 h6 h7 hav Nuav
211 212
3309 1293
414 257
563 3 19
6 68 3 57
6 91 3 37
6 72 351
7 37 337
38 4 2 46
4 40 341
3748 1942
213 214 215 216 217 218
c of 2nd 1 516 1235
1919 2712 3320 4153 4704
1532 2447 35 46 4312 5567 74 29
2 1 87 3312 4225 52 86 6902 8 6 50
2360 3555 4340 56 12 7 0 49 8 9 40
2409 3598 4 8 85 5718 7713 9593
2347 2101 35 33 3453 48 00 49 62 5562 59 86 72~6 7 8 79 93 76 11237
1243 20 64 3054 4 2 8 1 5114 6983
2326 35 00 4638 5545 7225 91 40
132 13 200 27 26672 31968 41711 52811
bull
67
TABLE IV
PRESSURE PROFILE DATA
Baffle Flow Qpening Rate ~p
(Inches) Position (CFM) (Inches 295 S G Fluid)
1 364 l2 11 U 1012 0 254 1248 0197 1493 0 141 1718 0112
c 1000 9 80 1210 1710 1436 28 75 1746 4320 1011 1080 1277 2050 1393 3020 1 6 28 4450
12D 1011 9 75 1236 1520 1450 2510 1603 3450
1 D 1011 975 1256 1700 1480 2690 158 1 4070
1 12D 1010 950 1259 1750 1462 2650 1631 3710
2 11 D 1124 1315 1360 2130 1505 2850 1689 4125
1 216 12U 1294 045 1949 0324 2374 0282 2704 0225 3367 0169
c 1326 265 18 81 5 90 2313 990 2731 1480 3439 2660
12D 1272 2 49 1957 661
68
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Pos ition (CPM) Inches 2 95 S G Fluid)
2559 1275 3033 1940 3639 3025
1 216 1nD 1257 242 16 96 476 2117 8 05 2561 1280 2990 1895 3431 26 bull00
1 316 12U 1309 0 479 2004 0422 28 28 0 352 3526 0281 42 28 0225 5199 0225
c 1308 1 43 1998 272 28 14 5 10 3478 795 4248 1235 5048 1885
l2D 1286 140 2005 3 45 2831 725 3495 1180 4194 1805 5046 2945
1 11D 1322 150 2039 352 2841 735 43 77 1980 5378 3440
1 516 12U 1278 0493 2732 0493 4315 0408 5744 0352 7494 0352 8932 0422
c 1300 0 506 2731 1985 4310 348 6080 6 45
69
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Position (CPM) (Inches 295 SG Fluid)
7607 1090 8830 1585
l2D 1343 0549 2738 225 4566 583 6112 1195 7536 2055 9043 3415
1 516 1uD 1249 0464 2713 224 4155 579 5620 1150 7428 2115 90 70 3405
1 12D 1301 0493 2735 220 4501 616 61 50 1235 7440 2065 8862 3445
2D 1265 0 478 2750 226 4366 594 6578 1270 7678 2240 8945 5280
2 12D 1295 0493 2725 222 4293 600 5807 1120 7568 2200 9070 3615
TABLE V
RATE OF HEAT TR AN SFER Ar THE BAFFL~~ CID-TT ER
Orifice Size
(Inches)
Flow Rate
( CFM)
Re d e G tU
R~) 055 Nuav NuPr-l3
1 364 10 26 12 90
8 075 10015
43400 54 600
85 11 99 64
95 83 112 19
1416 11 140 59 900 110 30 124 20 16 27 12 800 68 900 126 64 142 60 17 29 13 610 73 200 135 79 152 90 17 76 13980 75 200 147 59 166 19
1 216 11 35 14 06
8 600 10 660
27000 33500
6 4 96 76 56
73 14 8 6 12
1517 11500 36100 82 51 9291 20 34 15400 48400 10229 115 18 23 11 17500 55000 118 31 13322 2348 17 800 55900 11947 13452 2666 20 200 63400 13508 15210 27 16 20 600 64700 135 05 152 07 32 47 24600 77200 161 57 18 193 3392 25 700 80700 17390 195 8 1
1 316 1344 19 36
9898 14 260
24800 35 700
63 8 7 8 2 77
71 92 93 20
28 46 20 9 60 52 500 111 08 125 08 34 84 25 660 64200 131 38 147 93 40 66 50 12
29900 36900
74800 92400
150 78 18046
169 78 203 20
~ 0
TABLE V Continued
Orifice Flow Re Size Rate d e G R~rmiddot55 NuPr-13(Inches) (CFM) U Nuav
1 516 12 70 8 847 16800 54 ~0 61 14 2 14 18 900 35800 82 42 92 80 43 10 30 000 56900 11349 127 79 60 12 41900 79400 14416 16232 7279 50700 96100 17326 19509 86 90 60540 115000 20098 22529
TABLE VI
RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
Orifice Size
(Inches)
1 364
1 216
1 316
Flow Rate
(CFM)
1054 1294 1431 1681 1770
1068 1399 1669 1959 2295 2636 3390
1299 1973 2788 34 73 4118 4973
Re deG Mshy
8 300 9870
11260 13200 13 930
8100 10600 12650 14850 17400 19980 25700
9 570 14500 20500 25600 30300 36600
R~r-6 51900 61700 70500 82 500 87 100
28200 36900 44000 51700 60 600 69500 89400
26100 39600 56000 69900 82700 99 900
Nuav
2416 293 5 3187 4018 4805
14938 18968 21712 25156 30680 37938 59601
14736 21290 28781 36052 439 85 60225
Uu Pr-1 3
27204 33050 3589 4524 541 0
16820 21358 24448 28326 34546 427 18 67111
16593 23973 32407 40595 495 1 678 13
TABLE VI Continued
Orifice Flow Re Size Rate deG R~rmiddot6 NuPr-13(Inches) (CFM ) M- Nuav
1 516 1268 88 30 17700 108 8 1225 2689 18700 37400 1835 2066 3980 27700 55700 2591 2917 4177 29100 58 500 2713 3055 5712 39800 80000 378 0 425 6 7362 51300 103000 5581 6284 8 604 59 900 120000 8529 9604
74
TABLE VII
EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER
l 516 Inch Orifice
Center ot 2nd Baffle 4 Downstream
Plow Rate (CFM)
1235 1919 2712 3320 4153 4704
Flow Rate (CFM)
1270 2714 4310 6012 7279 8690
(Re)eb -8600 1321
13400 2003 18900 2687 23100 5197 28900 4171 32800 5281
Center ot Single Battle
-8847 543
18900 824 30000 1135 41900 1442 50700 1733 60540 2001
(Nu)(Pr)-l3
1487 2255 3003 3600 4697 5946
(Nu)(Pr)-13
611 928
1278 1623 1951 2253
75
ABLE VIII
HEAT TRANSFER IN THE TEST SECTION WITHOUT ORIFICE
CFM Ute) 0b h Nu
1293 5-951 3 41 1942
33 09 15251 649 3746
5236 24193 827 4802
7387 34001 1111 6474
9433 43419 1346 7848
11496 52-914 1524 8883
76
TABLE IX
PRESSURE DROP FUNCTION
Orltlee Size Flow Rate incbea ~CFM (Re)eb X 10bull8
1 364 1011 7957 0808 1256 9885 1468 1480 11648 2765 1581 12443 4160 1689 1_3293 4 020
1 216 1257 9530 1327 1696 12858 2663 2117 16049 4615 2561 19415 7581 2990 22668 11560 3431 26011 16440
l 316 1322 9736 1819 2039 15016 4332 2845 20952 9275 3495 25739 15300 4377 32014 26800 5378 39607 50100
1 516 1011 7 957 oaos 1256 9885 1469 1480 11646 2765 1581 12443 4160 1689 13293 4020
77
TABLE X
EXPERIMENTAL DATA
Baffle Hole Diameter Run No
1 - 59
60 - 102
103 - 138
139 - 206
207 - 212
213 - 218
(Inches)
1 364
1 216
1 316
1 516
No Baffle
2nd - 1 516
TABLE X
EXPERIMENTAL DATA
Run Thermocouple Reading s (mv) No Position CFM I tc1 tc2 tc3 tc4 t c 5 tc6 tc7 tcair
1 c 1026 530 2055 1825 1768 1782 1802 1837 1965 1198 2 1290 612 2059 18 65 1809 18 32 1851 1880 1965 1160 3 1416 714 2151 1970 1931 1965 1988 2026 209 5 1130 4 1627 8 21 2235 2084 2 049 2093 2126 2173 2266 1130 5 1776 865 2203 2033 1970 2015 2084 2159 2 264 1121 6 12D 1109 542 1636 1507 1499 1499 1498 1498 1528 1218 7 1258 651 1670 1522 1503 1513 1513 1516 1548 1221 8 1433 750 1625 1480 1467 148 3 1487 1487 1516 1153 9 168 1 8 73 1656 1494 148 1 1511 1517 1517 1543 1159
10 1rtD 1102 485 1545 1450 1437 1446 1447 1442 1466 1220 11 13 08 6 10 1571 1470 1460 1476 1476 1469 1498 1194 12 1464 730 1 623 1509 1508 1528 1 5 32 1524 1548 1173 13 11 06 8 71 1663 1559 158 1 1606 160 6 1 583 1601 1190 14 1 12D 1115 520 1698 1579 1575 1 577 1580 1590 1615 1280 15 1275 6 10 1692 1567 1558 1 561 1570 1580 1601 1234 16 1498 770 1760 1619 1630 1 635 1642 1645 1661 1204 17 1695 912 1775 1635 1670 1689 1686 168 6 1701 1165 18 2D 1049 510 1736 15~2 1567 1558 1 553 1558 1620 1236 19 12 41 610 1655 1517 149 1 148 1 148 1 148 4 1546 1108 20 1 5 32 7 35 1720 1550 1530 1520 1519 1523 158 0 1104 21 16 74 8 8 0 1900 1 727 1714 1696 1691 1692 1753 1169 22 1U 1074 38 5 3 324 2740 2534 2478 2 465 2503 258 0 1210 23 1287 4 35 3510 2 870 2682 2 610 2599 2638 27 1 9 1190 24 1 5 08 470 3 618 2920 2690 2 637 2627 2 664 2747 1177 25 18 07 525 4 088 3235 2962 2905 2910 2988 3130 1169
z ())
TABLE X Continued
Run No Position CFM I tc1 tc 2
Thermocouple Readings te3 tc4 tc5
(mv) tc6 tc7 tcair
26 c 10~29 6 32 2340 2~092 2032 2060 2~097 2152 2~213 1211 27 12 66 679 2270 2 047 1993 2013 2069 2142 2 210 1 182 28 1430 723 2336 2097 2033 2080 2153 2~255 2 356 1 138 29 1729 8 52 2318 2070 1980 2061 2158 2279 2367 1121 30 12D 1054 570 1520 1 4 20 1402 1400 1396 1400 1 443 1159 31 1294 6 69 1599 1469 1444 1439 1433 1 442 1485 1168 32 1430 7 88 1720 1562 1536 1532 1528 1537 158 0 118 5 33 1770 8 81 1641 1488 1450 1~441 1 441 1_466 1518 1 163 34 1D 1058 548 1579 1498 1495 1526 1553 1_557 1 571 1 276 35 1263 640 1609 1509 1515 1570 1599 1598 1 598 1 266 36 18 36 8 47 1538 1452 1483 1553 1602 1 590 1 558 1195 37 1 12D 1029 5 41 1 578 1499 148 4 1473 1461 1465 1-512 1200 38 1315 6 30 159 1 1504 1493 1482 1470 1470 1505 118 5 39 1 4 26 743 1765 168 1666 1660 1645 1642 1678 1270 40 1757 8 54 1744 1648 1634 1620 1598 1 593 - 1612 1223 41 2D 1080 5 30 1734 1604 1570 1 570 1570 1 588 1 640 128 1 42 1305 6 40 1744 1622 1589 1 608 1593 1 609 1 661 1240 43 1434 750 1798 1687 1658 1 636 -1641 1 661 1 711 1_220 44 18 04 8 41 1 764 1666 1607 1605 1614 1 635 1 675 1205 45 12nu 1088 415 2614 2295 2195 2 169 2174 2217 2256 1171 46 1318 477 2805 2477 2371 2342 2364 2 401 2 438 1 163 47 1413 5 28 2930 2 646 2 555 2 526 2532 2570 2 577 1 199 48 1773 550 2740 2518 2450 2431 2448 2 479 2 480 1 170 49 1 11 U 1054 380 3175 2670 2505 2 461 2467 2 534 2 621 1 258 50 1240 420 3268 2738 2 546 2 510 2 508 258 2 2 649 1214 51 1419 451 3364 2B07 2 632 2590 2 590 2 651 2773 1 215 52 1 12U 1032 360 3 165 2 629 2 450 2402 2403 2 473 2 bull568 1 163
--I lt0
TABLE X Continued
Run No Position CFM I tc1 tc2
lhermocoup1e Reading s tc3 tc4 t c 5
(mv) tc6 tc7 tc a ir
5 3 1314 38 9 3178 2592 2411 2367 2361 2432 2555 1140 54 1448 403 3095 2544 238 1 2336 2336 2390 2476 1158 55 178 2 427 3006 2434 2286 2253 255 3 2299 2397 1154 56 2 11U 1061 360 3369 2814 2619 2567 2560 2650 2833 1220 57 1216 360 3044 2512 2338 2290 2288 2374 2566 1150 58 1322 387 3196 2614 2425 2383 2382 2472 2670 1138 59 1639 403 3020 2438 2272 2238 2238 2318 2502 1127
60 1D 1068 612 1552 1424 1400 1395 1396 1426 1745 0945 61 1399 612 1355 1246 1230 1229 1230 1250 1509 0872 62 1669 710 1436 1293 1272 1265 1266 1286 1551 0847 63 1959 900 159 5 1468 1444 14 38 1432 1446 1720 0851 64 2295 730 1169 1105 1098 1099 1108 1100 1298 0781 65 2636 8 80 1202 1129 1121 1126 1 138 1115 1342 0748 66 3390 9 35 1060 o 9s7 0999 1001 1017 0971 1154 0703 67 1nu 1190 370 2225 2188 2104 2080 2120 2209 2 7 15 0990 68 1559 368 2005 1950 1871 18 48 1876 1951 2408 0916 69 1904 368 1870 18 1 4 17 34 1711 1730 18 07 2238 0875 70 22 bull11 471 228 6 2 204 2099 2063 2092 218 $ 2732 0840 71 2289 471 2030 2000 1925 1895 18 96 19 5 2498 0785 72 2727 4 71 1854 18 23 1753 17 23 1716 3758 2241 0743 73 3210 471 1680 1651 158 6 1559 1551 158 1 1950 omiddot7o9 74 2uD 1210 404 1261 1212 1198 1197 1205 1222 139 1 0978 75 14 20 540 1321 1260 1242 1 240 1249 1268 148 7 0918 76 1692 7 18 1467 138 6 1364 1361 1376 1405 1678 0883 77 18 94 903 1708 1 591 1565 1560 1575 1603 1948 0 857 78 2301 903 1530 1432 1407 1402 1415 1432 1738 0815
ro 0
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc117 tcair
79 2621 6 50 1069 1 020 1009 1009 1009 1007 1~189 o739 80 3230 901 1200 1128 1113 1119 1119 1086 1341 0694 81 82
l2D 1155 1689
360 575
1191 1345
1142 1252
1122 1218
1118 1210
1118 1209
1132 1228
1292 1446
0916 0822
83 1244 430 1163 1134 1131 1130 1129 1132 1292 0877 84 2100 645 1175 1135 1147 1 142 1138 1122 1286 0757 85 2292 8 25 1 354 1310 1327 1330 1323 1285 148 6 0728 86 2907 8 23 1180 1138 1151 1158 1149 1107 1268 0687 87 3380 902 1113 1049 1025 1011 1006 1042 1178 0673 88 89
1 12D 1427 1875
480 615
118 2 1140
1140 1095
1124 1077
1125 1075
1129 1072
1137 1072
1290 1243
0880 0790
90 2259 8 41 1296 1231 1207 1206 1203 1182 1419 0757 91 2682 8 80 1231 1170 1149 1147 1142 1112 1350 0731 92 3417 940 1142 1092 1076 1076 1069 1021 1252 0693 93 c 15 17 431 1321 1298 1268 1249 1250 1273 1522 0841 94 2034 505 1285 1263 1235 1209 1205 1206 1464 0759 95 2348 6 10 1395 1379 1334 1302 1286 1268 1536 0732 96 2716 706 1486 1480 1427 1383 1358 1311 1572 0 700 97 3247 7 56 1417 1430 1375 1320 1284 1223 1450 0660 98 1135 400 1425 1388 1352 1329 1330 1 364 1651 0893 99 14 06 440 1379 1341 1304 128 2 1281 1305 1583 0 831
100 2311 680 1602 1593 1553 1514 1502 1480 1 7 27 0 802 101 2666 680 1471 1469 1428 1390 1372 1335 1564 0761 102 3392 798 1491 1 509 1449 1395 1372 1305 1534 0 719
103 1U 1235 410 2469 2295 2173 2165 2226 2361 3120 0 897 104 2010 410 2017 1848 1 737 1706 1747 1865 2582 0753 105 28 14 410 1682 1535 1457 1427 1437 1520 2109 0 660
00 t-
TABLE X Continued
Ru n Thermocouple Rea ding s (mv No Positi on CFM I tc1 tc2 tc3 tc4 tc5 tc6 tc7 tcair
106 3492 440 1649 1499 1420 1391 1390 1470 2042 0620 107 4395 550 18 33 1679 1597 1564 1570 1640 2223 0583 108 5075 588 1779 1642 1580 1550 1552 1 615 2 191 0548 109 c 1344 398 1464 1 399 1364 1353 1350 1380 1689 0 907 110 1936 459 1369 1290 1253 1242 1 237 1259 1574 078 2 111 2846 580 1347 128 5 1251 1232 1220 1215 1 5 23 0 683 112 34 8 4 700 1392 1369 1339 1317 1299 1259 1599 0 636 113 4066 8 13 1449 1458 1427 1391 1363 1270 1595 0 591 114 5012 930 1484 1530 1500 1453 1420 1272 1580 0 580 115 1D 1362 513 1269 1218 1 217 1214 1220 1238 1460 0 893 116 19 58 600 1187 1122 1121 1120 1124 1133 1352 0798 117 2812 705 1052 1008 1015 1010 1011 1001 1218 0691 118 34 32 913 1105 1075 1085 1081 1086 1047 1301 0645 119 4022 980 1038 1021 1026 1023 1029 0983 1211 0 609 120 5026 982 0 8 61 0839 0836 0836 0837 0791 0955 0570 121 2D 1244 475 1320 1246 1233 1240 1255 1275 1434 0925 122 1 9 60 5 50 1160 1088 1074 1079 1089 1100 1260 078 7 123 2817 6 80 1096 1024 1 013 1018 1029 1022 1201 0 700 124 3491 960 1248 1175 1163 1172 1192 1153 1435 0 658 125 4096 989 1141 1089 1078 108 9 1105 1051 1310 0629 126 50 37 989 0983 0933 0929 0 936 0949 0880 1090 0 602 127 128
12D 1278 1947
402 545
1270 1261
1 230 1216
1228 1216
1230 1 215
1235 1223
1242 1219
1483 1514
0 913 0778shy
129 2769 695 1273 1234 1237 1221 1251 1212 1525 0678 130 131 132
34 39 4103 4978
8 40 9 80 9 80
1336 1448 1271
1322 1458 1 288
1328 1 462 1286
1 259 1 356 1157
1353 1492 1311
1261 1329 1138
1 555 160 7 1343
0 629 0 600 0599
(l) l)
TABLE X Continued
Run No Position CFM I tel tc 2
Thermocouple Readings tc3 tc4 tc5
( mv) tc6 tc7 tcair
133 1 l2D 1299 5 16 1 28 1 1212 1196 1195 1205 1221 1478 0869 134 1973 6 15 1163 1098 1073 1071 1079 1083 1343 0751 135 136
27 88 34 73
802 9 -_78
1187 1214
1099 1131
1069 1104
1066 1101
1075 1~110
1l061 1066
1370 1360
0662 0618
137 4118 9 81 1084 1010 0983 0979 0982 o937 1209 0581 138 4973 98 1 0969 0897 0 868 0855 0860 0799 1041 0572
139 1D 1253 409 1371 1293 1298 1301 1309 1321 1578 0928 140 2366 480 1130 1 090 1 121 1130 1137 1132 1390 0744 141 34 61 6 38 1081 1086 1152 1161 1147 1069 1382 0644 142 143 144
4325 5677 6759
7 90 939 998
1110 1115 1034
1161 1208 1139
1253 1268 1180
1265 1302 1215
1228 1230 1123
1080 1056 0970
13$913r12 8
0601 0561 0542
145 84 08 989 0863 0961 0934 0895 0871 0 785 09 9 0530 146 86 54 9 80 0808 0901 0 872 0821 0809 0733 0891 0498 147 7376 9 80 0 927 1032 1027 1 040 0961 0889 1032 0511 148 2D 4254 776 1 050 0 981 0965 0961 0962 0922 1155 0579 149 5708 991 1102 1031 1014 1009 1010 0931 1227 0528 150 69 78 990 0914 0853 0839 0 839 0843 0759 0996 0521 151 1254 490 1 479 1352 1329 1334 1351 1379 1607 0930 152 2713 7 00 1310 1220 1201 1201 1211 1209 1516 0723 153 8730 991 0809 0756 0742 0745 0 748 0663 0874 0543 154 5811 966 1219 1108 108 6 1081 1079 1033 1330 0650 155 42 46 8 02 1248 1136 1114 1114 1118 1103 1376 0 699 156 c 1270 429 1671 1571 1551 1545 1563 1600 1933 0929 157 2714 488 1398 1285 1 267 1258 1262 1275 1628 0729 158 4310 642 1424 1318 1299 1282 1283 1261 1683 0617
co ~
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc7 tc a 1r
159 60 12 780 1461 1388 1370 1349 1343 1279 1700 0 573 160 72 79 8 60 1402 1344 1330 1312 1292 1189 1 566 0 520 161 8690 982 1472 1442 1437 1 422 1392 1224 1602 0 521 162 163
12D 4368 5833
6 30 8 30
1195 1368
1105 1270
1111 1283
1117 1294
1131 1313
1081 1194
1369 1553
0613 0 553
164 76 43 959 1428 1338 1348 1341 1371 1180 1488 0535 165 8739 984 1345 1272 1272 1208 129 3 1059 1361 0550 166 1268 459 1701 1548 1541 1547 1589 1 625 1976 0 973 167 2678 570 1485 1351 1349 1356 138 1 1 385 1795 0760 168 169
1 12D 128 3 2729
448 650
1664 1314
1501 1232
1425 1233
1428 1229
1491 1229
1527 1232
1869 1571
0 962 0767
170 4345 847 1245 1179 1187 1182 1172 1132 1476 0 650 171 6036 9 76 1139 1109 1117 1114 1095 1020 1332 0588 172 6578 9 72 0982 0949 0942 0938 0926 0 8 50 1079 0560 173 87 84 9 72 0880 0854 0 8 36 0822 0818 0 749 0941 0585 174 1278 480 1564 1416 1397 1403 1417 1445 1733 0998 175 2711 590 128 3 1175 4 1178 1182 1187 1195 1493 0796 176 4351 8 90 1331 1259 1266 1275 1272 1235 1592 0 682 177 5994 9 60 1228 1152 1150 1151 1143 1075 1 360 0644 178 lU 1223 408 2282 2140 2052 2052 2106 2188 2626 0 878 179 2351 408 178 1 1623 158 5 1519 1556 1634 2068 0717 180 3448 482 1888 1675 1570 1541 1572 1665 2199 0629 181 4513 563 2026 1797 168 4 1644 1670 1770 2385 0583 182 5714 589 1913 1700 1610 1568 1580 1 682 2382 0551 middot 183 6997 653 1903 1718 1643 1611 1612 1700 2326 0 549 184 8709 6 80 1738 158 3 1543 1510 1498 1519 1 912 0577 185 186
2 12D 4249 5737
660 9 74
1055 1221
0 979 1122
0960 1093
0 952 1088
0959 1090
0 956 1054
1147 1350
0661 0602
187 7432 9 8 1 1065 0981 0951 0942 0 939 0881 1135 0582 CD ~
TABLE X Continued
Run No Position CFM I t o1 to 2
188 87 23 9 83 0944 0 879 189 1435 585 18 26 1630 190 2718 690 1433 1298 191 7507 950 1070 0961 192 85 44 964 0982 0 881 193 1287 600 1806 1668 194 2717 7 80 1579 1444 195 4253 8 81 1371 1260 196 60 68 9 78 1252 1152 197 73 89 975 1100 1000 198 86 88 973 0953 0 871 199 58 64 9 81 1269 1155 200 2D 4 1 77 915 1362 1251 201 5712 975 1213 1111 202 7363 9 78 1036 0 951 203 8 604 973 0932 0861 204 1268 6 95 2015 18 20 205 2659 6 96 1405 1295 206 39 80 7 98 1261 1174
No 207 Orifice 114 96 509 1325 1148 208 94 33 509 1477 1243 209 7487 5 09 1686 1409 210 5236 505 2094 1691 211 3309 428 2188 1 778 212 1293 392 2976 2560
Thermo ooup1e Readin g s (mv) to 3 to4 to
5 to
6 to7 toair
0 851 0847 0 8 29 0759 0987 0592 158 4 1583 1611 1647 1993 0986 1270 1266 1 279 1298 1604 0 789 0916 0908 0900 0 858 1115 0602 08 39 0 823 0 818 0 770 1035 0602 1609 1602 1629 1676 2153 0979 139 1 1385 1400 1 430 1938 0776 1212 1201 1205 1201 1601 0669 1 105 1086 1086 1 052 1371 0621 0952 0936 0923 0870 1195 0582 0 8 20 0 801 078 1 0 729 1044 0569 1108 1090 108 2 1043 1407 0610 1218 1221 1241 1202 1582 0659 1081 1083 1084 1031 1 368 0622 0921 0924 0919 0 841 1111 0 610 08 34 0831 0 821 0 751 1003 0 630 1761 1761 1 809 1861 2399 0966 1271 1271 1295 1311 1650 0797 1150 1150 1161 1149 1440 0703
1083 1057 1053 1109 1566 0~530 1158 1125 1138 1217 1763 0 526 1291 1250 1278 1383 2038 0542 1518 1478 1519 1657 2420 0 589 1596 1557 1601 1737 2441 0688 2370 2344 2409 2561 3 297 0921
()) (11
TABLE X Continued
Run Thermocouple Readings (mv) No Position CFM I tc 1 tc2 tc3 tc4 tc tc tc tc i5 6 7 a r
C of 2nd 213 516 1235 4 63 1 432 1291 1265 1258 1 268 1 308 1550 0 971 214 1919 6 17 1357 1223 1196 1191 1199 1211 1461 0 851 215 27 12 8 35 1401 1259 1278 1220 1230 1218 1511 0 762 216 3320 981 1439 1305 1270 1259 1275 1238 1450 0719 217 41 53 980 1251 1142 1132 1094 1121 1088 1305 0 695 218 404 987 1102 1042 1030 1 bull006 1014 0960 1133 0681
Supplementary Equations
Calculating temperatures from thermocouple readings
t = -026tc)2 + 3512(tc) + 3201 (26)
where t is the temp in deg F and tc is the thermocouple reading in millishyvolts
Calculation of the thermal conductivity of air
k = 00000245ta + 0 0132 (27)
where k is the thermal conductivity in Btuhr rt2 degFft and ta is the air temp 1n OF
I I
bull co m
16
Pressure Probe
A probe was designed to measure the pressure drop
between the pressure tap 13 i nches upstream from the ori shy
fice baff le and any point downstream from the tap The
probe eonsisted of a l~in OD copper tube with six 132
i n ch holes even l y s paced around the tube The upstream
pressure tap and the pressure probe were connected to a
differential manometer so the pressure drop to various
points up- and downstream of the orifice could be measshy
ured
17
CHAPTER IV
EXPERIMENTAL PROGRAM
The experimental program was designed to measure the
heat transfer coefficients and pressure drops in the vicinshy
ity of annular orifices The four orifice sizes studied
were 1 364 1 216 l 316 and 1 516 inches~ The inner
tube used in each case was a 1-in OD alumintim tube
Hence tube to baffle clearances were respectively 3128
232 332 and 532 of an inch
Heat transfer coefficients were measured at poait~ons
1 i nch upstream at the orifice center and at 12 1
1 12 and 2 inches downstream for all orifices In addishy
middottion the heat transfer coefficient at a point 2 12
inches downstream from the 1 516 inch orifice was measured
and at the points 12 l 12 and 2 inches upstream from
the 1 364 inch orifice
The heat transfer coefficients at each point were
measured at five different flow rates for the 1 364 inch
orifice and at six different flow rates for the other orishy
fice sizes The high pressure drop through the small orishy
fice size limited the number of flow rates which could be
studied
The flow rate was calculated from the pressure drop
across the flow orifice This flow was corrected to cubic
feet per minute at 68degF and one atmosphere pressure by
18
using the orifice pressure and the test section pressure
which were measured by pressure gages
It was desired to determine a relationship between the
heat transfer coefficient and the total pressure drop for
each orifice size The pressure drop across each orifice
at various flow rates was measured by means of the presshy
sure probe described in Chapter III It was also desired
to obtain pressure profiles for each orifice size since
these might be similar to the heat transfer profiles The
pressure drop was measured from a point 13 inches upstream
of the orifice to points at 1 and 12 ineh upstream the
orifice center 12 1 1 12 and 2 inches downstream
The experimental program is summarized in Table I
TABLE I
SUla~RY OF EXPER IMENTAL PROGRAM
Position Investigated-Distance from Orifice-Inches
Orifice Range of Flow Rate Size Heat Transfer Pressure Drop CFM at 68degF amp 1 atm
1 364 2U 1 12U 1U 12U c 12U C 12D lD 10 - 18 l2D lD 1 12D 2D 1 12D 2D
1 216 1U c 12D lD 1 l2D 2D 12U c 12D lD 10 - 35
1 316 1U c 12D lD 1 l2D 2D l2U C 12D lD 12 - 50
1 516 1U c x2D lD 1 l2D 1U 12U C 12D 12 - 90 2D 2 1 2D l D 1 l2D 2D 2 12D
20
CHAPTER v
EXPERI MENTAL PROCEDURE
The experimental procedure for measuring the heat
transfer coefficients ~d corresponding flow rates reshy
quired the following procedure
(1) Install the orifice size to be studied in the
test section
(2) Place the heat transfer probe in the position up
or downstream from the orifice where the middot heat
transfer rate is to be studied
(3) Fill the cold junction thermos with cracked ice
(4) Measure the atmospheric pressure
(5 Open bypass line from blower and close line to
test section
(6) Turn on the cooling water for the exchangers used
to cool the air leaving the blower
(7) Start the automatic selen ium rectifier by turning
on the t 1mer bull
(8 ) Connect the voltage stabilizer to the wall outlet
(9) middot Set the slide wire resistor to the maximum re shy
s1atanee I
(10) Start the blower
(11 Open the line to the test section until the de shy
sired flow rate is obtained
(12) Switch on the probe direct current power source
21
(13) Adjust the slide wire resistor to obtain the
desired current
(14) After the thermocouples have reached equilibrium
values record the e m bullf across each of the
seven probe thermocouples and also the entering
air thermocouple
(15) Record the direct current amperage
(16) Record the gage pressure at the flow orifice and
the entrance to the test section
(17) Record the manometer measurement of the pressure
drop across the flow orifice and also the presshy
sure drop through the test section
22
CHAPTER VI
CALCULAT ION OF EXPERIMENTAL DATA
The local heat transfer coefficients were calculated
from the temperatures measured on the probe surface the
air temperature and the current input The results were
calculated by using the Alwae III-E computer
The general expression for calculation of the heat
transfer coefficients was derived by Ambrose (1 p 79)
The equation is derived by making an energy balance around
a small increment of the center resistance heating ribbon
The two ribbons tnstalled adjacent to the center ribbon
reduced the amount of logitudinal conduction and assured
little longitudinal temperature variation in the center
ribbon
A heat balan ce on this small increment of resistance
ribbon yields the following
(the heat conducted in) + (heat generated) = (heat
conducted out) +(Heat convected to the fluid) + (heat
radiated to the surroundings) + (Heat conducted into
the plastic center of the probe)
This gives the equation
kzw dtdS + 12RdS kzws [ t + (~) ds] + hwdS (t-ta )
+ ~Aad wd o middot+ qcAond 1 -~- wdS 5 )
23
Hence solving for h gi~ea
i2R kz d2t Qrad qcond w + -d$2 - ~- A
h = ( 6)t - ta
Since S = re where 9 equals the enclosed angle ~n radians
dS rd9 ( 7)
and
dt - dt (8)dS - rd9
Differentiating with respect to S
d2t (9)rd9dS
from which
(10)
Substitut1ng into the equation for heat transfer coeffishy
cient gives
h = i2R Qcond A (11)
w
The rate of radial heat conduction into the plastic
tube making up the probe was assumed to have negligible
effect on the heat transfer coefficient It was also
assumed that the heat loss by radiation from the ribbon
was negligible since all data were obtained with the ribbon
at a temperature less than 125degF
24
When t he rad iation and conduction terms are neglected
Eq (11) becomes
(12)
The following con stants are known
