Abstract
In this study, the heat transfer performance of heat sink is enhanced by electrohydrodynamic (EHD) technique imposed on the side edge. The aim of EHD is to increase the heat transfer rate of heat sink under the natural convection. The multiple needle electrodes are installed at the side of heat sink with a high voltage electric field applied between the heat sink and electrodes. During the voltage discharge process, the air in the electric field is ionized and then the heat dissipation will be enhanced by these moving ionized molecules which is called ionic winds. The heat transfer performance can be affected by the numbers of electrodes within the operating voltage range of 0-18 kV. For 10mm of the distance between the electrodes and the sink and negative voltage, 6 needle electrodes achieve the best heat transfer performance. The performance is 1.78 times than that for the sink only under the natural convection. Moreover, the mechanism of corona discharge can be changed due to the difference of voltage polarity. The cases for a negative voltage are better than those for a positive one. The effect of height of electrodes on heat dissipation is also taken into account in this study. When the needle electrodes are placed at the middle of height of heat sinks, the performance is enhanced 1.74 times. With an increase in humidity, the occurrence of ionic wind is retarded by these additional water molecules and thereby the heat dissipation of heat sink is decreased. Finally, the various systematic parameters such as the corona current across the EHD device, the power consumption of EHD and the junction temperature are discussed for the problem of interest.