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Author See Weng Tan

Compact Heat Exchangers: Effects of

dimpled/protruded surfaces on the performance

Supervisor V.Timchenko

Research Theme: Fundamental and Enabling Research

Background

With the miniaturization of electronic devices and theever increasing use of integrated circuits, there is agrowing need for thermal management. One effectivemethod is to transfer the heat from electronic chips to

Results

Flow Structure

method is to transfer the heat from electronic chips toa remote heat exchanger, typically a parallel platecompact heat exchanger, where heat is dissipated tothe surroundings. The overall size of the coolingsystem depends on the efficiency of the compact heatexchanger. As dimpled and protruded surfaces on aheat exchanger have been shown to increase the heattransfer rate, a thorough investigation on its effect onthe performance of heat exchanger is carried out.

Heat Flux Distribution

Fig. 3: Velocity streamline of fluid over protrusion (Left) & dimple (Right).

Aims

To study the effects of dimpled and protruded surfaceson the heat transfer performance of compact heatexchangers at different Reynolds numbers.

Numerical Solution Process

Geometry Creation

Heat Flux Distribution

Geometry CreationBoth dimpled and protruded surfaces are modelled with similar geometric parameters as shown:

Fig. 1: Dimensions

(Left: Top view

Right: Front View)

Performance EnhancementComparing the performance factor between dimpled &protruded surfaces at different Reynolds numbers:D

L

L/D = 0.8/D = 0.22

Fig. 4: Heat flux around the vicinity of protrusion (Left) & dimple (Right).

/D = 0.22H/D = 0.3

HH

Defining Boundary Conditions (BC)The following BC are defined for both dimpled and protruded cases:Dimpled/protruded surface: T = 200C Flat Surface: T = 450CLeft &Right Ends: Symmetry & AdiabaticInlet & Outlet: Periodic

Conclusion

Within the working range of a compact heatexchanger (200