Numerical Analysis of Buoyancy-Induced Flow and Heat Transfer in an Enclosure With Vents

This paper reports a numerical study of buoyancy-induced flow and heat transfer in an enclosure with vents. The geometry closely resembles a “set-top-box” application frequently encountered in electronics cooling applications. The heat generating module is modeled as a planar heat source placed on a conducting printed circuit board (PCB). Full 3D and simplified 2D conjugate heat transfer models accounting for conduction and radiation in the solids and conduction and convection in the fluid were used Experiments performed to validate the 3D model have shown excellent comparisons with numerical results. A parametric study involving vent size, power dissipation, number of high conductivity power planes in the PCB has been performed with both the 3D and the 2D models. Although the quantitative results obtained from both types of analyses are similar only under certain conditions, qualitatively, the 2D analysis can be used to obtain useful insights into the complex overall transport mechanisms.