Investigation of heat transfer enhancement of vertical heat sinks by piezoelectric fan

This study examines the influence of positions and arrangements of a piezofan having 12-mm wide and 70-mm-long Mylar blade on the thermal performance of two different types of vertical heat sinks. Heat sinks having 11 plate-fins and 100 square pin-fins are tested. The heat transfer coefficient is measured with either a vertical fan and a horizontal fan located at five different locations with distance of 16 mm over fin tip. It is found that the tip amplitude of the Mylar blade is about 7.2 mm. Besides, it is shown that heat transfer coefficient of present heat sinks induced by piezofan show 1.1-2.3 times higher than that under natural convection depending on the fan arrangements and positions. The maximum heat transfer enhancement usually occurs at x/L = 0.5 with either fan arrangement. The heat transfer coefficient is more enhanced with a vertical fan than that with a horizontal fan for either heat sink.