Analysis of straight and wavy miniature heat sinks equipped with straight and wavy pin-fins

Abstract

The use of pin-fins is an effective technique for improving the performance of miniature heat sinks. Generally, this improvement is due to the larger heat transfer area as well as the chaotic advection of fluid and thermal boundary layer interruption, which are produced by pin-fins. In this analysis, the performance of straight miniature heat sink (SMHS) and wavy miniature heat sink (WMHS) is investigated in the presence of straight and wavy pin-fins and the obtained results are compared with the smooth cases. Results show us that noticeable differences of velocity and temperature fields between the enhanced cases and the smooth cases exist, and they differ from shape to shape of channel and pin-fin. It is also found that both the heat transfer coefficient and the pressure drop of SMHSs and WMHSs equipped with pin-fins are always higher than those of without pin-fins. At the studied range of Reynolds number (i.e. 100 to 1000), the enhanced cases show 0.05 to 2.3 times enhancement in the heat transfer coefficient and 2.6 to 13.6 times augmentation in the pressure drop compared with the smooth cases. The highest values are recorded for the WMHS equipped with wavy pin-fins having an opposite spin. However, it is shown that for the same pumping power the heat removal of all enhanced cases is higher than that in the smooth cases. Overall analysis using the ratio of heat transfer rate to pumping power is done to detect the best configuration: a better performance is observed for the SMHS with straight pin-fins and the WMHS with wavy pin-fins having an identical spin.