Optimum design of a radial heat sink with a fin-height profile for high-power LED lighting applications

Abstract

Light-emitting diode (LED) lighting offers greater energy efficiency than conventional lighting. However, if the heat from the LEDs is not properly dissipated, the lifespan and luminous efficiency are diminished. In the present study, a heat sink of LED lighting was optimized with respect to its fin-height profile to obtain reliable cooling performance for high-power LED lighting applications. Natural convection and radiation heat transfer were taken into consideration and an experiment was conducted to validate the numerical model. Fin-height profiles reflecting a three-dimensional chimney-flow pattern were proposed. The outermost fin height, the difference between fin heights, and the number of fin arrays were adopted as design variables via sensitivity analysis, and the heat sink configuration was optimized in three dimensions. Optimization was conducted to simultaneously minimize the thermal resistance and mass. The result was compared with the Pareto fronts of a plate-fin heat sink examined in a previous study. The cooling performance of the optimized design showed an improvement of more than 45% while preserving a mass similar to that of the plate-fin heat sink.