Single-phase Modeling in Microchannel with Piranha Pin Fin · Single-phase Modeling in Microchannel with Piranha Pin Fin. Xiangfei YU. 1. C. Woodcock. 1, Prof. J. Plawsky. 1, Prof

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

1

Presenter

Presentation Notes

self introduction name RPI phd student title consistency Hi Everyone, This is Xiangfei from RPI. My topic today is about a study on flow boiling in microchannel with piranha pin fin.

Overview

Summary and ongoing work

Results and discussion

Methodology

Motivation

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Presenter

Presentation Notes

Here is the outline We will start from the motivation which could answer the questions why we need flow boiling in microchannel with PPF. Then we move forward to Methodology, which will show details about methods how did we realize this idea. Following by results and discussion, that are what we have achieved so far . At last it's about the future work.

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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Presenter

Presentation Notes

This is an article written by Philip Ball titled feeling the heat. Picture on the left shows stream carries heat away from Google's data center in Dalles, Oregon. It is very impressive. So much heat needs to be dissipated by streams. Just as Philip said. The more that microcircuits are shrunk, the hotter they get. Engineers are on the hunt for ways to cool off computing. So we are the hunters on our way trying to find creative way to cool off computing.

Challenges of cooling

Radar system

Medical systemMRI

Lighting

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Presenter

Presentation Notes

Furthermore, the challenges of cooling are not limited in computing area. They are also in Radar system, medical system and lighting area and so on.

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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Presenter

Presentation Notes

For heat dissipation, we have air cooling and liquid cooling, for liquid cooling, we have single-phase and flow boiling. Flow boiling stands out because latent heat is utilized, temperature distribution can be more uniform and as a result high heat flux can be removed. In combination of microchannel which has small dimension high surface/volume ratio. Tuckerman and Pease firstly demonstrated microchannel can dissipate heat flux 800W/cm2 in 1981.

Piranha pin finCavity for nucleation site

Recirculation zone Vapor is vented out

Bubbles departure Pin fin increases heattransfer area

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Presenter

Presentation Notes

Here is what we proposed PPF.

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

0

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60

80

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120

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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60

80

100

120

0 50 100 150 200 250 300

Tw(℃

)

q"(W/cm2)

Average surface temperature Tw


Working fluid HFE 7000; Tsat=77℃; Gin=474 kg/m2; open flow

0

5

10

15

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25

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40

45

0 50 100 150 200 250 300

h(kW

/m2 K

)

q"(W/cm2)

Heat transfer coefficient h


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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Presenter

Presentation Notes

We would like to thank DARPA for their sponsorship and our research partners in UCF and CREARE for their contributions. I would like to acknowledge all of the organizations that have contributed to my research and you all for coming.

Thank you

Documents

Single-phase Modeling in Microchannel with Piranha Pin Fin · Single-phase Modeling in Microchannel with Piranha Pin Fin. Xiangfei YU. 1. C. Woodcock. 1, Prof. J. Plawsky. 1, Prof