International Journal of Engineering Trends and Technology (IJETT) – Volume 27 Number 5 - September 2015
Optimization of Liquid Cold Plates Using Computational Fluid
Dynamics
P.Sivakumar*1, P.Srihari*2, Prof. N.HariBabu*3
*Department of Mechanical Engineering, Aditya Institute of Technology and Management, Tekkali;
Srikakulam Dist.,532201. Andhra Pradesh, India.
Abstract-Water cooling is a method of heat removal
from components in industrial equipment with the help
of cooling plates. These cooling plates are used in
naval applications, heavy electronic industries and
inverters. Generally electronic equipment having
IGBT’s and each IGBT dissipates 791W of power. The
safe limit for industrial equipment, the temperature
should not exceed 900C.The objective of this work is
comparing 3 different profiles of cooling plates to
maintain the equipment in safe temperature condition.
In this study, evaluation of3 different types of cooling
plates through CFD analysis by fixing the diameters of
inlet and outlet portions are kept constant. The design
of cooling plate placed upon 8 IGBT’s and the analysis
of flow by using solid works flow simulation software.
Comparing three different cooling plates i.e. the Form
tube, Machined channel and Deep drilled cold plate
and Optimization is done by considering weight of the
cold plate and better temperature distribution.
cold plate the heat flux and power dissipation increases,
the contact resistance of the plate and the tube wall
become unacceptably high. In this design, deep holes
are drilled in the plane of the substrate plate. In
Machined channel cooling plate the heat flux increase,
it becomes necessary to improve the thermal
performance of the channels. In this design, channels
are machine-cut into the base plate and a cover is
soldered in place to form the flow passages.
In the literature thermal analysis of form tube,
machined channel and Deep drill cold plates at different
working environment has been done4. This shows there
is a lack of study in the behavior of three different cold
plates at same working environment. In this work the
Optimization is achieved by comparing the thermal
characteristics of three types of cold plates at same
working environment and proposed the best method
that can be adopted in different industrial equipment for
safe conditions.
Keywords - Cold plates, Temperature Distribution,
Weight of the cold plates, CFD Analysis.
2. MODELING
1.
INTRODUCTION
In heavy electronic equipped industries, high
temperatures are attained in working conditions. The
safe temperature limit for the electronic equipment’s
900C.This raise in temperature will take an adverse
effect on the equipment’s and sometimes fails at these
conditions. This is due to the electronic equipment’s
life time will be reduced. So the equipment maintain
safe temperature condition which is below 900C,
maintain the desired condition liquid cooling is provide
effectively.
Liquid cooling is a convective heat transfer process.
The cooling plates are classified as follows:
1) Formed Tube Cooling Plate (FTCP)
2) Deep Drilled Cooling Plate (DDCP)
3) Machined channel Cooling Plate (MCCP) 4
Form tube liquid cold plates ensure minimum thermal
resistance between the device and the cold plate by
placing the coolant tube in direct contact with the
device base plate. In this design, copper plate is
generally used, although aluminum is sometimes
employed in low power applications. In Deep drilled
ISSN: 2231-5381
Modeling of form tube, machined channel and deep
drill cooling plates are done by using Unigraphics
(NX7.5). For all the three cold plates, length, width and
thickness are kept constant. Material’s considered for
all the three plates are same i.e. for plates- copper and
for tubes aluminum materials are considered.
2.1 Form Tube Cooling Plate
The 3D modeling of the form tube cold plate is shown
below.
Fig. 1.3D Modeling for Form Tube Cold Plate
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International Journal of Engineering Trends and Technology (IJETT) – Volume 27 Number 5 - September 2015
2.2Machined Channel Cooling Plate
Length = 0.6m, width = 0.4m of the cold plate.
The 3D modeling of the Machined channel cold plate is
shown below.
Fig. 2. 3D Modeling for Machined channel Cold Plate
2.3 Deep Drilled Cold Plate
The 3D modeling of the Machined channel cold plate is
shown below.
A=Surface area of the total plate (m2)
=0.609X0.406m2=0.24m2.
Using this formula we can calculate the surface
temperature (Ts)
Form tube cold plate: mCp(T2-T1) = hA (Ts-T∞)
6.3x 4.182(100-75) = 115x 0.24(Ts-25);Ts = 369 K.
Machined channel cold plate: mCp(T2-T1)=hA(Ts-T∞)
6.2x4.182(100-75) = 115x0.24(Ts-25);Ts = 366 K.
Deep drilled cold plate:mCp(T2-T1) = hA (Ts-T∞)
5.9x 4.182(100-75) = 115x0.24(Ts-25);Ts = 354 K.
4. CFD Analysis for Cold Plates
The designed model is imported to solid works by
exporting as Para solid format.
4.1 Boundary Conditions
Mass flow rate: 1.89 Kg/s
Static Pressure: 101325 Pa
From the above Boundary conditions9 are given to the
cold plates. In the inlet section the fluid enters with a
1.89 Kg/smass flow rate and Static Pressure is given to
the outlet section.The appliedboundary conditions are
shown in the below figure.
