Project Report for Major 1

A study on the a silicon based micro jet impingement heat sink

Submitted in the partial fulfillment of the requirement for the award of degree of

Master of Technology
In
Thermal Engg.

Submitted by:
RAHUL KUMAR
(2K14/THE/16)

Under the guidance of

Mr. Md. ZUNAID

(Assistant Professor)

DELHI TECHNOLOGICAL UNIVERSITY

 CANDIDATE’S DECLARATION

I hereby declare that the project entitled “A study on a silicon based micro jet
impingement heat sink” being submitted by me is an authentic work carried
out under the supervision of Mr. ZUNAID, Assistant Professor, Mechanical
Engineering Department, Delhi Technological University, Delhi

RAHUL KUMAR
2K14/THE/16
 CERTIFICATE

This is to certify that the above statement made by the candidate is correct to the best of my
knowledge.

Mr Md. ZUNAID

Assistant Professor
Department of Mechanical Engineering
Delhi Technological University
 ACKNOWLEDGEMENT

Generally, individuals set aims, but more often than not, their conquest are by the efforts of not just one
but many determined people. This complete project could be accomplished because of contribution of a
number of people. I take it as a privilege to appreciate and acknowledge the efforts of all those who
have, directly or indirectly, helped me achieving my aim .

I take great pride in expressing my unfeigned appreciation and gratitude to my learned mentor, Mr. Md
ZUNAID, Assistant Professor, Department of Mechanical Engineering, for his invaluable inspiration,
guidance and continuous encouragement throughout this project work. His critics and suggestions on my
experiments have always guided me towards perfection. This work is simply the reflection of his
thoughts, ideas, concepts and above all his efforts. Working under his guidance has been a privilege and
an excellent learning experience that I will cherish for a long time.

I express my deepest gratitude to proff. Dr R S MISHRA Head, Department of Mechanical engineering

and proff. NAVEEN KUMAR Department of Mechanical Engineering DTU.Proff Naveen kumar has been our
major 1 in-charge and supervisor. He always encouraged us and advised us to keep in constant touch with
our mentors. He is a source of great knowledge and he is always working hard to do the best for his
students.

RAHUL KUMAR

2K14/THE/16
Declaration 1
CONTENTS
Acknowledgement
4

1.Introduction
7

2.litreture review
16

3. Statement and problem

18

4.work done
22

6. Result and discussion

24

7.Conclusion
27
 INTRODUCTION

In this study silicon- based micro jet impingement heat sink used for
electronic cooling application several particle and staggered micro-jet
configuration will be used for study. The effectiveness of micro jet
configuration will be analyzing at various flow rates for the maximum
temperature-rise and pressure drop.

The shape optimization of a micro-channel heat sink with a grooved structure

has been performed using a multi objective evolutionary algorithm. . The
thermal-resistance and pumping-power characteristics of the micro-channel
heat sink have been investigated numerically
For optimization, four design variables, i.e., the ratios of the groove depth
to the micro channel height, the groove pitch to the micro-channel height,
the groove diameter to pitch, and the micro-channel width to height are
selected. The thermal resistance and the pumping power are the objective
functions.

The thermal resistance in a grooved micro channel is lower than that in a

smooth micro-channel for a fixed pumping power. The ratio of the groove
pitch to micro-channel height is found to be the most Pareto-sensitive
(sensitive along the Pareto-optimal front), whereas the ratio of the micro-
channel width to height is found to be the least Pareto-sensitive variable .
 CFD

Computational Fluid Dynamics (CFD) is the science of predicting fluid flow, heat
transfer, mass transfer, chemical reactions, and related phenomena by solving the
mathematical equations which govern these processes using a numerical process (that
is, on a computer).The result of CFD analyses is relevant engineering data used in:

– Conceptual studies of new designs

– Detailed product development

– troubleshooting

– redesign

CFD analysis complements testing and experimentation.

 Analysis and Design

1. Simulation-based design instead of “build & test”

q More cost effective and more rapid than EFD

q CFD provides high-fidelity database for diagnosing flow field

2. Simulation of physical fluid phenomena that are difficult for experiments

q Full scale simulations (e.g., ships and airplanes)

q Environmental effects (wind, weather, etc.)

q Hazards (e.g., explosions, radiation, pollution)

 Steps to CFD-

1. Divide the fluid volume (surface) up into manageable chunks (gridding)

2. Simplify the equations to be solved

3. Set boundary conditions

4. Initialize the other grid values

5. Step through the grid ensuring that these simplified equations are satisfied

a the grid points and nearest neighbor

 CFD process-
.Purposes of CFD codes will be different for different applications:

investigation of bubble

Fluid interactions for bubbly flows, study of wave induced massively

separated flows for

free-surface, etc.

• Depend on the specific purpose and flow conditions of the problem,

different CFD

codes can be chosen for different applications (aerospace, marines,

combustion, multi-

phase flows, etc.)

