LAUSR

Abstract Extended surfaces are widely used in various industries as passive methods for enhancing heat transfer. The thermal boundary layer formed at the heat exchange surfaces is considered as a barrier to heat transfer from the surface and restrains their efficiency. As an active and inexpensive method of enhancing heat transfer, electrohydrodynamics (EHD) can be used to solve this problem and strengthen the heat transfer rate. In the present study, by combining the active and inactive methods of heat transfer enhancement, the effect of electrohydrodynamics on natural heat transfer is examined experimentally on a rectangular surface with vertical fin. The base plate of the fins is subjected to constant heat flux and the temperature of the plate is measured during the test period. The experiments were performed for different angles, including acute and obtuse angles, and by applying different voltages. Based on the obtained results, experimental equations for calculating the electrohydrodynamic Nusselt number at the finned surface are presented as a function of the applied voltage. Experimental results show that the electrostatic field has a significant effect on increasing the heat transfer from this extended surface. Finally, the formed corona wind vortexes between electrodes, caused by applying high voltage electrostatic field is detected.