Conjugate heat transfer of jet impingement on short fins with different shapes

Abstract

This study examines numerically details of the flow and temperature fields of heat sinks with short plate fins cooled by impinging jet. The main focus is on the effect of fin shapes on the heat sink performance. Conjugate heat transfer between airflow convection and conduction inside the fin and base is considered. Three different shapes under study are rectangular, round-headed and elliptic, while the fin height keeps relatively short. Reynolds number or jet velocity is spanned to cover both laminar and turbulent flows. Distributed heat transfer coefficient is presented and compared. It is observed that the fin shapes affect largely both the heat transfer and pressure drop, especially of the short fin cases. Based on the same fin height, the total heat transfer with rectangular fins is 1.4 times that with elliptic fins in one of the cases studied, while the surface area ratio is 1.1. For longer fins, the shape effect on heat transfer becomes relatively less important than that on pressure drop. The results of this paper can help in design of heat sinks with jet impingement, which are commonly used in electronic cooling.