—

MR No. E5L03’

,,,’

NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS-=..,. _. .,...- . .. . *c ... .,_—

WAK’’IME Iuwolr”ORIGINALLY ISSUED

January 1946 asMemorandum Report E5L03

CORRELATION OF MIXTURE TEMPERATURE DATA OBTAINED

FROM BARE INTAKE -MANIFOLD THERMOCOUPLES

By H. Jack White and Goldie L. Gammon

Aircraft Engine Research LaboratoryCleveland, Ohio

NACAWASHINGTON

NACA WARTIME REPORTS are reprints of papers origimlly issued to provide rapid distribution ofadvance research results to an authorized group requiring them for the war effort. They were pre-viously held under a security status but ~e now unclassified. Some of these reports were not tech-nically edited. All have been reproduced without change in order to expedite general distribution.

E -273

31176013636640

lUICA MR NO. E5103

NmroIww AIJVISORY comI!i?mE Ron Amomw!l?xcs

Alr Technical

CORRELATION OF

IH?OMBARE

I’4moFimDuMmPoR!r

for the

Servloe Commnd, Army Air Foroes

METURE4TMIXRATUR!Z QNl?AOB’I!AINED

IN!!K!z-MANIl!’WIDTHERMOCOUPLES

By H. Jack White and Coldfl.eL. Mumon

A relatively simplefalr accm.racy,varicitio.1

eqution has been found to express, with~n maniPol.Z-c12arZc towzarature with chuwe

in en@w opetiti~ con;;t;ons. This equa~lon a.iiassociated cur;eshave been chocked hy mult.ic:linder-eagineilfltc,both teat stand andf1~@t, ovor a wide range oi operating condlticmo.

Ave:”n&e❑’.xtm’etemper[~tmesj ~~wdicted b;’the equations of thisreport, awe iY?aGC)~~l)l~well.w~tn results wl~hin tlm srme ral~e ofcai*bw*etor-airt,eupemiures from laboratories and ieGt stands otherthan tileNACA.

IIi’’lIROrnJCTiON

This pa~r is mte.aded to demonstrate the degree io whichmLxture-temperaturedata “waybe redu~ed to al~ebrcIc te~ andcorrelated m terms of the several pert~nent eng ne-o~rat~~ enddesign vallables. Ths info~matlon presented herein wes obtainedin the multlcylinder-a@ne phase of the trlptane and h~&h-performanoe fuel eveluat5on pro&g’am,requested by the Alr TechnioalService Command, Army A~r Forces. Much of the data ~ncluded hereinhave been presented in d“l.fPerent form in earlier repGrts (refer-ences 1, 2, and 3). In reference 2, a brief aualysla of them= bure-tempezzihz’ecorrulatlon was mde. The present reportextends the correintion to several other en@nes and includes dateobtained over a wider range of conditions.

2 ?ulCA MR No, E5L03ti

Reduction of mixture-tempratura data to m a~ebraic relat~onis of ~utereat ~or se~elal reaeons. .hni~o id-charge Lempmut .uresare of importance in en@e-cooling studies as well as in the col’re-lation of fuel knock-lzmit data foi-both ~ingle-cylinder and mnlti-cyllndel”test e~jnus. Tileprediction of average mixizwo hempe~~tureat any opel’atlW coudi+.?on permits fuel ‘tauxl:limlts to be e~timotodfrom a m!ninmm amcunt of teeb data, t-hereby~wmltil~ the el~minntiouof a greak volume of exyerimeutal tasting. Thh I!16thOdd WdJ L-31Sfurthermore leuds itsel.~’to varloufle~ines and may be used to ailvan-tage in con~i*l~ d~ff~nut e~lnco as to the.r lelatlve sever.t~upon fuels inasmuch as mixtw’e Leriperatureis suc;len inyur!,antvayiahle in f’ut’lLllockchal’acter.~sk+cs. MaLching of mlticyllndorknock-tesb cmllt: ons bj sihg:.e-q 1.”rider13LW’.IBZ!Is Clua-cly fac-1;tetodby an accuraLo evel”~.t.m of ?tilxiu’?eumymabuma for both.