• Once purposes and CFD codes chosen, “CFD process” is the steps to set up
the IBVP

problem and run

STEPS-
1. Geometry

2. Physics

3. Mesh

4. Solve

5. Reports

6. Post processing
 JET IMPINGEMENT

Like micro-channel, jet impingement creates effective means

for convective heat transfer due to its high heat and mass
transfer rate. It is used in wide industrial applications such as
tempering of material, annealing, cooling of plastics and drying
of paper fabric. Heat transfer characteristics of multiple jets
could differ substantially from those of single jets depending on
the geometrical conditions. They also noted that in-between
jets spacing has greater influence on the amount of heat
transfer. Design of multiple jets configuration has been a
mirage because of large number of militating factors one of
which is complexity in comparing one result to another.
However, the complexity of comparing one result to another
has led to development of correlations as in Sung and Medawar.
Reynolds number and nozzle to impingement surface distance,
H/D and angle of impingement are some of the vital parameters
that determine the performance of jet impingement
configuration. Multiple jets geometry design has been a mirage
because of more number of militating factors in which is
complexity in comparing one result to another. So that the
complex of comparing the result one to another has led to
development of correlation as in sung and mudawar.
Reynolds number (Re) and nozzle to impingement surface
distance, H/D and angle of impingement are some of the
parameter tha determine the effectiveness of jet impingement.
Sung and Mudawar have carried out various experiment as well
as numerical simulation on micro-channel and jet-impingement
system to minimize the issue of pressure drop and temperature
gradient in micro-channel on the electronic device , and
stagnation of fluid flow and rapid development of thermal
boundary layer away from impingement zone in jet
impingement. Sung and Mudawar noted that results obtained
from the 3-dimensional heat transfer characteristics analysis of
the hybrid scheme using water, DIUF water, PF-5052,HF-7100
as working fluid were agreement with result to improve the
individual technologies.
Also, the performance of pattern were studied experimentally and
numerical simulation using HFE-7100 as working fluid. Use of
refrigeration in indirect way for cooling was applied to minimize
the coolant temperature in order to provide low wall
temperatures of micro during high heat flux dissipation. Their
studies and numerical simulation showed excellent accuracy in
predicting micro channel wall temperature. The numerical results
showed that the hybrid cooling system involves complex iteration
of jet impingement and micro-channel fluid flow
 Background: micro channel heat sink
•Micro channel heat sink has been studied as an efficient
cooling device for electronics, avionics, and micro
refrigerators etc.

• Experimental studies have been carried out to understand

the heat transfer and fluid flow in micro channels.

•Analytical and numerical models have been developed with

certain assumptions to optimize the system for effective use
of space and available pumping power at micro-level.

•The growing demand for higher heat dissipation and

miniaturization have directed research to optimization and
to apply alternative designs to the micro channel heat
sinking.
Geometry of micro channel
 LITERATURE REVIEW
Tuckerman and Pease were the first to carry out an experimental study on
micro-channel heat sinks and developed a new concept for researchers for
further optimization and experimental investigation.

Salaam reported correlations for the thermal resistance based on a

theoretical study of micro channels.

Fedora and Visconti developed a 3-D model to investigate the flow and
conjugate heat transfer in an MCHS. The continuing demand for spreading
out ever-increasing heat fluxes necessitates further techniques for enhancing
heat transfer for various applications.

Park et al. performed a numerical and experimental investigation of a heat

sink under laminar flow for passive heat-transfer augmentation.

Wang et al. numerically investigated the frictional characteristics of 2-D

single-phase flows in a micro channel with various elements of roughness and
found that surface roughness exerted a substantial influence on heat transfer
augmentation.
.
Ligrani et al. conducted an exhaustive review of techniques for heat-transfer
augmentation and observed that shear-layer attachment and recirculation
are significant phenomena in heat-transfer augmentation around ribs.

Husain and Kim numerically investigated MCHSs with rib structures with
regard to the thermal resistance and pumping power and performed multi
objective shape optimization using a multi objective evolutionary algorithm.

Husain and Kim numerically investigated 3-D fluid flows and heat transfer in
a rectangular micro-channel and presented a procedure for single-objective
optimization that was based on surrogate methods

Knight et al. analytically presented a solution procedure for laminar and

turbulent flows in an MCHS. They derived the governing equations for fluid
flow and heat transfer and came up with a scheme for solving these

Li and Peterson carried out a numerical study on a rectangular micro-channel

by varying the various parameters to find out the optimal thermal resistance
at a constant pumping power.

