Orientation effects on thermal performance of radial heat sinks subject to natural convection

Abstract

Numerical study is carried out on natural convection heat transfer from three radial heat sinks subject to the influence of orientation. A finite volume method (FVM) numerical model was used to analyze the thermal performance of the radial heat sinks under upward, sideward and downward orientations. The effects of orientation with respect to gravity, fin number (15–30), the thickness of concentric ring (0.15–0.60) and Elenbaas number (15–55) on Nusselt number are investigated. Numerical results indicate that radiation is non-negligible in this study due to its high influence on thermal performance. The Nusselt number is relatively insensitive to the smaller ring thickness. The sideward facing orientation yields the worst thermal performance despite fin number changing. It is found that the thermal performance of heat sinks in upward and downward orientations depend on the number of fins significantly.