Numerical study on thermal analysis of square micro pin fins under forced convection

In this experimental and numerical study, the heat transfer enhancement of heat sink using square micro-pin fins is investigated under forced convection. Micro pin fins of various height and spacing are considered in this analysis. Twenty five heat sinks are tested for three different heat load and Reynolds number range 4500 to 6500. The results show that the dimensionless heat transfer coefficient (Nusselt number) increases with increasing pin fin height and Reynolds number however, it decreases with increasing fin spacing. On the other hand, the heat sink of large fin height has lower thermal resistance at the cost of large pressure drop. The cooling performance of micro pin fin heat sinks is about 10% higher than the plate fin under forced convection. But, it is slightly more sensitive to pin-fin height compared to the pin-fin spacing. Further, it was observed that the heat sink of pin fin height 7.1 mu m and fin spacing 35 mu m possesses comparatively better system performance and fin effectivity to other heat sinks. The numerical results of pressure drop (Delta p) and Nusselt Number (Nu) agree well with the experimental results with typical discrepancies in the prediction of Delta p and Nu of 15% and 25%, respectively.