Fig. 3.3D Modeling for Deep Drilled Cold Plate
Fig.4.Boundary conditions for Form Tube Liquid Plate (FTCP)
4.2 Case 1: Formed Tube Cold Plate
3. Theoretical Calculations
Amount of heat exchanged in shell and tube heat
exchanger = Amount of heat transferred by convection
Q = m Cp (T2-T1) = hA (Ts -T∞)
M=mass of the each plate (kgs).
T1= Fluid inlet temperature (oC).
T2= Fluid outlet temperature (oC).
Ts= Surface temp of the cold plate (oC).
T∞=Atmosphere temperature (oC)=25 oC.
Cp=specific heat of the fluid (kj/kgsK)
The fluid Cp value is 4.182 kj/kgsk.
H=convective heat transfer coefficient (w/m2K)
For liquids in free convection the convective heat
transfer coefficient is 115w/m2K.
ISSN: 2231-5381
Fig.5.Temperature Distribution for Formed Tube Cold Plate
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International Journal of Engineering Trends and Technology (IJETT) – Volume 27 Number 5 - September 2015
From the analysis the temperature obtained in the form
tube cold plate is 370K.
Weight: Weight of the Form Tube Liquid Plate is
6394.46gms.
Fig.8.Weight of the Machined Channel Cold Plate
4.4Case 3: Deep Drilled Cold Plate
Fig.6.Weight of the Form Tube Liquid Plate
4.3 Case 2: Machined Channel Cold Plate
Fig.9.Temperature Distribution for Drilled Cold Plate
From the observations the temperature obtained in the
Machined Channel Cold Plate is 359K.
Weight: Weight of the Deep Drilled Cold Plate is
5906.17gms.
Fig.7.Temperature distribution for Machined Channel Cold
Plate
From the study the temperature shows in the Machined
Channel Cold Plate is 363K.
Weight: Weight of the Machined Channel Cold Plate is
6026.3gms.
Fig.10.Weight of the Deep Drilled Cold Plate
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International Journal of Engineering Trends and Technology (IJETT) – Volume 27 Number 5 - September 2015
5. Results and Discussion
The Analysis has been carried out for the form tube,
machined channel and deep drilled cold plates. The
temperatures obtained of three different cold plates are
shown in Table1. A comparison of the theoretically
calculated temperatures and the analytically obtained
temperatures are shown in Table 2.
S.No
Results
1
Temperature(k)
Form
tube
370
Machine
tube
363
Deep
drilled
359
Table 1.Comparison of 3 Types of Cold Plates
Results
Analysis
Theoretical
Temperature(k)
Temperature(k)
Form
tube
370
369
Machine
tube
363
366
Deep
drilled
359
354
Table 2.Comparisonof the results with theoretical calculations
In all the 3 cases the area and thickness of the plates are
same. From the analysis Form Tube cold plate shows
output temperature is 370Kin this case the heat removal
rate is less, so this is not withstanding the conditions. In
Machined channel cold plate the temperature obtained is
363K from the results the heat removal rate is less and
notwithstanding the criteria. The deep drilled cold plate is
attained temperature is 359K and from the results the heat
removal rate is more, this is within the safe limit.
[2]. Nicholas Palumbo presented a paper on “Thermal Analysis of an
Integrated Power Electronics Module” Integrated power electronics
such as IGBT.
[3]. W.M. Healy presented a paper on “Using Finite Element
Analysis to Design a New Guarded Hot Plate Apparatus for
Measuring the Thermal Conductivity of Insulating Materials”.
[4]. SatishG.Kandlikara,CliffordN.HaynerIIb hasPublished a paper on
“Liquid Cooled Cold Plates for Industrial High-Power Electronic
Devices—Thermal Design and Manufacturing Considerations”.
[5]. VikasKumar, D.Gangacharyulu, Parlapalli MS Rao and R. S.
Barve presented a paper on “CFD Analysis of Cross Flow Air to Air
Tube Type Heat Exchanger”.
[6].R.J Haywood, G.J. Brown, L.J. Irons and M.Stark published a
paper on “Using CFD to Reduce Commissioning Time for
electrostatic Precipitators”.
[7].Darin J.Sharar, Nicholas R. Jankowski, and Avram Bar-Cohen
presented paper on “Flow Regime Transition in Inner Grooved Mini
channel Cold Plates for Cooling Hybrid Electric Power Electronics”.
[8].Mr. SAROJ KUMAR PATRA presented paper on “CFD Analysis
of Electronics Chip Cooling”.
[9].Dupati Ramesh Babu and V KrishnaReddy
“Evaluationof Liquid Cooling Plate through CFD Analysis”.
6. Conclusions
The physical characteristics shown in the results are
different in each model. From the above results the heat
removal rate is more in deep drilled cold plate. When
comparing the weights of three cold plates, deep drilled
cold plate have less in weight, than other two cold
plates. By considering these results the behavior
showed by the deep drilled cold plate is within the safe
temperature limit. This is due to carry the more amount
of heat according to design of deep drilled cold plate
and finally this is the best method of cold plate to
maintain the industrial equipment in a safe desired
conditions. This concludes that, the optimized method
i.e. deep drilled cold plate can be adopted for heavy
electronic equipment and naval applications.
REFERENCES
[1] .Ephraim M. Sparrow, John P. Abraham, and Paul W. Chevalier
presented a paper on “The Design of Cold Plates for the Thermal
Management of Electronic Equipment”.
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