R = 0 271 ohmsft
w = 100 i n ches
k = 763 Btuhr rt2 degFft
z = 0 002 inches
r = 12 inch
Eq (12) putting 9 in degrees then reduces to
1110 12 + 2404 d 2t d92
( 15)h = ------~--~-------t - ta
Thi s equation was programed for the Alwac III- E comshy
puter and used to calculate the local heat transfer coefshy
ficients from the observed data
The average heat transfer coefficient around the tube
at a given position in the t est section was calculated by
averaging the local coefficients calculated from Eq (13 )
It was found 1n the course of the experimental work
that thermocouple numbers 1 and 7 were indicating higher
temperatures than would be expected This resulted in h1
and ~ being lower than the other local coefficients around
the tube Since the fluid was flowing parallel to the axis
of the probe the circumferential variation i n rate of heat
25
transfer should be small Hence in obtaining the average
coefficient around the tube the values of h1 and h7 were
not used even though they were calculated and are tabulated
1n Table I II in the Appendix
Then
(14
A Nusselt number as calculated from this aver age heat
transfer coefficient using the tube diameter as the characshy
teristic dimension
(15)
The air flow rates through the test section were calshy
culated by measuring the pressure drop across the flow orishy
fice the air temperature the pressure at the flow orifice
and the pressure at the entrance to the test section The
orifice calibration curves (1 p 166 ) were used to obtain
a value of the orifice coefficient f8e where Q equals
the flow in cubic feet per minute at 68deg F and one atmosmiddot
phere pressure and te is the density of air at the exchanger
and e the density of the air at the flow orifice The
den sity of the air can be expressed by
e = 2 703 p (16)T
where T equals the temperature in OR and P equals the absoshy
lUte pressure i n lb1n2 Using the value of e Qfo from
26
the calibration charts as A and Eq (16) solving for Q
gives
( 17
This equation was used to calculate the flow rate for
each flow studied
The Reynolds number used i n the correlation of the
data was the equivalent Reynolds number defined as
Re)eb ~ d2 - dl)Uf ( 18 ) lL
where d1 is the outside diameter of the inner tube and d2
is the orifice diameter U is the flow velocity through the
annular orifice e is the density of the air and U- is t he
viscosity of the air This equation can be transformed t o
(Re) b = 1611 Q (19) e dl + d2
where d1 and d2 are in inches
The pressure drop data were calculated i nto a dimenshy
sionless pressure drop function cent where
d1 )22( ~ P)gc f av(d2 shycent 2 bull (20
M-
For air this equation reduces to
where d2 and d1 are in i nches D P is expressed i n inches of
2 95 specific gravity fluid and P av is expressed as lbft3
27
CHAPTER VII
ANALYSIS OF DATA
In analyzing the heat transfer data an attempt was
made to correlate it 1n terms of the dimensionless groups
(Nusselt number Prandtl number and Reynolds number) which
appear in Eqs (3) and (4) Consequently all of the av~
erage heat transfer coefficients hav were brought into
the form ( Nu)( Pr)~3 bull The Nusselt number was based on the
tube diameter and the thermal conductivity of the air at
the flowing temperature The tube diameter was used in the
Nusselt number because comparison could then be made with
previous experimental work on heat exchangers which have
commonly used the Nusselt number defined as in Eq (15)
From the standpoint of dimensional analysis this is
equivalent to considering the tube diameter as the characshy
teristic length so far as the heat transfer is concerned
The Prandtl number of the air was taken as 0 7 in all
cases
Variation of Heat Transfer Rate with Distance from the Baffle
Considerable variation was observed in the rate of
heat transfer in the vicinity of the baffle In order to
obtain the variation with respect to position the term
(Nu)(Pr)-13 was plotted versus the flow rate Q for each
position and orifice studied Cros s plots were then made
28
at constant flow rates in order to obtain the variation of
(Nu)(Pr) -13 with position The resulting cross plots are
shown 1n Fi gures 5 6 and 7 for the four orifices studshy
ied
About one inch upstream from the orifice the heat
transfer coefficient begins to rise rapidly and continues
to do so until it reaches a maximum some distance downshy
stream After the maximum point the heat transfer coef fi shy
cient decreased slowly The heat transfer rate was found
to reach a maximum at a different position downstream for
each orifice size These figures also show that for a
given orifice size the maximum heat transfer rate occurs
a pproximately at the same point for all flow rates The
position of the maximum point f or each or ifice size is
shown in Table II
The region immediately downstream from the orifice is
one of h i gh turbulence due to the jetting action of the air
flowing through the orifice As the air flows t hrough the
orifice the streamlines continue to converge for some dis shy
tance downstream The point of maximum heat transfer is
probably at the point where the streamlines be gin to diverge
and a boundary layer begins to build up on the tube Tle
decreasing heat transfer coefficient beyond the maximum
point indicated the formation of a boundary layer
Since the position of the maximum point is independent
of flow rate middot it is possible to correlate it with respect
_ ct 11shyz-
100
0 136 ORIFICE
(
I 0
I )
~ 00
~p 0
I 0
--r--- ~
ISCFIII
-_ OCFM
rbull abull
~ middot~ a-1 z-
12fORIFICE
100
200
100
0 0 UPITRAM ORIFICE DISTANCE CENTER
CFM
h I DOWNSTREAM
DISTANCE
FIGURE 5 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLpound
30
too
700
800
100 ~ f gtf
400
z ~
100
100
100
0
13fORIFICE
~ -~ -- ---
)
~
~
-
I ~ ~OCFM
I vI~-~ OCFM
J ---
Iamp CFM
I 0 I I UPSTREAM ORIFICE DOWNSTREAM DIITANOE GENTER DIITANCI
FIGURE 6 VARIATION OF HEAT TRANSFER RATE WITH DISllNCE FROM BAFFLE
--
--- --
31
100
100
700
100
_ 100
f 9- 400 z-
100
tOO
100
0 - I 0 I I I UHTRIAM OAtfiCI DOWIIITMAM
+ I tyl6 ORIFICE
v I
~~ ~CFM
I v ~CFMI
v v 7
~~ v ~ iOCFM
- ~~ I-shy1-shy ~ICFM
DIITMCI OINTIR DIITANCI
FIGURE 7 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLE
32
TABLE II
POSITION OF MAXIMUM HEAT TRANSFER
Position of Maximum Orifice Size Heat Transfer
(inches) (inches downstream)
1 364 050
1 216 100
1 316 125
1 516 200
33
to orifice size Figure 8 shows the effect of the orifice
size on the position and value of the maximum heat transfer
at a constant flow rate of 15 cubic feet per minute It
can be seen that the larger the orifice size the further
downstream the point of maximum heat transfer occurs
Also as the orifice size increased the rate of heat
transfer decreased for a given flow rate The broken line
indicates the variation of the point of maximum heat transshy
fer with position and size The position of the point of
maximum heat transfer rate downstream from the orifice was
correlated with orifice size by means of the dimensionless
groups (Lde) and (d1de) where L is the distance downshy
stream from the orifice where the maximum rate of heat
transfer occurs d1 is the outside diameter of the inner
tube and de is the equivalent diameter of the orifice
ie de = d2-dlbull
Figure 9 shows a plot of Ld 6 versus d1d6 for the
four orifice sizes studied The four points on this logshy
log plot are approximately in a straight line and the
equation of this line is
Lde = 0 44 d1de)028 (22)
Although the above relationship represents a correlashy
tion of dimensionless groups it is based upon only one
tube diameter and needs to be substantiated further by
studying other tube diameters and other orifice sizes
34
aoo
400
aoo ~
-~ middot-CLshyJ z
200 -
100
0
ORIFICE CENTER
l~
l
t
I J~
1pound~
I
0 I I~
AT 15 CFM
-
bull ~ 1~6~
~ v~
~
~--~~6
~~~ ___ v v V -_
~ o q
~ I 16
v
~
ogWNSTREANI STANCE
FIGURE 8 EFFECT OF ORIFICE SIZE ON POSITION AND VALUE OF MAXIMUM HEAT TRANSFER
35
50
loshy____ -~
~ ~ -shylltl-shy~ r0
2 10 30
FIGURE 9 CORRELATION OF THE POINT OF MAXIMUM HEAT TRANSFER WITH
ORIFICE SIZE
36
Correlation of Data at the Baffle
The heat transfer data were correlated by obtaining a
relationship between the group (Nu)(Pr)-13 and a
Reynolds number based on twice the clearance (d2 - d1
between the tube and the baffle It was found that the
most satisfactory correlation could be obtained when the
term - d1 was used as the length term in the Reynoldsd2
number
Figure 10 shows the variation of the heat transfer
rate at the center of the orifice e xpressed as a function
of Reynolds number and the orifice size This shows that
for a given Reynolds number the heat transfer at the center
of the orifice is greatest for the smallest orifice size
In order to obtain a general correlation of the data
shown i n F1gure 10 the effect of the dimensionless ratio
d1de was considered This ratio considers all of the
geometric factor s needed to describe the annular orifice
The thiclaless of the orifice plate is also a factor but
was constant i n this i nvestigation
The data for the heat transfer at the baffle center
are shown in Figure 11 in which (Nu)( Pr)-13 is plotted
versus (Re)ebd1 de) 0 55 This data on a log-log plot
lies on a straight line for (Re)eb( dld8 )0 55 greater
than 3 x 104 The equation for cor relating the heat
37
4XI~middot~-r~------~--~~------~
Icf t--to_+--_c-c-________ SYMBOL SIZE
0 1~4
6 ~~
9 ~~ -o ~
(Re)eb
FIGURE 10 RATE OF HEAT TRANSFER AT BAFFLE CENTER
38
500
0
4 0 lcf
~ ~
~ ~iC-
~ ~
~IL 0~ 0 SYMBOL SIZE-
p 0 1364-
r 6 1~16 -~ -
9 1~16 --o 1~16
I I
FIGURE II CORRELATION OF HEAT TRANSFER DATA AT BAFFLE CENTER
39
transfer at the center bullOf the a nnular orifice was found by
the method of least s quares to be
(Nu)( Pr)-1 3 = 0018 ( Re)ebO Bl( dlde)04~ (23)
3 x 104 ltRe)eb(a1de)055 lt 105)
Rate of Heat Transfer at the Point of Maximum Heat Transfer-The heat transfer rate at the point of maximum heat
transfer is plotted in Figure 12 to show the variation with
Reynolds number and the size of the orifice It is shown
gives the h1gh st heat transfer ~ate at its point of maxibull
that for a given Reynolds number the smallest orifice size yen il
mum heat transfer
The data ~or the maximum poi~t could be correlated by
plotting (Nu) Pr)-13 versus (Re)eb(d1de)06 This plot
is shown 1n Figure 13 and the resulting eurve shows that
(Nu(Pr)-13 is not a simple p0wer function of the Reynolds
number as was the case for heat transfer at the baffle
center The reason for this is probably because other
factors such as intensity and scala of turbulence should
be considered At the orifice center the streamlines of
the flowing stream are converging_ and thus the flow is
quite stable Downstream from the orifice is a region of
large eddy currents and probably large scale turbulence
These factors could con ceivably cause the results which
were obtained for the point of maximum heat transfer
40
If)
~middotshy Q_-I z_
10~~~--------r----~~--~--
SYMBOL SIZE
0 13$4
6 1~8
Q 13-18
-o 1~8
7)(104
(Re)eb
FIGURE 12 RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
41
Ia ~
0 I
c ~ ~ c v
~ ~lt w ~
17
~ b
v ~ ( SYMBOL SIZE
-~ 0 f-64 -v ~ 6 t211e
~ Q I~~~
-o - l~rs I I
FIGURE 13 CORRELATION OF HEAT TRANSFER DATA AT THE POINT OF MAXIMUM HEAT TRANSFER
4 2
Effect of Upstream Baffles on Heat Transfer at the Orifice Center
The heat transfer rate at the orifice center using the
single orifice in a test section is a pproximately 13 of the
value that was obtained by Lee (7) using a model heat exshy
changer with orifice baffles Lee investigated the cent r al
baffles of the heat exchanger and thus the coeff icients he
obtained would be affected by the presence of a number of
upstream baffles To determine the effect of upstream
baffles an additional l 516 inch baffle was placed four
inches upstream 1n the test section The resulting data are
shown in Figure 14 where (Nu)(Prmiddot)-13 is plotted versus
(Re) eb for the case of a single baffle 1n the test section
and also the case of an additional baffle placed four inches
upstream Comparison is made with the results obtained by
Lee middot(7) using a four-baffle and a ten-baffle model heat exshy
changer Good a greement is obtained with Lees work and the
results show the marked effect that upstream baffles have on
the downstream heat transfer rate The additional up tream
ba ffle caused sufficient turbulence 1n the test section to
i n crease the heat transfer rate nearly three-fold at the
center of the next baffle
Heat Transfer i n the Test Section with No Orifice
In order to check the accuracy 6f the equipment the
orifice baffle was removed and the heat transfer mea sured
with the probe in the empty test section The data were
43
~~BAFFLES
0 l BAFFLE -shy
ll_9 2 BAFFLES
V 4 BAFFLES-LEE
4 10 BAFFLES- LEE lJf ~
~rv ~~ ~ v flvv ~~
I ~ J ~ L v
0
v
( V
40 3XIo 7XIa
(Re)eb
FIGURE 14 EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER AT BAFFLE CENTER
44
compared with heat transfe r coefficients predicted by the
equations for annuli which are recommended in the litera shy9
ture The two equa~ ions u sed tor comparison were
(hfe)=0 023 (rltGr e (~~ur4 (~r45 (24)
which was presente~ by Wiegant (10)
and ( h ) (cnM~5(M~l o14 o 023 CPG k j Mij - (de GJMb )0 2 ( 2 5)
which was presented by McAdams (8 p 242) The comparshy
i son is s hown in Figure 15 lq (25) gives a value which
is low by about ten percent while Eq (24) g ives values
which are high by as much as twenty -five percent when comshy
pared with the experimental data The se equations are gembull
erally considered to give coefficients with an accuracy of
about twenty percent Therefore the present experimental
data are within the accuracy of these equations Also the
plot indicate s that for a Reynold s number greater than 2 x
104 the slope of the line is the same for the experimental
data as for the equations
Pressure Drop Data
The total pressure drop across the orifice was measured
as a function of the flow rate and the orifice size The
pressure drop was expressed as a d1mens1onleas quantity r)
which ie plCltted ver sus the Reynolds number in Figure 18
The pressure drop function cent correlates for all or1f1oe
45
200
100
s z
10 5XI10 10
0 EXPERIMENTAL
--McADAMS
-WIEGAND L
V
~ ~ ~
P ~ ~
LL~ L
v~
~
v v
v 1 ~ ~ v
v -gt
~
~ ~
~
6Xid
FIGURE 15 HEAT TRANSFER WITH NO BAFFLE
46
0 1~4 -~ a 6 t216
Q t316 lJ J
-0 as a )t
A LEE I -shy SULLIVAN 8
p
10bull
BERGELIN
I _ll I
I ~
i I
~middot
lo II
f fl
J j
~middot
A)101
1q
I Ill
1 I3 X 10ao1
FIGURE 16 ORIFICE PRESSURE DROP FUNCTION VS REYNOLDS NUMBER
47
sizes- The present data extends the range covered by preshy
vious workers and agrees well with their work The preshy
vious work of Lee () for a heat exchanger containing 10
orifice baffles and also the data of Su livan and Bergelin
(9) for pressure drop in a model heat exchanger with a
single baffle is shown 1n Figure 16 long with the present
results~ This figure may be used to predict the preseure
drop from the equivalent Reynolds number of the annular
orifice
The pressure drop between individual points 1n the
vicinity of the orifice and an upstream pressure tap wa s
measured to obtain a pressure drop profile As might be
expected 1n all cases the profiles showed a rapid decrea e
in static pressure immediately upstream from the orifice
There was however little or no recovery of the pressure
loss downstream The 1 364 inch orifice did show a maxishy
mum point in the pressure drop but this maximum occurred at
the orifice center and total recovery was reached about 12
inch downstream
Heat Transfer at the Baffle and Maximum Point as a Function of Pressure Drop
In order to compare the effect of the total pressure
drop on the heat transfer at the baffle and the point of
maximum heat transfer Figure 17 was plotted showing
(Nu)(Pr)-13 as a function of the total pressure drop This
shows that for a given pressure drop the largest orifice
48
1200
1000
~ a -sshyz-
100
60 100 700
AT MAXIMUM POINT I 15116 2 13116 3 1~6 4 1364
AT ORIFICE CENTER
60
1
v
r ~ ~ ~
5
~
8 7
13116
8
~
1364
v
~
e6
1~6
v
~~ v ~ ~ -~ ~
~
~ v
l
~
vamp
I ~ ~
~
v L ~
v
I-
5
k= ~~
~ ~ ~
--I
v ~
FIGURE 17 HEAT TRANSFER AT THE BAFFLE AND MAXIMUM POINT AS A FUNCTION OF
ORIFICE PRESSURE DROP
49
size has the greatest heat transfer coefficient This is
true at both the orifice center and at the point of maxishy
mum heat transfer
Another comparison can be made by plotting the heat
transfer coefficient and the pressure drop versus the orishy
fice size at a constant flow rate Figure 18 shows this
plot This graph shows that at a constant flow rate the
pressure drop as well as the heat transfer coefficient
increases as the size of the orifice is decreased In
choosing an orifice size for maximum efficiency 1t would
be necessary to know the pumping power available as well
as the heat transfer desired
70 I I 700
AT 15 CFM 60 ---
~ aug
50 ---
NV
40 ~
~ ~ ~
~ _
MAXIMUM POINT ---- --- ~
1-----t---~ _
~00Qj ~
~t--- ORIFICE CENTER 10 1100
1---~ n
u0 01 02 03 Q35
a ltl
de inches
FIGURE 18 VARIATION OF HEAT TRANSFER RATE AND PRESSURE DROP WITH ORIFICE SIZE AT A CONSTANT FLOW RATE
cn 0
51
CHAPTER VI II
SUMMARY OF RESULTS
This study revealed several significant facts about
the heat transfer in the vicinity of annular orifices
Probably the most important contribution was the presshy
entation of the heat transfer profiles in the vicinity ot
the annular orifice ~ r s shown that t~ local heat
transfer coeffieient re~ches a maximum at a point downshy
stream from the orifice The distance downstream at which
this maximum oocurs is t1ven by the equation
22
The heat transfer coefficients at the center of the
orifice were correlated and found to follow the equation
(Nu)(Pr)-13 = 00176 (Re)eb08l(d 1de) 0 middot4~ (23)
3 x 104 lt( Re) 9 b( d1d6 )055 ltlo5 )
The heat transfer at the point of maximum heat trans
fer for each orifice size was correlated and presented in
Figure 13 as a plot of (Nu)(Pr)-l3 versus (Re)eb(d1de) 06
No simple po-orer relationship exists between the terms
Intensity and scale of turbulence downstream from the orishy
fice are probably important factors which affect the heat
transfer
The large effect of an upstream orifice on the heat
transfer rate at the second orifice was demonstrated by the
52
study of two 1 516 inch orifices in the test section The
added turbulence at the center of the second orifice was
found to raise the heat transfer rate almost three times
over that obtained for a single baffle
The pressure profiles in the vicinity of the orifice
indicate that nearly all the pressure drop occurs at the
orifice center~ Total pressure drop data were correlated
by a pressure drop function cent as a function of the Reynolds
number and good agreement obtained with the results of other
workers
The pressure drop and heat transfer data were correbull
lated by plotting the heat transfer as a function of the
pressure drop for each orifice size It was shown that for
a given pressure drop the largest orifice size gives the
greatest heat transfer coefficient
As a final presentation it was shown that the pressure
drop and the heat transfer coefficient both i ncrease i n
value at a constant flow rate as the orifice size is de shy
creased This is important in choosing the optimum clearshy
ance for orifice baffles
53
CHAPTER IX
RECOMMENDATIONS
A great deal of work remains to be done in the field of
evaluating shellmiddotside heat transfer coefficients This
study included only one tube size and air was the only f luid
used It is recommended that further studies be conducted
using other fluids and tube sizes It will also be necessary
to study several baffle types
The adde d turbulence due to a s e cond baffle placed upbull
s t ream would suggest that the heat transfer coef ficients at
a certain position i n relation to a baffle would increase as
the flow progressed through the exchanger It is recomshy
mended that an extensive s t udy should be made between baffles
the full length of a model heat exchanger
It is further recommended that the pressure drop study
be continued to include other fluids tube sizes and baffle
arrangements
Effects of turbulence downstream from the baff le should
be studied by i n vestigations with hot-wire anemometer equipshy
ment to determi ne t urbulence scale and i ntensity
54
NOMENCLATURE
Area of heat transfer
Heat capacity of the fluid
Outside diameter of the tube
Orifice diameter
Equivalent diameter of the orifice (d2 - dl)
Inside diameter of the test section
Inside diameter of the tube
Gravitational constant
G Mass velocity
h Local heat transfer coefficient
Coefficient of heat transfer from surface to fluid
i Direct current amperes
k Thermal conductivity of the fluid
L Distance downstream of the point of maximum heat transfer
p Absolute pressure
L P Total pressure drop across the orifice
Q Flow in cubio feet per minute at 1 atmosphere and 680 F
q Heat transferred
Thermal energy conducted into the sensing probe
Thermal energy radiated from the resistance ribbon
Resistivity of the resistance ribbon
s Length of the resistance ribbon
T Temperature oR
55
t Temperature of the resistance ribbon deg F
ta Temperature of the bulk stream oF
tw Wall temperature of the tube OF
U Veloc ity of the fluid
w Width of the resistance ribbon
z Thickness of the resistance ribbon
eeuro Density of the fluid in the test section
Density of the fluid at the flow orificef 0
AL Viscosity of the fluid
E9 Angle measured around the tube
Dimensionl ess groups
(Nu) Nusselt number hd1k
(Pr Prandtl number C~k
(Re)eb Equivalent Reynolds number at the baffle (d2 - d1 )uejt-Lshy
(Re)e Equivalent Reynolds number in the test section ( d 8 - d 1 )U fu
cent Orifice pressure drop function 2(~P ) gc~av(d2 - d1) 2
Al
56
BI BLIOGRAPHY
1 Ambrose Tommy W Local shell-side heat transfer coefshyficients in baffled tubular heat exchanger PhD thesis Corvallis Oregon State College 1957 183 numb leaves
2 Bell K J and o P Bergelin Flow through annular orif ices Transactions of the American Society of Mechanical Engineers 70593-601 1957
3 Colburn Allan P A method of correlating forced con shyvection heat transfer data and a comparison with fluid friction Transactions of the American Institute of Chemical Engineers 24 174-210 1933
4 Dittus F w and L M K Boelter Heat transfer 1n automobile radiators of the tubular type University of California Publications in Engineering 2443-461 1930
5 Gurushankariah M s Local shell-side heat transfer coefficients in the vicinity of baffles in tubular heat exchangers Masters thesis Corvallis Ore gon State Colle ge 1958 97 numb leaves
6 Knudsen James G and Donald L Katz Fluid dynamics and heat transfer New York McGraw-Hill 1958 576 p
7 Lee Kyu Sung Local shell-side heat transfer coeffishycients and pressure drop in a tubular heat exchanger with orifice baffles Masters thesis Corvallis Oregon State College 1959 118 numb leaves
8 McAdams William H Heat transmission 3d ed New York McGra ~-Hill 1954 532 p
9 Sullivan F W and 0 P Bergelin Heat transfer and fluid friction in a shell-andbulltube exchanger with a single baffle Chemica l Engineer ing Progress Symposium Series 52 ( 18) 85-94 1956
10 Wiegand J H Discussion on annular heat transfer coshyef f icients for turbulent flow Transactions of American Institut e of Chemical Eng i n eers 41147-153 1945
AP PENDIX
57
TABLE III
CALCULATED HEAT TRANSFER DATA
Baffle Hole Diameter Run No (inches)
1 - 59 1 364
60 - 102 1 216
103 - 138 1 316
139 - 206 1 516
207 - 212 No orifice
213 - 218 2nd - 1 516
TABLE III
CALCULATED HEAT TRANSFER DATA
Local Heat Transfer Coefficients Run
T0 bull Po s ition CFM hr h2 h3 h4 hs he ~ hav Nuav
1 c 1026 10 59 1476 16 09 1559 1510 1435 1203 1518 8511 2 1290 1369 1738 1878 18 05 1755 1689 1515 1773 9964 3 1416 1636 198 1 2068 1977 1924 1845 1715 1959 11030 4 1627 1991 2301 2382 2268 2194 20 ~98 1929 2249 12664 5 1776 2252 2669 2863 2713 2517 2338 2126 2620 14759 6 l2ttD 1109 2311 3317 3386 3373 3387 3394 3071 3371 18888 7 1258 3089 4583 4866 4683 4701 4643 4194 4695 26301 8 1433 38 8 5 55 83 5791 5495 5430 5436 5008 5547 31192 9 1681 4992 7378 7649 6980 6864 6870 64 28 7148 40180
10 1 D 1102 2371 3332 3511 3356 3342 3427 3102 3394 19012 11 1308 3218 4379 45 24 42 53 4255 4373 3965 43 57 24446 12 14 64 38 58 5146 5142 4839 4787 4903 4597 4963 278 79 13 1706 5218 6664 6269 58 81 5884 6237 5973 61 87 34718 14 15
1 l2D 1115 1275
2131 2661
2955 3638
2972 3720
2941 3675
2913 3576
28 22 34 74
2613 3278
2921 36 17
163 09 20246
16 1498 34 87 4644 4503 4441 4371 4343 4194 4460 25010 17 1695 4449 5743 5324 5222 5154 5157 5015 5320 298 97 18 2D 1049 1715 23 90 2550 2610 2656 2624 2208 2566 14363 19 1241 2117 2964 3145 3218 3221 3203 2759 3150 17757 20 1532 28 67 3936 4100 4188 4201 4167 3676 4118 23224 21 1674 3459 4508 4598 4746 4795 4792 4299 4688 26337 22 lU 1074 253 340 380 3 86 388 377 354 374 2097 23 1287 292 392 433 440 441 429 406 427 2394 24 1508 322 439 492 498 499 487 461 48 3 2713 25 18 07 3 38 464 519 5 24 520 499 463 5 05 28 40
