Department of Electrical and Computer Engineering C.U.I ,
ATD Campus.
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Simulation and Optimization of Splayed Heat Sink
Using COMSOL Multiphysics® Software
Presenters

Takbeer Zahid (FA18-EPE-012)

Umar Rahman (FA18-EPE-015)

Muhammad Rehan (FA18-EPE-166)
Supervisor
Engr. Zulfiqar Khattak
Department of Electrical and Computer Engineering C.U.I ,
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Project Outline
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Objectives
Introduction
Modern Heat sink
Splayed Heat sink
Uses
Literature Review
Engineering Problem
Methodology
Block Diagram
Proposed Solution
Mathematical modeling
COMSOL Software
Project work-flow
Optimization
Objective function and constraints
Results
References
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Objectives
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Simulation & thermal analysis of Commercial
Splayed Heat Sink using Comsol Multiphysics®
software
Study & Implementation of Optimization tools for
modification and efficiency enhancement of splayed
Heat sink
Comparison of results generated from commercial and
optimized splayed heat sink
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ATD Campus.
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Introduction
o The heatsink is typically a metallic heat exchanger
which can be attached to a device releasing energy in
the form of heat
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Splayed Heat Sink
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[4]
Splayed heat sinks are relatively new derivatives of the standard pin fin heat
sink
Unlike standard heat sink it contain an
array of vertically oriented pins that gradually bend outwards
Curving the pins in this way increases the spacing
between them
Surface area of heat sink remains same.
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Uses

It is used in Solar Inverter
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It is used for IC Cooling in an
electronics devices
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It is used in street light LED
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It is used in dc power supply
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It is used in Computer for IC cooling
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Literature Review
Previously, the work done on Heat Sink was based on
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Height of fins
Distance between fins
Size of heat sink
Angle shift between fins
Optimization for enhancing efficiency was performed on
basis of the angle shift of fins (i.e 90° 𝑡𝑜 80° )
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Engineering Problem

Design and enhancing efficiency of Splayed
Heat Sink using optimization tools in
COMSOL Multiphysics Software
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Methodology
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Designed CAD model (AUTOCAD)
Import CAD model to COMSOL MultiPhysics
Performing optimization to enhance efficiency
Mathematical expressions & results
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Block Diagram
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Mathematical Modeling
Thermal resistance
𝑹𝒕𝒉 =
𝟏
𝒉𝒐×(𝑨𝒃+𝑵.𝑨𝒇𝒊𝒏)
Pressure drop
Where ,
Rth=Thermal resistance
ho=Heat Co-efficient
ΔP=f ×
𝝆×𝒗
𝟐
Ab=Area of base
N=Number of fins
Afin=Area
Reynold ‘s Number
𝝆×𝑼𝒎𝒂𝒙×𝑫𝒉
Re=
µ
𝝆=Density of air
Umax= maximum velocity
Dh=hydraulic diameter
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Proposed Solution
Optimizing commercial splayed heat sink on the basis of
parametric variations which are:
•
Angle shift
•
Fins diameter
•
Material
•
Size
Our main objective will be its optimization on the basis of
angle shift
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COMSOL Software
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COMSOL Multiphysics
GUI Based Software
Modeling and solving of mathematical and designing problem
Geometry, mesh, visualization and results.
Optimization Interface available
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, ATD Campus
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Project Workflow
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ATD Campus.
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Optimization
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Optimization is a tool that you can use in conjunction with any existing COMSOL
Multiphysics Product.
Term Optimization Means improving your COMSOL Multiphysics model
This improvement involve four steps
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First, you define your objective function – a figure of merit that describes your
system
Second, you define a set of design variables – the inputs to the model that you
would like to change
Third, you define a set of constraints, bounds on your design variables, or operating
conditions that need to be satisfied
Last, you use the Optimization Module to improve your design by changing the
design variables, while satisfying your constraints.
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Objective function and constraints
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Defined parameters
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Splayed Heat Sink Design (80 ° )
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Tunnel view
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Mesh plot
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Surface Temperature (Deg)
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Iso-surface Temperature (K)
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Velocity slices
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Pressure
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Velocity streamline
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Thermal Resistance vs Velocity
Department of Electrical and
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Velocity
Thermal
Resistance[k
/W]
5
0.098700
10
0.082200
15
0.070400
20
0.061700
25
0.049300
27
Thermal resistance vs Heat Flux
Department of Electrical and
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Heat Flux[W]
Thermal
Resistance[
k/W]
10
0.098700
30
0.082200
50
0.070400
70
0.061700
90
0.049300
28
Thermal Resistance VS Heat coefficient
:
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Computer Engineering C.U.I ATD
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Heat
Coefficient
[W/𝑚2 𝑘]
Thermal
Resistance[
k/W]
10
0.0987
12
0.0822
14
0.0704
16
0.0617
20
0.0493
29
Splayed Heat Sink Design (75 ° ) :
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Tunnel View
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Surface Temperature (Deg):
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Mesh plot
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Iso-surface Temperature (K)
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Velocity slices
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Pressure
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Velocity streamline:
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Thermal resistance vs Velocity:
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C.U.I ATD Campus
Velocity
Thermal
Resistance[k
/W]
5
0.094700
10
0.079200
15
0.068400
20
0.059700
25
0.047300
38
Thermal resistance vs heat flux:
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Heat Flux[W]
Thermal
Resistance[k
/W]
10
0.094700
30
0.079200
50
0.068400
70
0.059700
90
0.047300
39
Thermal resistance vs heat coefficient
Department of Electrical and Computer
Engineering C.U.I ATD Campus
Heat
Coefficient
[W/𝑚2 𝑘]
Thermal
Resistance[
k/W]
10
0.0947
12
0.0792
14
0.0684
16
0.0597
20
0.0473
40
References:
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https://www.radianheatsinks.com/heatsink/
K. Nishino et al., 1996. Turbulence statistics in the stagnation region of an axisymmetric
impinging jet flow, Int. J. Heat Fluid Flow, 17, 193-201
https://uk.rs-online.com/web/generalDisplay.html?id=ideas-and-advice/heatsinks-guide
https://www.ijert.org/research/cfd-analysis-of-splayed-pin-fin-heat-sink-for-electroniccooling-IJERTV1IS10473.pdf
Khattak, Zulfiqar, and Hafiz Muhammad Ali. "Air cooled heat sink geometries subjected
to forced flow: A critical review." International Journal of Heat and Mass Transfer 130
(2019): 141-161.]
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