EAT216 Computer Aided Engineering

CFD Assignment: 3D Heat-Sink Design using ANSYS-FLUENT

1.1 Problem Definition

Computer central processing units (CPUs) are becoming more compact, thus heat flux per unit

area increases dramatically. As a result, an improvement of heat sink design is necessary. It is

important to note that CPU performance is stable if the temperature of such electronic

components does not exceed a certain level. Theoretically, if this temperature reaches 100 oC a

CPU will stop executing.

Figure 1. Channel for testing the heat-sink performance (ANSYS-FLUENT)

Fig.1 shows a heat sink design for the application to simulate the thermal dissipation of a CPU

component (see Figure 1, component A). The working fluid is assumed to be incompressible air

(of three different inlet velocities: 5, 10, 15 ms-1). The heat flux contributed by the CPU is given

to be 90 kW/m2. Each student is expected to come out with their own designs (three designs and

one control) by adding different: (i) plate fins, (ii) pin fins, (iii) porous media, or other creative

arrangements, in order to efficiently reduce the surface temperature of the simulated CPU (not to

sacrifice too much pressure loss, , before and after the heat sink).

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1.2 Assignment Requirement

The student must provide a formal written report (hard copy – binding) between 10-20 pages

(including tables and figures). Every of your model/solution files must be submitted through CD.

The report should include the following information,

1. Cover page [2

marks]

2. Abstract [6

marks]

3. Introduction and objectives. [10

marks]

4. Methodology (must include: governing equations and boundary conditions). [10

marks]

5. The flow chart of your simulation using ANSYS-FLUENT. [5

marks]

6. In the Results and Discussion,

a. What are the convergence criteria of the simulation? [6

marks]

b. Discussion with figures showing the meshing of the geometry. [10

marks]

c. Two-dimensional (2D) Flow speed and surface temperature distributions showing the

different between using laminar and the turbulent model. [10

marks]

d. The comparisons between smooth empty channel and your design. [10

marks]

e. The 3D temperature contours of your heat sink designs. [10

marks]

f. Compare the thermal efficiency of all the designs. [6

marks]

g. What is the best parameter to represent the result of force convection heat transfer

related problem? What is the best parameter to represent pressure drop in this

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EAT216 Computer Aided Engineering

investigation? [10

marks]

7. Conclusion [5

marks]

1.3 Important Notes

1. ANSYS-GEOMETRY must be used for all the mechanical drawing.

2. There should not be two exactly identical designs in the class, once identified,

zero mark shall be granted.

3. The present assignment account for 25% of the whole module. For any late

submission, 5% will be deducted per day.

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