Numerical Simulation of Heat Transfer Behaviors in Conical Pin Fins Heat Sinks

Abstract

The present study is a numerical investigation of the effect of the shape of pin fins on the overall performances of heat sinks. Conical shaped pin fins with varying conical size ratio (Hcp/d) are considered. Five geometrical cases are explored, namely Hcp/d = 0.167, 0.333, 0.500, 0.667 and 0.833. The distribution and values of temperature, Nusselt number, thermal resistance, pressure drop, as well as the hydrothermal performance factor are determined for various Reynolds numbers (up to 8,000). In addition, the performances of conical shaped fins are compared to those of the cylindrical fins. The obtained results revealed a decrease in the thermal resistance with increasing Re and Hcp/d ratio. At Re = 8000 and when changing (Hcp/d) from 0.167 to 0.833, the thermal resistance is decreased from 192.30% to 83.52% compared to the cylindrical pin fins. However, the increased (Hcp/d) ratio yields an increase in the pressure drop. At Re = 8000, the values of pressure drop for the conical fins are lower than those of the cylindrical fins by 343.32%, 275.92%, 205.79%, 144.86% and 100.38% for Hcp/d = 0.167, 0.333, 0.500, 0.667 and 0.833, respectively. The values of the hydrothermal performance factor (h) for the conical fins are greater than those of the cylindrical fins. Also, an increase in (h) values is observed with decreasing Hcp/d ratio. The highest (h) value of 1.51 is reached with the case Hcp/d = 0.167 at Re = 8,000.