Wei and Joshi numerically investigated and optimized a stacked micro-

channel for the minimum overall thermal resistance at a constant pumping
power and a constant flow.
 STATEMENT OF PROBLEM

•We have taken a micro-channel jet impingement heat sink

in which we have mounted two nozzle in symmetry at 90
angle to the top surface of rectangle slab at symmetry
•We have passed fluid through nozzle and these fluid take
out the heat which are generated through the in the
component
 NUMERICAL METHOD

3-D flow through micro-channels, the governing equations for

the conservation Of mass, momentum, and energy for conjugate
heat-transfer can be written in vector form as

MASS
•∇ · (ρfV) = 0

MOMENTUM
V · ∇(ρfV) = −∇p + ∇ · (μf∇V).

ENERGY

V · ∇(ρfCp,f Tf) = ∇ · (k f∇Tf ) (for the fluid)

 OPTIMIZATION TECHNIQUES

For the optimization of the geometry, four design

variables, viz., d/Hc(α), pg/Hc(β), D/pg(γ), and Wc/Hc(η),
were chosen which influence the performance of the
system
Thermal resistance of the MCHS and pumping power
for driving coolant through the micro-channels were
selected as the two objective functions for
optimization

R = R(cond.) + R(conv.) + R(cal.) =Tmax/qAs

P = n · u(avg )· Ac · p
 Objectives

•To study and optimize the ribbed micro channel heat sinks.

• Effect of design variables on thermal performance of the

micro channel heat sink.

• Application of surrogate-based optimization techniques to

micro-fluid systems to speed up optimization process and to
save computational expenses and time.

Multi-objective optimization of micro channel heat sink

constructing a composite objective function comprising
thermal resistance and pumping power
 WORKDONE

-We have make geometry in solid work and import in ansys for
doing further analysis.

-Now reset geometry in ansys and updated

- Mesh the geometry with proper alignment

- Feed all the parameter which are requird for further analysis to
get the solution

-In the solver we feed requird number of solution to get the result
 RESULTS AND DISCUSSION

Hexahedral grid with 1001 × 42 × 70 grid points in the

x, y, and z directions, respectively, is used for a
geometry with the design variables, α = 0.069, β = 0.25,
γ = 0.379, and η = 0.18.

Different grids were taken in all directions to check for

grid independence; it was found that the 1001 × 42 ×
70 grid exhibited a change of about 2% in the highest
temperature in the substrate as compared with a
501×42×70 grid and a change of under 0.5% in
comparison with a 1001×52×90 grid. Thus,
1001×42×70 was employed as the optimum number
of grids.
TEMPRATURE VARIATION
PRESURE VARIATION
 FUTURE WORK

In focus of the result obtained from the numerical

study, the future scope is suggested

1-Impact of jet configuration.

2-Position of jet on the hybrid system

3-Angle of impingement of flow and distance

between impinging jets and surface to be
impinged

4-Phase change in the fluid flow.

 CONCLUSSION

A grooved micro-channel exhibited a lower thermal

resistance over a smooth micro-channel but at the
expense of pumping power.

If a higher pumping power is available at a constant

mass flow rate, a grooved micro channel is a better
choice.

The selected Pareto-optimal designs of the grooved

micro-channels showed higher coefficient of
performance as compared to their corresponding smooth
micro-channels.

Recently the application of micro-jet impingements on

the substrate were proposed to achieve higher
temperature uniformity and hot spot management of
electronics .
 REFERENCES
D. B. Tuckerman and R. F. W. Pease, “High-performance heat sinking for VLSI,”
IEEE Electron Device Lett., vol. 2, no. 5, pp. 126–129, May 1981.

V. K. Samalam, “Convective heat transfer in microchannels,” J. Electron

Mater., vol. 18, no. 5, pp. 611–618, 1989
.
A. G. Fedorov and R. Viskanta, “Three-dimensional conjugate heat transfer in
the microchannel heat sink for electronic packaging,” Int. J. Heat Mass
Transfer, vol. 43, no. pp. 399–415, Feb. 2000.

D. Park, C. Silva, E. Marotta, and L. Fletcher, “Study of laminar forced

convection heat
transfer for dimpled heat sink,” J. Thermophys. Heat Transfer, vol. 22, no. 2,
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X.-Q. Wang, C. Yap, and A. S. Mujumdar, “Effects of two-dimensional

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357–361, 2005.
[6] P. M. Ligrani, M. M. Oliveira, and T. Blaskovich, “Comparison of heat
transfer augmentation techniques,” AIAA J., vol. 41, no. 3, pp. 337–362, 2003.
 A. Husain and K.-Y. Kim, “Microchannel heat sink with designed roughness:
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342–351, 2008.

A. Husain and K.-Y. Kim, “Shape optimization of micro-channel heat sink for
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2, pp. 322–330, Jun. 2008.
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liquid flow,” IEEE Trans. Compon. Packag. Technol., vol. 29, no. 1, pp. 145–
154, Mar. 2006.

X. Wei and Y. Joshi, “Optimization study of stacked micro-channel heat sinks

for micro-electronic cooling,” IEEE Trans. Compon. Packag. Technol., vol. 26,
no. 1, pp. 55–61, Mar. 2003