Other measureuenta necessary 501’tti.eCOi’-WJAti-m of ?uxt.urotom-pcmaturos wure f’uel-alrrat:0 (requirin& fr.elflcw and a ;r fluw) audengine s~eei!!.Values of fuel IWw wum oh-~a~.&d by both a rotawtorand a react~on-ty?e z’lowmeter for the three flight engines and by arotameter for the test -6tanil en6ine. Au’ J?lGWwas determ~xmd iu f lj~iltf rum carlnmot or -rneterj w -prcseure data, suppiemnted by eilt-box cal’-brat Ion cumes, and ior the test stand ty a standard G--richflaz-platoorifice matalled acconiiqj to A.S .M.I!. lecommendab~om h a 2~l-jncll-dlmeter duct upstream of the carburetor. E~ii= sped was o?)~a~nodfrom electric tachometers in all casoc.

NACA MR No. E5L03

FOii.TION OF MIXTUNE-TEMPERMURM lZ~Vl?ION

A yartial flerivationOr th eqlmtiml Uecd in the analysis ofmixture-temperature data .fulbws. ~‘ symbols to be used are:

Tm

Tc

AT~

ATV

v

VI

,T

cl?

~

K

qQd

7

N

R

d

F/A

L

Cf

nunlfold-mixtme temperature, (%)

carbureLor-alr temperahr~e (screen tbermoooupl.e), (%’)

bem.peraturerise

temperature drop

across euperoharger, (%’)

due to fuel vaporlza%zon, (~)

Mower tip

blower t ~p

mectinical

Eq)eetl,(l’1/EJnc)

3

The mafi~dd-m; xture Wmuorature is ausmed equal to tLc!sumof the carburetor-&r temLmra%ure LJlus“LIIotemperature r“LGedue tooompresslon in ti supercimr~er lese the tomperat~re imp due tofuel Nanorlzati..n. In f’kym’o3 .s ahcrtm a scheymtic crcms sectionthrongh a typical au-cooled engine inducbion systum. The arrav.o-mont of the thermocouples typlfies that of’the dcublf.-row radial

4

air-cooled ewines discussedoharge t6m~eratures shown et

rwA MR No ■ IEL03

hgrei~. The trends in “dry” and “wet”the tog of this sketch are considered

repmsantat Xve of the genera1 variatIon in tmperatuzws to be expectedtbruugh an inductlon system of %uie t~e. !IWs,

Tu = Tc + ATS - ATv

(1)

If J 1S ‘/78,‘P

is 0.245, anl G 2s 32.2, equation (2) beccmes

ATSV2

=K— G’bo (3)

‘Thefactor K in eqnatiol (3) my be ovalna%d In tgrms of thephysical clm-acter~btics of the acl;unl.l-w~mllu and d~f;ueor. Thus,

+ q.~ATS = ~,u~-----

An average rat~o of 0.3@ ‘hasbeen i’oundexpe~imor.tnll?to be repre-sentative of su~lerchargcrs fol” th~s t~~>e Qf cngll~; tkGreI’Oi”ti

ATS = L.4G x 10-4 ? (4)

3.J.4Nli dHowever, blumr tlp speed V = ~X—U—

For engines A, ~, and C wLth tmpcllers oi’ 11.3 -~nch dlamoters and atlow Impeller gear ratio (/.15:1), equntlon (4) rmy be ex.nwascd

at hiLh ~mpeller Lear rat~o (C.’li’:i) uquation (5) becomes

ATB = 2.5U X 1.0-5# (6)

It sWUIC. be Vointed out that for ungil.eD mth en ~mpcller of ll.U-Iuoh ~iarmter both equations (5) and (5) wilJ.be sl.i~htlyd:fferent.

i?ml Mq no ● lmlo3 5

The tempemture drop due to fwl vaporizatloa for charge thermo-couples, aEIIns ballwl in these en@nes, has been found empkkd.ly *Obe appraxl~teii by “ , .. . s . .

ATV = 390 F/A (7)

Expression (7) differs considerably frcm a longer form, whichrmy express this Iimperature drop more preci~ely as follows:

LATV = ——. F/AGv + Cf FE

This sxpresslon is often shoti.enod(by eliminat?on of cf x F/A) to

=. F/~ATV = -&.