~~ (]I agt
TABLE III Continued
Run No Position CFM h 1 h2 ~3 h4 h5 h6 ~ h
av Nu
av 26 c 1029 1171 1491 1589 15 28 1 4 62 1377 1293 1489 83 44 27 1266 1395 1746 1853 18 02 1685 1556 1453 1728 9704 28 1430 1637 2037 2175 2060 1909 1735 1591 1983 11159 29 1729 1982 24 96 2751 2507 2268 2030 1886 2410 13579 30 12D 1054 2934 4041 4321 4326 4423 4359 3706 4298 24160 31 1294 3385 4 8 26 52 42 5326 5450 5277 4566 52 24 293 50 32 1431 3784 5347 5721 57 bull75 58 44 5700 5084 5677 31870 33 1770 52 75 7 7 33 87 35 9005 9007 8267 7059 85 49 48050 34 lD 1058 3235 4401 4444 3877 3496 3451 3294 3934 21973 35 1263 38 98 5484 5330 4347 3964 3981 3987 4621 25823 36 18 36 6701 89 17 7855 6369 5597 5769 6283 69 01 38718 37 1 12D 1029 2404 31 8 2 3333 3459 3624 3577 3045 3435 19264 38 1315 3182 4033 4162 4310 4496 4502 4015 4301 24142 39 1426 3628 4389 4510 4573 4760 4804 43 8 5 4607 25678 40 1757 4547 5559 5(35 5931 6282 63 70 6060 5975 33471 41 2 11D 1080 2034 28 38 3155 3144 3145 2966 2540 3050 17027 42 1305 2650 3 4 87 3aoz 3595 3751 3595 3153 36 46 20405 43 1434 3167 39 07 4156 4371 4320 4126 3709 4176 23395 44 1804 4096 4 9 66 5691 5714 5586 53 15 48 65 5454 30582 45 12U 1088 409 516 557 564 5 60 535 513 5 46 30 67 46 1318 470 579 6 22 631 6 17 5 97 579 6 09 3422 47 14 13 540 640 676 6 86 681 6 60 6 54 6 69 3754 48 1773 641 740 774 782 7 69 749 746 763 42 87 49 l 11 U 1054 270 356 391 397 393 3 71 346 38 2 2133 50 1240 303 399 446 449 447 4 21 398 432 2420 51 1419 361 476 522 530 528 507 467 493 2760 52 1 1(2U 1032 236 311 342 347 344 325 301 334 18 78 53 1314 270 366 403 407 408 386 351 394 2217
(Tt tO
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ h av Nu av
54 1448 301 408 447 454 452 431 403 438 24 61 55 1782 353 494 548 544 415 529 531 506 2843 56 2U 10 61 220 287 316 320 322 303 268 310 1735 57 1216 249 335 370 377 378 353 307 363 2044 58 1322 263 356 394 398 399 374 327 384 2159 59 1639 310 433 478 481 482 452 393 465 2617
60 1D 10 68 2011 2536 2657 2681 2694 2560 15 62 2625 14938 61 1399 2520 3239 3369 3371 33r82 32 39 1946 3320 18968 62 1669 2781 3655 3820 38 76 3883 3738 2355 3794 21712 63 1959 3524 42 37 4399 4438 4497 4417 3047 4397 25156 64 2295 4426 5288 5396 5372 5240 5410 3369 5341 30680 65 2636 5490 6531 6662 6565 6379 6820 4249 6591 37938 66 3390 7869 9538 9462 9387 8924 10508 62 91 9564 59601 67 1U 1190 352 368 401 413 407 395 293 397 2256 68 1559 397 422 462 475 471 456 331 4 57 2603 69 1904 434 465 5 13 529 528 504 358 508 2901 70 2211 493 526 573 5 92 588 564 4 15 569 3257 71 2289 569 587 6 30 649 6 61 6 49 460 635 36 44 72 2727 637 6 60 7 09 733 751 743 521 719 4140 73 3210 728 755 8 15 8 43 8 62 8 54 616 826 4765 74 2nD 1210 181 2256 2393 2399 2333 2206 1325 2317 13158 75 1420 2340 2752 2899 2913 2850 2728 1701 2828 16121 76 1692 2853 3306 3452 3471 3379 3217 2134 3365 19217 77 1894 3102 3588 3713 3736 3670 3557 2455 3653 20892 78 2301 3682 4259 4433 4467 43 83 4289 2892 4366 250 30 79 2621 4117 4828 5017 5012 5030 5109 3071 4999 28785
m 0
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ hav Nuav
80 3230 5158 6006 62 13 61 18 6134 6695 4094 6233 359 87 8 1 12nD 1155 15 27 1854 2028 2064 20 85 1987 1164 1968 118 31 82 1689 2046 24 8 2 2688 2739 2760 2658 1749 2665 152 73 83 1244 2088 2317 2339 2345 2373 2381 1487 2351 13432 84 2100 3211 3539 34 21 3462 3512 3696 2575 3526 20284 85 2292 3 5 05 3761 3648 36 25 36 79 3957 2933 3734 21517 86 2907 4420 48 22 4679 46 04 4705 5206 3792 48 03 27741 87 33 80 59 35 69 38 7404 77 10 7 8 36 7 0 86 5190 7394 427 44 88 1 12D 1 4 27 2 4 58 28 31 3037 3021 2987 2927 18 57 2 9 61 16913 89 18 75 34 75 3 9 87 4230 4255 4317 4337 2734 4225 24258 90 22 59 4221 4796 5046 5052 51 01 5389 3491 5077 29206 91 2682 4978 5664 5943 5966 6054 6573 408 1 60 40 34795 92 3417 63 16 71 02 7 3 93 7385 75 40 8 6 95 51 45 7623 44017 93 c 1 5 17 1240 1305 1399 1467 1479 1429 9 26 1423 8251 94 20 34 1554 1623 1720 18 21 18 53 18 72 1215 1778 10229 95 2 3 48 1795 1843 198 5 2097 2171 2274 1540 2074 11947 96 2716 2028 2048 22 01 2 3 44 2444 2661 18 90 2340 13505 97 3247 2410 2375 2663 2778 2949 3298 2378 2793 1615 98 11 35 967 1040 1124 1186 1200 1142 728 1138 6496 99 14 06 1135 1220 1318 1384 1403 1 3 61 8 77 1336 7656
100 2311 1 8 54 18 78 1980 20 90 2136 2227 1653 2062 118 31 10 1 2666 2085 2094 2227 2 3 62 2438 2626 1902 2349 13508 102 3392 2635 2582 28 01 3026 3141 3529 2567 3016 17390
103 1 U 1235 349 395 434 436 4 28 411 286 423 2416 104 20 10 434 5 02 559 577 569 5 37 345 552 3177 105 28 14 538 626 685 711 7 21 682 424 6 8 6 3966
Q) j-J
TABIE III Continued
Run No Position CFM h1 h2 h3 h4 h5 hu h7 hav Nuav
106 3492 614 7 1 6 7 84 8 13 8 33 7 85 4 88 7 87 4562 107 4395 7 86 894 964 996 1005 9 64 640 9 65 56 06 108 50 75 9 11 10 22 1081 1112 1125 1085 7 24 1085 63 16 109 G 1344 9 22 1042 1120 1 1 46 1173 1131 7 04 1120 63 87 110 1936 1162 1340 1442 1474 1509 14 7 3 9 09 1441 82 77 111 2846 1631 1797 1902 1966 2027 2079 1342 19 2 3 11108 112 3484 207e 2144 2236 2307 2385 2574 1694 2268 13138 113 4066 24 65 24 42 2535 2648 2757 31 71 2178 2 5 96 15078 114 50 12 3059 2916 30 1 5 3176 3312 4059 2849 3105 180 46 115 1D 1362 2268 26 13 2613 26 35 2605 2503 15 46 2617 14934 116 1958 2993 3580 3580 3586 3539 3 5 02 2144 3571 20492 117 2812 4430 50 32 4913 4 9 86 4991 5196 3088 4981 287 66 118 3432 58 16 62 13 6067 61 18 60 66 6698 4143 61 16 354 16 119 40 22 71 71 7 4 62 7369 7419 7329 82 74 51 8 1 7395 42909 120 5026 105 95 11456 115 81 11574 11548 14010 80 91 11540 671 15 121 2D 1244 18 57 2277 2363 2305 2210 2107 1466 2289 13038 122 1960 2622 3240 3388 33 23 3226 31 40 2)99 3294 18919 123 2817 3762 45 87 4739 46 56 45 14 4 6 47 30 15 4624 26689 124 3491 50 22 5723 58 53 57 44 5542 60 18 3871 57 16 330 73 125 4096 61 29 68 16 69 79 6805 65 90 74 79 4677 67 98 39400 126 5037 82 27 94 60 95 69 93 57 9023 11324 65 05 93 52 542 83 127 12D 1278 14 70 1 6 48 1652 1638 1 6 34 1641 9 73 1 6 43 9369 128 1947 19 63 2155 2149 2151 2131 2190 1347 2147 12342 129 2769 2615 2791 2773 28 52 2716 2954 18 96 2783 1 60 82 130 3439 3208 3265 3239 3593 3133 3624 2515 3308 19174 131 4103 3637 35 88 3577 4077 3459 42 66 3138 3676 21343 132 49 78 45 82 44 60 44 8 1 55 17 43 25 5749 4227 4700 27288
Q) tlgt
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
133 1 12D 1299 2094 2507 2622 2625 2567 2489 1465 2578 14736 134 1973 29 56 3505 3772 3790 3718 3718 2115 3700 21290 135 2788 3941 4727 5069 5099 5 0 07 5231 2984 4976 28781 136 3473 5155 59 81 6308 6339 62 39 68 96 4204 6217 36052 137 4118 6135 71 8 6 7662 7731 76 91 87 16 49 8 5 7568 43985 138 4973 7765 94 75 10396 10861 10694 13646 66 64 10357 602 25
139 1ttn 1253 1242 1493 1460 1442 1431 1424 8 84 1457 83 01 140 2366 1942 2150 1961 1910 1897 19 62 1206 1980 11400 141 3461 3007 2957 2562 2513 2606 3143 18 51 2660 15400 142 4325 3942 3571 3060 2999 3198 4248 2631 3207 18618 143 5677 508 6 4359 39 88 3800 42 29 57 78 36 26 4094 23824 144 67 59 64 55 5330 4988 47 25 5494 2517 48 09 5134 29906 145 84 08 9326 72 26 7726 85 56 9172 12319 7733 8170 47626 146 86 54 9831 7582 818 9 94 90 9869 13116 78 97 8783 512 96 147 7376 7335 58 7 6 5941 5796 68 29 81 65 5954 6111 35662 148 2 11 D 4254 4106 48 02 4994 5038 5042 56 78 3419 4969 28881 149 5708 5487 6253 6466 6524 6527 78 63 45 8 2 64 43 37566 150 69 7 8 7983 9440 9848 98 34 97 32 13249 6701 9714 566 59 151 1254 1434 18 53 1947 1915 1850 1760 1186 1891 10772 152 2713 2696 3175 32 94 3288 3237 3288 20 44 3249 18728 153 87 30 118 07 14733 15758 15504 15305 26297 9617 15325 892 71 154 5811 5278 6543 6861 69 30 69 82 7 8 74 4478 68 29 39531 155 4246 3780 4736 4975 49 66 4936 5162 3113 4903 28301 156 (v 1270 8 15 935 959 966 9 51 9 23 6 35 953 5430 157 2714 1164 1390 1427 1447 1454 1455 9 08 1430 8242 158 4310 1655 18 96 1942 1988 2002 2111 1305 1957 11349
(j) ~
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 fry hav Nuav
159 6012 2208 2400 2450 2513 2548 28 20 18 00 2478 14416 160 7279 2696 2881 2927 2989 3081 3599 2340 2970 17326 161 86 90 3257 3360 3 3 76 34 26 3558 4455 2943 3430 2000 162 12D 4368 2209 2600 2558 2518 2466 2774 1753 2536 14713 163 5833 2730 3092 3028 2974 2913 3501 2287 3002 174 78 164 7643 3320 3681 3630 3651 3530 4623 3181 3623 21116 165 87 39 3920 4303 4300 4708 4178 61 60 3937 4372 25456 166 1268 962 1203 1205 1186 1118 1084 725 1178 6693 167 2678 14 67 1785 1779 1752 1698 1726 10 70 1754 88 49 168 1 12D 12 83 936 1217 1414 1397 1239 1190 7 65 1317 7484 169 2729 2502 2930 2914 2934 2956 2979 17 52 2934 16866 170 4345 3884 4357 4283 4318 4421 4836 28 59 4345 25151 171 6036 5546 5858 5764 5791 6028 7129 4184 5860 34045 172 6578 7167 7769 7907 79 82 8263 10492 5915 7980 46437 173 87 84 10237 112 23 120 26 12727 12968 185 19 85 98 12236 71103 174 1278 1344 1803 18 72 1835 1790 1712 1063 1825 10355 175 2711 2328 2972 2932 2893 28 78 2863 1667 2919 167 51 176 4351 3934 4414 4353 4281 4321 4654 28 63 4342 25088 177 5994 5076 5824 5838 5818 59 29 6914 4205 5852 33885 178 1 11 U 1223 388 432 465 464 449 435 338 453 2585 179 2351 521 602 6 22 675 6 57 619 436 639 3687 180 34 48 6 05 1725 803 8 27 8 11 760 518 792 4593 181 4513 718 850 934 9 68 9 57 8 99 609 9 27 5386 18 2 5714 8 32 981 1060 1102 11 06 1034 6 59 1062 61 82 183 6997 1025 1182 1258 1295 1309 1234 8 18 1261 7 3 44 184 8709 1295 1487 1 5 42 1594 1626 1612 1156 1562 9080
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
185 2 12D 4249 3560 4400 4670 4791 4695 47 81 2931 4639 268 37 186 5737 4926 58 54 61 92 6248 62 38 67 78 4134 6131 35590 187 7432 6390 7726 83 46 85 44 86 34 10371 5658 8313 48310 188 8723 7718 107 88 11933 12099 13046 186 22 79 39 119 67 69505 189 1 4 35 1340 1735 18 57 18 52 17 81 1711 1144 18 06 10256 190 2718 2399 3023 3187 3207 3138 30 53 1931 3139 18025 191 7 5 07 6189 80 11 9200 9427 9703 11364 5720 9085 527 38 192 8544 78 42 10666 125 42 13312 13775 178 20 6976 125 74 729 86 193 1287 1417 16 97 18 7 18 69 18 08 1720 1046 1800 10223 194 27 17 2450 2940 3187 3214 3157 3054 1749 3125 17954 195 42 53 3560 4222 45 90 4679 46 63 4743 2741 4539 26247 196 6068 48 69 57 79 6335 65 8 6 66 04 7172 4338 63 26 366 78 197 7389 58 86 72 8 6 82 23 8584 8936 10658 50 60 8257 4798 6 198 86 88 78 91 100 27 120 56 130 29 14299 190 81 6492 12353 71850 199 5864 4694 5 6 67 61 94 6419 65 48 7192 3950 6207 360 14 200 2 D 4177 38 36 4547 48 09 4775 4628 5006 2715 46 90 261 30 201 5712 5170 62 39 66 38 6599 6604 7518 4167 65 20 378 00 202 73 63 7201 8986 98 43 9733 9914 13353 6219 9619 55810 203 8604 10043 13118 148 41 150 42 158 66 25206 82 5 3 14717 85290 204 12 68 1506 18 41 1971 1966 1868 1799 11 42 1913 10880 205 2659 2571 3127 3276 32 50 3130 3069 18 80 3196 18 350 206 39 80 36 76 4347 4573 45~67 4473 46 34 28 37 4490 25910
o 207 Orifice 11496 10 64 1360 15 39 1 5 80 1 6 15 1496 8 58 15 24 88 83 208 9433 8 95 11 78 13 26 1394 1386 1263 727 1346 78 48 209 7387 746 9 77 1123 1184 1159 1048 6 11 1111 64 74 210 52 36 566 7 66 900 934 909 8 21 499 8 27 48 02
0) CJ1
TABLE III Continued
Run No Position CFM h 1 h2 hs h4 h5 h6 h7 hav Nuav
211 212
3309 1293
414 257
563 3 19
6 68 3 57
6 91 3 37
6 72 351
7 37 337
38 4 2 46
4 40 341
3748 1942
213 214 215 216 217 218
c of 2nd 1 516 1235
1919 2712 3320 4153 4704
1532 2447 35 46 4312 5567 74 29
2 1 87 3312 4225 52 86 6902 8 6 50
2360 3555 4340 56 12 7 0 49 8 9 40
2409 3598 4 8 85 5718 7713 9593
2347 2101 35 33 3453 48 00 49 62 5562 59 86 72~6 7 8 79 93 76 11237
1243 20 64 3054 4 2 8 1 5114 6983
2326 35 00 4638 5545 7225 91 40
132 13 200 27 26672 31968 41711 52811
bull
67
TABLE IV
PRESSURE PROFILE DATA
Baffle Flow Qpening Rate ~p
(Inches) Position (CFM) (Inches 295 S G Fluid)
1 364 l2 11 U 1012 0 254 1248 0197 1493 0 141 1718 0112
c 1000 9 80 1210 1710 1436 28 75 1746 4320 1011 1080 1277 2050 1393 3020 1 6 28 4450
12D 1011 9 75 1236 1520 1450 2510 1603 3450
1 D 1011 975 1256 1700 1480 2690 158 1 4070
1 12D 1010 950 1259 1750 1462 2650 1631 3710
2 11 D 1124 1315 1360 2130 1505 2850 1689 4125
1 216 12U 1294 045 1949 0324 2374 0282 2704 0225 3367 0169
c 1326 265 18 81 5 90 2313 990 2731 1480 3439 2660
12D 1272 2 49 1957 661
68
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Pos ition (CPM) Inches 2 95 S G Fluid)
2559 1275 3033 1940 3639 3025
1 216 1nD 1257 242 16 96 476 2117 8 05 2561 1280 2990 1895 3431 26 bull00
1 316 12U 1309 0 479 2004 0422 28 28 0 352 3526 0281 42 28 0225 5199 0225
c 1308 1 43 1998 272 28 14 5 10 3478 795 4248 1235 5048 1885
l2D 1286 140 2005 3 45 2831 725 3495 1180 4194 1805 5046 2945
1 11D 1322 150 2039 352 2841 735 43 77 1980 5378 3440
1 516 12U 1278 0493 2732 0493 4315 0408 5744 0352 7494 0352 8932 0422
c 1300 0 506 2731 1985 4310 348 6080 6 45
69
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Position (CPM) (Inches 295 SG Fluid)
7607 1090 8830 1585
l2D 1343 0549 2738 225 4566 583 6112 1195 7536 2055 9043 3415
1 516 1uD 1249 0464 2713 224 4155 579 5620 1150 7428 2115 90 70 3405
1 12D 1301 0493 2735 220 4501 616 61 50 1235 7440 2065 8862 3445
2D 1265 0 478 2750 226 4366 594 6578 1270 7678 2240 8945 5280
2 12D 1295 0493 2725 222 4293 600 5807 1120 7568 2200 9070 3615
TABLE V
RATE OF HEAT TR AN SFER Ar THE BAFFL~~ CID-TT ER
Orifice Size
(Inches)
Flow Rate
( CFM)
Re d e G tU
R~) 055 Nuav NuPr-l3
1 364 10 26 12 90
8 075 10015
43400 54 600
85 11 99 64
95 83 112 19
1416 11 140 59 900 110 30 124 20 16 27 12 800 68 900 126 64 142 60 17 29 13 610 73 200 135 79 152 90 17 76 13980 75 200 147 59 166 19
1 216 11 35 14 06
8 600 10 660
27000 33500
6 4 96 76 56
73 14 8 6 12
1517 11500 36100 82 51 9291 20 34 15400 48400 10229 115 18 23 11 17500 55000 118 31 13322 2348 17 800 55900 11947 13452 2666 20 200 63400 13508 15210 27 16 20 600 64700 135 05 152 07 32 47 24600 77200 161 57 18 193 3392 25 700 80700 17390 195 8 1
1 316 1344 19 36
9898 14 260
24800 35 700
63 8 7 8 2 77
71 92 93 20
28 46 20 9 60 52 500 111 08 125 08 34 84 25 660 64200 131 38 147 93 40 66 50 12
29900 36900
74800 92400
150 78 18046
169 78 203 20
~ 0
TABLE V Continued
Orifice Flow Re Size Rate d e G R~rmiddot55 NuPr-13(Inches) (CFM) U Nuav
1 516 12 70 8 847 16800 54 ~0 61 14 2 14 18 900 35800 82 42 92 80 43 10 30 000 56900 11349 127 79 60 12 41900 79400 14416 16232 7279 50700 96100 17326 19509 86 90 60540 115000 20098 22529
TABLE VI
RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
Orifice Size
(Inches)
1 364
1 216
1 316
Flow Rate
(CFM)
1054 1294 1431 1681 1770
1068 1399 1669 1959 2295 2636 3390
1299 1973 2788 34 73 4118 4973
Re deG Mshy
8 300 9870
11260 13200 13 930
8100 10600 12650 14850 17400 19980 25700
9 570 14500 20500 25600 30300 36600
R~r-6 51900 61700 70500 82 500 87 100
28200 36900 44000 51700 60 600 69500 89400
26100 39600 56000 69900 82700 99 900
Nuav
2416 293 5 3187 4018 4805
14938 18968 21712 25156 30680 37938 59601
14736 21290 28781 36052 439 85 60225
Uu Pr-1 3
27204 33050 3589 4524 541 0
16820 21358 24448 28326 34546 427 18 67111
16593 23973 32407 40595 495 1 678 13
TABLE VI Continued
Orifice Flow Re Size Rate deG R~rmiddot6 NuPr-13(Inches) (CFM ) M- Nuav
1 516 1268 88 30 17700 108 8 1225 2689 18700 37400 1835 2066 3980 27700 55700 2591 2917 4177 29100 58 500 2713 3055 5712 39800 80000 378 0 425 6 7362 51300 103000 5581 6284 8 604 59 900 120000 8529 9604
74
TABLE VII
EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER
l 516 Inch Orifice
Center ot 2nd Baffle 4 Downstream
Plow Rate (CFM)
1235 1919 2712 3320 4153 4704
Flow Rate (CFM)
1270 2714 4310 6012 7279 8690
(Re)eb -8600 1321
13400 2003 18900 2687 23100 5197 28900 4171 32800 5281
Center ot Single Battle
-8847 543
18900 824 30000 1135 41900 1442 50700 1733 60540 2001
(Nu)(Pr)-l3
1487 2255 3003 3600 4697 5946
(Nu)(Pr)-13
611 928
1278 1623 1951 2253
75
ABLE VIII
HEAT TRANSFER IN THE TEST SECTION WITHOUT ORIFICE
CFM Ute) 0b h Nu
1293 5-951 3 41 1942
33 09 15251 649 3746
5236 24193 827 4802
7387 34001 1111 6474
9433 43419 1346 7848
11496 52-914 1524 8883
76
TABLE IX
PRESSURE DROP FUNCTION
Orltlee Size Flow Rate incbea ~CFM (Re)eb X 10bull8
1 364 1011 7957 0808 1256 9885 1468 1480 11648 2765 1581 12443 4160 1689 1_3293 4 020
1 216 1257 9530 1327 1696 12858 2663 2117 16049 4615 2561 19415 7581 2990 22668 11560 3431 26011 16440
l 316 1322 9736 1819 2039 15016 4332 2845 20952 9275 3495 25739 15300 4377 32014 26800 5378 39607 50100
1 516 1011 7 957 oaos 1256 9885 1469 1480 11646 2765 1581 12443 4160 1689 13293 4020
77
TABLE X
EXPERIMENTAL DATA
Baffle Hole Diameter Run No
1 - 59
60 - 102
103 - 138
139 - 206
207 - 212
213 - 218
(Inches)
1 364
1 216
1 316
1 516
No Baffle
2nd - 1 516
TABLE X
EXPERIMENTAL DATA
Run Thermocouple Reading s (mv) No Position CFM I tc1 tc2 tc3 tc4 t c 5 tc6 tc7 tcair
1 c 1026 530 2055 1825 1768 1782 1802 1837 1965 1198 2 1290 612 2059 18 65 1809 18 32 1851 1880 1965 1160 3 1416 714 2151 1970 1931 1965 1988 2026 209 5 1130 4 1627 8 21 2235 2084 2 049 2093 2126 2173 2266 1130 5 1776 865 2203 2033 1970 2015 2084 2159 2 264 1121 6 12D 1109 542 1636 1507 1499 1499 1498 1498 1528 1218 7 1258 651 1670 1522 1503 1513 1513 1516 1548 1221 8 1433 750 1625 1480 1467 148 3 1487 1487 1516 1153 9 168 1 8 73 1656 1494 148 1 1511 1517 1517 1543 1159
10 1rtD 1102 485 1545 1450 1437 1446 1447 1442 1466 1220 11 13 08 6 10 1571 1470 1460 1476 1476 1469 1498 1194 12 1464 730 1 623 1509 1508 1528 1 5 32 1524 1548 1173 13 11 06 8 71 1663 1559 158 1 1606 160 6 1 583 1601 1190 14 1 12D 1115 520 1698 1579 1575 1 577 1580 1590 1615 1280 15 1275 6 10 1692 1567 1558 1 561 1570 1580 1601 1234 16 1498 770 1760 1619 1630 1 635 1642 1645 1661 1204 17 1695 912 1775 1635 1670 1689 1686 168 6 1701 1165 18 2D 1049 510 1736 15~2 1567 1558 1 553 1558 1620 1236 19 12 41 610 1655 1517 149 1 148 1 148 1 148 4 1546 1108 20 1 5 32 7 35 1720 1550 1530 1520 1519 1523 158 0 1104 21 16 74 8 8 0 1900 1 727 1714 1696 1691 1692 1753 1169 22 1U 1074 38 5 3 324 2740 2534 2478 2 465 2503 258 0 1210 23 1287 4 35 3510 2 870 2682 2 610 2599 2638 27 1 9 1190 24 1 5 08 470 3 618 2920 2690 2 637 2627 2 664 2747 1177 25 18 07 525 4 088 3235 2962 2905 2910 2988 3130 1169
z ())
TABLE X Continued
Run No Position CFM I tc1 tc 2
Thermocouple Readings te3 tc4 tc5
(mv) tc6 tc7 tcair
26 c 10~29 6 32 2340 2~092 2032 2060 2~097 2152 2~213 1211 27 12 66 679 2270 2 047 1993 2013 2069 2142 2 210 1 182 28 1430 723 2336 2097 2033 2080 2153 2~255 2 356 1 138 29 1729 8 52 2318 2070 1980 2061 2158 2279 2367 1121 30 12D 1054 570 1520 1 4 20 1402 1400 1396 1400 1 443 1159 31 1294 6 69 1599 1469 1444 1439 1433 1 442 1485 1168 32 1430 7 88 1720 1562 1536 1532 1528 1537 158 0 118 5 33 1770 8 81 1641 1488 1450 1~441 1 441 1_466 1518 1 163 34 1D 1058 548 1579 1498 1495 1526 1553 1_557 1 571 1 276 35 1263 640 1609 1509 1515 1570 1599 1598 1 598 1 266 36 18 36 8 47 1538 1452 1483 1553 1602 1 590 1 558 1195 37 1 12D 1029 5 41 1 578 1499 148 4 1473 1461 1465 1-512 1200 38 1315 6 30 159 1 1504 1493 1482 1470 1470 1505 118 5 39 1 4 26 743 1765 168 1666 1660 1645 1642 1678 1270 40 1757 8 54 1744 1648 1634 1620 1598 1 593 - 1612 1223 41 2D 1080 5 30 1734 1604 1570 1 570 1570 1 588 1 640 128 1 42 1305 6 40 1744 1622 1589 1 608 1593 1 609 1 661 1240 43 1434 750 1798 1687 1658 1 636 -1641 1 661 1 711 1_220 44 18 04 8 41 1 764 1666 1607 1605 1614 1 635 1 675 1205 45 12nu 1088 415 2614 2295 2195 2 169 2174 2217 2256 1171 46 1318 477 2805 2477 2371 2342 2364 2 401 2 438 1 163 47 1413 5 28 2930 2 646 2 555 2 526 2532 2570 2 577 1 199 48 1773 550 2740 2518 2450 2431 2448 2 479 2 480 1 170 49 1 11 U 1054 380 3175 2670 2505 2 461 2467 2 534 2 621 1 258 50 1240 420 3268 2738 2 546 2 510 2 508 258 2 2 649 1214 51 1419 451 3364 2B07 2 632 2590 2 590 2 651 2773 1 215 52 1 12U 1032 360 3 165 2 629 2 450 2402 2403 2 473 2 bull568 1 163
--I lt0
TABLE X Continued
Run No Position CFM I tc1 tc2
lhermocoup1e Reading s tc3 tc4 t c 5
(mv) tc6 tc7 tc a ir
5 3 1314 38 9 3178 2592 2411 2367 2361 2432 2555 1140 54 1448 403 3095 2544 238 1 2336 2336 2390 2476 1158 55 178 2 427 3006 2434 2286 2253 255 3 2299 2397 1154 56 2 11U 1061 360 3369 2814 2619 2567 2560 2650 2833 1220 57 1216 360 3044 2512 2338 2290 2288 2374 2566 1150 58 1322 387 3196 2614 2425 2383 2382 2472 2670 1138 59 1639 403 3020 2438 2272 2238 2238 2318 2502 1127
60 1D 1068 612 1552 1424 1400 1395 1396 1426 1745 0945 61 1399 612 1355 1246 1230 1229 1230 1250 1509 0872 62 1669 710 1436 1293 1272 1265 1266 1286 1551 0847 63 1959 900 159 5 1468 1444 14 38 1432 1446 1720 0851 64 2295 730 1169 1105 1098 1099 1108 1100 1298 0781 65 2636 8 80 1202 1129 1121 1126 1 138 1115 1342 0748 66 3390 9 35 1060 o 9s7 0999 1001 1017 0971 1154 0703 67 1nu 1190 370 2225 2188 2104 2080 2120 2209 2 7 15 0990 68 1559 368 2005 1950 1871 18 48 1876 1951 2408 0916 69 1904 368 1870 18 1 4 17 34 1711 1730 18 07 2238 0875 70 22 bull11 471 228 6 2 204 2099 2063 2092 218 $ 2732 0840 71 2289 471 2030 2000 1925 1895 18 96 19 5 2498 0785 72 2727 4 71 1854 18 23 1753 17 23 1716 3758 2241 0743 73 3210 471 1680 1651 158 6 1559 1551 158 1 1950 omiddot7o9 74 2uD 1210 404 1261 1212 1198 1197 1205 1222 139 1 0978 75 14 20 540 1321 1260 1242 1 240 1249 1268 148 7 0918 76 1692 7 18 1467 138 6 1364 1361 1376 1405 1678 0883 77 18 94 903 1708 1 591 1565 1560 1575 1603 1948 0 857 78 2301 903 1530 1432 1407 1402 1415 1432 1738 0815
ro 0
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc117 tcair
79 2621 6 50 1069 1 020 1009 1009 1009 1007 1~189 o739 80 3230 901 1200 1128 1113 1119 1119 1086 1341 0694 81 82
l2D 1155 1689
360 575
1191 1345
1142 1252
1122 1218
1118 1210
1118 1209
1132 1228
1292 1446
0916 0822
83 1244 430 1163 1134 1131 1130 1129 1132 1292 0877 84 2100 645 1175 1135 1147 1 142 1138 1122 1286 0757 85 2292 8 25 1 354 1310 1327 1330 1323 1285 148 6 0728 86 2907 8 23 1180 1138 1151 1158 1149 1107 1268 0687 87 3380 902 1113 1049 1025 1011 1006 1042 1178 0673 88 89
1 12D 1427 1875
480 615
118 2 1140
1140 1095
1124 1077
1125 1075
1129 1072
1137 1072
1290 1243
0880 0790
90 2259 8 41 1296 1231 1207 1206 1203 1182 1419 0757 91 2682 8 80 1231 1170 1149 1147 1142 1112 1350 0731 92 3417 940 1142 1092 1076 1076 1069 1021 1252 0693 93 c 15 17 431 1321 1298 1268 1249 1250 1273 1522 0841 94 2034 505 1285 1263 1235 1209 1205 1206 1464 0759 95 2348 6 10 1395 1379 1334 1302 1286 1268 1536 0732 96 2716 706 1486 1480 1427 1383 1358 1311 1572 0 700 97 3247 7 56 1417 1430 1375 1320 1284 1223 1450 0660 98 1135 400 1425 1388 1352 1329 1330 1 364 1651 0893 99 14 06 440 1379 1341 1304 128 2 1281 1305 1583 0 831
100 2311 680 1602 1593 1553 1514 1502 1480 1 7 27 0 802 101 2666 680 1471 1469 1428 1390 1372 1335 1564 0761 102 3392 798 1491 1 509 1449 1395 1372 1305 1534 0 719
103 1U 1235 410 2469 2295 2173 2165 2226 2361 3120 0 897 104 2010 410 2017 1848 1 737 1706 1747 1865 2582 0753 105 28 14 410 1682 1535 1457 1427 1437 1520 2109 0 660
00 t-
TABLE X Continued
Ru n Thermocouple Rea ding s (mv No Positi on CFM I tc1 tc2 tc3 tc4 tc5 tc6 tc7 tcair
106 3492 440 1649 1499 1420 1391 1390 1470 2042 0620 107 4395 550 18 33 1679 1597 1564 1570 1640 2223 0583 108 5075 588 1779 1642 1580 1550 1552 1 615 2 191 0548 109 c 1344 398 1464 1 399 1364 1353 1350 1380 1689 0 907 110 1936 459 1369 1290 1253 1242 1 237 1259 1574 078 2 111 2846 580 1347 128 5 1251 1232 1220 1215 1 5 23 0 683 112 34 8 4 700 1392 1369 1339 1317 1299 1259 1599 0 636 113 4066 8 13 1449 1458 1427 1391 1363 1270 1595 0 591 114 5012 930 1484 1530 1500 1453 1420 1272 1580 0 580 115 1D 1362 513 1269 1218 1 217 1214 1220 1238 1460 0 893 116 19 58 600 1187 1122 1121 1120 1124 1133 1352 0798 117 2812 705 1052 1008 1015 1010 1011 1001 1218 0691 118 34 32 913 1105 1075 1085 1081 1086 1047 1301 0645 119 4022 980 1038 1021 1026 1023 1029 0983 1211 0 609 120 5026 982 0 8 61 0839 0836 0836 0837 0791 0955 0570 121 2D 1244 475 1320 1246 1233 1240 1255 1275 1434 0925 122 1 9 60 5 50 1160 1088 1074 1079 1089 1100 1260 078 7 123 2817 6 80 1096 1024 1 013 1018 1029 1022 1201 0 700 124 3491 960 1248 1175 1163 1172 1192 1153 1435 0 658 125 4096 989 1141 1089 1078 108 9 1105 1051 1310 0629 126 50 37 989 0983 0933 0929 0 936 0949 0880 1090 0 602 127 128
12D 1278 1947
402 545
1270 1261
1 230 1216
1228 1216
1230 1 215
1235 1223
1242 1219
1483 1514
0 913 0778shy
129 2769 695 1273 1234 1237 1221 1251 1212 1525 0678 130 131 132
34 39 4103 4978
8 40 9 80 9 80
1336 1448 1271
1322 1458 1 288
1328 1 462 1286
1 259 1 356 1157
1353 1492 1311
1261 1329 1138
1 555 160 7 1343
0 629 0 600 0599
(l) l)
TABLE X Continued
Run No Position CFM I tel tc 2
Thermocouple Readings tc3 tc4 tc5
( mv) tc6 tc7 tcair
133 1 l2D 1299 5 16 1 28 1 1212 1196 1195 1205 1221 1478 0869 134 1973 6 15 1163 1098 1073 1071 1079 1083 1343 0751 135 136
27 88 34 73
802 9 -_78
1187 1214
1099 1131
1069 1104
1066 1101
1075 1~110
1l061 1066
1370 1360
0662 0618
137 4118 9 81 1084 1010 0983 0979 0982 o937 1209 0581 138 4973 98 1 0969 0897 0 868 0855 0860 0799 1041 0572
139 1D 1253 409 1371 1293 1298 1301 1309 1321 1578 0928 140 2366 480 1130 1 090 1 121 1130 1137 1132 1390 0744 141 34 61 6 38 1081 1086 1152 1161 1147 1069 1382 0644 142 143 144
