Abstract: In order to enhance the heat transfer of heat sink with straight fins of the high power LED lamps working under natural convection, the structure optimization of this kind of heat sinks was carried out. Based on a method of the minimum entropy generation, the influences of the important parameters on the heat transfer and fluid friction of the heat sink were analyzed, such as the fin thickness and the numbers, the height of fin, total quality of the heat sink and wind speed. The results showed that the dimensionless entropy generation and the temperature entropy generation first increased, and then decreased with the number of fins increasing, and the entropy generation caused by temperature was about ten times of that by friction. In addition, under a given heat flux, there existed the best geometry parameters of heat sink fins, which could minimize the entropy generation, and could improve the whole performance of the heat sinks.

Key words: heat sink, minimum entropy generation, numerical simulation, structure optimization, natural convection