P

or approxhnately

Aff

v= 530 F/A for an AT-F-Zd fuel (7a)

Equation (7a) differs tlom (“i) oily In tno u~,r!.tudeof the prol]or-t;onelity co,lstant. This ulfi’e~nce moy h the effect of o@parttal vapor?.zatio’~of tho fnel in the intnke mani:’okdsup to thepoint whore tie ~heimo~cupl~eart>locahd, aa shuw.1In f’l~:ro3.Tne d.~fl’cmxmc6butveon equationa (7) and (7a) me~ also Gz’isefromthe fact thnt the coolYw uffcct of fuel vaym~zat-’.undumnfi corl-preasion in kho supei’charflcrhas not cons.Lde~”edInasmuch ea ATV

was aosumed to talw place jude~rd.en~.lyof tho c~TleSSi>lL Troqcss.

l?lnally, the gwertil f’orw of the equation nay be wr; ttun,mkl~ use of expmaaion (4), /’

Tm =To+l.48x 13”4$-39G F/A ~ (8)

or .

Tm = Tc + 4.1 X 10-8V12 - 590 F/A. “ “

For sgecific application to engines A, B, and.C this equhtionbecomes

.Low blower:

Tm = Tc + 1.03 X lU-5 # -“390 F/A

.

moA m Ho. E51K)3

High blower: (engl=s B and C only)

Tm = Tc + 2.58 X 10-5 # - 390 T/A

Tna clwes In figure 4 ara presented as a Lemorsiratioa of theappl:cahion of such equat IOIIS. With these relations it becomesToss-tileto dutemiua Vjtiiease the avcnuga opom tlz~ mixtuzw tmpor-ature for a wide rawe of engina condlt~ons.

.

RNSJL’IEAm DiSCXiSSION

Tho cozzwlotod. udxttwa --temwratur.e data for the four engines cueshown in f igurs 6. TLG ran&os of en&lw cc.mii~tio~em dkown im thekey to this fl~o . The scatit~r of these data Is gcnurally i~ithina band of 10° F. The range in mixtui’e tewjeruture (from approx’ima ie~120° to 280° F) repro seLts variation In engine condj t Ions from 1890rym, low blower at g~” F C~b W@50r-aii* t~mw~ turw, to 2WlJ r.gm,hi&h blower at 10U” d carb~ Lor -air tmpera cum.

It 5.s of interest to cGm-garothf3CGrrebt jon Gq~tiOn deter-mined in th:s rqort with data from outsjdo sources. !Nx#erdthisend, figure 7 is jncluded to show thu i@?ee of slmilarit~ b&Lweonthis conwlat 1on and that presented 2n zufei’ence 5. ‘IIw b sl~d .curve (without data polfits ) is the t for a carburetor-air iwqwratureof 100° F ati a fuel-am ratio of 0.05 obtained from tiie oqwtlon

-..

reported herein. The difference between the two cur~es is aopn tobe appraxi.mately2° F at the hl@-temperature end (28!)0F) and 15° F.at,~hp .low;temppratqreend (120” F). The curve from’refcn’ouce.5wes ~ound to fit tho e~r~&ukal’ daka with ‘aban” devY.atlon of+6.6 ?F. This curve can be rou@ly approximated”by the f011@Q6equation: . , .

.,-. ...

Tm = 0.7 To + 3.7 x 10- %12 .-600 F/A + 60 “ (9)..

When equation [9) Ia.mmpared. wi\h equation (8) it is seen th& thefirst two terms after the equal blgh”ard dlfferont in magnitude butare climunsio~l~u and exponeptial~ alike. The chief differmmsto be discurned.are the variation in uffect of rarburetm-aiz tGm-ymature, tho nm~i”~udo of tcxupui-aturedrop due tu fuel va~orizat~on,and tho final consLarit. AfJpreviously menticmod, the offoct ofcarburetor-air tcmpum+.ure was n~.ttnv~st!~ated owr a very widerange for the tests in the p.ws,~nti~~~o~b; consequently it is notfult that this tm’ in thu equaLIGn ~a as corta~n ovur as wide aran~c of variction as are tho GE%l’s.

A bettor apnroximatiou to tihocor..mlationcurvo for tho datafrom ruferonc~ 5 (f.Ig.7) was ob”balncdby thu use of tho equation

0.7 T, + !5.2 X 10-10 VIZ-37 - 6C0 F/A + 70Tm = , (lo)

Equation (10) fits th curve shxm from rderunce 5 w.:tha mealdeviation of app-qoxiwutoly+1° F o~or the total ran@ of tl.w curve,wh~reas equation (9) (;.nvolv.!.ugV1 ) %s a moan dcv~.at:.cnof ap~rox-mntely &3° F.