4325 5677 6759
7 90 939 998
1110 1115 1034
1161 1208 1139
1253 1268 1180
1265 1302 1215
1228 1230 1123
1080 1056 0970
13$913r12 8
0601 0561 0542
145 84 08 989 0863 0961 0934 0895 0871 0 785 09 9 0530 146 86 54 9 80 0808 0901 0 872 0821 0809 0733 0891 0498 147 7376 9 80 0 927 1032 1027 1 040 0961 0889 1032 0511 148 2D 4254 776 1 050 0 981 0965 0961 0962 0922 1155 0579 149 5708 991 1102 1031 1014 1009 1010 0931 1227 0528 150 69 78 990 0914 0853 0839 0 839 0843 0759 0996 0521 151 1254 490 1 479 1352 1329 1334 1351 1379 1607 0930 152 2713 7 00 1310 1220 1201 1201 1211 1209 1516 0723 153 8730 991 0809 0756 0742 0745 0 748 0663 0874 0543 154 5811 966 1219 1108 108 6 1081 1079 1033 1330 0650 155 42 46 8 02 1248 1136 1114 1114 1118 1103 1376 0 699 156 c 1270 429 1671 1571 1551 1545 1563 1600 1933 0929 157 2714 488 1398 1285 1 267 1258 1262 1275 1628 0729 158 4310 642 1424 1318 1299 1282 1283 1261 1683 0617
co ~
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc7 tc a 1r
159 60 12 780 1461 1388 1370 1349 1343 1279 1700 0 573 160 72 79 8 60 1402 1344 1330 1312 1292 1189 1 566 0 520 161 8690 982 1472 1442 1437 1 422 1392 1224 1602 0 521 162 163
12D 4368 5833
6 30 8 30
1195 1368
1105 1270
1111 1283
1117 1294
1131 1313
1081 1194
1369 1553
0613 0 553
164 76 43 959 1428 1338 1348 1341 1371 1180 1488 0535 165 8739 984 1345 1272 1272 1208 129 3 1059 1361 0550 166 1268 459 1701 1548 1541 1547 1589 1 625 1976 0 973 167 2678 570 1485 1351 1349 1356 138 1 1 385 1795 0760 168 169
1 12D 128 3 2729
448 650
1664 1314
1501 1232
1425 1233
1428 1229
1491 1229
1527 1232
1869 1571
0 962 0767
170 4345 847 1245 1179 1187 1182 1172 1132 1476 0 650 171 6036 9 76 1139 1109 1117 1114 1095 1020 1332 0588 172 6578 9 72 0982 0949 0942 0938 0926 0 8 50 1079 0560 173 87 84 9 72 0880 0854 0 8 36 0822 0818 0 749 0941 0585 174 1278 480 1564 1416 1397 1403 1417 1445 1733 0998 175 2711 590 128 3 1175 4 1178 1182 1187 1195 1493 0796 176 4351 8 90 1331 1259 1266 1275 1272 1235 1592 0 682 177 5994 9 60 1228 1152 1150 1151 1143 1075 1 360 0644 178 lU 1223 408 2282 2140 2052 2052 2106 2188 2626 0 878 179 2351 408 178 1 1623 158 5 1519 1556 1634 2068 0717 180 3448 482 1888 1675 1570 1541 1572 1665 2199 0629 181 4513 563 2026 1797 168 4 1644 1670 1770 2385 0583 182 5714 589 1913 1700 1610 1568 1580 1 682 2382 0551 middot 183 6997 653 1903 1718 1643 1611 1612 1700 2326 0 549 184 8709 6 80 1738 158 3 1543 1510 1498 1519 1 912 0577 185 186
2 12D 4249 5737
660 9 74
1055 1221
0 979 1122
0960 1093
0 952 1088
0959 1090
0 956 1054
1147 1350
0661 0602
187 7432 9 8 1 1065 0981 0951 0942 0 939 0881 1135 0582 CD ~
TABLE X Continued
Run No Position CFM I t o1 to 2
188 87 23 9 83 0944 0 879 189 1435 585 18 26 1630 190 2718 690 1433 1298 191 7507 950 1070 0961 192 85 44 964 0982 0 881 193 1287 600 1806 1668 194 2717 7 80 1579 1444 195 4253 8 81 1371 1260 196 60 68 9 78 1252 1152 197 73 89 975 1100 1000 198 86 88 973 0953 0 871 199 58 64 9 81 1269 1155 200 2D 4 1 77 915 1362 1251 201 5712 975 1213 1111 202 7363 9 78 1036 0 951 203 8 604 973 0932 0861 204 1268 6 95 2015 18 20 205 2659 6 96 1405 1295 206 39 80 7 98 1261 1174
No 207 Orifice 114 96 509 1325 1148 208 94 33 509 1477 1243 209 7487 5 09 1686 1409 210 5236 505 2094 1691 211 3309 428 2188 1 778 212 1293 392 2976 2560
Thermo ooup1e Readin g s (mv) to 3 to4 to
5 to
6 to7 toair
0 851 0847 0 8 29 0759 0987 0592 158 4 1583 1611 1647 1993 0986 1270 1266 1 279 1298 1604 0 789 0916 0908 0900 0 858 1115 0602 08 39 0 823 0 818 0 770 1035 0602 1609 1602 1629 1676 2153 0979 139 1 1385 1400 1 430 1938 0776 1212 1201 1205 1201 1601 0669 1 105 1086 1086 1 052 1371 0621 0952 0936 0923 0870 1195 0582 0 8 20 0 801 078 1 0 729 1044 0569 1108 1090 108 2 1043 1407 0610 1218 1221 1241 1202 1582 0659 1081 1083 1084 1031 1 368 0622 0921 0924 0919 0 841 1111 0 610 08 34 0831 0 821 0 751 1003 0 630 1761 1761 1 809 1861 2399 0966 1271 1271 1295 1311 1650 0797 1150 1150 1161 1149 1440 0703
1083 1057 1053 1109 1566 0~530 1158 1125 1138 1217 1763 0 526 1291 1250 1278 1383 2038 0542 1518 1478 1519 1657 2420 0 589 1596 1557 1601 1737 2441 0688 2370 2344 2409 2561 3 297 0921
()) (11
TABLE X Continued
Run Thermocouple Readings (mv) No Position CFM I tc 1 tc2 tc3 tc4 tc tc tc tc i5 6 7 a r
C of 2nd 213 516 1235 4 63 1 432 1291 1265 1258 1 268 1 308 1550 0 971 214 1919 6 17 1357 1223 1196 1191 1199 1211 1461 0 851 215 27 12 8 35 1401 1259 1278 1220 1230 1218 1511 0 762 216 3320 981 1439 1305 1270 1259 1275 1238 1450 0719 217 41 53 980 1251 1142 1132 1094 1121 1088 1305 0 695 218 404 987 1102 1042 1030 1 bull006 1014 0960 1133 0681
Supplementary Equations
Calculating temperatures from thermocouple readings
t = -026tc)2 + 3512(tc) + 3201 (26)
where t is the temp in deg F and tc is the thermocouple reading in millishyvolts
Calculation of the thermal conductivity of air
k = 00000245ta + 0 0132 (27)
where k is the thermal conductivity in Btuhr rt2 degFft and ta is the air temp 1n OF
I I
bull co m
17
CHAPTER IV
EXPERIMENTAL PROGRAM
The experimental program was designed to measure the
heat transfer coefficients and pressure drops in the vicinshy
ity of annular orifices The four orifice sizes studied
were 1 364 1 216 l 316 and 1 516 inches~ The inner
tube used in each case was a 1-in OD alumintim tube
Hence tube to baffle clearances were respectively 3128
232 332 and 532 of an inch
Heat transfer coefficients were measured at poait~ons
1 i nch upstream at the orifice center and at 12 1
1 12 and 2 inches downstream for all orifices In addishy
middottion the heat transfer coefficient at a point 2 12
inches downstream from the 1 516 inch orifice was measured
and at the points 12 l 12 and 2 inches upstream from
the 1 364 inch orifice
The heat transfer coefficients at each point were
measured at five different flow rates for the 1 364 inch
orifice and at six different flow rates for the other orishy
fice sizes The high pressure drop through the small orishy
fice size limited the number of flow rates which could be
studied
The flow rate was calculated from the pressure drop
across the flow orifice This flow was corrected to cubic
feet per minute at 68degF and one atmosphere pressure by
18
using the orifice pressure and the test section pressure
which were measured by pressure gages
It was desired to determine a relationship between the
heat transfer coefficient and the total pressure drop for
each orifice size The pressure drop across each orifice
at various flow rates was measured by means of the presshy
sure probe described in Chapter III It was also desired
to obtain pressure profiles for each orifice size since
these might be similar to the heat transfer profiles The
pressure drop was measured from a point 13 inches upstream
of the orifice to points at 1 and 12 ineh upstream the
orifice center 12 1 1 12 and 2 inches downstream
The experimental program is summarized in Table I
TABLE I
SUla~RY OF EXPER IMENTAL PROGRAM
Position Investigated-Distance from Orifice-Inches
Orifice Range of Flow Rate Size Heat Transfer Pressure Drop CFM at 68degF amp 1 atm
1 364 2U 1 12U 1U 12U c 12U C 12D lD 10 - 18 l2D lD 1 12D 2D 1 12D 2D
1 216 1U c 12D lD 1 l2D 2D 12U c 12D lD 10 - 35
1 316 1U c 12D lD 1 l2D 2D l2U C 12D lD 12 - 50
1 516 1U c x2D lD 1 l2D 1U 12U C 12D 12 - 90 2D 2 1 2D l D 1 l2D 2D 2 12D
20
CHAPTER v
EXPERI MENTAL PROCEDURE
The experimental procedure for measuring the heat
transfer coefficients ~d corresponding flow rates reshy
quired the following procedure
(1) Install the orifice size to be studied in the
test section
(2) Place the heat transfer probe in the position up
or downstream from the orifice where the middot heat
transfer rate is to be studied
(3) Fill the cold junction thermos with cracked ice
(4) Measure the atmospheric pressure
(5 Open bypass line from blower and close line to
test section
(6) Turn on the cooling water for the exchangers used
to cool the air leaving the blower
(7) Start the automatic selen ium rectifier by turning
on the t 1mer bull
(8 ) Connect the voltage stabilizer to the wall outlet
(9) middot Set the slide wire resistor to the maximum re shy
s1atanee I
(10) Start the blower
(11 Open the line to the test section until the de shy
sired flow rate is obtained
(12) Switch on the probe direct current power source
21
(13) Adjust the slide wire resistor to obtain the
desired current
(14) After the thermocouples have reached equilibrium
values record the e m bullf across each of the
seven probe thermocouples and also the entering
air thermocouple
(15) Record the direct current amperage
(16) Record the gage pressure at the flow orifice and
the entrance to the test section
(17) Record the manometer measurement of the pressure
drop across the flow orifice and also the presshy
sure drop through the test section
22
CHAPTER VI
CALCULAT ION OF EXPERIMENTAL DATA
The local heat transfer coefficients were calculated
from the temperatures measured on the probe surface the
air temperature and the current input The results were
calculated by using the Alwae III-E computer
The general expression for calculation of the heat
transfer coefficients was derived by Ambrose (1 p 79)
The equation is derived by making an energy balance around
a small increment of the center resistance heating ribbon
The two ribbons tnstalled adjacent to the center ribbon
reduced the amount of logitudinal conduction and assured
little longitudinal temperature variation in the center
ribbon
A heat balan ce on this small increment of resistance
ribbon yields the following
(the heat conducted in) + (heat generated) = (heat
conducted out) +(Heat convected to the fluid) + (heat
radiated to the surroundings) + (Heat conducted into
the plastic center of the probe)
This gives the equation
kzw dtdS + 12RdS kzws [ t + (~) ds] + hwdS (t-ta )
+ ~Aad wd o middot+ qcAond 1 -~- wdS 5 )
23
Hence solving for h gi~ea
i2R kz d2t Qrad qcond w + -d$2 - ~- A
h = ( 6)t - ta
Since S = re where 9 equals the enclosed angle ~n radians
dS rd9 ( 7)
and
dt - dt (8)dS - rd9
Differentiating with respect to S
d2t (9)rd9dS
from which
(10)
Substitut1ng into the equation for heat transfer coeffishy
cient gives
h = i2R Qcond A (11)
w
The rate of radial heat conduction into the plastic
tube making up the probe was assumed to have negligible
effect on the heat transfer coefficient It was also
assumed that the heat loss by radiation from the ribbon
was negligible since all data were obtained with the ribbon
at a temperature less than 125degF
24
When t he rad iation and conduction terms are neglected
Eq (11) becomes
(12)
The following con stants are known
R = 0 271 ohmsft
w = 100 i n ches
k = 763 Btuhr rt2 degFft
z = 0 002 inches
r = 12 inch
Eq (12) putting 9 in degrees then reduces to
1110 12 + 2404 d 2t d92
( 15)h = ------~--~-------t - ta
Thi s equation was programed for the Alwac III- E comshy
puter and used to calculate the local heat transfer coefshy
ficients from the observed data
The average heat transfer coefficient around the tube
at a given position in the t est section was calculated by
averaging the local coefficients calculated from Eq (13 )
It was found 1n the course of the experimental work
that thermocouple numbers 1 and 7 were indicating higher
temperatures than would be expected This resulted in h1
and ~ being lower than the other local coefficients around
the tube Since the fluid was flowing parallel to the axis
of the probe the circumferential variation i n rate of heat
25
transfer should be small Hence in obtaining the average
coefficient around the tube the values of h1 and h7 were
not used even though they were calculated and are tabulated
1n Table I II in the Appendix
Then
(14
A Nusselt number as calculated from this aver age heat
transfer coefficient using the tube diameter as the characshy
teristic dimension
(15)
The air flow rates through the test section were calshy
culated by measuring the pressure drop across the flow orishy
fice the air temperature the pressure at the flow orifice
and the pressure at the entrance to the test section The
orifice calibration curves (1 p 166 ) were used to obtain
a value of the orifice coefficient f8e where Q equals
the flow in cubic feet per minute at 68deg F and one atmosmiddot
phere pressure and te is the density of air at the exchanger
and e the density of the air at the flow orifice The
den sity of the air can be expressed by
e = 2 703 p (16)T
where T equals the temperature in OR and P equals the absoshy
lUte pressure i n lb1n2 Using the value of e Qfo from
26
the calibration charts as A and Eq (16) solving for Q
gives
( 17
This equation was used to calculate the flow rate for
each flow studied
The Reynolds number used i n the correlation of the
data was the equivalent Reynolds number defined as
Re)eb ~ d2 - dl)Uf ( 18 ) lL
where d1 is the outside diameter of the inner tube and d2
is the orifice diameter U is the flow velocity through the
annular orifice e is the density of the air and U- is t he
viscosity of the air This equation can be transformed t o
(Re) b = 1611 Q (19) e dl + d2
where d1 and d2 are in inches
The pressure drop data were calculated i nto a dimenshy
sionless pressure drop function cent where
d1 )22( ~ P)gc f av(d2 shycent 2 bull (20
M-
For air this equation reduces to
where d2 and d1 are in i nches D P is expressed i n inches of
2 95 specific gravity fluid and P av is expressed as lbft3
27
CHAPTER VII
ANALYSIS OF DATA
In analyzing the heat transfer data an attempt was
made to correlate it 1n terms of the dimensionless groups
(Nusselt number Prandtl number and Reynolds number) which
appear in Eqs (3) and (4) Consequently all of the av~
erage heat transfer coefficients hav were brought into
the form ( Nu)( Pr)~3 bull The Nusselt number was based on the
tube diameter and the thermal conductivity of the air at
the flowing temperature The tube diameter was used in the
Nusselt number because comparison could then be made with
previous experimental work on heat exchangers which have
commonly used the Nusselt number defined as in Eq (15)
From the standpoint of dimensional analysis this is
equivalent to considering the tube diameter as the characshy
teristic length so far as the heat transfer is concerned
The Prandtl number of the air was taken as 0 7 in all
cases
Variation of Heat Transfer Rate with Distance from the Baffle
Considerable variation was observed in the rate of
heat transfer in the vicinity of the baffle In order to
obtain the variation with respect to position the term
(Nu)(Pr)-13 was plotted versus the flow rate Q for each
position and orifice studied Cros s plots were then made
28
at constant flow rates in order to obtain the variation of
(Nu)(Pr) -13 with position The resulting cross plots are
shown 1n Fi gures 5 6 and 7 for the four orifices studshy
ied
About one inch upstream from the orifice the heat
transfer coefficient begins to rise rapidly and continues
to do so until it reaches a maximum some distance downshy
stream After the maximum point the heat transfer coef fi shy
cient decreased slowly The heat transfer rate was found
to reach a maximum at a different position downstream for
each orifice size These figures also show that for a
given orifice size the maximum heat transfer rate occurs
a pproximately at the same point for all flow rates The
position of the maximum point f or each or ifice size is
shown in Table II
The region immediately downstream from the orifice is
one of h i gh turbulence due to the jetting action of the air
flowing through the orifice As the air flows t hrough the
orifice the streamlines continue to converge for some dis shy
tance downstream The point of maximum heat transfer is
probably at the point where the streamlines be gin to diverge
and a boundary layer begins to build up on the tube Tle
decreasing heat transfer coefficient beyond the maximum
point indicated the formation of a boundary layer
Since the position of the maximum point is independent
of flow rate middot it is possible to correlate it with respect
_ ct 11shyz-
100
0 136 ORIFICE
(
I 0
I )
~ 00
~p 0
I 0
--r--- ~
ISCFIII
-_ OCFM
rbull abull
~ middot~ a-1 z-
12fORIFICE
100
200
100
0 0 UPITRAM ORIFICE DISTANCE CENTER
CFM
h I DOWNSTREAM
DISTANCE
FIGURE 5 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLpound
30
too
700
800
100 ~ f gtf
400
z ~
100
100
100
0
13fORIFICE
~ -~ -- ---
)
~
~
-
I ~ ~OCFM
I vI~-~ OCFM
J ---
Iamp CFM
I 0 I I UPSTREAM ORIFICE DOWNSTREAM DIITANOE GENTER DIITANCI
FIGURE 6 VARIATION OF HEAT TRANSFER RATE WITH DISllNCE FROM BAFFLE
--
--- --
31
100
100
700
100
_ 100
f 9- 400 z-
100
tOO
100
0 - I 0 I I I UHTRIAM OAtfiCI DOWIIITMAM
+ I tyl6 ORIFICE
v I
~~ ~CFM
I v ~CFMI
v v 7
~~ v ~ iOCFM
- ~~ I-shy1-shy ~ICFM
DIITMCI OINTIR DIITANCI
FIGURE 7 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLE
32
TABLE II
POSITION OF MAXIMUM HEAT TRANSFER
Position of Maximum Orifice Size Heat Transfer
(inches) (inches downstream)
1 364 050
1 216 100
1 316 125
1 516 200
33
to orifice size Figure 8 shows the effect of the orifice
size on the position and value of the maximum heat transfer
at a constant flow rate of 15 cubic feet per minute It
can be seen that the larger the orifice size the further
downstream the point of maximum heat transfer occurs
Also as the orifice size increased the rate of heat
transfer decreased for a given flow rate The broken line
indicates the variation of the point of maximum heat transshy
fer with position and size The position of the point of
maximum heat transfer rate downstream from the orifice was
correlated with orifice size by means of the dimensionless
groups (Lde) and (d1de) where L is the distance downshy
stream from the orifice where the maximum rate of heat
transfer occurs d1 is the outside diameter of the inner
tube and de is the equivalent diameter of the orifice
ie de = d2-dlbull
Figure 9 shows a plot of Ld 6 versus d1d6 for the
four orifice sizes studied The four points on this logshy
log plot are approximately in a straight line and the
equation of this line is
Lde = 0 44 d1de)028 (22)
Although the above relationship represents a correlashy
tion of dimensionless groups it is based upon only one
tube diameter and needs to be substantiated further by
studying other tube diameters and other orifice sizes
34
aoo
400
aoo ~
-~ middot-CLshyJ z
200 -
100
0
ORIFICE CENTER
l~
l
t
I J~
1pound~
I
0 I I~
AT 15 CFM
-
bull ~ 1~6~
~ v~
~
~--~~6
~~~ ___ v v V -_
~ o q
~ I 16
v
~
ogWNSTREANI STANCE
FIGURE 8 EFFECT OF ORIFICE SIZE ON POSITION AND VALUE OF MAXIMUM HEAT TRANSFER
35
50
loshy____ -~
~ ~ -shylltl-shy~ r0
2 10 30
FIGURE 9 CORRELATION OF THE POINT OF MAXIMUM HEAT TRANSFER WITH
ORIFICE SIZE
36
Correlation of Data at the Baffle
The heat transfer data were correlated by obtaining a
relationship between the group (Nu)(Pr)-13 and a
Reynolds number based on twice the clearance (d2 - d1
between the tube and the baffle It was found that the
most satisfactory correlation could be obtained when the
term - d1 was used as the length term in the Reynoldsd2
number
Figure 10 shows the variation of the heat transfer
rate at the center of the orifice e xpressed as a function
of Reynolds number and the orifice size This shows that
for a given Reynolds number the heat transfer at the center
of the orifice is greatest for the smallest orifice size
In order to obtain a general correlation of the data
shown i n F1gure 10 the effect of the dimensionless ratio
d1de was considered This ratio considers all of the
geometric factor s needed to describe the annular orifice
The thiclaless of the orifice plate is also a factor but
was constant i n this i nvestigation
The data for the heat transfer at the baffle center
are shown in Figure 11 in which (Nu)( Pr)-13 is plotted
versus (Re)ebd1 de) 0 55 This data on a log-log plot
lies on a straight line for (Re)eb( dld8 )0 55 greater
than 3 x 104 The equation for cor relating the heat
37
4XI~middot~-r~------~--~~------~
Icf t--to_+--_c-c-________ SYMBOL SIZE
0 1~4
6 ~~
9 ~~ -o ~
(Re)eb
FIGURE 10 RATE OF HEAT TRANSFER AT BAFFLE CENTER
38
500
0
4 0 lcf
~ ~
~ ~iC-
~ ~
~IL 0~ 0 SYMBOL SIZE-
p 0 1364-
r 6 1~16 -~ -
9 1~16 --o 1~16
I I
FIGURE II CORRELATION OF HEAT TRANSFER DATA AT BAFFLE CENTER
39
transfer at the center bullOf the a nnular orifice was found by
the method of least s quares to be
(Nu)( Pr)-1 3 = 0018 ( Re)ebO Bl( dlde)04~ (23)
3 x 104 ltRe)eb(a1de)055 lt 105)
Rate of Heat Transfer at the Point of Maximum Heat Transfer-The heat transfer rate at the point of maximum heat
transfer is plotted in Figure 12 to show the variation with
Reynolds number and the size of the orifice It is shown
gives the h1gh st heat transfer ~ate at its point of maxibull
that for a given Reynolds number the smallest orifice size yen il
mum heat transfer
The data ~or the maximum poi~t could be correlated by
plotting (Nu) Pr)-13 versus (Re)eb(d1de)06 This plot
is shown 1n Figure 13 and the resulting eurve shows that
(Nu(Pr)-13 is not a simple p0wer function of the Reynolds
number as was the case for heat transfer at the baffle
center The reason for this is probably because other
factors such as intensity and scala of turbulence should
be considered At the orifice center the streamlines of
the flowing stream are converging_ and thus the flow is
quite stable Downstream from the orifice is a region of
large eddy currents and probably large scale turbulence
These factors could con ceivably cause the results which
were obtained for the point of maximum heat transfer
40
If)
~middotshy Q_-I z_
10~~~--------r----~~--~--
SYMBOL SIZE
0 13$4
6 1~8
Q 13-18
-o 1~8
7)(104
(Re)eb
FIGURE 12 RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
41
Ia ~
0 I
c ~ ~ c v
~ ~lt w ~
17
~ b
v ~ ( SYMBOL SIZE
-~ 0 f-64 -v ~ 6 t211e
~ Q I~~~
-o - l~rs I I
FIGURE 13 CORRELATION OF HEAT TRANSFER DATA AT THE POINT OF MAXIMUM HEAT TRANSFER
4 2
Effect of Upstream Baffles on Heat Transfer at the Orifice Center
The heat transfer rate at the orifice center using the
single orifice in a test section is a pproximately 13 of the
value that was obtained by Lee (7) using a model heat exshy
changer with orifice baffles Lee investigated the cent r al
baffles of the heat exchanger and thus the coeff icients he
obtained would be affected by the presence of a number of
upstream baffles To determine the effect of upstream
baffles an additional l 516 inch baffle was placed four
inches upstream 1n the test section The resulting data are
shown in Figure 14 where (Nu)(Prmiddot)-13 is plotted versus
(Re) eb for the case of a single baffle 1n the test section
and also the case of an additional baffle placed four inches
upstream Comparison is made with the results obtained by
Lee middot(7) using a four-baffle and a ten-baffle model heat exshy
changer Good a greement is obtained with Lees work and the
results show the marked effect that upstream baffles have on
the downstream heat transfer rate The additional up tream
ba ffle caused sufficient turbulence 1n the test section to
i n crease the heat transfer rate nearly three-fold at the
center of the next baffle
Heat Transfer i n the Test Section with No Orifice
In order to check the accuracy 6f the equipment the
orifice baffle was removed and the heat transfer mea sured
with the probe in the empty test section The data were
43
~~BAFFLES
0 l BAFFLE -shy
ll_9 2 BAFFLES
V 4 BAFFLES-LEE
4 10 BAFFLES- LEE lJf ~
~rv ~~ ~ v flvv ~~
I ~ J ~ L v
0
v
( V
40 3XIo 7XIa
(Re)eb
FIGURE 14 EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER AT BAFFLE CENTER
44
compared with heat transfe r coefficients predicted by the
equations for annuli which are recommended in the litera shy9
ture The two equa~ ions u sed tor comparison were
(hfe)=0 023 (rltGr e (~~ur4 (~r45 (24)
which was presente~ by Wiegant (10)
and ( h ) (cnM~5(M~l o14 o 023 CPG k j Mij - (de GJMb )0 2 ( 2 5)
which was presented by McAdams (8 p 242) The comparshy
i son is s hown in Figure 15 lq (25) gives a value which
is low by about ten percent while Eq (24) g ives values
which are high by as much as twenty -five percent when comshy
pared with the experimental data The se equations are gembull
erally considered to give coefficients with an accuracy of
about twenty percent Therefore the present experimental
data are within the accuracy of these equations Also the
plot indicate s that for a Reynold s number greater than 2 x
104 the slope of the line is the same for the experimental
data as for the equations
Pressure Drop Data
The total pressure drop across the orifice was measured
as a function of the flow rate and the orifice size The
pressure drop was expressed as a d1mens1onleas quantity r)
which ie plCltted ver sus the Reynolds number in Figure 18
The pressure drop function cent correlates for all or1f1oe
45
200
100
s z
10 5XI10 10
0 EXPERIMENTAL
--McADAMS
-WIEGAND L
V
~ ~ ~
P ~ ~
LL~ L
v~
~
v v
v 1 ~ ~ v
v -gt
~
~ ~
~
6Xid
FIGURE 15 HEAT TRANSFER WITH NO BAFFLE
46
0 1~4 -~ a 6 t216
Q t316 lJ J
-0 as a )t
A LEE I -shy SULLIVAN 8
p
10bull
BERGELIN
I _ll I
