1 Geometry Parameters Analysis of CPU Heat Sinks GlacialTech, INC. 27th September 2002.
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Transcript of 1 Geometry Parameters Analysis of CPU Heat Sinks GlacialTech, INC. 27th September 2002.
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www.glacialtech.com
Geometry Parameters Analysis
of CPU Heat Sinks
GlacialTech, INC.
27th September 2002
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www.glacialtech.com
To understand the effects of the geometry parameters for aluminum extrusion fins, we employed PHOENICS and experimentation to prove the results each other. The parameters are:
the ratio of thickness and pitch between fins
fin number
length for heat sink
height of fins
Introduction
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Phoenics simulation
VR-EDITOR1. Build physics module2. B.C. setting 3. Phoenics setting
EARTH( Iteration)
Convergence
Yes
No
VR-VIEWERGenerate temperature、 velocity and pressure field
Decide the geometry parameter of heat sinks
Manufacturing extrusion fins
Check thermocouple
Keep environment temp. is 35℃
Steady
Yes
No
Measure CPU temp.
1.Calculate thermal resistance2. Discussion of results
Experimentation
Flowchart for the research
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Physics model
environment temp. is
35 ℃
heat flux is 45 W
Flow rate is 17 CFM
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PHOENICS Setting
steady state
elliptic – staggered formulation
cartesian coordinate system
the fluid is incompressible
k-ε turbulence model
convergence criterion is 0.1 ﹪
no heat flux in heat sink
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Insulate
Insulate Insulate
Fan
Heat Sink Copper
Computer Display
Power supply
Th
erm
al Co
up
le
Insulate
Insulate Insulate Fan
Heat Sink
Computer & Data
Acquisition Board
Power Supply
Ambient Temperature = 35¢XC
Heat Source
(Copper or CPU)
Thermal Couple
Pressure Load
Closed Chamber
Experimentation
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Discussion :Ⅰ
785.01092.11036.3104.7 13243 xxxyblue line:
green line:
9156.110294.810256.2104.2 22335 xxxy
The ratio of thickness and pitch between fins
Fin number
p: pitch of fins
t: thickness of fins
We have better performance in more fins in the same ratio of p/t.
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Discussion :Ⅱ Length for heat sink
1047.11094.3109.7 325 xxy
The effect of increasing length of heat sinks is not apparent for decreasing thermal resistance.
The good value of length of heat sink is about 75 mm.
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Discussion :Ⅲ Height of fins
412234 101.110111.210136.110711.1 xxxy
When the height of fins is less than 20 mm, thermal resistance has large drop.
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Conclusion and Development
1. Thermal resistance will decrease when thickness were increased, but
increasing fin number has bigger effect than increasing thickness of fins.
2. Increasing height of fins will provide good solution but increasing
length of heat sinks is not apparent for decreasing thermal resistance.
3. We will build a system which will help us to design extrusion fins
quickly in the future.
4. General extrusion ratio is 20 now, but the ratio in GlacialTech is 28, so
to promote extrusion ratio is our purpose in the future.
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•Power dissipation=70W
•Environment Temp. = 35℃
•Flow rate = 13.3CFM
•Noise=25 dB •Thermal Resistance=0.357 ℃/W
Application