. . . .

The following results were oMaitid from a la??ge”amount ofqixture response fuel bock data fr& fow”dduble~rti ”fiadial air-cooled ehginee: . “ . . . .. .“. . .

“’ 1. Average engine mlrture ter@erat&esWdr& co-lated by the&nekl equation . . . -,. .

...

~ = To + 1.48 X 10+ V2 -“390 F/A “ -. .

where -.” .’

. . . . . .

“ Tm mhnifold-mitiure .tempez&turg, (OF) . . “. . . . . . .

0 HAcAm Ho:

To carburetor-alr temperature (screen thermocouple), (OF)

v blower tip speed, (ft/see)

F/A fuel-alr mtio

2. For the engines A, B, and C, this equatim oan be written

Low bluwer:

Tm = Tc + 1.83x 10-5 N2 -390 F/A ~

where N Is engine speed h revolutions per minute.

High blower:

Tm = To + 2.58 X 10-5 N2 - 390 F/A

3. The mixture-temperature correlation equations obtained inthis work agree fairly well with the correlation data reported byan outBide source.

Aircmft Engine Researoh Laborat~,Mhtlonal Advisory Committee for Aeronautics,

Cleveland, Ohio.

REFERENCES

1. White, H. Jaok, Blaokman, Calvln C., and Werner, Milton: Flightand Te&Stand Investigation of High-Performance Fuels in Double-Row Radial Air-Cooled Ehglnee. II - Flight Knook Wta and Com-parison of Fuel Knock Limits with En@ne Coollng Limits in Flight.NACA MR No. E4L20, 1944.

2. White, H. Jack, Pragliola, Philip C., and Blackmn, Calvln C.:Flight and Test-Stand Investigation of High-PezYormanoe Fuels InModif led Double-Row Radial Air-Cooled Engine s.. II - Flight KnmkIkLta and Comparison of Fuel Knock Limits with lhglne Cooling LlmitaIn Flight. NACAMRNo. E5H04, 1945.

3. Blaclman, klvin C., and White, H. Jaok: Flight and Test-StandUmestigatlon of High-Performnce Fuels In ModMied Double-RowRadial Air-Cooled Engines. III - hock-Llmlted Performno e of 33-Ras Compared with a Triptane Blend and 28-R In Flight. NACA.MRNo. EEC8, 1945.

4. Werner, Mlltou, Illackmn, Calvin C., and Whlto, H. Jaok: ‘Flightand Test-Stand Invest:.gatlon of Hlbb-l?crformnoe Fuels inModiflod Double-RmT Radial Air-CoolfidE@uea. 1 - Determin-ation of the Cooli-~ “C-har&oterlsticeof the Flj&ht Engine.~cA ~ NO. E5G4)9,1945.

5. Webb, R. M., Mason, J. M., Jr., and Soanoskl, 13.: EfifoctofAiroraft Engine Opaatlng Variables (m Manii%ltlMixture Tom-poratlll-es. Ser. No. AIL-858, Aero. Eng. Lab., Naval AirMatorlal Center, Naval .41rI&p. Sta. (Pufladolphia),Bur.Aero., Navy Ik@.,. Juno 28, 1945.

‘Fig

ure

I.-

Inst

alla

tion

ofm

ixtu

reth

erm

ocou

ples

indo

uble

-row

radi

alai

r-co

oled

engi

ne

inta

kepi

pes.

C.13269

9.28.45

z ● wF

igur

e2.

-In

stal

Iat

ion

ofdu

alca

rbur

etor

-scr

een

ther

moc

oupl

es.

5 w

NACA MR No. E5L03

II

T-!.. ——— ———-1Dry

i ATV

1’Tm

AT3 /Withfuel

I

1Tc

II I I /

Figure 3. - Schematic sectinduction system.

/

Tc Thermocoupleon screen

Tm Thermocouplein manifold

.

