Numerical analysis of electric force influence on heat transfer in a channel flow (theory based on saturated porous medium approach)

The present paper reports the influence of electrode and ground arrangement on electrically-driven airflow and heat transfer enhancement in a saturated porous medium placed in a channel flow. In simulations, the inlet velocity and temperature of air entering a test section are controlled at 0.35 m/s and 60 °C, respectively. High electrical voltage is tested in the range of 0-30 kV. The numerical results show+ that when electric field is applied, swirling flow caused by shear flow effect is observed. When electrode is placed near ground, swirling flow is small but it has a high strength. In addition, the strength of swirling flow is increased by increasing electrical voltage. With occurrence of swirling flow, the heat transfer is totally higher than the case of conventional hot-airflow. By comparing with a single ground, swirling flow created by multiple ground effect spreads wider over the surface of sample. This causes temperature of the sample to increase faster. It is found from flow visualization that behaviors of swirling flow obtained by smoke incense technique and simulation have a good agreement. Furthermore, enhancement of heat transfer in the sample depended on the arrangement of electrode and ground, as well as, the position of the sample.