Effect of Bypass on Overall Performance of Pin-Fin Heat Sinks

摘要

One of the most important factors influencing the overall performance of cylindrical pin-fin heat sinks is the bypass phenomenon. Depending upon the total bypass area in comparison to the flow area between pin fins, a significant portion of the approaching airflow bypasses the heat sink. In this study, the effects of side and top bypass on the hydraulic and thermal performances of a cylindrical pin-fin heat sink will be investigated in laminar forced convection. Theoretical models, based on laws of conservation of mass, momentum, and energy, are developed to predict flow velocity, pressure drop, and heat transfer from the heat sink and the bypass regions. These models will help in determining hydraulic and thermal resistances in each region. Both in-line and staggered arrangements are analyzed in this study. Analytical and empirical correlations are used to determine friction factors and heat transfer coefficients in both arrangements. The effects of thermal spreading and joint resistances are neglected in this study.