NATIONAL ADVISORYCOMMITTEE FOR AERONAUTICS

on of a typical radial-enqine

NACAJ4R No. E5L03

NATIONAL ADVISORYCOWtTTEE FOR AERONAUTICS

Ourves plotted by use of followlng equation:

Tn =

——---- .10

200

&

; 180f.w“L

2a

: 160QE::

: 140

2 0

.:.: 120d

:

0

100

d’ K0 /

80

/

60

401600 1800 2000 2200 2400 2600 2800

Engine speed, rpm

(a) MW blower (7.15:1);enginv A,B,~nac.

Figure 4. - Calculated relation between engine speed, carbureto-alr temperature, fMel-alr ratio,~d mixture temperature. Impeller diameter, 11.3 inches.

— —— ,- —m— —m-l- mm— -11— -Immm mll lmml11-11-1 -1

NACA MR No. E5L03

320NATIONAL AOViSORY

COMMITTEE FOR AERf)NAuTICs II

““ Cwwc Plottad -by use of following equation:300 —

Tm = T= + 2.* ~ lo-5& - -j90 ~/A

Fu:;i:; r

2s0 0.06.— .06 0---- .10 /

260. /

c,cl

240

g.

j 220

$!s ~e~

200g

: / <//

/

: t

/ ‘/ ,

//

: 180

zuuz

/ /’ / / /

; 160usu / ‘

140.

/ ,“/

0 /

120 / /

/

/’

./

// /“ / ‘

/ // ‘/

100

/ ,/

/ ,-/

80/

60

1600 1600 20C0 2200 2400 2600Enel”a s~ed, ~W

2800

(b) HIRh blower ratio (g.q7:l); engines Band C.

fi~m 4. - Conohded.

NA

TIO

NA

LA

DV

ISO

RY

CO

MM

ITT

EE

FO

RA

ER

ON

AU

TIC

S

165

A)

/\/i

/ \\ t/ \\ t

/\/ .\ <

/ \\ {/&

<

160

‘<M

YE

ngi

ne

Man

ifol

dF

uel

-A

vera

geE

ngi

ne

Inst

alla

tion

spee

d(~

)(i

~;~

~%

.)

%’0

(o~

.o&

155

g;F

ligh

t22

504/

3.3

0.06

516

2*“

GT

est

stan

d22

5049

.1.0

6416

317

0ni

ght

2250

46.s

.066

162

iu

2230

{16

5.0

7216

5

c*

i1

f$

160

~..

As

1Y

j15

5‘

~16

5‘

)/\

t\/\

f\<

zP.

\8

160

‘\r

.Jt

\,.,

/\t*

3

,

=17

0‘

165

‘/k

4

160

123

b5

678

9101

1121

31+

Cylinder

mgt

lre5.

-Manifoldmixture-temperaturedistributionpattema

forfourdouble-rowradialair-oooled

erglnes.

Impellerear

ratio,7.I.5:1.

I

NACA MR No. E5L03

●

NATIONAL ADVISORYCOMMITTEE FOR AERONAUTICS

260 ‘●

Hl@ blower: Tm= To+ 2.5s XIO-5N2 - 390 FIALaw blower: Tm = To + 1.g3 X 10-5 N2 - 390 F/A

260-

24cl

220 ❑

❑ ❑

LH=ttll-1111,,,,,I--u-L

1 -1/ 1 1 I I I 1 I

A

II

o~ * ?,. ;:~’;2:wEngine

160

o

140 #

1111 , 2w30 \ ioo-l O.ZO 13~R2 --trlptaneI I 1“”-” I~ B lTest stand lgoo to ~-to 0.06 to 22-R

120

E

I I I I I I I I 1 I 3P mlldlne

120 140 160I

1s0 200 220 Awl -t% -a-Average meaxured mixture temperature, OF ‘“- ‘“” ‘“

F@re 6. - l?OhtlOn bOtWOn calculated and awwage wamrad mlxtum temperature for &ubh.- ndtilair-cooled enginee in flight and teet-stati opention.

,.

NACA MR NO. E5L03

NATIONAL ADvISORYCOMMITTEE FOR AERONAUTICS .

360

Y340 -

320 /t

*

30o’

2go I

I ‘

J

I

g 260- 07.

