Improved Design of Heat Sink Including Porous Pin Fins with Different Arrangements: A Numerical Turbulent Flow and Heat Transfer Study

Author(s):  
Ali Mohammad Ranjbar ◽  
Zeinab Pouransari ◽  
Majid Siavashi
Author(s):  
Huanling Liu ◽  
Bin Zhang

Abstract In this paper, we propose a new type of DL-MCHS to improve the substrate temperature uniformity of the microchannel heat sink, and conduct the optimization of the New DL-MCHS. The heat transfer and friction characteristics of the novel DL-MCHS are studied by numerical simulation. We compare the heat transfer performance the new DL-MCHS with the traditional TDL-MCHS (the DL-MCHS with truncated top channels λ = 0.38). The results prove the effectiveness of the improved design by FLUENT simulation. When the inlet velocity is kept constant and coolant is water, the heat transfer performance of the New DL-MCHS is higher than that of TDL-MCHS leading to an increase of the temperature uniformity. In order to achieving the best overall heat transfer performance, an optimization of New DL-MCHS is performed by GA (genetic algorithm).


Author(s):  
A. K. Saha ◽  
Sumanta Acharya

An unsteady three-dimensional numerical study is performed to explore flow and heat transfer in a periodic array of cubic pin-fins housed inside a narrow channel. Short cubic pin-fins are arranged in an inline pattern with both streamwise and transverse periodicity set to 2.5 times the pin-fin dimension. Calculations are done in the turbulent flow regime for Reynolds numbers in the range of 7090–13280. The unsteady Reynolds-Averaged Navier Stokes (RANS) and energy equations are solved using higher order temporal and spatial discretization schemes. An unsteady k-ε turbulence model is employed to model the unresolved turbulence fluctuations. The unsteady RANS results are able to resolve discrete large scale spatial and temporal fluctuations in the flow. These fluctuations appear to mostly influence the flow in the region between the cubic fins, but are linked to low amplitude oscillations in the outer flow. Three thermal boundary conditions are studied: (1) only channel wall heated (2) only pin-fins heated and (3) both channel wall and pin-fins heated. The overall heat transfer enhancement is about 1.8–2.0 times the heat transfer from a smooth duct flow. The heat transfer from pin-fins is found to be 5–9% higher than that from the top wall at low Reynolds number (7090 and 8900), while it is of comparable magnitude at higher Reynolds number (=13280).


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