I ~
i I
~middot
lo II
f fl
J j
~middot
A)101
1q
I Ill
1 I3 X 10ao1
FIGURE 16 ORIFICE PRESSURE DROP FUNCTION VS REYNOLDS NUMBER
47
sizes- The present data extends the range covered by preshy
vious workers and agrees well with their work The preshy
vious work of Lee () for a heat exchanger containing 10
orifice baffles and also the data of Su livan and Bergelin
(9) for pressure drop in a model heat exchanger with a
single baffle is shown 1n Figure 16 long with the present
results~ This figure may be used to predict the preseure
drop from the equivalent Reynolds number of the annular
orifice
The pressure drop between individual points 1n the
vicinity of the orifice and an upstream pressure tap wa s
measured to obtain a pressure drop profile As might be
expected 1n all cases the profiles showed a rapid decrea e
in static pressure immediately upstream from the orifice
There was however little or no recovery of the pressure
loss downstream The 1 364 inch orifice did show a maxishy
mum point in the pressure drop but this maximum occurred at
the orifice center and total recovery was reached about 12
inch downstream
Heat Transfer at the Baffle and Maximum Point as a Function of Pressure Drop
In order to compare the effect of the total pressure
drop on the heat transfer at the baffle and the point of
maximum heat transfer Figure 17 was plotted showing
(Nu)(Pr)-13 as a function of the total pressure drop This
shows that for a given pressure drop the largest orifice
48
1200
1000
~ a -sshyz-
100
60 100 700
AT MAXIMUM POINT I 15116 2 13116 3 1~6 4 1364
AT ORIFICE CENTER
60
1
v
r ~ ~ ~
5
~
8 7
13116
8
~
1364
v
~
e6
1~6
v
~~ v ~ ~ -~ ~
~
~ v
l
~
vamp
I ~ ~
~
v L ~
v
I-
5
k= ~~
~ ~ ~
--I
v ~
FIGURE 17 HEAT TRANSFER AT THE BAFFLE AND MAXIMUM POINT AS A FUNCTION OF
ORIFICE PRESSURE DROP
49
size has the greatest heat transfer coefficient This is
true at both the orifice center and at the point of maxishy
mum heat transfer
Another comparison can be made by plotting the heat
transfer coefficient and the pressure drop versus the orishy
fice size at a constant flow rate Figure 18 shows this
plot This graph shows that at a constant flow rate the
pressure drop as well as the heat transfer coefficient
increases as the size of the orifice is decreased In
choosing an orifice size for maximum efficiency 1t would
be necessary to know the pumping power available as well
as the heat transfer desired
70 I I 700
AT 15 CFM 60 ---
~ aug
50 ---
NV
40 ~
~ ~ ~
~ _
MAXIMUM POINT ---- --- ~
1-----t---~ _
~00Qj ~
~t--- ORIFICE CENTER 10 1100
1---~ n
u0 01 02 03 Q35
a ltl
de inches
FIGURE 18 VARIATION OF HEAT TRANSFER RATE AND PRESSURE DROP WITH ORIFICE SIZE AT A CONSTANT FLOW RATE
cn 0
51
CHAPTER VI II
SUMMARY OF RESULTS
This study revealed several significant facts about
the heat transfer in the vicinity of annular orifices
Probably the most important contribution was the presshy
entation of the heat transfer profiles in the vicinity ot
the annular orifice ~ r s shown that t~ local heat
transfer coeffieient re~ches a maximum at a point downshy
stream from the orifice The distance downstream at which
this maximum oocurs is t1ven by the equation
22
The heat transfer coefficients at the center of the
orifice were correlated and found to follow the equation
(Nu)(Pr)-13 = 00176 (Re)eb08l(d 1de) 0 middot4~ (23)
3 x 104 lt( Re) 9 b( d1d6 )055 ltlo5 )
The heat transfer at the point of maximum heat trans
fer for each orifice size was correlated and presented in
Figure 13 as a plot of (Nu)(Pr)-l3 versus (Re)eb(d1de) 06
No simple po-orer relationship exists between the terms
Intensity and scale of turbulence downstream from the orishy
fice are probably important factors which affect the heat
transfer
The large effect of an upstream orifice on the heat
transfer rate at the second orifice was demonstrated by the
52
study of two 1 516 inch orifices in the test section The
added turbulence at the center of the second orifice was
found to raise the heat transfer rate almost three times
over that obtained for a single baffle
The pressure profiles in the vicinity of the orifice
indicate that nearly all the pressure drop occurs at the
orifice center~ Total pressure drop data were correlated
by a pressure drop function cent as a function of the Reynolds
number and good agreement obtained with the results of other
workers
The pressure drop and heat transfer data were correbull
lated by plotting the heat transfer as a function of the
pressure drop for each orifice size It was shown that for
a given pressure drop the largest orifice size gives the
greatest heat transfer coefficient
As a final presentation it was shown that the pressure
drop and the heat transfer coefficient both i ncrease i n
value at a constant flow rate as the orifice size is de shy
creased This is important in choosing the optimum clearshy
ance for orifice baffles
53
CHAPTER IX
RECOMMENDATIONS
A great deal of work remains to be done in the field of
evaluating shellmiddotside heat transfer coefficients This
study included only one tube size and air was the only f luid
used It is recommended that further studies be conducted
using other fluids and tube sizes It will also be necessary
to study several baffle types
The adde d turbulence due to a s e cond baffle placed upbull
s t ream would suggest that the heat transfer coef ficients at
a certain position i n relation to a baffle would increase as
the flow progressed through the exchanger It is recomshy
mended that an extensive s t udy should be made between baffles
the full length of a model heat exchanger
It is further recommended that the pressure drop study
be continued to include other fluids tube sizes and baffle
arrangements
Effects of turbulence downstream from the baff le should
be studied by i n vestigations with hot-wire anemometer equipshy
ment to determi ne t urbulence scale and i ntensity
54
NOMENCLATURE
Area of heat transfer
Heat capacity of the fluid
Outside diameter of the tube
Orifice diameter
Equivalent diameter of the orifice (d2 - dl)
Inside diameter of the test section
Inside diameter of the tube
Gravitational constant
G Mass velocity
h Local heat transfer coefficient
Coefficient of heat transfer from surface to fluid
i Direct current amperes
k Thermal conductivity of the fluid
L Distance downstream of the point of maximum heat transfer
p Absolute pressure
L P Total pressure drop across the orifice
Q Flow in cubio feet per minute at 1 atmosphere and 680 F
q Heat transferred
Thermal energy conducted into the sensing probe
Thermal energy radiated from the resistance ribbon
Resistivity of the resistance ribbon
s Length of the resistance ribbon
T Temperature oR
55
t Temperature of the resistance ribbon deg F
ta Temperature of the bulk stream oF
tw Wall temperature of the tube OF
U Veloc ity of the fluid
w Width of the resistance ribbon
z Thickness of the resistance ribbon
eeuro Density of the fluid in the test section
Density of the fluid at the flow orificef 0
AL Viscosity of the fluid
E9 Angle measured around the tube
Dimensionl ess groups
(Nu) Nusselt number hd1k
(Pr Prandtl number C~k
(Re)eb Equivalent Reynolds number at the baffle (d2 - d1 )uejt-Lshy
(Re)e Equivalent Reynolds number in the test section ( d 8 - d 1 )U fu
cent Orifice pressure drop function 2(~P ) gc~av(d2 - d1) 2
Al
56
BI BLIOGRAPHY
1 Ambrose Tommy W Local shell-side heat transfer coefshyficients in baffled tubular heat exchanger PhD thesis Corvallis Oregon State College 1957 183 numb leaves
2 Bell K J and o P Bergelin Flow through annular orif ices Transactions of the American Society of Mechanical Engineers 70593-601 1957
3 Colburn Allan P A method of correlating forced con shyvection heat transfer data and a comparison with fluid friction Transactions of the American Institute of Chemical Engineers 24 174-210 1933
4 Dittus F w and L M K Boelter Heat transfer 1n automobile radiators of the tubular type University of California Publications in Engineering 2443-461 1930
5 Gurushankariah M s Local shell-side heat transfer coefficients in the vicinity of baffles in tubular heat exchangers Masters thesis Corvallis Ore gon State Colle ge 1958 97 numb leaves
6 Knudsen James G and Donald L Katz Fluid dynamics and heat transfer New York McGraw-Hill 1958 576 p
7 Lee Kyu Sung Local shell-side heat transfer coeffishycients and pressure drop in a tubular heat exchanger with orifice baffles Masters thesis Corvallis Oregon State College 1959 118 numb leaves
8 McAdams William H Heat transmission 3d ed New York McGra ~-Hill 1954 532 p
9 Sullivan F W and 0 P Bergelin Heat transfer and fluid friction in a shell-andbulltube exchanger with a single baffle Chemica l Engineer ing Progress Symposium Series 52 ( 18) 85-94 1956
10 Wiegand J H Discussion on annular heat transfer coshyef f icients for turbulent flow Transactions of American Institut e of Chemical Eng i n eers 41147-153 1945
AP PENDIX
57
TABLE III
CALCULATED HEAT TRANSFER DATA
Baffle Hole Diameter Run No (inches)
1 - 59 1 364
60 - 102 1 216
103 - 138 1 316
139 - 206 1 516
207 - 212 No orifice
213 - 218 2nd - 1 516
TABLE III
CALCULATED HEAT TRANSFER DATA
Local Heat Transfer Coefficients Run
T0 bull Po s ition CFM hr h2 h3 h4 hs he ~ hav Nuav
1 c 1026 10 59 1476 16 09 1559 1510 1435 1203 1518 8511 2 1290 1369 1738 1878 18 05 1755 1689 1515 1773 9964 3 1416 1636 198 1 2068 1977 1924 1845 1715 1959 11030 4 1627 1991 2301 2382 2268 2194 20 ~98 1929 2249 12664 5 1776 2252 2669 2863 2713 2517 2338 2126 2620 14759 6 l2ttD 1109 2311 3317 3386 3373 3387 3394 3071 3371 18888 7 1258 3089 4583 4866 4683 4701 4643 4194 4695 26301 8 1433 38 8 5 55 83 5791 5495 5430 5436 5008 5547 31192 9 1681 4992 7378 7649 6980 6864 6870 64 28 7148 40180
10 1 D 1102 2371 3332 3511 3356 3342 3427 3102 3394 19012 11 1308 3218 4379 45 24 42 53 4255 4373 3965 43 57 24446 12 14 64 38 58 5146 5142 4839 4787 4903 4597 4963 278 79 13 1706 5218 6664 6269 58 81 5884 6237 5973 61 87 34718 14 15
1 l2D 1115 1275
2131 2661
2955 3638
2972 3720
2941 3675
2913 3576
28 22 34 74
2613 3278
2921 36 17
163 09 20246
16 1498 34 87 4644 4503 4441 4371 4343 4194 4460 25010 17 1695 4449 5743 5324 5222 5154 5157 5015 5320 298 97 18 2D 1049 1715 23 90 2550 2610 2656 2624 2208 2566 14363 19 1241 2117 2964 3145 3218 3221 3203 2759 3150 17757 20 1532 28 67 3936 4100 4188 4201 4167 3676 4118 23224 21 1674 3459 4508 4598 4746 4795 4792 4299 4688 26337 22 lU 1074 253 340 380 3 86 388 377 354 374 2097 23 1287 292 392 433 440 441 429 406 427 2394 24 1508 322 439 492 498 499 487 461 48 3 2713 25 18 07 3 38 464 519 5 24 520 499 463 5 05 28 40
~~ (]I agt
TABLE III Continued
Run No Position CFM h 1 h2 ~3 h4 h5 h6 ~ h
av Nu
av 26 c 1029 1171 1491 1589 15 28 1 4 62 1377 1293 1489 83 44 27 1266 1395 1746 1853 18 02 1685 1556 1453 1728 9704 28 1430 1637 2037 2175 2060 1909 1735 1591 1983 11159 29 1729 1982 24 96 2751 2507 2268 2030 1886 2410 13579 30 12D 1054 2934 4041 4321 4326 4423 4359 3706 4298 24160 31 1294 3385 4 8 26 52 42 5326 5450 5277 4566 52 24 293 50 32 1431 3784 5347 5721 57 bull75 58 44 5700 5084 5677 31870 33 1770 52 75 7 7 33 87 35 9005 9007 8267 7059 85 49 48050 34 lD 1058 3235 4401 4444 3877 3496 3451 3294 3934 21973 35 1263 38 98 5484 5330 4347 3964 3981 3987 4621 25823 36 18 36 6701 89 17 7855 6369 5597 5769 6283 69 01 38718 37 1 12D 1029 2404 31 8 2 3333 3459 3624 3577 3045 3435 19264 38 1315 3182 4033 4162 4310 4496 4502 4015 4301 24142 39 1426 3628 4389 4510 4573 4760 4804 43 8 5 4607 25678 40 1757 4547 5559 5(35 5931 6282 63 70 6060 5975 33471 41 2 11D 1080 2034 28 38 3155 3144 3145 2966 2540 3050 17027 42 1305 2650 3 4 87 3aoz 3595 3751 3595 3153 36 46 20405 43 1434 3167 39 07 4156 4371 4320 4126 3709 4176 23395 44 1804 4096 4 9 66 5691 5714 5586 53 15 48 65 5454 30582 45 12U 1088 409 516 557 564 5 60 535 513 5 46 30 67 46 1318 470 579 6 22 631 6 17 5 97 579 6 09 3422 47 14 13 540 640 676 6 86 681 6 60 6 54 6 69 3754 48 1773 641 740 774 782 7 69 749 746 763 42 87 49 l 11 U 1054 270 356 391 397 393 3 71 346 38 2 2133 50 1240 303 399 446 449 447 4 21 398 432 2420 51 1419 361 476 522 530 528 507 467 493 2760 52 1 1(2U 1032 236 311 342 347 344 325 301 334 18 78 53 1314 270 366 403 407 408 386 351 394 2217
(Tt tO
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ h av Nu av
54 1448 301 408 447 454 452 431 403 438 24 61 55 1782 353 494 548 544 415 529 531 506 2843 56 2U 10 61 220 287 316 320 322 303 268 310 1735 57 1216 249 335 370 377 378 353 307 363 2044 58 1322 263 356 394 398 399 374 327 384 2159 59 1639 310 433 478 481 482 452 393 465 2617
60 1D 10 68 2011 2536 2657 2681 2694 2560 15 62 2625 14938 61 1399 2520 3239 3369 3371 33r82 32 39 1946 3320 18968 62 1669 2781 3655 3820 38 76 3883 3738 2355 3794 21712 63 1959 3524 42 37 4399 4438 4497 4417 3047 4397 25156 64 2295 4426 5288 5396 5372 5240 5410 3369 5341 30680 65 2636 5490 6531 6662 6565 6379 6820 4249 6591 37938 66 3390 7869 9538 9462 9387 8924 10508 62 91 9564 59601 67 1U 1190 352 368 401 413 407 395 293 397 2256 68 1559 397 422 462 475 471 456 331 4 57 2603 69 1904 434 465 5 13 529 528 504 358 508 2901 70 2211 493 526 573 5 92 588 564 4 15 569 3257 71 2289 569 587 6 30 649 6 61 6 49 460 635 36 44 72 2727 637 6 60 7 09 733 751 743 521 719 4140 73 3210 728 755 8 15 8 43 8 62 8 54 616 826 4765 74 2nD 1210 181 2256 2393 2399 2333 2206 1325 2317 13158 75 1420 2340 2752 2899 2913 2850 2728 1701 2828 16121 76 1692 2853 3306 3452 3471 3379 3217 2134 3365 19217 77 1894 3102 3588 3713 3736 3670 3557 2455 3653 20892 78 2301 3682 4259 4433 4467 43 83 4289 2892 4366 250 30 79 2621 4117 4828 5017 5012 5030 5109 3071 4999 28785
m 0
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ hav Nuav
80 3230 5158 6006 62 13 61 18 6134 6695 4094 6233 359 87 8 1 12nD 1155 15 27 1854 2028 2064 20 85 1987 1164 1968 118 31 82 1689 2046 24 8 2 2688 2739 2760 2658 1749 2665 152 73 83 1244 2088 2317 2339 2345 2373 2381 1487 2351 13432 84 2100 3211 3539 34 21 3462 3512 3696 2575 3526 20284 85 2292 3 5 05 3761 3648 36 25 36 79 3957 2933 3734 21517 86 2907 4420 48 22 4679 46 04 4705 5206 3792 48 03 27741 87 33 80 59 35 69 38 7404 77 10 7 8 36 7 0 86 5190 7394 427 44 88 1 12D 1 4 27 2 4 58 28 31 3037 3021 2987 2927 18 57 2 9 61 16913 89 18 75 34 75 3 9 87 4230 4255 4317 4337 2734 4225 24258 90 22 59 4221 4796 5046 5052 51 01 5389 3491 5077 29206 91 2682 4978 5664 5943 5966 6054 6573 408 1 60 40 34795 92 3417 63 16 71 02 7 3 93 7385 75 40 8 6 95 51 45 7623 44017 93 c 1 5 17 1240 1305 1399 1467 1479 1429 9 26 1423 8251 94 20 34 1554 1623 1720 18 21 18 53 18 72 1215 1778 10229 95 2 3 48 1795 1843 198 5 2097 2171 2274 1540 2074 11947 96 2716 2028 2048 22 01 2 3 44 2444 2661 18 90 2340 13505 97 3247 2410 2375 2663 2778 2949 3298 2378 2793 1615 98 11 35 967 1040 1124 1186 1200 1142 728 1138 6496 99 14 06 1135 1220 1318 1384 1403 1 3 61 8 77 1336 7656
100 2311 1 8 54 18 78 1980 20 90 2136 2227 1653 2062 118 31 10 1 2666 2085 2094 2227 2 3 62 2438 2626 1902 2349 13508 102 3392 2635 2582 28 01 3026 3141 3529 2567 3016 17390
103 1 U 1235 349 395 434 436 4 28 411 286 423 2416 104 20 10 434 5 02 559 577 569 5 37 345 552 3177 105 28 14 538 626 685 711 7 21 682 424 6 8 6 3966
Q) j-J
TABIE III Continued
Run No Position CFM h1 h2 h3 h4 h5 hu h7 hav Nuav
106 3492 614 7 1 6 7 84 8 13 8 33 7 85 4 88 7 87 4562 107 4395 7 86 894 964 996 1005 9 64 640 9 65 56 06 108 50 75 9 11 10 22 1081 1112 1125 1085 7 24 1085 63 16 109 G 1344 9 22 1042 1120 1 1 46 1173 1131 7 04 1120 63 87 110 1936 1162 1340 1442 1474 1509 14 7 3 9 09 1441 82 77 111 2846 1631 1797 1902 1966 2027 2079 1342 19 2 3 11108 112 3484 207e 2144 2236 2307 2385 2574 1694 2268 13138 113 4066 24 65 24 42 2535 2648 2757 31 71 2178 2 5 96 15078 114 50 12 3059 2916 30 1 5 3176 3312 4059 2849 3105 180 46 115 1D 1362 2268 26 13 2613 26 35 2605 2503 15 46 2617 14934 116 1958 2993 3580 3580 3586 3539 3 5 02 2144 3571 20492 117 2812 4430 50 32 4913 4 9 86 4991 5196 3088 4981 287 66 118 3432 58 16 62 13 6067 61 18 60 66 6698 4143 61 16 354 16 119 40 22 71 71 7 4 62 7369 7419 7329 82 74 51 8 1 7395 42909 120 5026 105 95 11456 115 81 11574 11548 14010 80 91 11540 671 15 121 2D 1244 18 57 2277 2363 2305 2210 2107 1466 2289 13038 122 1960 2622 3240 3388 33 23 3226 31 40 2)99 3294 18919 123 2817 3762 45 87 4739 46 56 45 14 4 6 47 30 15 4624 26689 124 3491 50 22 5723 58 53 57 44 5542 60 18 3871 57 16 330 73 125 4096 61 29 68 16 69 79 6805 65 90 74 79 4677 67 98 39400 126 5037 82 27 94 60 95 69 93 57 9023 11324 65 05 93 52 542 83 127 12D 1278 14 70 1 6 48 1652 1638 1 6 34 1641 9 73 1 6 43 9369 128 1947 19 63 2155 2149 2151 2131 2190 1347 2147 12342 129 2769 2615 2791 2773 28 52 2716 2954 18 96 2783 1 60 82 130 3439 3208 3265 3239 3593 3133 3624 2515 3308 19174 131 4103 3637 35 88 3577 4077 3459 42 66 3138 3676 21343 132 49 78 45 82 44 60 44 8 1 55 17 43 25 5749 4227 4700 27288
Q) tlgt
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
133 1 12D 1299 2094 2507 2622 2625 2567 2489 1465 2578 14736 134 1973 29 56 3505 3772 3790 3718 3718 2115 3700 21290 135 2788 3941 4727 5069 5099 5 0 07 5231 2984 4976 28781 136 3473 5155 59 81 6308 6339 62 39 68 96 4204 6217 36052 137 4118 6135 71 8 6 7662 7731 76 91 87 16 49 8 5 7568 43985 138 4973 7765 94 75 10396 10861 10694 13646 66 64 10357 602 25
139 1ttn 1253 1242 1493 1460 1442 1431 1424 8 84 1457 83 01 140 2366 1942 2150 1961 1910 1897 19 62 1206 1980 11400 141 3461 3007 2957 2562 2513 2606 3143 18 51 2660 15400 142 4325 3942 3571 3060 2999 3198 4248 2631 3207 18618 143 5677 508 6 4359 39 88 3800 42 29 57 78 36 26 4094 23824 144 67 59 64 55 5330 4988 47 25 5494 2517 48 09 5134 29906 145 84 08 9326 72 26 7726 85 56 9172 12319 7733 8170 47626 146 86 54 9831 7582 818 9 94 90 9869 13116 78 97 8783 512 96 147 7376 7335 58 7 6 5941 5796 68 29 81 65 5954 6111 35662 148 2 11 D 4254 4106 48 02 4994 5038 5042 56 78 3419 4969 28881 149 5708 5487 6253 6466 6524 6527 78 63 45 8 2 64 43 37566 150 69 7 8 7983 9440 9848 98 34 97 32 13249 6701 9714 566 59 151 1254 1434 18 53 1947 1915 1850 1760 1186 1891 10772 152 2713 2696 3175 32 94 3288 3237 3288 20 44 3249 18728 153 87 30 118 07 14733 15758 15504 15305 26297 9617 15325 892 71 154 5811 5278 6543 6861 69 30 69 82 7 8 74 4478 68 29 39531 155 4246 3780 4736 4975 49 66 4936 5162 3113 4903 28301 156 (v 1270 8 15 935 959 966 9 51 9 23 6 35 953 5430 157 2714 1164 1390 1427 1447 1454 1455 9 08 1430 8242 158 4310 1655 18 96 1942 1988 2002 2111 1305 1957 11349
(j) ~
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 fry hav Nuav
159 6012 2208 2400 2450 2513 2548 28 20 18 00 2478 14416 160 7279 2696 2881 2927 2989 3081 3599 2340 2970 17326 161 86 90 3257 3360 3 3 76 34 26 3558 4455 2943 3430 2000 162 12D 4368 2209 2600 2558 2518 2466 2774 1753 2536 14713 163 5833 2730 3092 3028 2974 2913 3501 2287 3002 174 78 164 7643 3320 3681 3630 3651 3530 4623 3181 3623 21116 165 87 39 3920 4303 4300 4708 4178 61 60 3937 4372 25456 166 1268 962 1203 1205 1186 1118 1084 725 1178 6693 167 2678 14 67 1785 1779 1752 1698 1726 10 70 1754 88 49 168 1 12D 12 83 936 1217 1414 1397 1239 1190 7 65 1317 7484 169 2729 2502 2930 2914 2934 2956 2979 17 52 2934 16866 170 4345 3884 4357 4283 4318 4421 4836 28 59 4345 25151 171 6036 5546 5858 5764 5791 6028 7129 4184 5860 34045 172 6578 7167 7769 7907 79 82 8263 10492 5915 7980 46437 173 87 84 10237 112 23 120 26 12727 12968 185 19 85 98 12236 71103 174 1278 1344 1803 18 72 1835 1790 1712 1063 1825 10355 175 2711 2328 2972 2932 2893 28 78 2863 1667 2919 167 51 176 4351 3934 4414 4353 4281 4321 4654 28 63 4342 25088 177 5994 5076 5824 5838 5818 59 29 6914 4205 5852 33885 178 1 11 U 1223 388 432 465 464 449 435 338 453 2585 179 2351 521 602 6 22 675 6 57 619 436 639 3687 180 34 48 6 05 1725 803 8 27 8 11 760 518 792 4593 181 4513 718 850 934 9 68 9 57 8 99 609 9 27 5386 18 2 5714 8 32 981 1060 1102 11 06 1034 6 59 1062 61 82 183 6997 1025 1182 1258 1295 1309 1234 8 18 1261 7 3 44 184 8709 1295 1487 1 5 42 1594 1626 1612 1156 1562 9080
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
185 2 12D 4249 3560 4400 4670 4791 4695 47 81 2931 4639 268 37 186 5737 4926 58 54 61 92 6248 62 38 67 78 4134 6131 35590 187 7432 6390 7726 83 46 85 44 86 34 10371 5658 8313 48310 188 8723 7718 107 88 11933 12099 13046 186 22 79 39 119 67 69505 189 1 4 35 1340 1735 18 57 18 52 17 81 1711 1144 18 06 10256 190 2718 2399 3023 3187 3207 3138 30 53 1931 3139 18025 191 7 5 07 6189 80 11 9200 9427 9703 11364 5720 9085 527 38 192 8544 78 42 10666 125 42 13312 13775 178 20 6976 125 74 729 86 193 1287 1417 16 97 18 7 18 69 18 08 1720 1046 1800 10223 194 27 17 2450 2940 3187 3214 3157 3054 1749 3125 17954 195 42 53 3560 4222 45 90 4679 46 63 4743 2741 4539 26247 196 6068 48 69 57 79 6335 65 8 6 66 04 7172 4338 63 26 366 78 197 7389 58 86 72 8 6 82 23 8584 8936 10658 50 60 8257 4798 6 198 86 88 78 91 100 27 120 56 130 29 14299 190 81 6492 12353 71850 199 5864 4694 5 6 67 61 94 6419 65 48 7192 3950 6207 360 14 200 2 D 4177 38 36 4547 48 09 4775 4628 5006 2715 46 90 261 30 201 5712 5170 62 39 66 38 6599 6604 7518 4167 65 20 378 00 202 73 63 7201 8986 98 43 9733 9914 13353 6219 9619 55810 203 8604 10043 13118 148 41 150 42 158 66 25206 82 5 3 14717 85290 204 12 68 1506 18 41 1971 1966 1868 1799 11 42 1913 10880 205 2659 2571 3127 3276 32 50 3130 3069 18 80 3196 18 350 206 39 80 36 76 4347 4573 45~67 4473 46 34 28 37 4490 25910
o 207 Orifice 11496 10 64 1360 15 39 1 5 80 1 6 15 1496 8 58 15 24 88 83 208 9433 8 95 11 78 13 26 1394 1386 1263 727 1346 78 48 209 7387 746 9 77 1123 1184 1159 1048 6 11 1111 64 74 210 52 36 566 7 66 900 934 909 8 21 499 8 27 48 02
0) CJ1
TABLE III Continued
Run No Position CFM h 1 h2 hs h4 h5 h6 h7 hav Nuav
211 212
3309 1293
414 257
563 3 19
6 68 3 57
6 91 3 37
6 72 351
7 37 337
38 4 2 46
4 40 341
3748 1942
213 214 215 216 217 218
c of 2nd 1 516 1235
1919 2712 3320 4153 4704
1532 2447 35 46 4312 5567 74 29
2 1 87 3312 4225 52 86 6902 8 6 50
2360 3555 4340 56 12 7 0 49 8 9 40
2409 3598 4 8 85 5718 7713 9593
2347 2101 35 33 3453 48 00 49 62 5562 59 86 72~6 7 8 79 93 76 11237
1243 20 64 3054 4 2 8 1 5114 6983
2326 35 00 4638 5545 7225 91 40
132 13 200 27 26672 31968 41711 52811
bull
67
TABLE IV
PRESSURE PROFILE DATA
Baffle Flow Qpening Rate ~p
(Inches) Position (CFM) (Inches 295 S G Fluid)
1 364 l2 11 U 1012 0 254 1248 0197 1493 0 141 1718 0112
c 1000 9 80 1210 1710 1436 28 75 1746 4320 1011 1080 1277 2050 1393 3020 1 6 28 4450
12D 1011 9 75 1236 1520 1450 2510 1603 3450
1 D 1011 975 1256 1700 1480 2690 158 1 4070
1 12D 1010 950 1259 1750 1462 2650 1631 3710
2 11 D 1124 1315 1360 2130 1505 2850 1689 4125
1 216 12U 1294 045 1949 0324 2374 0282 2704 0225 3367 0169
c 1326 265 18 81 5 90 2313 990 2731 1480 3439 2660
12D 1272 2 49 1957 661
68
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Pos ition (CPM) Inches 2 95 S G Fluid)
2559 1275 3033 1940 3639 3025
1 216 1nD 1257 242 16 96 476 2117 8 05 2561 1280 2990 1895 3431 26 bull00
1 316 12U 1309 0 479 2004 0422 28 28 0 352 3526 0281 42 28 0225 5199 0225
c 1308 1 43 1998 272 28 14 5 10 3478 795 4248 1235 5048 1885
l2D 1286 140 2005 3 45 2831 725 3495 1180 4194 1805 5046 2945
1 11D 1322 150 2039 352 2841 735 43 77 1980 5378 3440
1 516 12U 1278 0493 2732 0493 4315 0408 5744 0352 7494 0352 8932 0422
c 1300 0 506 2731 1985 4310 348 6080 6 45
69
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Position (CPM) (Inches 295 SG Fluid)
7607 1090 8830 1585
l2D 1343 0549 2738 225 4566 583 6112 1195 7536 2055 9043 3415
1 516 1uD 1249 0464 2713 224 4155 579 5620 1150 7428 2115 90 70 3405
1 12D 1301 0493 2735 220 4501 616 61 50 1235 7440 2065 8862 3445
2D 1265 0 478 2750 226 4366 594 6578 1270 7678 2240 8945 5280
2 12D 1295 0493 2725 222 4293 600 5807 1120 7568 2200 9070 3615
TABLE V
RATE OF HEAT TR AN SFER Ar THE BAFFL~~ CID-TT ER
Orifice Size
(Inches)
Flow Rate
( CFM)
Re d e G tU
R~) 055 Nuav NuPr-l3
1 364 10 26 12 90
8 075 10015
43400 54 600
85 11 99 64
95 83 112 19
1416 11 140 59 900 110 30 124 20 16 27 12 800 68 900 126 64 142 60 17 29 13 610 73 200 135 79 152 90 17 76 13980 75 200 147 59 166 19
1 216 11 35 14 06
8 600 10 660
27000 33500
6 4 96 76 56
73 14 8 6 12
1517 11500 36100 82 51 9291 20 34 15400 48400 10229 115 18 23 11 17500 55000 118 31 13322 2348 17 800 55900 11947 13452 2666 20 200 63400 13508 15210 27 16 20 600 64700 135 05 152 07 32 47 24600 77200 161 57 18 193 3392 25 700 80700 17390 195 8 1
1 316 1344 19 36
9898 14 260
24800 35 700
63 8 7 8 2 77
71 92 93 20
28 46 20 9 60 52 500 111 08 125 08 34 84 25 660 64200 131 38 147 93 40 66 50 12
29900 36900
74800 92400
150 78 18046
169 78 203 20
~ 0
TABLE V Continued
Orifice Flow Re Size Rate d e G R~rmiddot55 NuPr-13(Inches) (CFM) U Nuav
1 516 12 70 8 847 16800 54 ~0 61 14 2 14 18 900 35800 82 42 92 80 43 10 30 000 56900 11349 127 79 60 12 41900 79400 14416 16232 7279 50700 96100 17326 19509 86 90 60540 115000 20098 22529
TABLE VI
RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
Orifice Size
(Inches)
1 364
1 216
1 316
Flow Rate
(CFM)
1054 1294 1431 1681 1770
