Numerical Study on Thermal Performance of Radial Heat Sinks for LED Lamps

Abstract

AbstractA large portion of the energy input to an LED lamp, usually about 70%, is dissipated as heat. A suitable arrangement is necessary to transfer this heat to the ambient and a radial heat sink may be an attractive option. Thermal performance of radial heat sink has been carried out numerically considering free convection as the sole mode of energy transport. The heat sink base is placed horizontally upon which a number of plate fins are attached at equal angular space. The heat sink draws the surrounding air toward it. The air enters the heat sink nearly horizontally which then removes the heat from the LED, becomes warmer and finally goes out from the heat sink almost vertically. Fins appreciably augment the rate of heat dissipation over that of the smooth circular plate. Effect of the variables such as Grashof number, number of fins, and fin height on heat losses from heat sink has been studied. Heat transfer monotonically rises with rise in Grashof number and fin height. But with increasing fin number, the improvement in heat transfer is not monotonic. At a given Gr and fin height, maximum heat transfer occurs at a particular fin number. For most of the realistic cases, 20 numbers of fins are a worthy choice with fin length equal to radius of the base plate.KeywordsFinRadial heat sinkNatural convectionFree convectionVorticity vector potential