Thermally driven rarefied flows induced by a partially heated diamond in a channel

Abstract

The present work uses the direct simulation Monte Carlo (DSMC) method to investigate thermally-driven rarefied flow induced by the partially heated diamond in a channel. Two types of flows are generated in the medium: the radiometric flow induced from the middle tip of the diamond with various temperatures on its side and the rightward thermal edge flow induced by the temperature difference between the diamond and the medium. The accommodation coefficients of the top and bottom borders were considered, and it is observed that the thermal edge flow is weakened if we set the top and bottom channels' walls as specular. In this work, we studied the influence of the geometrical parameters and operating conditions on the rarefied gas flow under specular conditions of the top and bottom walls. This includes the sizes of the diamond, the working pressure represented by the Knudsen number (Kn), and the temperature difference. The results show that varying the accommodation coefficients of channel walls affect the velocity field and results in the generation of vortices behind the diamond in the channel. We show that the drag force of the diamond is proportional to the temperature difference and increases slightly with the increase of Kn.