1068 1399 1669 1959 2295 2636 3390
1299 1973 2788 34 73 4118 4973
Re deG Mshy
8 300 9870
11260 13200 13 930
8100 10600 12650 14850 17400 19980 25700
9 570 14500 20500 25600 30300 36600
R~r-6 51900 61700 70500 82 500 87 100
28200 36900 44000 51700 60 600 69500 89400
26100 39600 56000 69900 82700 99 900
Nuav
2416 293 5 3187 4018 4805
14938 18968 21712 25156 30680 37938 59601
14736 21290 28781 36052 439 85 60225
Uu Pr-1 3
27204 33050 3589 4524 541 0
16820 21358 24448 28326 34546 427 18 67111
16593 23973 32407 40595 495 1 678 13
TABLE VI Continued
Orifice Flow Re Size Rate deG R~rmiddot6 NuPr-13(Inches) (CFM ) M- Nuav
1 516 1268 88 30 17700 108 8 1225 2689 18700 37400 1835 2066 3980 27700 55700 2591 2917 4177 29100 58 500 2713 3055 5712 39800 80000 378 0 425 6 7362 51300 103000 5581 6284 8 604 59 900 120000 8529 9604
74
TABLE VII
EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER
l 516 Inch Orifice
Center ot 2nd Baffle 4 Downstream
Plow Rate (CFM)
1235 1919 2712 3320 4153 4704
Flow Rate (CFM)
1270 2714 4310 6012 7279 8690
(Re)eb -8600 1321
13400 2003 18900 2687 23100 5197 28900 4171 32800 5281
Center ot Single Battle
-8847 543
18900 824 30000 1135 41900 1442 50700 1733 60540 2001
(Nu)(Pr)-l3
1487 2255 3003 3600 4697 5946
(Nu)(Pr)-13
611 928
1278 1623 1951 2253
75
ABLE VIII
HEAT TRANSFER IN THE TEST SECTION WITHOUT ORIFICE
CFM Ute) 0b h Nu
1293 5-951 3 41 1942
33 09 15251 649 3746
5236 24193 827 4802
7387 34001 1111 6474
9433 43419 1346 7848
11496 52-914 1524 8883
76
TABLE IX
PRESSURE DROP FUNCTION
Orltlee Size Flow Rate incbea ~CFM (Re)eb X 10bull8
1 364 1011 7957 0808 1256 9885 1468 1480 11648 2765 1581 12443 4160 1689 1_3293 4 020
1 216 1257 9530 1327 1696 12858 2663 2117 16049 4615 2561 19415 7581 2990 22668 11560 3431 26011 16440
l 316 1322 9736 1819 2039 15016 4332 2845 20952 9275 3495 25739 15300 4377 32014 26800 5378 39607 50100
1 516 1011 7 957 oaos 1256 9885 1469 1480 11646 2765 1581 12443 4160 1689 13293 4020
77
TABLE X
EXPERIMENTAL DATA
Baffle Hole Diameter Run No
1 - 59
60 - 102
103 - 138
139 - 206
207 - 212
213 - 218
(Inches)
1 364
1 216
1 316
1 516
No Baffle
2nd - 1 516
TABLE X
EXPERIMENTAL DATA
Run Thermocouple Reading s (mv) No Position CFM I tc1 tc2 tc3 tc4 t c 5 tc6 tc7 tcair
1 c 1026 530 2055 1825 1768 1782 1802 1837 1965 1198 2 1290 612 2059 18 65 1809 18 32 1851 1880 1965 1160 3 1416 714 2151 1970 1931 1965 1988 2026 209 5 1130 4 1627 8 21 2235 2084 2 049 2093 2126 2173 2266 1130 5 1776 865 2203 2033 1970 2015 2084 2159 2 264 1121 6 12D 1109 542 1636 1507 1499 1499 1498 1498 1528 1218 7 1258 651 1670 1522 1503 1513 1513 1516 1548 1221 8 1433 750 1625 1480 1467 148 3 1487 1487 1516 1153 9 168 1 8 73 1656 1494 148 1 1511 1517 1517 1543 1159
10 1rtD 1102 485 1545 1450 1437 1446 1447 1442 1466 1220 11 13 08 6 10 1571 1470 1460 1476 1476 1469 1498 1194 12 1464 730 1 623 1509 1508 1528 1 5 32 1524 1548 1173 13 11 06 8 71 1663 1559 158 1 1606 160 6 1 583 1601 1190 14 1 12D 1115 520 1698 1579 1575 1 577 1580 1590 1615 1280 15 1275 6 10 1692 1567 1558 1 561 1570 1580 1601 1234 16 1498 770 1760 1619 1630 1 635 1642 1645 1661 1204 17 1695 912 1775 1635 1670 1689 1686 168 6 1701 1165 18 2D 1049 510 1736 15~2 1567 1558 1 553 1558 1620 1236 19 12 41 610 1655 1517 149 1 148 1 148 1 148 4 1546 1108 20 1 5 32 7 35 1720 1550 1530 1520 1519 1523 158 0 1104 21 16 74 8 8 0 1900 1 727 1714 1696 1691 1692 1753 1169 22 1U 1074 38 5 3 324 2740 2534 2478 2 465 2503 258 0 1210 23 1287 4 35 3510 2 870 2682 2 610 2599 2638 27 1 9 1190 24 1 5 08 470 3 618 2920 2690 2 637 2627 2 664 2747 1177 25 18 07 525 4 088 3235 2962 2905 2910 2988 3130 1169
z ())
TABLE X Continued
Run No Position CFM I tc1 tc 2
Thermocouple Readings te3 tc4 tc5
(mv) tc6 tc7 tcair
26 c 10~29 6 32 2340 2~092 2032 2060 2~097 2152 2~213 1211 27 12 66 679 2270 2 047 1993 2013 2069 2142 2 210 1 182 28 1430 723 2336 2097 2033 2080 2153 2~255 2 356 1 138 29 1729 8 52 2318 2070 1980 2061 2158 2279 2367 1121 30 12D 1054 570 1520 1 4 20 1402 1400 1396 1400 1 443 1159 31 1294 6 69 1599 1469 1444 1439 1433 1 442 1485 1168 32 1430 7 88 1720 1562 1536 1532 1528 1537 158 0 118 5 33 1770 8 81 1641 1488 1450 1~441 1 441 1_466 1518 1 163 34 1D 1058 548 1579 1498 1495 1526 1553 1_557 1 571 1 276 35 1263 640 1609 1509 1515 1570 1599 1598 1 598 1 266 36 18 36 8 47 1538 1452 1483 1553 1602 1 590 1 558 1195 37 1 12D 1029 5 41 1 578 1499 148 4 1473 1461 1465 1-512 1200 38 1315 6 30 159 1 1504 1493 1482 1470 1470 1505 118 5 39 1 4 26 743 1765 168 1666 1660 1645 1642 1678 1270 40 1757 8 54 1744 1648 1634 1620 1598 1 593 - 1612 1223 41 2D 1080 5 30 1734 1604 1570 1 570 1570 1 588 1 640 128 1 42 1305 6 40 1744 1622 1589 1 608 1593 1 609 1 661 1240 43 1434 750 1798 1687 1658 1 636 -1641 1 661 1 711 1_220 44 18 04 8 41 1 764 1666 1607 1605 1614 1 635 1 675 1205 45 12nu 1088 415 2614 2295 2195 2 169 2174 2217 2256 1171 46 1318 477 2805 2477 2371 2342 2364 2 401 2 438 1 163 47 1413 5 28 2930 2 646 2 555 2 526 2532 2570 2 577 1 199 48 1773 550 2740 2518 2450 2431 2448 2 479 2 480 1 170 49 1 11 U 1054 380 3175 2670 2505 2 461 2467 2 534 2 621 1 258 50 1240 420 3268 2738 2 546 2 510 2 508 258 2 2 649 1214 51 1419 451 3364 2B07 2 632 2590 2 590 2 651 2773 1 215 52 1 12U 1032 360 3 165 2 629 2 450 2402 2403 2 473 2 bull568 1 163
--I lt0
TABLE X Continued
Run No Position CFM I tc1 tc2
lhermocoup1e Reading s tc3 tc4 t c 5
(mv) tc6 tc7 tc a ir
5 3 1314 38 9 3178 2592 2411 2367 2361 2432 2555 1140 54 1448 403 3095 2544 238 1 2336 2336 2390 2476 1158 55 178 2 427 3006 2434 2286 2253 255 3 2299 2397 1154 56 2 11U 1061 360 3369 2814 2619 2567 2560 2650 2833 1220 57 1216 360 3044 2512 2338 2290 2288 2374 2566 1150 58 1322 387 3196 2614 2425 2383 2382 2472 2670 1138 59 1639 403 3020 2438 2272 2238 2238 2318 2502 1127
60 1D 1068 612 1552 1424 1400 1395 1396 1426 1745 0945 61 1399 612 1355 1246 1230 1229 1230 1250 1509 0872 62 1669 710 1436 1293 1272 1265 1266 1286 1551 0847 63 1959 900 159 5 1468 1444 14 38 1432 1446 1720 0851 64 2295 730 1169 1105 1098 1099 1108 1100 1298 0781 65 2636 8 80 1202 1129 1121 1126 1 138 1115 1342 0748 66 3390 9 35 1060 o 9s7 0999 1001 1017 0971 1154 0703 67 1nu 1190 370 2225 2188 2104 2080 2120 2209 2 7 15 0990 68 1559 368 2005 1950 1871 18 48 1876 1951 2408 0916 69 1904 368 1870 18 1 4 17 34 1711 1730 18 07 2238 0875 70 22 bull11 471 228 6 2 204 2099 2063 2092 218 $ 2732 0840 71 2289 471 2030 2000 1925 1895 18 96 19 5 2498 0785 72 2727 4 71 1854 18 23 1753 17 23 1716 3758 2241 0743 73 3210 471 1680 1651 158 6 1559 1551 158 1 1950 omiddot7o9 74 2uD 1210 404 1261 1212 1198 1197 1205 1222 139 1 0978 75 14 20 540 1321 1260 1242 1 240 1249 1268 148 7 0918 76 1692 7 18 1467 138 6 1364 1361 1376 1405 1678 0883 77 18 94 903 1708 1 591 1565 1560 1575 1603 1948 0 857 78 2301 903 1530 1432 1407 1402 1415 1432 1738 0815
ro 0
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc117 tcair
79 2621 6 50 1069 1 020 1009 1009 1009 1007 1~189 o739 80 3230 901 1200 1128 1113 1119 1119 1086 1341 0694 81 82
l2D 1155 1689
360 575
1191 1345
1142 1252
1122 1218
1118 1210
1118 1209
1132 1228
1292 1446
0916 0822
83 1244 430 1163 1134 1131 1130 1129 1132 1292 0877 84 2100 645 1175 1135 1147 1 142 1138 1122 1286 0757 85 2292 8 25 1 354 1310 1327 1330 1323 1285 148 6 0728 86 2907 8 23 1180 1138 1151 1158 1149 1107 1268 0687 87 3380 902 1113 1049 1025 1011 1006 1042 1178 0673 88 89
1 12D 1427 1875
480 615
118 2 1140
1140 1095
1124 1077
1125 1075
1129 1072
1137 1072
1290 1243
0880 0790
90 2259 8 41 1296 1231 1207 1206 1203 1182 1419 0757 91 2682 8 80 1231 1170 1149 1147 1142 1112 1350 0731 92 3417 940 1142 1092 1076 1076 1069 1021 1252 0693 93 c 15 17 431 1321 1298 1268 1249 1250 1273 1522 0841 94 2034 505 1285 1263 1235 1209 1205 1206 1464 0759 95 2348 6 10 1395 1379 1334 1302 1286 1268 1536 0732 96 2716 706 1486 1480 1427 1383 1358 1311 1572 0 700 97 3247 7 56 1417 1430 1375 1320 1284 1223 1450 0660 98 1135 400 1425 1388 1352 1329 1330 1 364 1651 0893 99 14 06 440 1379 1341 1304 128 2 1281 1305 1583 0 831
100 2311 680 1602 1593 1553 1514 1502 1480 1 7 27 0 802 101 2666 680 1471 1469 1428 1390 1372 1335 1564 0761 102 3392 798 1491 1 509 1449 1395 1372 1305 1534 0 719
103 1U 1235 410 2469 2295 2173 2165 2226 2361 3120 0 897 104 2010 410 2017 1848 1 737 1706 1747 1865 2582 0753 105 28 14 410 1682 1535 1457 1427 1437 1520 2109 0 660
00 t-
TABLE X Continued
Ru n Thermocouple Rea ding s (mv No Positi on CFM I tc1 tc2 tc3 tc4 tc5 tc6 tc7 tcair
106 3492 440 1649 1499 1420 1391 1390 1470 2042 0620 107 4395 550 18 33 1679 1597 1564 1570 1640 2223 0583 108 5075 588 1779 1642 1580 1550 1552 1 615 2 191 0548 109 c 1344 398 1464 1 399 1364 1353 1350 1380 1689 0 907 110 1936 459 1369 1290 1253 1242 1 237 1259 1574 078 2 111 2846 580 1347 128 5 1251 1232 1220 1215 1 5 23 0 683 112 34 8 4 700 1392 1369 1339 1317 1299 1259 1599 0 636 113 4066 8 13 1449 1458 1427 1391 1363 1270 1595 0 591 114 5012 930 1484 1530 1500 1453 1420 1272 1580 0 580 115 1D 1362 513 1269 1218 1 217 1214 1220 1238 1460 0 893 116 19 58 600 1187 1122 1121 1120 1124 1133 1352 0798 117 2812 705 1052 1008 1015 1010 1011 1001 1218 0691 118 34 32 913 1105 1075 1085 1081 1086 1047 1301 0645 119 4022 980 1038 1021 1026 1023 1029 0983 1211 0 609 120 5026 982 0 8 61 0839 0836 0836 0837 0791 0955 0570 121 2D 1244 475 1320 1246 1233 1240 1255 1275 1434 0925 122 1 9 60 5 50 1160 1088 1074 1079 1089 1100 1260 078 7 123 2817 6 80 1096 1024 1 013 1018 1029 1022 1201 0 700 124 3491 960 1248 1175 1163 1172 1192 1153 1435 0 658 125 4096 989 1141 1089 1078 108 9 1105 1051 1310 0629 126 50 37 989 0983 0933 0929 0 936 0949 0880 1090 0 602 127 128
12D 1278 1947
402 545
1270 1261
1 230 1216
1228 1216
1230 1 215
1235 1223
1242 1219
1483 1514
0 913 0778shy
129 2769 695 1273 1234 1237 1221 1251 1212 1525 0678 130 131 132
34 39 4103 4978
8 40 9 80 9 80
1336 1448 1271
1322 1458 1 288
1328 1 462 1286
1 259 1 356 1157
1353 1492 1311
1261 1329 1138
1 555 160 7 1343
0 629 0 600 0599
(l) l)
TABLE X Continued
Run No Position CFM I tel tc 2
Thermocouple Readings tc3 tc4 tc5
( mv) tc6 tc7 tcair
133 1 l2D 1299 5 16 1 28 1 1212 1196 1195 1205 1221 1478 0869 134 1973 6 15 1163 1098 1073 1071 1079 1083 1343 0751 135 136
27 88 34 73
802 9 -_78
1187 1214
1099 1131
1069 1104
1066 1101
1075 1~110
1l061 1066
1370 1360
0662 0618
137 4118 9 81 1084 1010 0983 0979 0982 o937 1209 0581 138 4973 98 1 0969 0897 0 868 0855 0860 0799 1041 0572
139 1D 1253 409 1371 1293 1298 1301 1309 1321 1578 0928 140 2366 480 1130 1 090 1 121 1130 1137 1132 1390 0744 141 34 61 6 38 1081 1086 1152 1161 1147 1069 1382 0644 142 143 144
4325 5677 6759
7 90 939 998
1110 1115 1034
1161 1208 1139
1253 1268 1180
1265 1302 1215
1228 1230 1123
1080 1056 0970
13$913r12 8
0601 0561 0542
145 84 08 989 0863 0961 0934 0895 0871 0 785 09 9 0530 146 86 54 9 80 0808 0901 0 872 0821 0809 0733 0891 0498 147 7376 9 80 0 927 1032 1027 1 040 0961 0889 1032 0511 148 2D 4254 776 1 050 0 981 0965 0961 0962 0922 1155 0579 149 5708 991 1102 1031 1014 1009 1010 0931 1227 0528 150 69 78 990 0914 0853 0839 0 839 0843 0759 0996 0521 151 1254 490 1 479 1352 1329 1334 1351 1379 1607 0930 152 2713 7 00 1310 1220 1201 1201 1211 1209 1516 0723 153 8730 991 0809 0756 0742 0745 0 748 0663 0874 0543 154 5811 966 1219 1108 108 6 1081 1079 1033 1330 0650 155 42 46 8 02 1248 1136 1114 1114 1118 1103 1376 0 699 156 c 1270 429 1671 1571 1551 1545 1563 1600 1933 0929 157 2714 488 1398 1285 1 267 1258 1262 1275 1628 0729 158 4310 642 1424 1318 1299 1282 1283 1261 1683 0617
co ~
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc7 tc a 1r
159 60 12 780 1461 1388 1370 1349 1343 1279 1700 0 573 160 72 79 8 60 1402 1344 1330 1312 1292 1189 1 566 0 520 161 8690 982 1472 1442 1437 1 422 1392 1224 1602 0 521 162 163
12D 4368 5833
6 30 8 30
1195 1368
1105 1270
1111 1283
1117 1294
1131 1313
1081 1194
1369 1553
0613 0 553
164 76 43 959 1428 1338 1348 1341 1371 1180 1488 0535 165 8739 984 1345 1272 1272 1208 129 3 1059 1361 0550 166 1268 459 1701 1548 1541 1547 1589 1 625 1976 0 973 167 2678 570 1485 1351 1349 1356 138 1 1 385 1795 0760 168 169
1 12D 128 3 2729
448 650
1664 1314
1501 1232
1425 1233
1428 1229
1491 1229
1527 1232
1869 1571
0 962 0767
170 4345 847 1245 1179 1187 1182 1172 1132 1476 0 650 171 6036 9 76 1139 1109 1117 1114 1095 1020 1332 0588 172 6578 9 72 0982 0949 0942 0938 0926 0 8 50 1079 0560 173 87 84 9 72 0880 0854 0 8 36 0822 0818 0 749 0941 0585 174 1278 480 1564 1416 1397 1403 1417 1445 1733 0998 175 2711 590 128 3 1175 4 1178 1182 1187 1195 1493 0796 176 4351 8 90 1331 1259 1266 1275 1272 1235 1592 0 682 177 5994 9 60 1228 1152 1150 1151 1143 1075 1 360 0644 178 lU 1223 408 2282 2140 2052 2052 2106 2188 2626 0 878 179 2351 408 178 1 1623 158 5 1519 1556 1634 2068 0717 180 3448 482 1888 1675 1570 1541 1572 1665 2199 0629 181 4513 563 2026 1797 168 4 1644 1670 1770 2385 0583 182 5714 589 1913 1700 1610 1568 1580 1 682 2382 0551 middot 183 6997 653 1903 1718 1643 1611 1612 1700 2326 0 549 184 8709 6 80 1738 158 3 1543 1510 1498 1519 1 912 0577 185 186
2 12D 4249 5737
660 9 74
1055 1221
0 979 1122
0960 1093
0 952 1088
0959 1090
0 956 1054
1147 1350
0661 0602
187 7432 9 8 1 1065 0981 0951 0942 0 939 0881 1135 0582 CD ~
TABLE X Continued
Run No Position CFM I t o1 to 2
188 87 23 9 83 0944 0 879 189 1435 585 18 26 1630 190 2718 690 1433 1298 191 7507 950 1070 0961 192 85 44 964 0982 0 881 193 1287 600 1806 1668 194 2717 7 80 1579 1444 195 4253 8 81 1371 1260 196 60 68 9 78 1252 1152 197 73 89 975 1100 1000 198 86 88 973 0953 0 871 199 58 64 9 81 1269 1155 200 2D 4 1 77 915 1362 1251 201 5712 975 1213 1111 202 7363 9 78 1036 0 951 203 8 604 973 0932 0861 204 1268 6 95 2015 18 20 205 2659 6 96 1405 1295 206 39 80 7 98 1261 1174
No 207 Orifice 114 96 509 1325 1148 208 94 33 509 1477 1243 209 7487 5 09 1686 1409 210 5236 505 2094 1691 211 3309 428 2188 1 778 212 1293 392 2976 2560
Thermo ooup1e Readin g s (mv) to 3 to4 to
5 to
6 to7 toair
0 851 0847 0 8 29 0759 0987 0592 158 4 1583 1611 1647 1993 0986 1270 1266 1 279 1298 1604 0 789 0916 0908 0900 0 858 1115 0602 08 39 0 823 0 818 0 770 1035 0602 1609 1602 1629 1676 2153 0979 139 1 1385 1400 1 430 1938 0776 1212 1201 1205 1201 1601 0669 1 105 1086 1086 1 052 1371 0621 0952 0936 0923 0870 1195 0582 0 8 20 0 801 078 1 0 729 1044 0569 1108 1090 108 2 1043 1407 0610 1218 1221 1241 1202 1582 0659 1081 1083 1084 1031 1 368 0622 0921 0924 0919 0 841 1111 0 610 08 34 0831 0 821 0 751 1003 0 630 1761 1761 1 809 1861 2399 0966 1271 1271 1295 1311 1650 0797 1150 1150 1161 1149 1440 0703
1083 1057 1053 1109 1566 0~530 1158 1125 1138 1217 1763 0 526 1291 1250 1278 1383 2038 0542 1518 1478 1519 1657 2420 0 589 1596 1557 1601 1737 2441 0688 2370 2344 2409 2561 3 297 0921
()) (11
TABLE X Continued
Run Thermocouple Readings (mv) No Position CFM I tc 1 tc2 tc3 tc4 tc tc tc tc i5 6 7 a r
C of 2nd 213 516 1235 4 63 1 432 1291 1265 1258 1 268 1 308 1550 0 971 214 1919 6 17 1357 1223 1196 1191 1199 1211 1461 0 851 215 27 12 8 35 1401 1259 1278 1220 1230 1218 1511 0 762 216 3320 981 1439 1305 1270 1259 1275 1238 1450 0719 217 41 53 980 1251 1142 1132 1094 1121 1088 1305 0 695 218 404 987 1102 1042 1030 1 bull006 1014 0960 1133 0681
Supplementary Equations
Calculating temperatures from thermocouple readings
t = -026tc)2 + 3512(tc) + 3201 (26)
where t is the temp in deg F and tc is the thermocouple reading in millishyvolts
Calculation of the thermal conductivity of air
k = 00000245ta + 0 0132 (27)
where k is the thermal conductivity in Btuhr rt2 degFft and ta is the air temp 1n OF
I I
bull co m
18
using the orifice pressure and the test section pressure
which were measured by pressure gages
It was desired to determine a relationship between the
heat transfer coefficient and the total pressure drop for
each orifice size The pressure drop across each orifice
at various flow rates was measured by means of the presshy
sure probe described in Chapter III It was also desired
to obtain pressure profiles for each orifice size since
these might be similar to the heat transfer profiles The
pressure drop was measured from a point 13 inches upstream
of the orifice to points at 1 and 12 ineh upstream the
orifice center 12 1 1 12 and 2 inches downstream
The experimental program is summarized in Table I
TABLE I
SUla~RY OF EXPER IMENTAL PROGRAM
Position Investigated-Distance from Orifice-Inches
Orifice Range of Flow Rate Size Heat Transfer Pressure Drop CFM at 68degF amp 1 atm
1 364 2U 1 12U 1U 12U c 12U C 12D lD 10 - 18 l2D lD 1 12D 2D 1 12D 2D
1 216 1U c 12D lD 1 l2D 2D 12U c 12D lD 10 - 35
1 316 1U c 12D lD 1 l2D 2D l2U C 12D lD 12 - 50
1 516 1U c x2D lD 1 l2D 1U 12U C 12D 12 - 90 2D 2 1 2D l D 1 l2D 2D 2 12D
20
CHAPTER v
EXPERI MENTAL PROCEDURE
The experimental procedure for measuring the heat
transfer coefficients ~d corresponding flow rates reshy
quired the following procedure
(1) Install the orifice size to be studied in the
test section
(2) Place the heat transfer probe in the position up
or downstream from the orifice where the middot heat
transfer rate is to be studied
(3) Fill the cold junction thermos with cracked ice
(4) Measure the atmospheric pressure
(5 Open bypass line from blower and close line to
test section
(6) Turn on the cooling water for the exchangers used
to cool the air leaving the blower
(7) Start the automatic selen ium rectifier by turning
on the t 1mer bull
(8 ) Connect the voltage stabilizer to the wall outlet
(9) middot Set the slide wire resistor to the maximum re shy
s1atanee I
(10) Start the blower
(11 Open the line to the test section until the de shy
sired flow rate is obtained
(12) Switch on the probe direct current power source
21
(13) Adjust the slide wire resistor to obtain the
desired current
(14) After the thermocouples have reached equilibrium
values record the e m bullf across each of the
seven probe thermocouples and also the entering
air thermocouple
(15) Record the direct current amperage
(16) Record the gage pressure at the flow orifice and
the entrance to the test section
(17) Record the manometer measurement of the pressure
drop across the flow orifice and also the presshy
sure drop through the test section
22
CHAPTER VI
CALCULAT ION OF EXPERIMENTAL DATA
The local heat transfer coefficients were calculated
from the temperatures measured on the probe surface the
air temperature and the current input The results were
calculated by using the Alwae III-E computer
The general expression for calculation of the heat
transfer coefficients was derived by Ambrose (1 p 79)
The equation is derived by making an energy balance around
a small increment of the center resistance heating ribbon
The two ribbons tnstalled adjacent to the center ribbon
reduced the amount of logitudinal conduction and assured
little longitudinal temperature variation in the center
ribbon
A heat balan ce on this small increment of resistance
ribbon yields the following
(the heat conducted in) + (heat generated) = (heat
conducted out) +(Heat convected to the fluid) + (heat
radiated to the surroundings) + (Heat conducted into
the plastic center of the probe)
This gives the equation
kzw dtdS + 12RdS kzws [ t + (~) ds] + hwdS (t-ta )
+ ~Aad wd o middot+ qcAond 1 -~- wdS 5 )
23
Hence solving for h gi~ea
i2R kz d2t Qrad qcond w + -d$2 - ~- A
h = ( 6)t - ta
Since S = re where 9 equals the enclosed angle ~n radians
dS rd9 ( 7)
and
dt - dt (8)dS - rd9
Differentiating with respect to S
d2t (9)rd9dS
from which
(10)
Substitut1ng into the equation for heat transfer coeffishy
cient gives
h = i2R Qcond A (11)
w
The rate of radial heat conduction into the plastic
tube making up the probe was assumed to have negligible
effect on the heat transfer coefficient It was also
assumed that the heat loss by radiation from the ribbon
was negligible since all data were obtained with the ribbon
at a temperature less than 125degF
24
When t he rad iation and conduction terms are neglected
Eq (11) becomes
(12)
The following con stants are known
R = 0 271 ohmsft
w = 100 i n ches
k = 763 Btuhr rt2 degFft
z = 0 002 inches
r = 12 inch
Eq (12) putting 9 in degrees then reduces to
1110 12 + 2404 d 2t d92
( 15)h = ------~--~-------t - ta
Thi s equation was programed for the Alwac III- E comshy
puter and used to calculate the local heat transfer coefshy
ficients from the observed data
The average heat transfer coefficient around the tube
at a given position in the t est section was calculated by
averaging the local coefficients calculated from Eq (13 )
It was found 1n the course of the experimental work
that thermocouple numbers 1 and 7 were indicating higher
temperatures than would be expected This resulted in h1
and ~ being lower than the other local coefficients around
the tube Since the fluid was flowing parallel to the axis
of the probe the circumferential variation i n rate of heat
25
transfer should be small Hence in obtaining the average
coefficient around the tube the values of h1 and h7 were
not used even though they were calculated and are tabulated
1n Table I II in the Appendix
Then
(14
A Nusselt number as calculated from this aver age heat
transfer coefficient using the tube diameter as the characshy
teristic dimension
(15)
The air flow rates through the test section were calshy
culated by measuring the pressure drop across the flow orishy
fice the air temperature the pressure at the flow orifice
and the pressure at the entrance to the test section The
orifice calibration curves (1 p 166 ) were used to obtain
a value of the orifice coefficient f8e where Q equals
the flow in cubic feet per minute at 68deg F and one atmosmiddot
phere pressure and te is the density of air at the exchanger
and e the density of the air at the flow orifice The
den sity of the air can be expressed by
e = 2 703 p (16)T
where T equals the temperature in OR and P equals the absoshy
lUte pressure i n lb1n2 Using the value of e Qfo from
26
the calibration charts as A and Eq (16) solving for Q
gives
( 17
This equation was used to calculate the flow rate for
each flow studied
The Reynolds number used i n the correlation of the
data was the equivalent Reynolds number defined as
Re)eb ~ d2 - dl)Uf ( 18 ) lL
where d1 is the outside diameter of the inner tube and d2
is the orifice diameter U is the flow velocity through the
annular orifice e is the density of the air and U- is t he
viscosity of the air This equation can be transformed t o
(Re) b = 1611 Q (19) e dl + d2
where d1 and d2 are in inches
The pressure drop data were calculated i nto a dimenshy
sionless pressure drop function cent where
d1 )22( ~ P)gc f av(d2 shycent 2 bull (20
M-
For air this equation reduces to
where d2 and d1 are in i nches D P is expressed i n inches of
2 95 specific gravity fluid and P av is expressed as lbft3
27
CHAPTER VII
ANALYSIS OF DATA
In analyzing the heat transfer data an attempt was
made to correlate it 1n terms of the dimensionless groups
(Nusselt number Prandtl number and Reynolds number) which
appear in Eqs (3) and (4) Consequently all of the av~
erage heat transfer coefficients hav were brought into
the form ( Nu)( Pr)~3 bull The Nusselt number was based on the
tube diameter and the thermal conductivity of the air at
the flowing temperature The tube diameter was used in the
Nusselt number because comparison could then be made with
previous experimental work on heat exchangers which have
commonly used the Nusselt number defined as in Eq (15)
From the standpoint of dimensional analysis this is
equivalent to considering the tube diameter as the characshy
teristic length so far as the heat transfer is concerned
The Prandtl number of the air was taken as 0 7 in all
cases
Variation of Heat Transfer Rate with Distance from the Baffle
Considerable variation was observed in the rate of
heat transfer in the vicinity of the baffle In order to
obtain the variation with respect to position the term
(Nu)(Pr)-13 was plotted versus the flow rate Q for each
position and orifice studied Cros s plots were then made
28
at constant flow rates in order to obtain the variation of
(Nu)(Pr) -13 with position The resulting cross plots are
shown 1n Fi gures 5 6 and 7 for the four orifices studshy
ied
About one inch upstream from the orifice the heat
transfer coefficient begins to rise rapidly and continues
to do so until it reaches a maximum some distance downshy
stream After the maximum point the heat transfer coef fi shy
cient decreased slowly The heat transfer rate was found
to reach a maximum at a different position downstream for
each orifice size These figures also show that for a
given orifice size the maximum heat transfer rate occurs
a pproximately at the same point for all flow rates The
position of the maximum point f or each or ifice size is
shown in Table II
The region immediately downstream from the orifice is
one of h i gh turbulence due to the jetting action of the air
flowing through the orifice As the air flows t hrough the
orifice the streamlines continue to converge for some dis shy