!

h /4

g%2 40~ p+. *

2

I +

/~ 220

,z

N~g Engine Source of data

g2 00 + ~liSOn V-171OF Alllson

X Alllson V-1710-gl NACA-Cleveland# Wright R-lg20 C90C Wright Aemnautlcal

h Wright R-1E20-56Corporation

160, hLJ [

/,

1

E p. & w. XR-1E30-74

@ /4O wright R-Is20-56❑ Wright R-lg20-22 A.E.L.

O P. & W. R-2gO0..22

160 ~ Wright R-3350-I4V Wright R->J50-lk

/e

P ‘ / — Mixture-temperature correlation presented in1Ml / reference 5

I

/ / --- Correlation for data of this rep rt

v/Equation: 8Tm - Tc + 4.1 X lb V12 - 390 F/A

/

120 /

100 30 40 50 60 70 go x 103

Blower tip m-d, VI, Tth.in

Figure 7. - Carrel.atlon of mlxturs-temPera~re data from outside sources. Carburetor-air temper-ature. 100° F; fuel-air ratio, 0.05. Plot obtained from plate 1+c,freference 5.

IJhite, H • Jack Gammon, Goldio

AUTHORS)

QGOTDDCTO®

IWVISraNsPoner Plants, Reciprocating (6) SJCTtON: Induction and Supercharging (2) dOSS nSERB^CES: Riel-air mixtures - Temperature Eeasurement (42262.7)

lAlTO- 1S802 [ORIG. AGENCY NUM3EQ

tl.R. ESL03 REVISION

AMEQ. TITLE: Correlation of mizture-temperature data obtained from hare intake-manifold thermocouples

FORG-N. TITLE:

OMGINATIXG AGEMCY: Rational Advisory Committee for Aeronautics, Washington, D.C. TRANSLATION:

COUNTOY U.S.

LANGUAGE VOOG-NOASS U. SXLASS.I DATE I PAGES Restr. | Jan'46 | 17

FEATUOES photos, dlagr, graphs

The degreo to nhlch mixture-temperature data Eay be reduced to algebraic terms is demonstrated and correlated in terms of the several pertinent engine-operating and design variables. A relatively simple equation has been found to express, oith fair accuracy, variation in canlfold-charge temperature uith change in engine operating conditions. This equation and associated curves have been cheeked by multicylinder data, both test stand and flight, over a uide range of operating conditions.

HOTE: Bsquooto for copios of this report must bo oddroocod toi H.A.C.A., tjaohington, D. C.

T-2. KQ, AQ MATEtra COMMAND AnVECK«!CAL ONDEH WRIGHT FIELD. OHIO, USAAF /,. ^ OJ-O-11 UAH 47 Tl.r~~>

T50i«FC*e9A (I3MIHT) RESTRICTED .-

DIVISION:Power Plants, Reciprocating (6) U SECTION: Induction and Supercharging (2) CROSS REFERENCES: Fuel-air mixtures - Temperature measurement (42262.7)

ATI- 15802 White, H . Jack Gammon, Goldie

ORIG. AGENCY NUMBER

M.R. 59*63

AUTHOR(S) REVISION

AMER. TITLE: Correlation of mixture-temperature data obtained from bare intake-manifold thermocouples

FORG-N. TITLE:

ORIGINATING AGENCY:National Advisory Committee for Aeronautics, Washington, D.C. TRANSLATION:

COUNTRY U.S.

LANGUAGE FORG'N.CLASS U. S.CLASS. Eng. Hestr.

DATE Jan'46

PAGES 17

FEATURES photos, diagr, graphs

ABSTRACT The degree to which mixture-temperature data may be reduced to algebraic terms is

demonstrated and correlated in terms of the several pertinent engine-operating and design variables. A relatively simple equation has been found to express, with fair accuracy, variation in manifold-charge temperature with change in engine operating conditions. This equation and associated curves have been checked by multicylinder data, both test stand and flight, over a wide range of operating conditions.

NOTE: Requests for copies of this report must be addreseed toi N.A.C.A., Waahinjrton, D. C.

T-2. HQ., AIR MATERIEL COMMAND AIR TECHNICAL INDEX RESTRICTED

WRIGHT FIELD, OHIO. USAAF /,. ^ WF-O-21 MAI 47 K.5C0

UNCLASSIFIED MS nVMORITZ*. INDEX OF liAGk TECHKICaL iUBLICATIOHS DA'iED 31 DEC&IBER 1947.