Active Enhancement in Industrial Heat Exchangers 1 Active Enhancement in Industrial Heat Exchangers...
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09/05/2011 1 Active Enhancement in Industrial Heat Exchangers Dr. Juan P. Solano Technical University of Cartagena Technical University of Cartagena Spain Departamento de Ingenieria Termica y de Fluidos Universidad Politecnica de Cartagena Reciprocating Scraped Surface Heat Exchanger (RSSHE) 2 Introduction Characteristics Spring Session PIN NL – Utrecht, May 11 th , 2011 • Hydraulic Piston Advantages: Characteristics •Reciprocating Movement • Scraping inner walls HRS‐Spiratube, S.L. • Self‐cleaning • Tube‐side enhancement • No down‐time
Transcript of Active Enhancement in Industrial Heat Exchangers 1 Active Enhancement in Industrial Heat Exchangers...
09/05/2011
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Active Enhancement in Industrial Heat Exchangersin Industrial Heat xchangers
Dr. Juan P. Solano
Technical University of CartagenaTechnical University of Cartagena
Spain
Departamento de Ingenieria Termica y de FluidosUniversidad Politecnica de Cartagena
Reciprocating Scraped SurfaceHeat Exchanger (RSSHE)
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Introduction
Characteristics
Spring Session PIN NL – Utrecht, May 11th , 2011
• Hydraulic Piston
Advantages:
Characteristics
•Reciprocating Movement
• Scraping inner walls
HRS‐Spiratube, S.L.
• Self‐cleaning
• Tube‐side enhancement
• No down‐time
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Applications• Food industry: sticky, long running times
Introduction
E t i l i
Spring Session PIN NL – Utrecht, May 11th , 2011
• Evaporator: pig slurries
• Bio‐fuels: continuous thermal hydrolisis
• Ice slurry production
Research methodology
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Thermal
• pressure drop
• heat transfer
• scraping power
• performance evaluation
Spring Session PIN NL – Utrecht, May 11th , 2011
Heat transfer enhancement
Thermal‐hydraulicdata
heat transfer performance evaluation
enhancement
Numerical simulation
Flow pattern
• local shear stress
• local heat transfer
• pressure forces
• scraper design
• macroscopicstructures
• pressure dropmechanisms
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Outline
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Spring Session PIN NL – Utrecht, May 11th , 2011
o Experimental technique
o Flow pattern description
o Thermal‐hydraulic results
o Performance evaluation
o Conclusions
Outline
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Spring Session PIN NL – Utrecht, May 11th , 2011
o Experimental technique
o Flow pattern description
o Thermal‐hydraulic results
o Performance evaluation
o Conclusions
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Visualization test rig
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Experimental technique
acrylic tube
Spring Session PIN NL – Utrecht, May 11th , 2011
propylenglycol/water
D=32 mm
Q(ℓ/h) =[100 – 250]
T (oC) = [20 – 70]
Reh = [20 – 20000]
hydraulic piston
electric heater
flow meter MAG
gear pump
Particle Image Velocimetry (PIV)
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laser
Spring Session PIN NL – Utrecht, May 11th , 2011
CMOScamera
external trigger
seededflow
• quasi‐steady flow: phase‐averaged
counter‐current
co‐current
time (s)
f
s
v
v• velocity ratio
• fs = 500 Hz
• 160 × 80 mm • resolution 90 μm/pix
• 1280 × 1024 pix
• adaptive cross‐correlation
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Thermal‐hydraulic test rig
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Ti T
10
15
16 peq pccp 1
p 211 128 9
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Experimental technique Spring Session PIN NL – Utrecht, May 11th , 2011
Tin Tout17
13
l
lp
h
23
T
19
11
21
22
p1
4
2 18 245 20
• secondary circuit
• chiller loop
Features• test circuit
Isothermal tests Data logger
• Regulation NI FieldPoint
• HP 34970A
• Control LabView
Uniform heat flux
• D=18 mm ‐ L=3 m
• propylene‐glycol
2
3h
22
ph
m32
DdDpf
)x(T)x(T
IV
kD
DNu
pfmppi
ee
h
hh
2t
pp
4
SDDW
cceq2
p2c
• Joule effect
• PT100 – TC Type T
Outline
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Spring Session PIN NL – Utrecht, May 11th , 2011
o Experimental technique
o Flow pattern description
o Thermal‐hydraulic results
o Performance evaluation
o Conclusions
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Visualization plane
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Experimental flow description
zr
θ
Spring Session PIN NL – Utrecht, May 11th , 2011
SIDE A
θ
P=5D
over the symmetry plane
Features
• periodic flow
• radial inversion every p/2
• assembly
SIDE B
0
,,2
,,2
zv
rzvrPzv
rzvrPzv
