Numerical Simulation of Electrothermal Convection in Dielectric Liquids Enclosed within Rectangular Cavities

Abstract: Electrothermal convection demonstrates the huge potential for the active enhancement of heat transfer, but an in-depth understanding of many related processes is still superficial. In this paper, electrothermal convection subjected to unipolar injection within rectangular cavities is investigated. A series of simulations under different Rayleigh number Ra and electric Rayleigh number T are carried out and the stability diagram of the flow motion in the Ra-T plane is obtained. The stability diagram can serve as a benchmark for the study of electrothermal convection. Besides, the impact of charge in the injection direction (with charge in injection from below or from above) and different aspect ratios are studied. It turns out interestingly that the injection directions do not modify the stability thresholds, the maximum velocity, and the heat transfer efficiency. Moreover, it is found that the geometric size has a significant influence on the flow pattern, and a more complex transition process occurs at a larger aspect ratio.