Numerical and experimental study of heat-transfer characteristics of needle-to-ring-type ionic wind generator for heated-plate cooling

摘要

Ionic wind generators have shown significant application potential in devices for cooling, air actuation, and flow control. In this study, a needle-to-ring electrode ionic wind generator with optimized parameters was employed to cool a heated copper plate. A three-dimensional numerical simulation was conducted to obtain the electric, flow, and temperature fields of the ionic wind generator. To verify the ionic wind generator's capacity to cool the heated plate, an ionic wind generator prototype was fabricated and experimentally tested. The temperature distribution of the plate heated by a uniform distributed heat flux and non-uniform heat flux with a local hot spot was analyzed. Results show that the applied voltage should be less than the threshold voltage of spark discharge to ensure effective and stable operation of the ionic wind generator. When the plate is heated by a uniform heat flux, the temperature distribution in most areas around the center of the plate is relatively uniform. If a hot spot exists, the temperature of the central plate is higher than that of the surrounding areas, and the radial temperature difference gradually increases with the increase of the hot-spot heat flux. Moreover, the high-temperature area in the center of the plate gradually expands with increasing hot-spot radius. Besides, the increase in the copper plate thickness has little influence on the final temperature distribution. The heated plate with a uniform heat flux below 2 kW/m(2) could be cooled to below 80 degrees C by the ionic wind generator at an applied voltage of 11 kV. When the plate is heated by a non-uniform heat flux with a hot spot, compared with the experimental results of natural convection, ionic wind can effectively reduce the temperature of the plate (a temperature drop of at least 45 degrees C was observed). This study provides a potential solution for commercial chip cooling with needle-to-ring-type ionic wind generators.