rr
zz
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Experimental flow description Spring Session PIN NL – Utrecht, May 11th , 2011
vortex
high velocity region
recirculation
g y g
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Motionless scraper
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Experimental flow description
mean flow directionReh=36
Spring Session PIN NL – Utrecht, May 11th , 2011
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Reh=36
Reh=58
Reh=87
Reh=106
Reh=72
Reh=106
0
1
2
V/V
me
d
tubo concéntrico
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Reh=132
Reh=170
Reh=213
Reh=265
0,25 0,5 0,75 1 0
1
2
r/R
V/V
med
Reh=265
tubo concéntrico
Counter‐current motion
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ω=0
Experimental flow description
mean flow directionReh=80 ω=‐0.5
Spring Session PIN NL – Utrecht, May 11th , 2011
ω=‐0.5
ω=‐1
Reh=80 ω=‐1
ω=‐2
Reh=80 ω=‐2
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Co‐current motion
Experimental flow description
mean flow directionReh=80 ω=0.5
Spring Session PIN NL – Utrecht, May 11th , 2011
Blockage parameter
f
rf
v
vv
0
0
h
Reh=80 ω=1
fv
0
Reh=80 ω=2
Outline
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Spring Session PIN NL – Utrecht, May 11th , 2011
o Experimental technique
o Flow pattern description
o Thermal‐hydraulic results
o Performance evaluation
o Conclusions
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Time‐dependent pressure drop
Pressure drop tests Spring Session PIN NL – Utrecht, May 11th , 2011
Features
• periodic signal
• square wave
• overpressure incounter‐current
Processing
counter‐current
• end‐of‐stroketransients
• n > 30
• average window
time (s)
co‐current
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101
CP=0=0,1=0,5=1=1,5
CP =0=0,1=0,3=0,5
0f
CP=0=0,1=0,5=1=1 5
counter‐current co‐current averaged
Pressure drop tests Spring Session PIN NL – Utrecht, May 11th , 2011
101
102
103
10-1
100
Re
fh,cc
=2
tubo liso
101
102
103
10-1
100
R
fh,eq
=0,75=1
tubo liso
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102
103
10-1
100
R
fh 1,5
=2
tubo liso
plain tubeplain tube
laminar turbulent
0≤ω<1
1≤ω≤2
21 mmh1cc,h 1,0ReCf
2m
5h
43cc,h
5
C
1,0
Re
ClogCf
2m
8h
76cc,h
6
CRe
ClogCf
33 mm
h2cc,h ReCf
Reh Re
hRe
h
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Measurement of the scraping power Spring Session PIN NL – Utrecht, May 11th , 2011
0
0
ω=0.1
ω=0.5ω=1
ω=2
40
60
g power (W)
20
30
40
g power (W)
friction
counter‐current
0
0
0 500 1000
20
flow rate (l/h)
scraping
400 600 800 1000 12000
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flow rate (l/h)
scrapin
hydraulicpiston
co‐current
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Heat transfer results
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CP =0
Spring Session PIN NL – Utrecht, May 11th , 2011
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Nu h
Pr=150Pr=300Pr=700
I II III
laminar turbulent
ω=0
0.1≤ω<1
1≤ω≤2
21 mmh1h PrReCNu
3
mh
m2m
h1m
hCRe
CReCPrNu
4
321
23 mmh2h PrReCNu
101
102
103
Reh
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Outline
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Spring Session PIN NL – Utrecht, May 11th , 2011
o Experimental technique
o Flow pattern description
o Thermal‐hydraulic results
o Performance Evaluation
o Conclusions
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Performance evaluation ‐Motionless Spring Session PIN NL – Utrecht, May 11th , 2011
Heat transfer enhancement for:
• same pumping power• same heat transfer area
smooth
augmented
Nu
NuR 3
233 ha dDDf
RR
SMX
Kenics
• same heat transfer area 3
33
hs
h,ah,as
D
d
fReRe
Kenics
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Performance evaluation ‐ Dynamic Spring Session PIN NL – Utrecht, May 11th , 2011
scrapingpumping WWW Total power consumption smooth
augmented
Nu
NuR 3
scrah
h,ah,as
s WD
D
dDDfRe
fRe
3
22
3
233 21
Conclusions
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o Definition of flow mechanism: recirculation bubble acceleration and vortex
Flow pattern
Spring Session PIN NL – Utrecht, May 11th , 2011
o Definition of flow mechanism: recirculation bubble, acceleration and vortex
o Time‐resolved and time‐averaged measurement of pressure drop. Correlations
Heat transfer and pressure drop
o Time‐averaged measurement of heat transfer. Correlations
o Influence of velocity ratio on the flow structures
o Mechanism of the power consumption: piston, friction and flow resistances
Performance evaluation
o Performance comparison with static mixers
o Positive effect of the scrapers motion for Res>1000
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Thank you for your attention!
