The orientation effect for cylindrical heat sinks with application to LED light bulbs

This research examined the orientation effect for a cylindrical heat sink used to cool an LED light bulb. Natural convection and radiation were taken into account in the simulation, and the numerical model was validated experimentally. Changes in the cooling performance of a cylindrical heat sink with increasing angle of inclination were examined. The orientation effect was analyzed by considering the flow characteristics and drag coefficient, and the influence of geometric parameters on the cooling performance of a cylindrical heat sink was evaluated. The orientation effect was intensified when the number of fins and the fin length increased, whereas the influence of fin height on the orientation effect was relatively insignificant. Finally, a correlation was proposed to predict the Nusselt number around an inclined cylindrical heat sink.