tance downstream The point of maximum heat transfer is
probably at the point where the streamlines be gin to diverge
and a boundary layer begins to build up on the tube Tle
decreasing heat transfer coefficient beyond the maximum
point indicated the formation of a boundary layer
Since the position of the maximum point is independent
of flow rate middot it is possible to correlate it with respect
_ ct 11shyz-
100
0 136 ORIFICE
(
I 0
I )
~ 00
~p 0
I 0
--r--- ~
ISCFIII
-_ OCFM
rbull abull
~ middot~ a-1 z-
12fORIFICE
100
200
100
0 0 UPITRAM ORIFICE DISTANCE CENTER
CFM
h I DOWNSTREAM
DISTANCE
FIGURE 5 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLpound
30
too
700
800
100 ~ f gtf
400
z ~
100
100
100
0
13fORIFICE
~ -~ -- ---
)
~
~
-
I ~ ~OCFM
I vI~-~ OCFM
J ---
Iamp CFM
I 0 I I UPSTREAM ORIFICE DOWNSTREAM DIITANOE GENTER DIITANCI
FIGURE 6 VARIATION OF HEAT TRANSFER RATE WITH DISllNCE FROM BAFFLE
--
--- --
31
100
100
700
100
_ 100
f 9- 400 z-
100
tOO
100
0 - I 0 I I I UHTRIAM OAtfiCI DOWIIITMAM
+ I tyl6 ORIFICE
v I
~~ ~CFM
I v ~CFMI
v v 7
~~ v ~ iOCFM
- ~~ I-shy1-shy ~ICFM
DIITMCI OINTIR DIITANCI
FIGURE 7 VARIATION OF HEAT TRANSFER RATE WITH DISTANCE FROM BAFFLE
32
TABLE II
POSITION OF MAXIMUM HEAT TRANSFER
Position of Maximum Orifice Size Heat Transfer
(inches) (inches downstream)
1 364 050
1 216 100
1 316 125
1 516 200
33
to orifice size Figure 8 shows the effect of the orifice
size on the position and value of the maximum heat transfer
at a constant flow rate of 15 cubic feet per minute It
can be seen that the larger the orifice size the further
downstream the point of maximum heat transfer occurs
Also as the orifice size increased the rate of heat
transfer decreased for a given flow rate The broken line
indicates the variation of the point of maximum heat transshy
fer with position and size The position of the point of
maximum heat transfer rate downstream from the orifice was
correlated with orifice size by means of the dimensionless
groups (Lde) and (d1de) where L is the distance downshy
stream from the orifice where the maximum rate of heat
transfer occurs d1 is the outside diameter of the inner
tube and de is the equivalent diameter of the orifice
ie de = d2-dlbull
Figure 9 shows a plot of Ld 6 versus d1d6 for the
four orifice sizes studied The four points on this logshy
log plot are approximately in a straight line and the
equation of this line is
Lde = 0 44 d1de)028 (22)
Although the above relationship represents a correlashy
tion of dimensionless groups it is based upon only one
tube diameter and needs to be substantiated further by
studying other tube diameters and other orifice sizes
34
aoo
400
aoo ~
-~ middot-CLshyJ z
200 -
100
0
ORIFICE CENTER
l~
l
t
I J~
1pound~
I
0 I I~
AT 15 CFM
-
bull ~ 1~6~
~ v~
~
~--~~6
~~~ ___ v v V -_
~ o q
~ I 16
v
~
ogWNSTREANI STANCE
FIGURE 8 EFFECT OF ORIFICE SIZE ON POSITION AND VALUE OF MAXIMUM HEAT TRANSFER
35
50
loshy____ -~
~ ~ -shylltl-shy~ r0
2 10 30
FIGURE 9 CORRELATION OF THE POINT OF MAXIMUM HEAT TRANSFER WITH
ORIFICE SIZE
36
Correlation of Data at the Baffle
The heat transfer data were correlated by obtaining a
relationship between the group (Nu)(Pr)-13 and a
Reynolds number based on twice the clearance (d2 - d1
between the tube and the baffle It was found that the
most satisfactory correlation could be obtained when the
term - d1 was used as the length term in the Reynoldsd2
number
Figure 10 shows the variation of the heat transfer
rate at the center of the orifice e xpressed as a function
of Reynolds number and the orifice size This shows that
for a given Reynolds number the heat transfer at the center
of the orifice is greatest for the smallest orifice size
In order to obtain a general correlation of the data
shown i n F1gure 10 the effect of the dimensionless ratio
d1de was considered This ratio considers all of the
geometric factor s needed to describe the annular orifice
The thiclaless of the orifice plate is also a factor but
was constant i n this i nvestigation
The data for the heat transfer at the baffle center
are shown in Figure 11 in which (Nu)( Pr)-13 is plotted
versus (Re)ebd1 de) 0 55 This data on a log-log plot
lies on a straight line for (Re)eb( dld8 )0 55 greater
than 3 x 104 The equation for cor relating the heat
37
4XI~middot~-r~------~--~~------~
Icf t--to_+--_c-c-________ SYMBOL SIZE
0 1~4
6 ~~
9 ~~ -o ~
(Re)eb
FIGURE 10 RATE OF HEAT TRANSFER AT BAFFLE CENTER
38
500
0
4 0 lcf
~ ~
~ ~iC-
~ ~
~IL 0~ 0 SYMBOL SIZE-
p 0 1364-
r 6 1~16 -~ -
9 1~16 --o 1~16
I I
FIGURE II CORRELATION OF HEAT TRANSFER DATA AT BAFFLE CENTER
39
transfer at the center bullOf the a nnular orifice was found by
the method of least s quares to be
(Nu)( Pr)-1 3 = 0018 ( Re)ebO Bl( dlde)04~ (23)
3 x 104 ltRe)eb(a1de)055 lt 105)
Rate of Heat Transfer at the Point of Maximum Heat Transfer-The heat transfer rate at the point of maximum heat
transfer is plotted in Figure 12 to show the variation with
Reynolds number and the size of the orifice It is shown
gives the h1gh st heat transfer ~ate at its point of maxibull
that for a given Reynolds number the smallest orifice size yen il
mum heat transfer
The data ~or the maximum poi~t could be correlated by
plotting (Nu) Pr)-13 versus (Re)eb(d1de)06 This plot
is shown 1n Figure 13 and the resulting eurve shows that
(Nu(Pr)-13 is not a simple p0wer function of the Reynolds
number as was the case for heat transfer at the baffle
center The reason for this is probably because other
factors such as intensity and scala of turbulence should
be considered At the orifice center the streamlines of
the flowing stream are converging_ and thus the flow is
quite stable Downstream from the orifice is a region of
large eddy currents and probably large scale turbulence
These factors could con ceivably cause the results which
were obtained for the point of maximum heat transfer
40
If)
~middotshy Q_-I z_
10~~~--------r----~~--~--
SYMBOL SIZE
0 13$4
6 1~8
Q 13-18
-o 1~8
7)(104
(Re)eb
FIGURE 12 RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
41
Ia ~
0 I
c ~ ~ c v
~ ~lt w ~
17
~ b
v ~ ( SYMBOL SIZE
-~ 0 f-64 -v ~ 6 t211e
~ Q I~~~
-o - l~rs I I
FIGURE 13 CORRELATION OF HEAT TRANSFER DATA AT THE POINT OF MAXIMUM HEAT TRANSFER
4 2
Effect of Upstream Baffles on Heat Transfer at the Orifice Center
The heat transfer rate at the orifice center using the
single orifice in a test section is a pproximately 13 of the
value that was obtained by Lee (7) using a model heat exshy
changer with orifice baffles Lee investigated the cent r al
baffles of the heat exchanger and thus the coeff icients he
obtained would be affected by the presence of a number of
upstream baffles To determine the effect of upstream
baffles an additional l 516 inch baffle was placed four
inches upstream 1n the test section The resulting data are
shown in Figure 14 where (Nu)(Prmiddot)-13 is plotted versus
(Re) eb for the case of a single baffle 1n the test section
and also the case of an additional baffle placed four inches
upstream Comparison is made with the results obtained by
Lee middot(7) using a four-baffle and a ten-baffle model heat exshy
changer Good a greement is obtained with Lees work and the
results show the marked effect that upstream baffles have on
the downstream heat transfer rate The additional up tream
ba ffle caused sufficient turbulence 1n the test section to
i n crease the heat transfer rate nearly three-fold at the
center of the next baffle
Heat Transfer i n the Test Section with No Orifice
In order to check the accuracy 6f the equipment the
orifice baffle was removed and the heat transfer mea sured
with the probe in the empty test section The data were
43
~~BAFFLES
0 l BAFFLE -shy
ll_9 2 BAFFLES
V 4 BAFFLES-LEE
4 10 BAFFLES- LEE lJf ~
~rv ~~ ~ v flvv ~~
I ~ J ~ L v
0
v
( V
40 3XIo 7XIa
(Re)eb
FIGURE 14 EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER AT BAFFLE CENTER
44
compared with heat transfe r coefficients predicted by the
equations for annuli which are recommended in the litera shy9
ture The two equa~ ions u sed tor comparison were
(hfe)=0 023 (rltGr e (~~ur4 (~r45 (24)
which was presente~ by Wiegant (10)
and ( h ) (cnM~5(M~l o14 o 023 CPG k j Mij - (de GJMb )0 2 ( 2 5)
which was presented by McAdams (8 p 242) The comparshy
i son is s hown in Figure 15 lq (25) gives a value which
is low by about ten percent while Eq (24) g ives values
which are high by as much as twenty -five percent when comshy
pared with the experimental data The se equations are gembull
erally considered to give coefficients with an accuracy of
about twenty percent Therefore the present experimental
data are within the accuracy of these equations Also the
plot indicate s that for a Reynold s number greater than 2 x
104 the slope of the line is the same for the experimental
data as for the equations
Pressure Drop Data
The total pressure drop across the orifice was measured
as a function of the flow rate and the orifice size The
pressure drop was expressed as a d1mens1onleas quantity r)
which ie plCltted ver sus the Reynolds number in Figure 18
The pressure drop function cent correlates for all or1f1oe
45
200
100
s z
10 5XI10 10
0 EXPERIMENTAL
--McADAMS
-WIEGAND L
V
~ ~ ~
P ~ ~
LL~ L
v~
~
v v
v 1 ~ ~ v
v -gt
~
~ ~
~
6Xid
FIGURE 15 HEAT TRANSFER WITH NO BAFFLE
46
0 1~4 -~ a 6 t216
Q t316 lJ J
-0 as a )t
A LEE I -shy SULLIVAN 8
p
10bull
BERGELIN
I _ll I
I ~
i I
~middot
lo II
f fl
J j
~middot
A)101
1q
I Ill
1 I3 X 10ao1
FIGURE 16 ORIFICE PRESSURE DROP FUNCTION VS REYNOLDS NUMBER
47
sizes- The present data extends the range covered by preshy
vious workers and agrees well with their work The preshy
vious work of Lee () for a heat exchanger containing 10
orifice baffles and also the data of Su livan and Bergelin
(9) for pressure drop in a model heat exchanger with a
single baffle is shown 1n Figure 16 long with the present
results~ This figure may be used to predict the preseure
drop from the equivalent Reynolds number of the annular
orifice
The pressure drop between individual points 1n the
vicinity of the orifice and an upstream pressure tap wa s
measured to obtain a pressure drop profile As might be
expected 1n all cases the profiles showed a rapid decrea e
in static pressure immediately upstream from the orifice
There was however little or no recovery of the pressure
loss downstream The 1 364 inch orifice did show a maxishy
mum point in the pressure drop but this maximum occurred at
the orifice center and total recovery was reached about 12
inch downstream
Heat Transfer at the Baffle and Maximum Point as a Function of Pressure Drop
In order to compare the effect of the total pressure
drop on the heat transfer at the baffle and the point of
maximum heat transfer Figure 17 was plotted showing
(Nu)(Pr)-13 as a function of the total pressure drop This
shows that for a given pressure drop the largest orifice
48
1200
1000
~ a -sshyz-
100
60 100 700
AT MAXIMUM POINT I 15116 2 13116 3 1~6 4 1364
AT ORIFICE CENTER
60
1
v
r ~ ~ ~
5
~
8 7
13116
8
~
1364
v
~
e6
1~6
v
~~ v ~ ~ -~ ~
~
~ v
l
~
vamp
I ~ ~
~
v L ~
v
I-
5
k= ~~
~ ~ ~
--I
v ~
FIGURE 17 HEAT TRANSFER AT THE BAFFLE AND MAXIMUM POINT AS A FUNCTION OF
ORIFICE PRESSURE DROP
49
size has the greatest heat transfer coefficient This is
true at both the orifice center and at the point of maxishy
mum heat transfer
Another comparison can be made by plotting the heat
transfer coefficient and the pressure drop versus the orishy
fice size at a constant flow rate Figure 18 shows this
plot This graph shows that at a constant flow rate the
pressure drop as well as the heat transfer coefficient
increases as the size of the orifice is decreased In
choosing an orifice size for maximum efficiency 1t would
be necessary to know the pumping power available as well
as the heat transfer desired
70 I I 700
AT 15 CFM 60 ---
~ aug
50 ---
NV
40 ~
~ ~ ~
~ _
MAXIMUM POINT ---- --- ~
1-----t---~ _
~00Qj ~
~t--- ORIFICE CENTER 10 1100
1---~ n
u0 01 02 03 Q35
a ltl
de inches
FIGURE 18 VARIATION OF HEAT TRANSFER RATE AND PRESSURE DROP WITH ORIFICE SIZE AT A CONSTANT FLOW RATE
cn 0
51
CHAPTER VI II
SUMMARY OF RESULTS
This study revealed several significant facts about
the heat transfer in the vicinity of annular orifices
Probably the most important contribution was the presshy
entation of the heat transfer profiles in the vicinity ot
the annular orifice ~ r s shown that t~ local heat
transfer coeffieient re~ches a maximum at a point downshy
stream from the orifice The distance downstream at which
this maximum oocurs is t1ven by the equation
22
The heat transfer coefficients at the center of the
orifice were correlated and found to follow the equation
(Nu)(Pr)-13 = 00176 (Re)eb08l(d 1de) 0 middot4~ (23)
3 x 104 lt( Re) 9 b( d1d6 )055 ltlo5 )
The heat transfer at the point of maximum heat trans
fer for each orifice size was correlated and presented in
Figure 13 as a plot of (Nu)(Pr)-l3 versus (Re)eb(d1de) 06
No simple po-orer relationship exists between the terms
Intensity and scale of turbulence downstream from the orishy
fice are probably important factors which affect the heat
transfer
The large effect of an upstream orifice on the heat
transfer rate at the second orifice was demonstrated by the
52
study of two 1 516 inch orifices in the test section The
added turbulence at the center of the second orifice was
found to raise the heat transfer rate almost three times
over that obtained for a single baffle
The pressure profiles in the vicinity of the orifice
indicate that nearly all the pressure drop occurs at the
orifice center~ Total pressure drop data were correlated
by a pressure drop function cent as a function of the Reynolds
number and good agreement obtained with the results of other
workers
The pressure drop and heat transfer data were correbull
lated by plotting the heat transfer as a function of the
pressure drop for each orifice size It was shown that for
a given pressure drop the largest orifice size gives the
greatest heat transfer coefficient
As a final presentation it was shown that the pressure
drop and the heat transfer coefficient both i ncrease i n
value at a constant flow rate as the orifice size is de shy
creased This is important in choosing the optimum clearshy
ance for orifice baffles
53
CHAPTER IX
RECOMMENDATIONS
A great deal of work remains to be done in the field of
evaluating shellmiddotside heat transfer coefficients This
study included only one tube size and air was the only f luid
used It is recommended that further studies be conducted
using other fluids and tube sizes It will also be necessary
to study several baffle types
The adde d turbulence due to a s e cond baffle placed upbull
s t ream would suggest that the heat transfer coef ficients at
a certain position i n relation to a baffle would increase as
the flow progressed through the exchanger It is recomshy
mended that an extensive s t udy should be made between baffles
the full length of a model heat exchanger
It is further recommended that the pressure drop study
be continued to include other fluids tube sizes and baffle
arrangements
Effects of turbulence downstream from the baff le should
be studied by i n vestigations with hot-wire anemometer equipshy
ment to determi ne t urbulence scale and i ntensity
54
NOMENCLATURE
Area of heat transfer
Heat capacity of the fluid
Outside diameter of the tube
Orifice diameter
Equivalent diameter of the orifice (d2 - dl)
Inside diameter of the test section
Inside diameter of the tube
Gravitational constant
G Mass velocity
h Local heat transfer coefficient
Coefficient of heat transfer from surface to fluid
i Direct current amperes
k Thermal conductivity of the fluid
L Distance downstream of the point of maximum heat transfer
p Absolute pressure
L P Total pressure drop across the orifice
Q Flow in cubio feet per minute at 1 atmosphere and 680 F
q Heat transferred
Thermal energy conducted into the sensing probe
Thermal energy radiated from the resistance ribbon
Resistivity of the resistance ribbon
s Length of the resistance ribbon
T Temperature oR
55
t Temperature of the resistance ribbon deg F
ta Temperature of the bulk stream oF
tw Wall temperature of the tube OF
U Veloc ity of the fluid
w Width of the resistance ribbon
z Thickness of the resistance ribbon
eeuro Density of the fluid in the test section
Density of the fluid at the flow orificef 0
AL Viscosity of the fluid
E9 Angle measured around the tube
Dimensionl ess groups
(Nu) Nusselt number hd1k
(Pr Prandtl number C~k
(Re)eb Equivalent Reynolds number at the baffle (d2 - d1 )uejt-Lshy
(Re)e Equivalent Reynolds number in the test section ( d 8 - d 1 )U fu
cent Orifice pressure drop function 2(~P ) gc~av(d2 - d1) 2
Al
56
BI BLIOGRAPHY
1 Ambrose Tommy W Local shell-side heat transfer coefshyficients in baffled tubular heat exchanger PhD thesis Corvallis Oregon State College 1957 183 numb leaves
2 Bell K J and o P Bergelin Flow through annular orif ices Transactions of the American Society of Mechanical Engineers 70593-601 1957
3 Colburn Allan P A method of correlating forced con shyvection heat transfer data and a comparison with fluid friction Transactions of the American Institute of Chemical Engineers 24 174-210 1933
4 Dittus F w and L M K Boelter Heat transfer 1n automobile radiators of the tubular type University of California Publications in Engineering 2443-461 1930
5 Gurushankariah M s Local shell-side heat transfer coefficients in the vicinity of baffles in tubular heat exchangers Masters thesis Corvallis Ore gon State Colle ge 1958 97 numb leaves
6 Knudsen James G and Donald L Katz Fluid dynamics and heat transfer New York McGraw-Hill 1958 576 p
7 Lee Kyu Sung Local shell-side heat transfer coeffishycients and pressure drop in a tubular heat exchanger with orifice baffles Masters thesis Corvallis Oregon State College 1959 118 numb leaves
8 McAdams William H Heat transmission 3d ed New York McGra ~-Hill 1954 532 p
9 Sullivan F W and 0 P Bergelin Heat transfer and fluid friction in a shell-andbulltube exchanger with a single baffle Chemica l Engineer ing Progress Symposium Series 52 ( 18) 85-94 1956
10 Wiegand J H Discussion on annular heat transfer coshyef f icients for turbulent flow Transactions of American Institut e of Chemical Eng i n eers 41147-153 1945
AP PENDIX
57
TABLE III
CALCULATED HEAT TRANSFER DATA
Baffle Hole Diameter Run No (inches)
1 - 59 1 364
60 - 102 1 216
103 - 138 1 316
139 - 206 1 516
207 - 212 No orifice
213 - 218 2nd - 1 516
TABLE III
CALCULATED HEAT TRANSFER DATA
Local Heat Transfer Coefficients Run
T0 bull Po s ition CFM hr h2 h3 h4 hs he ~ hav Nuav
1 c 1026 10 59 1476 16 09 1559 1510 1435 1203 1518 8511 2 1290 1369 1738 1878 18 05 1755 1689 1515 1773 9964 3 1416 1636 198 1 2068 1977 1924 1845 1715 1959 11030 4 1627 1991 2301 2382 2268 2194 20 ~98 1929 2249 12664 5 1776 2252 2669 2863 2713 2517 2338 2126 2620 14759 6 l2ttD 1109 2311 3317 3386 3373 3387 3394 3071 3371 18888 7 1258 3089 4583 4866 4683 4701 4643 4194 4695 26301 8 1433 38 8 5 55 83 5791 5495 5430 5436 5008 5547 31192 9 1681 4992 7378 7649 6980 6864 6870 64 28 7148 40180
10 1 D 1102 2371 3332 3511 3356 3342 3427 3102 3394 19012 11 1308 3218 4379 45 24 42 53 4255 4373 3965 43 57 24446 12 14 64 38 58 5146 5142 4839 4787 4903 4597 4963 278 79 13 1706 5218 6664 6269 58 81 5884 6237 5973 61 87 34718 14 15
1 l2D 1115 1275
2131 2661
2955 3638
2972 3720
2941 3675
2913 3576
28 22 34 74
2613 3278
2921 36 17
163 09 20246
16 1498 34 87 4644 4503 4441 4371 4343 4194 4460 25010 17 1695 4449 5743 5324 5222 5154 5157 5015 5320 298 97 18 2D 1049 1715 23 90 2550 2610 2656 2624 2208 2566 14363 19 1241 2117 2964 3145 3218 3221 3203 2759 3150 17757 20 1532 28 67 3936 4100 4188 4201 4167 3676 4118 23224 21 1674 3459 4508 4598 4746 4795 4792 4299 4688 26337 22 lU 1074 253 340 380 3 86 388 377 354 374 2097 23 1287 292 392 433 440 441 429 406 427 2394 24 1508 322 439 492 498 499 487 461 48 3 2713 25 18 07 3 38 464 519 5 24 520 499 463 5 05 28 40
~~ (]I agt
TABLE III Continued
Run No Position CFM h 1 h2 ~3 h4 h5 h6 ~ h
av Nu
av 26 c 1029 1171 1491 1589 15 28 1 4 62 1377 1293 1489 83 44 27 1266 1395 1746 1853 18 02 1685 1556 1453 1728 9704 28 1430 1637 2037 2175 2060 1909 1735 1591 1983 11159 29 1729 1982 24 96 2751 2507 2268 2030 1886 2410 13579 30 12D 1054 2934 4041 4321 4326 4423 4359 3706 4298 24160 31 1294 3385 4 8 26 52 42 5326 5450 5277 4566 52 24 293 50 32 1431 3784 5347 5721 57 bull75 58 44 5700 5084 5677 31870 33 1770 52 75 7 7 33 87 35 9005 9007 8267 7059 85 49 48050 34 lD 1058 3235 4401 4444 3877 3496 3451 3294 3934 21973 35 1263 38 98 5484 5330 4347 3964 3981 3987 4621 25823 36 18 36 6701 89 17 7855 6369 5597 5769 6283 69 01 38718 37 1 12D 1029 2404 31 8 2 3333 3459 3624 3577 3045 3435 19264 38 1315 3182 4033 4162 4310 4496 4502 4015 4301 24142 39 1426 3628 4389 4510 4573 4760 4804 43 8 5 4607 25678 40 1757 4547 5559 5(35 5931 6282 63 70 6060 5975 33471 41 2 11D 1080 2034 28 38 3155 3144 3145 2966 2540 3050 17027 42 1305 2650 3 4 87 3aoz 3595 3751 3595 3153 36 46 20405 43 1434 3167 39 07 4156 4371 4320 4126 3709 4176 23395 44 1804 4096 4 9 66 5691 5714 5586 53 15 48 65 5454 30582 45 12U 1088 409 516 557 564 5 60 535 513 5 46 30 67 46 1318 470 579 6 22 631 6 17 5 97 579 6 09 3422 47 14 13 540 640 676 6 86 681 6 60 6 54 6 69 3754 48 1773 641 740 774 782 7 69 749 746 763 42 87 49 l 11 U 1054 270 356 391 397 393 3 71 346 38 2 2133 50 1240 303 399 446 449 447 4 21 398 432 2420 51 1419 361 476 522 530 528 507 467 493 2760 52 1 1(2U 1032 236 311 342 347 344 325 301 334 18 78 53 1314 270 366 403 407 408 386 351 394 2217
(Tt tO
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ h av Nu av
54 1448 301 408 447 454 452 431 403 438 24 61 55 1782 353 494 548 544 415 529 531 506 2843 56 2U 10 61 220 287 316 320 322 303 268 310 1735 57 1216 249 335 370 377 378 353 307 363 2044 58 1322 263 356 394 398 399 374 327 384 2159 59 1639 310 433 478 481 482 452 393 465 2617
60 1D 10 68 2011 2536 2657 2681 2694 2560 15 62 2625 14938 61 1399 2520 3239 3369 3371 33r82 32 39 1946 3320 18968 62 1669 2781 3655 3820 38 76 3883 3738 2355 3794 21712 63 1959 3524 42 37 4399 4438 4497 4417 3047 4397 25156 64 2295 4426 5288 5396 5372 5240 5410 3369 5341 30680 65 2636 5490 6531 6662 6565 6379 6820 4249 6591 37938 66 3390 7869 9538 9462 9387 8924 10508 62 91 9564 59601 67 1U 1190 352 368 401 413 407 395 293 397 2256 68 1559 397 422 462 475 471 456 331 4 57 2603 69 1904 434 465 5 13 529 528 504 358 508 2901 70 2211 493 526 573 5 92 588 564 4 15 569 3257 71 2289 569 587 6 30 649 6 61 6 49 460 635 36 44 72 2727 637 6 60 7 09 733 751 743 521 719 4140 73 3210 728 755 8 15 8 43 8 62 8 54 616 826 4765 74 2nD 1210 181 2256 2393 2399 2333 2206 1325 2317 13158 75 1420 2340 2752 2899 2913 2850 2728 1701 2828 16121 76 1692 2853 3306 3452 3471 3379 3217 2134 3365 19217 77 1894 3102 3588 3713 3736 3670 3557 2455 3653 20892 78 2301 3682 4259 4433 4467 43 83 4289 2892 4366 250 30 79 2621 4117 4828 5017 5012 5030 5109 3071 4999 28785
m 0
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 ~ hav Nuav
80 3230 5158 6006 62 13 61 18 6134 6695 4094 6233 359 87 8 1 12nD 1155 15 27 1854 2028 2064 20 85 1987 1164 1968 118 31 82 1689 2046 24 8 2 2688 2739 2760 2658 1749 2665 152 73 83 1244 2088 2317 2339 2345 2373 2381 1487 2351 13432 84 2100 3211 3539 34 21 3462 3512 3696 2575 3526 20284 85 2292 3 5 05 3761 3648 36 25 36 79 3957 2933 3734 21517 86 2907 4420 48 22 4679 46 04 4705 5206 3792 48 03 27741 87 33 80 59 35 69 38 7404 77 10 7 8 36 7 0 86 5190 7394 427 44 88 1 12D 1 4 27 2 4 58 28 31 3037 3021 2987 2927 18 57 2 9 61 16913 89 18 75 34 75 3 9 87 4230 4255 4317 4337 2734 4225 24258 90 22 59 4221 4796 5046 5052 51 01 5389 3491 5077 29206 91 2682 4978 5664 5943 5966 6054 6573 408 1 60 40 34795 92 3417 63 16 71 02 7 3 93 7385 75 40 8 6 95 51 45 7623 44017 93 c 1 5 17 1240 1305 1399 1467 1479 1429 9 26 1423 8251 94 20 34 1554 1623 1720 18 21 18 53 18 72 1215 1778 10229 95 2 3 48 1795 1843 198 5 2097 2171 2274 1540 2074 11947 96 2716 2028 2048 22 01 2 3 44 2444 2661 18 90 2340 13505 97 3247 2410 2375 2663 2778 2949 3298 2378 2793 1615 98 11 35 967 1040 1124 1186 1200 1142 728 1138 6496 99 14 06 1135 1220 1318 1384 1403 1 3 61 8 77 1336 7656
100 2311 1 8 54 18 78 1980 20 90 2136 2227 1653 2062 118 31 10 1 2666 2085 2094 2227 2 3 62 2438 2626 1902 2349 13508 102 3392 2635 2582 28 01 3026 3141 3529 2567 3016 17390
103 1 U 1235 349 395 434 436 4 28 411 286 423 2416 104 20 10 434 5 02 559 577 569 5 37 345 552 3177 105 28 14 538 626 685 711 7 21 682 424 6 8 6 3966
Q) j-J
TABIE III Continued
Run No Position CFM h1 h2 h3 h4 h5 hu h7 hav Nuav
