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Single-phase Modeling in Microchannel with Piranha Pin Fin
Xiangfei YU1
C. Woodcock1, Prof. J. Plawsky 1, Prof. Y. Peles 2
1 Rensselaer Polytechnic Institute2 University of Central Florida
October 8th 2015
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Overview
Summary and ongoing work
Results and discussion
Methodology
Motivation
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Motivation
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Feeling the heat
Philip Ball, Computer engineering: Feeling the heat . 174, Nature News, Vol 492, Dec. 2012
Steam carries heat away fromGoogle's data centre in Dalles,Oregon.
“The more that microcircuits are shrunk, thehotter they get. Engineers are on the hunt forways to cool off computing.”
C. ZHOU/GOOGLE/ZUMAPRESS/EYEVINE
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Challenges of cooling
Radar system
Medical systemMRI
Lighting
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Methodology
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How to meet cooling challenges
Heat dissipation
Air cooling
Liquid cooling
Single-phase
Flow boiling
Tuckerman and Pease, 1981, microchannel, 800 W/cm2
MicrochannelSmall dimension
High surface/volume ratio
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Piranha pin finCavity for nucleation site
Recirculation zone Vapor is vented out
Bubbles departure Pin fin increases heattransfer area
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DELRIN PROBE PLATE
STAINLESS COVER PLATE
MEMS DEVICE
DELRIN MICRODEVICE PACKAGE
ELECTRICAL SPRING PROBES
BOROFLOAT GLASS
HEATING ELEMENT
SILICON SUBSTRATE
Apparatus
Apparatus
Working fluid: HFE700010
Results and discussion
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0 50 100 150 200 250 300
Tw(℃
)
q"(W/cm2)
Single phase Two phase
Working fluid HFE 7000; Tsat=77℃; Gin=474 kg/m2;
open flow
Experimental measurement
Single-phase set up
LiquidSolid
Conjugate heat transfer Laminar flow Heat transfer in solid & fluid
Pressure drop
Temperature
Temperature
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0 20 40 60 80 100 120 140
Tw (℃
)
Heat flux q" (W/cm2)
Gin=2460 kg/m2s open flow
T_ave_Device 7_exp
T_ave_Device 7_sim
AnalysisV (m/s)
Analysis
Streamlines
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100
120
0 50 100 150 200 250 300
Tw(℃
)
q"(W/cm2)
Average surface temperature Tw
Single phase Two phase
Working fluid HFE 7000; Tsat=77℃; Gin=474 kg/m2; open flow
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0 50 100 150 200 250 300
h(kW
/m2 K
)
q"(W/cm2)
Heat transfer coefficient h
Single phase Two phase
1.68 times single-phase h
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0 50 100 150 200 250 300
h (k
W/m
2 K)
q"(W/cm2)
q=160 W/cm2
Bubbly flow
Single phase
q=255 W/cm2
Bubble coalescence and attached to sidewall
Flow boiling
2D Two-phase modeling
Void fraction
Velocity
T
T=0 s T=3E-5 s T=6E-5 s
Summary and on going work
• Single-phase heat transfer has been studied with experiments and simulation
• Pin fins can realize heat dissipation effectively.• Optimization of PPFs is ongoing.• Two-phase modeling is ongoing.
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Thank you