Enhanced convection from horizontal printed-circuit board with lifted electronic components

Abstract

Convective heat transfer from the electronic component on a simulated horizontal printed-circuit board (PCB) assembly to the ambient air was found to be enhanced significantly by lifting the electronic components a vertical protrusion off from the board's surface. Effects of the gap between the lifted electronic component and the PCB's surface, the electronic component's pitch-to-height ratio and the Reynolds number of the air-flow on the heat dissipation from the PCB assembly were investigated experimentally. Heat transfer measurements were obtained for duct clearance-based Reynolds numbers from 400 to 19000. Enhanced convection was obtained by increasing the vertical protrusion of the lifted component, especially when the Reynolds number is high. When Reynolds number is lower than 2100, a maximum vertical protrusion of 6mm is recommended. Correlations for the prediction of the average heat transfer coefficient of the simulated horizontal PCB assembly by adopting the lifted electronic components were proposed.