106 3492 614 7 1 6 7 84 8 13 8 33 7 85 4 88 7 87 4562 107 4395 7 86 894 964 996 1005 9 64 640 9 65 56 06 108 50 75 9 11 10 22 1081 1112 1125 1085 7 24 1085 63 16 109 G 1344 9 22 1042 1120 1 1 46 1173 1131 7 04 1120 63 87 110 1936 1162 1340 1442 1474 1509 14 7 3 9 09 1441 82 77 111 2846 1631 1797 1902 1966 2027 2079 1342 19 2 3 11108 112 3484 207e 2144 2236 2307 2385 2574 1694 2268 13138 113 4066 24 65 24 42 2535 2648 2757 31 71 2178 2 5 96 15078 114 50 12 3059 2916 30 1 5 3176 3312 4059 2849 3105 180 46 115 1D 1362 2268 26 13 2613 26 35 2605 2503 15 46 2617 14934 116 1958 2993 3580 3580 3586 3539 3 5 02 2144 3571 20492 117 2812 4430 50 32 4913 4 9 86 4991 5196 3088 4981 287 66 118 3432 58 16 62 13 6067 61 18 60 66 6698 4143 61 16 354 16 119 40 22 71 71 7 4 62 7369 7419 7329 82 74 51 8 1 7395 42909 120 5026 105 95 11456 115 81 11574 11548 14010 80 91 11540 671 15 121 2D 1244 18 57 2277 2363 2305 2210 2107 1466 2289 13038 122 1960 2622 3240 3388 33 23 3226 31 40 2)99 3294 18919 123 2817 3762 45 87 4739 46 56 45 14 4 6 47 30 15 4624 26689 124 3491 50 22 5723 58 53 57 44 5542 60 18 3871 57 16 330 73 125 4096 61 29 68 16 69 79 6805 65 90 74 79 4677 67 98 39400 126 5037 82 27 94 60 95 69 93 57 9023 11324 65 05 93 52 542 83 127 12D 1278 14 70 1 6 48 1652 1638 1 6 34 1641 9 73 1 6 43 9369 128 1947 19 63 2155 2149 2151 2131 2190 1347 2147 12342 129 2769 2615 2791 2773 28 52 2716 2954 18 96 2783 1 60 82 130 3439 3208 3265 3239 3593 3133 3624 2515 3308 19174 131 4103 3637 35 88 3577 4077 3459 42 66 3138 3676 21343 132 49 78 45 82 44 60 44 8 1 55 17 43 25 5749 4227 4700 27288
Q) tlgt
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
133 1 12D 1299 2094 2507 2622 2625 2567 2489 1465 2578 14736 134 1973 29 56 3505 3772 3790 3718 3718 2115 3700 21290 135 2788 3941 4727 5069 5099 5 0 07 5231 2984 4976 28781 136 3473 5155 59 81 6308 6339 62 39 68 96 4204 6217 36052 137 4118 6135 71 8 6 7662 7731 76 91 87 16 49 8 5 7568 43985 138 4973 7765 94 75 10396 10861 10694 13646 66 64 10357 602 25
139 1ttn 1253 1242 1493 1460 1442 1431 1424 8 84 1457 83 01 140 2366 1942 2150 1961 1910 1897 19 62 1206 1980 11400 141 3461 3007 2957 2562 2513 2606 3143 18 51 2660 15400 142 4325 3942 3571 3060 2999 3198 4248 2631 3207 18618 143 5677 508 6 4359 39 88 3800 42 29 57 78 36 26 4094 23824 144 67 59 64 55 5330 4988 47 25 5494 2517 48 09 5134 29906 145 84 08 9326 72 26 7726 85 56 9172 12319 7733 8170 47626 146 86 54 9831 7582 818 9 94 90 9869 13116 78 97 8783 512 96 147 7376 7335 58 7 6 5941 5796 68 29 81 65 5954 6111 35662 148 2 11 D 4254 4106 48 02 4994 5038 5042 56 78 3419 4969 28881 149 5708 5487 6253 6466 6524 6527 78 63 45 8 2 64 43 37566 150 69 7 8 7983 9440 9848 98 34 97 32 13249 6701 9714 566 59 151 1254 1434 18 53 1947 1915 1850 1760 1186 1891 10772 152 2713 2696 3175 32 94 3288 3237 3288 20 44 3249 18728 153 87 30 118 07 14733 15758 15504 15305 26297 9617 15325 892 71 154 5811 5278 6543 6861 69 30 69 82 7 8 74 4478 68 29 39531 155 4246 3780 4736 4975 49 66 4936 5162 3113 4903 28301 156 (v 1270 8 15 935 959 966 9 51 9 23 6 35 953 5430 157 2714 1164 1390 1427 1447 1454 1455 9 08 1430 8242 158 4310 1655 18 96 1942 1988 2002 2111 1305 1957 11349
(j) ~
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 fry hav Nuav
159 6012 2208 2400 2450 2513 2548 28 20 18 00 2478 14416 160 7279 2696 2881 2927 2989 3081 3599 2340 2970 17326 161 86 90 3257 3360 3 3 76 34 26 3558 4455 2943 3430 2000 162 12D 4368 2209 2600 2558 2518 2466 2774 1753 2536 14713 163 5833 2730 3092 3028 2974 2913 3501 2287 3002 174 78 164 7643 3320 3681 3630 3651 3530 4623 3181 3623 21116 165 87 39 3920 4303 4300 4708 4178 61 60 3937 4372 25456 166 1268 962 1203 1205 1186 1118 1084 725 1178 6693 167 2678 14 67 1785 1779 1752 1698 1726 10 70 1754 88 49 168 1 12D 12 83 936 1217 1414 1397 1239 1190 7 65 1317 7484 169 2729 2502 2930 2914 2934 2956 2979 17 52 2934 16866 170 4345 3884 4357 4283 4318 4421 4836 28 59 4345 25151 171 6036 5546 5858 5764 5791 6028 7129 4184 5860 34045 172 6578 7167 7769 7907 79 82 8263 10492 5915 7980 46437 173 87 84 10237 112 23 120 26 12727 12968 185 19 85 98 12236 71103 174 1278 1344 1803 18 72 1835 1790 1712 1063 1825 10355 175 2711 2328 2972 2932 2893 28 78 2863 1667 2919 167 51 176 4351 3934 4414 4353 4281 4321 4654 28 63 4342 25088 177 5994 5076 5824 5838 5818 59 29 6914 4205 5852 33885 178 1 11 U 1223 388 432 465 464 449 435 338 453 2585 179 2351 521 602 6 22 675 6 57 619 436 639 3687 180 34 48 6 05 1725 803 8 27 8 11 760 518 792 4593 181 4513 718 850 934 9 68 9 57 8 99 609 9 27 5386 18 2 5714 8 32 981 1060 1102 11 06 1034 6 59 1062 61 82 183 6997 1025 1182 1258 1295 1309 1234 8 18 1261 7 3 44 184 8709 1295 1487 1 5 42 1594 1626 1612 1156 1562 9080
TABLE III Continued
Run No Position CFM h1 h2 h3 h4 h5 h6 h7 hav Nuav
185 2 12D 4249 3560 4400 4670 4791 4695 47 81 2931 4639 268 37 186 5737 4926 58 54 61 92 6248 62 38 67 78 4134 6131 35590 187 7432 6390 7726 83 46 85 44 86 34 10371 5658 8313 48310 188 8723 7718 107 88 11933 12099 13046 186 22 79 39 119 67 69505 189 1 4 35 1340 1735 18 57 18 52 17 81 1711 1144 18 06 10256 190 2718 2399 3023 3187 3207 3138 30 53 1931 3139 18025 191 7 5 07 6189 80 11 9200 9427 9703 11364 5720 9085 527 38 192 8544 78 42 10666 125 42 13312 13775 178 20 6976 125 74 729 86 193 1287 1417 16 97 18 7 18 69 18 08 1720 1046 1800 10223 194 27 17 2450 2940 3187 3214 3157 3054 1749 3125 17954 195 42 53 3560 4222 45 90 4679 46 63 4743 2741 4539 26247 196 6068 48 69 57 79 6335 65 8 6 66 04 7172 4338 63 26 366 78 197 7389 58 86 72 8 6 82 23 8584 8936 10658 50 60 8257 4798 6 198 86 88 78 91 100 27 120 56 130 29 14299 190 81 6492 12353 71850 199 5864 4694 5 6 67 61 94 6419 65 48 7192 3950 6207 360 14 200 2 D 4177 38 36 4547 48 09 4775 4628 5006 2715 46 90 261 30 201 5712 5170 62 39 66 38 6599 6604 7518 4167 65 20 378 00 202 73 63 7201 8986 98 43 9733 9914 13353 6219 9619 55810 203 8604 10043 13118 148 41 150 42 158 66 25206 82 5 3 14717 85290 204 12 68 1506 18 41 1971 1966 1868 1799 11 42 1913 10880 205 2659 2571 3127 3276 32 50 3130 3069 18 80 3196 18 350 206 39 80 36 76 4347 4573 45~67 4473 46 34 28 37 4490 25910
o 207 Orifice 11496 10 64 1360 15 39 1 5 80 1 6 15 1496 8 58 15 24 88 83 208 9433 8 95 11 78 13 26 1394 1386 1263 727 1346 78 48 209 7387 746 9 77 1123 1184 1159 1048 6 11 1111 64 74 210 52 36 566 7 66 900 934 909 8 21 499 8 27 48 02
0) CJ1
TABLE III Continued
Run No Position CFM h 1 h2 hs h4 h5 h6 h7 hav Nuav
211 212
3309 1293
414 257
563 3 19
6 68 3 57
6 91 3 37
6 72 351
7 37 337
38 4 2 46
4 40 341
3748 1942
213 214 215 216 217 218
c of 2nd 1 516 1235
1919 2712 3320 4153 4704
1532 2447 35 46 4312 5567 74 29
2 1 87 3312 4225 52 86 6902 8 6 50
2360 3555 4340 56 12 7 0 49 8 9 40
2409 3598 4 8 85 5718 7713 9593
2347 2101 35 33 3453 48 00 49 62 5562 59 86 72~6 7 8 79 93 76 11237
1243 20 64 3054 4 2 8 1 5114 6983
2326 35 00 4638 5545 7225 91 40
132 13 200 27 26672 31968 41711 52811
bull
67
TABLE IV
PRESSURE PROFILE DATA
Baffle Flow Qpening Rate ~p
(Inches) Position (CFM) (Inches 295 S G Fluid)
1 364 l2 11 U 1012 0 254 1248 0197 1493 0 141 1718 0112
c 1000 9 80 1210 1710 1436 28 75 1746 4320 1011 1080 1277 2050 1393 3020 1 6 28 4450
12D 1011 9 75 1236 1520 1450 2510 1603 3450
1 D 1011 975 1256 1700 1480 2690 158 1 4070
1 12D 1010 950 1259 1750 1462 2650 1631 3710
2 11 D 1124 1315 1360 2130 1505 2850 1689 4125
1 216 12U 1294 045 1949 0324 2374 0282 2704 0225 3367 0169
c 1326 265 18 81 5 90 2313 990 2731 1480 3439 2660
12D 1272 2 49 1957 661
68
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Pos ition (CPM) Inches 2 95 S G Fluid)
2559 1275 3033 1940 3639 3025
1 216 1nD 1257 242 16 96 476 2117 8 05 2561 1280 2990 1895 3431 26 bull00
1 316 12U 1309 0 479 2004 0422 28 28 0 352 3526 0281 42 28 0225 5199 0225
c 1308 1 43 1998 272 28 14 5 10 3478 795 4248 1235 5048 1885
l2D 1286 140 2005 3 45 2831 725 3495 1180 4194 1805 5046 2945
1 11D 1322 150 2039 352 2841 735 43 77 1980 5378 3440
1 516 12U 1278 0493 2732 0493 4315 0408 5744 0352 7494 0352 8932 0422
c 1300 0 506 2731 1985 4310 348 6080 6 45
69
TABLE IV Continued
Baffle Flow Opening Rate ~ p
(Inches) Position (CPM) (Inches 295 SG Fluid)
7607 1090 8830 1585
l2D 1343 0549 2738 225 4566 583 6112 1195 7536 2055 9043 3415
1 516 1uD 1249 0464 2713 224 4155 579 5620 1150 7428 2115 90 70 3405
1 12D 1301 0493 2735 220 4501 616 61 50 1235 7440 2065 8862 3445
2D 1265 0 478 2750 226 4366 594 6578 1270 7678 2240 8945 5280
2 12D 1295 0493 2725 222 4293 600 5807 1120 7568 2200 9070 3615
TABLE V
RATE OF HEAT TR AN SFER Ar THE BAFFL~~ CID-TT ER
Orifice Size
(Inches)
Flow Rate
( CFM)
Re d e G tU
R~) 055 Nuav NuPr-l3
1 364 10 26 12 90
8 075 10015
43400 54 600
85 11 99 64
95 83 112 19
1416 11 140 59 900 110 30 124 20 16 27 12 800 68 900 126 64 142 60 17 29 13 610 73 200 135 79 152 90 17 76 13980 75 200 147 59 166 19
1 216 11 35 14 06
8 600 10 660
27000 33500
6 4 96 76 56
73 14 8 6 12
1517 11500 36100 82 51 9291 20 34 15400 48400 10229 115 18 23 11 17500 55000 118 31 13322 2348 17 800 55900 11947 13452 2666 20 200 63400 13508 15210 27 16 20 600 64700 135 05 152 07 32 47 24600 77200 161 57 18 193 3392 25 700 80700 17390 195 8 1
1 316 1344 19 36
9898 14 260
24800 35 700
63 8 7 8 2 77
71 92 93 20
28 46 20 9 60 52 500 111 08 125 08 34 84 25 660 64200 131 38 147 93 40 66 50 12
29900 36900
74800 92400
150 78 18046
169 78 203 20
~ 0
TABLE V Continued
Orifice Flow Re Size Rate d e G R~rmiddot55 NuPr-13(Inches) (CFM) U Nuav
1 516 12 70 8 847 16800 54 ~0 61 14 2 14 18 900 35800 82 42 92 80 43 10 30 000 56900 11349 127 79 60 12 41900 79400 14416 16232 7279 50700 96100 17326 19509 86 90 60540 115000 20098 22529
TABLE VI
RATE OF HEAT TRANSFER AT THE POINT OF MAXIMUM HEAT TRANSFER
Orifice Size
(Inches)
1 364
1 216
1 316
Flow Rate
(CFM)
1054 1294 1431 1681 1770
1068 1399 1669 1959 2295 2636 3390
1299 1973 2788 34 73 4118 4973
Re deG Mshy
8 300 9870
11260 13200 13 930
8100 10600 12650 14850 17400 19980 25700
9 570 14500 20500 25600 30300 36600
R~r-6 51900 61700 70500 82 500 87 100
28200 36900 44000 51700 60 600 69500 89400
26100 39600 56000 69900 82700 99 900
Nuav
2416 293 5 3187 4018 4805
14938 18968 21712 25156 30680 37938 59601
14736 21290 28781 36052 439 85 60225
Uu Pr-1 3
27204 33050 3589 4524 541 0
16820 21358 24448 28326 34546 427 18 67111
16593 23973 32407 40595 495 1 678 13
TABLE VI Continued
Orifice Flow Re Size Rate deG R~rmiddot6 NuPr-13(Inches) (CFM ) M- Nuav
1 516 1268 88 30 17700 108 8 1225 2689 18700 37400 1835 2066 3980 27700 55700 2591 2917 4177 29100 58 500 2713 3055 5712 39800 80000 378 0 425 6 7362 51300 103000 5581 6284 8 604 59 900 120000 8529 9604
74
TABLE VII
EFFECT OF UPSTREAM BAFFLES ON HEAT TRANSFER
l 516 Inch Orifice
Center ot 2nd Baffle 4 Downstream
Plow Rate (CFM)
1235 1919 2712 3320 4153 4704
Flow Rate (CFM)
1270 2714 4310 6012 7279 8690
(Re)eb -8600 1321
13400 2003 18900 2687 23100 5197 28900 4171 32800 5281
Center ot Single Battle
-8847 543
18900 824 30000 1135 41900 1442 50700 1733 60540 2001
(Nu)(Pr)-l3
1487 2255 3003 3600 4697 5946
(Nu)(Pr)-13
611 928
1278 1623 1951 2253
75
ABLE VIII
HEAT TRANSFER IN THE TEST SECTION WITHOUT ORIFICE
CFM Ute) 0b h Nu
1293 5-951 3 41 1942
33 09 15251 649 3746
5236 24193 827 4802
7387 34001 1111 6474
9433 43419 1346 7848
11496 52-914 1524 8883
76
TABLE IX
PRESSURE DROP FUNCTION
Orltlee Size Flow Rate incbea ~CFM (Re)eb X 10bull8
1 364 1011 7957 0808 1256 9885 1468 1480 11648 2765 1581 12443 4160 1689 1_3293 4 020
1 216 1257 9530 1327 1696 12858 2663 2117 16049 4615 2561 19415 7581 2990 22668 11560 3431 26011 16440
l 316 1322 9736 1819 2039 15016 4332 2845 20952 9275 3495 25739 15300 4377 32014 26800 5378 39607 50100
1 516 1011 7 957 oaos 1256 9885 1469 1480 11646 2765 1581 12443 4160 1689 13293 4020
77
TABLE X
EXPERIMENTAL DATA
Baffle Hole Diameter Run No
1 - 59
60 - 102
103 - 138
139 - 206
207 - 212
213 - 218
(Inches)
1 364
1 216
1 316
1 516
No Baffle
2nd - 1 516
TABLE X
EXPERIMENTAL DATA
Run Thermocouple Reading s (mv) No Position CFM I tc1 tc2 tc3 tc4 t c 5 tc6 tc7 tcair
1 c 1026 530 2055 1825 1768 1782 1802 1837 1965 1198 2 1290 612 2059 18 65 1809 18 32 1851 1880 1965 1160 3 1416 714 2151 1970 1931 1965 1988 2026 209 5 1130 4 1627 8 21 2235 2084 2 049 2093 2126 2173 2266 1130 5 1776 865 2203 2033 1970 2015 2084 2159 2 264 1121 6 12D 1109 542 1636 1507 1499 1499 1498 1498 1528 1218 7 1258 651 1670 1522 1503 1513 1513 1516 1548 1221 8 1433 750 1625 1480 1467 148 3 1487 1487 1516 1153 9 168 1 8 73 1656 1494 148 1 1511 1517 1517 1543 1159
10 1rtD 1102 485 1545 1450 1437 1446 1447 1442 1466 1220 11 13 08 6 10 1571 1470 1460 1476 1476 1469 1498 1194 12 1464 730 1 623 1509 1508 1528 1 5 32 1524 1548 1173 13 11 06 8 71 1663 1559 158 1 1606 160 6 1 583 1601 1190 14 1 12D 1115 520 1698 1579 1575 1 577 1580 1590 1615 1280 15 1275 6 10 1692 1567 1558 1 561 1570 1580 1601 1234 16 1498 770 1760 1619 1630 1 635 1642 1645 1661 1204 17 1695 912 1775 1635 1670 1689 1686 168 6 1701 1165 18 2D 1049 510 1736 15~2 1567 1558 1 553 1558 1620 1236 19 12 41 610 1655 1517 149 1 148 1 148 1 148 4 1546 1108 20 1 5 32 7 35 1720 1550 1530 1520 1519 1523 158 0 1104 21 16 74 8 8 0 1900 1 727 1714 1696 1691 1692 1753 1169 22 1U 1074 38 5 3 324 2740 2534 2478 2 465 2503 258 0 1210 23 1287 4 35 3510 2 870 2682 2 610 2599 2638 27 1 9 1190 24 1 5 08 470 3 618 2920 2690 2 637 2627 2 664 2747 1177 25 18 07 525 4 088 3235 2962 2905 2910 2988 3130 1169
z ())
TABLE X Continued
Run No Position CFM I tc1 tc 2
Thermocouple Readings te3 tc4 tc5
(mv) tc6 tc7 tcair
26 c 10~29 6 32 2340 2~092 2032 2060 2~097 2152 2~213 1211 27 12 66 679 2270 2 047 1993 2013 2069 2142 2 210 1 182 28 1430 723 2336 2097 2033 2080 2153 2~255 2 356 1 138 29 1729 8 52 2318 2070 1980 2061 2158 2279 2367 1121 30 12D 1054 570 1520 1 4 20 1402 1400 1396 1400 1 443 1159 31 1294 6 69 1599 1469 1444 1439 1433 1 442 1485 1168 32 1430 7 88 1720 1562 1536 1532 1528 1537 158 0 118 5 33 1770 8 81 1641 1488 1450 1~441 1 441 1_466 1518 1 163 34 1D 1058 548 1579 1498 1495 1526 1553 1_557 1 571 1 276 35 1263 640 1609 1509 1515 1570 1599 1598 1 598 1 266 36 18 36 8 47 1538 1452 1483 1553 1602 1 590 1 558 1195 37 1 12D 1029 5 41 1 578 1499 148 4 1473 1461 1465 1-512 1200 38 1315 6 30 159 1 1504 1493 1482 1470 1470 1505 118 5 39 1 4 26 743 1765 168 1666 1660 1645 1642 1678 1270 40 1757 8 54 1744 1648 1634 1620 1598 1 593 - 1612 1223 41 2D 1080 5 30 1734 1604 1570 1 570 1570 1 588 1 640 128 1 42 1305 6 40 1744 1622 1589 1 608 1593 1 609 1 661 1240 43 1434 750 1798 1687 1658 1 636 -1641 1 661 1 711 1_220 44 18 04 8 41 1 764 1666 1607 1605 1614 1 635 1 675 1205 45 12nu 1088 415 2614 2295 2195 2 169 2174 2217 2256 1171 46 1318 477 2805 2477 2371 2342 2364 2 401 2 438 1 163 47 1413 5 28 2930 2 646 2 555 2 526 2532 2570 2 577 1 199 48 1773 550 2740 2518 2450 2431 2448 2 479 2 480 1 170 49 1 11 U 1054 380 3175 2670 2505 2 461 2467 2 534 2 621 1 258 50 1240 420 3268 2738 2 546 2 510 2 508 258 2 2 649 1214 51 1419 451 3364 2B07 2 632 2590 2 590 2 651 2773 1 215 52 1 12U 1032 360 3 165 2 629 2 450 2402 2403 2 473 2 bull568 1 163
--I lt0
TABLE X Continued
Run No Position CFM I tc1 tc2
lhermocoup1e Reading s tc3 tc4 t c 5
(mv) tc6 tc7 tc a ir
5 3 1314 38 9 3178 2592 2411 2367 2361 2432 2555 1140 54 1448 403 3095 2544 238 1 2336 2336 2390 2476 1158 55 178 2 427 3006 2434 2286 2253 255 3 2299 2397 1154 56 2 11U 1061 360 3369 2814 2619 2567 2560 2650 2833 1220 57 1216 360 3044 2512 2338 2290 2288 2374 2566 1150 58 1322 387 3196 2614 2425 2383 2382 2472 2670 1138 59 1639 403 3020 2438 2272 2238 2238 2318 2502 1127
60 1D 1068 612 1552 1424 1400 1395 1396 1426 1745 0945 61 1399 612 1355 1246 1230 1229 1230 1250 1509 0872 62 1669 710 1436 1293 1272 1265 1266 1286 1551 0847 63 1959 900 159 5 1468 1444 14 38 1432 1446 1720 0851 64 2295 730 1169 1105 1098 1099 1108 1100 1298 0781 65 2636 8 80 1202 1129 1121 1126 1 138 1115 1342 0748 66 3390 9 35 1060 o 9s7 0999 1001 1017 0971 1154 0703 67 1nu 1190 370 2225 2188 2104 2080 2120 2209 2 7 15 0990 68 1559 368 2005 1950 1871 18 48 1876 1951 2408 0916 69 1904 368 1870 18 1 4 17 34 1711 1730 18 07 2238 0875 70 22 bull11 471 228 6 2 204 2099 2063 2092 218 $ 2732 0840 71 2289 471 2030 2000 1925 1895 18 96 19 5 2498 0785 72 2727 4 71 1854 18 23 1753 17 23 1716 3758 2241 0743 73 3210 471 1680 1651 158 6 1559 1551 158 1 1950 omiddot7o9 74 2uD 1210 404 1261 1212 1198 1197 1205 1222 139 1 0978 75 14 20 540 1321 1260 1242 1 240 1249 1268 148 7 0918 76 1692 7 18 1467 138 6 1364 1361 1376 1405 1678 0883 77 18 94 903 1708 1 591 1565 1560 1575 1603 1948 0 857 78 2301 903 1530 1432 1407 1402 1415 1432 1738 0815
ro 0
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc117 tcair
79 2621 6 50 1069 1 020 1009 1009 1009 1007 1~189 o739 80 3230 901 1200 1128 1113 1119 1119 1086 1341 0694 81 82
l2D 1155 1689
360 575
1191 1345
1142 1252
1122 1218
1118 1210
1118 1209
1132 1228
1292 1446
0916 0822
83 1244 430 1163 1134 1131 1130 1129 1132 1292 0877 84 2100 645 1175 1135 1147 1 142 1138 1122 1286 0757 85 2292 8 25 1 354 1310 1327 1330 1323 1285 148 6 0728 86 2907 8 23 1180 1138 1151 1158 1149 1107 1268 0687 87 3380 902 1113 1049 1025 1011 1006 1042 1178 0673 88 89
1 12D 1427 1875
480 615
118 2 1140
1140 1095
1124 1077
1125 1075
1129 1072
1137 1072
1290 1243
0880 0790
90 2259 8 41 1296 1231 1207 1206 1203 1182 1419 0757 91 2682 8 80 1231 1170 1149 1147 1142 1112 1350 0731 92 3417 940 1142 1092 1076 1076 1069 1021 1252 0693 93 c 15 17 431 1321 1298 1268 1249 1250 1273 1522 0841 94 2034 505 1285 1263 1235 1209 1205 1206 1464 0759 95 2348 6 10 1395 1379 1334 1302 1286 1268 1536 0732 96 2716 706 1486 1480 1427 1383 1358 1311 1572 0 700 97 3247 7 56 1417 1430 1375 1320 1284 1223 1450 0660 98 1135 400 1425 1388 1352 1329 1330 1 364 1651 0893 99 14 06 440 1379 1341 1304 128 2 1281 1305 1583 0 831
100 2311 680 1602 1593 1553 1514 1502 1480 1 7 27 0 802 101 2666 680 1471 1469 1428 1390 1372 1335 1564 0761 102 3392 798 1491 1 509 1449 1395 1372 1305 1534 0 719
103 1U 1235 410 2469 2295 2173 2165 2226 2361 3120 0 897 104 2010 410 2017 1848 1 737 1706 1747 1865 2582 0753 105 28 14 410 1682 1535 1457 1427 1437 1520 2109 0 660
00 t-
TABLE X Continued
Ru n Thermocouple Rea ding s (mv No Positi on CFM I tc1 tc2 tc3 tc4 tc5 tc6 tc7 tcair
106 3492 440 1649 1499 1420 1391 1390 1470 2042 0620 107 4395 550 18 33 1679 1597 1564 1570 1640 2223 0583 108 5075 588 1779 1642 1580 1550 1552 1 615 2 191 0548 109 c 1344 398 1464 1 399 1364 1353 1350 1380 1689 0 907 110 1936 459 1369 1290 1253 1242 1 237 1259 1574 078 2 111 2846 580 1347 128 5 1251 1232 1220 1215 1 5 23 0 683 112 34 8 4 700 1392 1369 1339 1317 1299 1259 1599 0 636 113 4066 8 13 1449 1458 1427 1391 1363 1270 1595 0 591 114 5012 930 1484 1530 1500 1453 1420 1272 1580 0 580 115 1D 1362 513 1269 1218 1 217 1214 1220 1238 1460 0 893 116 19 58 600 1187 1122 1121 1120 1124 1133 1352 0798 117 2812 705 1052 1008 1015 1010 1011 1001 1218 0691 118 34 32 913 1105 1075 1085 1081 1086 1047 1301 0645 119 4022 980 1038 1021 1026 1023 1029 0983 1211 0 609 120 5026 982 0 8 61 0839 0836 0836 0837 0791 0955 0570 121 2D 1244 475 1320 1246 1233 1240 1255 1275 1434 0925 122 1 9 60 5 50 1160 1088 1074 1079 1089 1100 1260 078 7 123 2817 6 80 1096 1024 1 013 1018 1029 1022 1201 0 700 124 3491 960 1248 1175 1163 1172 1192 1153 1435 0 658 125 4096 989 1141 1089 1078 108 9 1105 1051 1310 0629 126 50 37 989 0983 0933 0929 0 936 0949 0880 1090 0 602 127 128
12D 1278 1947
402 545
1270 1261
1 230 1216
1228 1216
1230 1 215
1235 1223
1242 1219
1483 1514
0 913 0778shy
129 2769 695 1273 1234 1237 1221 1251 1212 1525 0678 130 131 132
34 39 4103 4978
8 40 9 80 9 80
1336 1448 1271
1322 1458 1 288
1328 1 462 1286
1 259 1 356 1157
1353 1492 1311
1261 1329 1138
1 555 160 7 1343
0 629 0 600 0599
(l) l)
TABLE X Continued
Run No Position CFM I tel tc 2
Thermocouple Readings tc3 tc4 tc5
( mv) tc6 tc7 tcair
133 1 l2D 1299 5 16 1 28 1 1212 1196 1195 1205 1221 1478 0869 134 1973 6 15 1163 1098 1073 1071 1079 1083 1343 0751 135 136
27 88 34 73
802 9 -_78
1187 1214
1099 1131
1069 1104
1066 1101
1075 1~110
1l061 1066
1370 1360
0662 0618
137 4118 9 81 1084 1010 0983 0979 0982 o937 1209 0581 138 4973 98 1 0969 0897 0 868 0855 0860 0799 1041 0572
139 1D 1253 409 1371 1293 1298 1301 1309 1321 1578 0928 140 2366 480 1130 1 090 1 121 1130 1137 1132 1390 0744 141 34 61 6 38 1081 1086 1152 1161 1147 1069 1382 0644 142 143 144
4325 5677 6759
7 90 939 998
1110 1115 1034
1161 1208 1139
1253 1268 1180
1265 1302 1215
1228 1230 1123
1080 1056 0970
13$913r12 8
0601 0561 0542
145 84 08 989 0863 0961 0934 0895 0871 0 785 09 9 0530 146 86 54 9 80 0808 0901 0 872 0821 0809 0733 0891 0498 147 7376 9 80 0 927 1032 1027 1 040 0961 0889 1032 0511 148 2D 4254 776 1 050 0 981 0965 0961 0962 0922 1155 0579 149 5708 991 1102 1031 1014 1009 1010 0931 1227 0528 150 69 78 990 0914 0853 0839 0 839 0843 0759 0996 0521 151 1254 490 1 479 1352 1329 1334 1351 1379 1607 0930 152 2713 7 00 1310 1220 1201 1201 1211 1209 1516 0723 153 8730 991 0809 0756 0742 0745 0 748 0663 0874 0543 154 5811 966 1219 1108 108 6 1081 1079 1033 1330 0650 155 42 46 8 02 1248 1136 1114 1114 1118 1103 1376 0 699 156 c 1270 429 1671 1571 1551 1545 1563 1600 1933 0929 157 2714 488 1398 1285 1 267 1258 1262 1275 1628 0729 158 4310 642 1424 1318 1299 1282 1283 1261 1683 0617
co ~
TABLE X Continued
Run No Position CFM I tc1 tc2
Thermocouple Readings tc 3 tc4 tc5
(mv) tc6 tc7 tc a 1r
159 60 12 780 1461 1388 1370 1349 1343 1279 1700 0 573 160 72 79 8 60 1402 1344 1330 1312 1292 1189 1 566 0 520 161 8690 982 1472 1442 1437 1 422 1392 1224 1602 0 521 162 163
12D 4368 5833
6 30 8 30
1195 1368
1105 1270
1111 1283
1117 1294
1131 1313
1081 1194
1369 1553
0613 0 553
164 76 43 959 1428 1338 1348 1341 1371 1180 1488 0535 165 8739 984 1345 1272 1272 1208 129 3 1059 1361 0550 166 1268 459 1701 1548 1541 1547 1589 1 625 1976 0 973 167 2678 570 1485 1351 1349 1356 138 1 1 385 1795 0760 168 169
1 12D 128 3 2729
448 650
1664 1314
1501 1232
1425 1233
1428 1229
1491 1229
1527 1232
1869 1571
0 962 0767
170 4345 847 1245 1179 1187 1182 1172 1132 1476 0 650 171 6036 9 76 1139 1109 1117 1114 1095 1020 1332 0588 172 6578 9 72 0982 0949 0942 0938 0926 0 8 50 1079 0560 173 87 84 9 72 0880 0854 0 8 36 0822 0818 0 749 0941 0585 174 1278 480 1564 1416 1397 1403 1417 1445 1733 0998 175 2711 590 128 3 1175 4 1178 1182 1187 1195 1493 0796 176 4351 8 90 1331 1259 1266 1275 1272 1235 1592 0 682 177 5994 9 60 1228 1152 1150 1151 1143 1075 1 360 0644 178 lU 1223 408 2282 2140 2052 2052 2106 2188 2626 0 878 179 2351 408 178 1 1623 158 5 1519 1556 1634 2068 0717 180 3448 482 1888 1675 1570 1541 1572 1665 2199 0629 181 4513 563 2026 1797 168 4 1644 1670 1770 2385 0583 182 5714 589 1913 1700 1610 1568 1580 1 682 2382 0551 middot 183 6997 653 1903 1718 1643 1611 1612 1700 2326 0 549 184 8709 6 80 1738 158 3 1543 1510 1498 1519 1 912 0577 185 186
2 12D 4249 5737
660 9 74
1055 1221
0 979 1122
0960 1093
0 952 1088
0959 1090
0 956 1054
1147 1350
0661 0602
187 7432 9 8 1 1065 0981 0951 0942 0 939 0881 1135 0582 CD ~
TABLE X Continued
Run No Position CFM I t o1 to 2
188 87 23 9 83 0944 0 879 189 1435 585 18 26 1630 190 2718 690 1433 1298 191 7507 950 1070 0961 192 85 44 964 0982 0 881 193 1287 600 1806 1668 194 2717 7 80 1579 1444 195 4253 8 81 1371 1260 196 60 68 9 78 1252 1152 197 73 89 975 1100 1000 198 86 88 973 0953 0 871 199 58 64 9 81 1269 1155 200 2D 4 1 77 915 1362 1251 201 5712 975 1213 1111 202 7363 9 78 1036 0 951 203 8 604 973 0932 0861 204 1268 6 95 2015 18 20 205 2659 6 96 1405 1295 206 39 80 7 98 1261 1174
No 207 Orifice 114 96 509 1325 1148 208 94 33 509 1477 1243 209 7487 5 09 1686 1409 210 5236 505 2094 1691 211 3309 428 2188 1 778 212 1293 392 2976 2560
Thermo ooup1e Readin g s (mv) to 3 to4 to
5 to
6 to7 toair
0 851 0847 0 8 29 0759 0987 0592 158 4 1583 1611 1647 1993 0986 1270 1266 1 279 1298 1604 0 789 0916 0908 0900 0 858 1115 0602 08 39 0 823 0 818 0 770 1035 0602 1609 1602 1629 1676 2153 0979 139 1 1385 1400 1 430 1938 0776 1212 1201 1205 1201 1601 0669 1 105 1086 1086 1 052 1371 0621 0952 0936 0923 0870 1195 0582 0 8 20 0 801 078 1 0 729 1044 0569 1108 1090 108 2 1043 1407 0610 1218 1221 1241 1202 1582 0659 1081 1083 1084 1031 1 368 0622 0921 0924 0919 0 841 1111 0 610 08 34 0831 0 821 0 751 1003 0 630 1761 1761 1 809 1861 2399 0966 1271 1271 1295 1311 1650 0797 1150 1150 1161 1149 1440 0703
1083 1057 1053 1109 1566 0~530 1158 1125 1138 1217 1763 0 526 1291 1250 1278 1383 2038 0542 1518 1478 1519 1657 2420 0 589 1596 1557 1601 1737 2441 0688 2370 2344 2409 2561 3 297 0921
()) (11
TABLE X Continued
Run Thermocouple Readings (mv) No Position CFM I tc 1 tc2 tc3 tc4 tc tc tc tc i5 6 7 a r
C of 2nd 213 516 1235 4 63 1 432 1291 1265 1258 1 268 1 308 1550 0 971 214 1919 6 17 1357 1223 1196 1191 1199 1211 1461 0 851 215 27 12 8 35 1401 1259 1278 1220 1230 1218 1511 0 762 216 3320 981 1439 1305 1270 1259 1275 1238 1450 0719 217 41 53 980 1251 1142 1132 1094 1121 1088 1305 0 695 218 404 987 1102 1042 1030 1 bull006 1014 0960 1133 0681
Supplementary Equations
Calculating temperatures from thermocouple readings
t = -026tc)2 + 3512(tc) + 3201 (26)
where t is the temp in deg F and tc is the thermocouple reading in millishyvolts
Calculation of the thermal conductivity of air
k = 00000245ta + 0 0132 (27)
where k is the thermal conductivity in Btuhr rt2 degFft and ta is the air temp 1n OF
I I
bull co m