Water cooled minichannel heat sinks for microprocessor

cooling: Effect of fin spacing

Saad Ayub, Wajahat Ali, Hafiz Muhammad, Aysha Maryam

• Department of Mechanical and Aeronautical Engineering

University of Engineering and Technology, Taxila, Pakistan

• Department of Electrical Engineering,

Comsats Institute of Information Technology, Wah, Pakistan

Presenters

• Danial Sohail ME-089

• Osaid Haq ME-102

• Daniyal Iqbal ME-103

• Owais Ali ME-105

Abstract

• Heat Sinks With Five Different Fin Spacing

• Lowest Base Temperature achieved from finest fin spacing

• Modifying Geometry results in 9% less base temperature than commercial heat sink

• 60% Higher Heat Transfer Coefficient in case of 0.2 mm fin spacing

Introduction

• Microprocessor Operating Temperature 60℃ to 80℃

• Air Cooling Limitations

• Optimize Liquid Cooling

• Modify Thermophysical Properties of Coolant

• Modify Heat Sink Geometry Using Ordinary Coolant

Optimize Liquid Cooling

Modify Thermophysical Properties of Coolant

• Use of Nanofluids

• Heat Transfer Enhancement from 20% to 160%

• Use is still Ambiguous due to:

• Higher Cost

• More Maintenance

Modify Heat Sink Geometry

• Heat Transfer increases by decreasing Channel

Width

• Miniature Jet Stream

• This paper deals with effect of Sink Geometry

Authors Area of Study Conclusion

X.L. Xie

W.Q. Tao

Y.L. He

Heat transfer characteristics of water cooled mini

channel heat sinks

• Heat removal increased with

decrease in channel width.

• Thermal resistance increase with

increase in channel width

B.P. Whelan

R. Kempers

CPU cooling by liquid jet array impingement water

block

• Increased heat transfer than

commercial cooling block

P. Naphon

S. Wongwises

Experimental analysis of liquid jet impingement

cooling system on real processor

• Lowered CPU temperature than

commercial cooling blocks

M.R.O. Panão

J.P.P.V. Guerreiro

Analysis of intermittent multi-jet spray system • Higher efficiency and intelligent

thermal management

C. Bower

A. Ortega

C. Green

Water cooled Silicon carbide mini channel heat

sink for high power electronic appliances

• Resulted higher performance than

air cooled Silicon carbide.

Literature Review

Authors Area of Study Conclusion

J.A. Eastman

S.U.S. Choi

S. Li

Anomalously increased effective thermal

conductivities of ethylene glycol based nano fluids

containing copper nanoparticles

• 40% increase in thermal

conductivity observed

A. Ijam

B. R. Saidur

Comparison of water cooled and nano fluid cooled

multichannel heat sinks

• Nano fluid performed better than

water.

N.A. Roberts

D.G. Walker

Performance of Al2O3 – water nano fluid in

commercial cooling system

• 20% enhancement in heat transfer

and comparatively higher nano

fluid temperature at outlet under

same heat flux conditions.

M.R.O. Panão

J.P.P.V. Guerreiro

A.L.N. Moreieira

Analysis of intermittent multi-jet spray system • Higher efficiency and intelligent

thermal management

C.T. Nguyen

G. Roy

C. Gauthier

N. Galanis

Heat transfer enhancement using Al2O3 - water

nano fluid for an electronic liquid cooling system

• Resulted 38%increase in

convective heat transfer coefficient

Parameters for comparison of 5 heat

sinks with different fin spacing

Base Temperature

(T base) Experiment

Overall heat transfer coefficient

(U)

𝑈 =𝑚 𝐶𝑝(𝑇𝑜𝑢𝑡 − 𝑇𝑖𝑛)

𝐴 (𝐿𝑀𝑇𝐷)

Thermal Resistance

(R th)

𝑅𝑡ℎ = 𝐿𝑀𝑇𝐷

𝑄

Active Area Enhancement (A en)

𝐴𝑒𝑛 =𝐴𝑐𝑡𝑖𝑣𝑒 𝑎𝑟𝑒𝑎 𝑜𝑓 𝑓𝑖𝑛𝑛𝑒𝑑 𝑕𝑒𝑎𝑡 𝑠𝑖𝑛𝑘

𝐴𝑐𝑡𝑖𝑣𝑒 𝑎𝑟𝑒𝑎 𝑜𝑓 𝑓𝑙𝑎𝑡 𝑝𝑙𝑎𝑡𝑒

Enhanced overall heat transfer coefficient

(U en)

𝑈𝑒𝑛 = 𝑈 𝑓𝑜𝑟 𝑓𝑖𝑛𝑛𝑒𝑑 𝑔𝑒𝑜𝑚𝑒𝑡𝑟𝑦

𝑈 𝑓𝑜𝑟 𝑓𝑙𝑎𝑡 𝑝𝑙𝑎𝑡𝑒 𝑕𝑒𝑎𝑡 𝑠𝑖𝑛𝑘

Schematic of experimental setup

Heat sink

Fin Material Copper

Fin thickness 1.0 mm

Fin height 3.0 mm

Fin base area 28.7 × 28.7 mm

Fin base protrusion 0.5 mm

Heating block

Block Material Copper

Heating Power 325 watts

DC power 197 watts 1.65 amp

Insulation Fiberglass wool

Liquid cooling system

Vendor – product Gigabyte - galaxy

Coolant Water

Experimental Apparatus

Experiment

• 0.2 mm

• 0.5 mm

• 1.0 mm

• 1.5 mm

• Flat surface

Fin Spacings

• 0.5 LPM

• 0.75 LPM

• 1.0 LPM

Flow rates

Results

• Comparison with commercially available Nano fluid. • Temperature of base is directly proportional to flow rate

Conclusion

• Lowest Base Temperature of 40.50C

• Usage of water

• Focus on Altering Geometries