DSMC study of the radiometric force acting on a thin plate with surface temperatures much higher than the environment temperature

Abstract

Radiometric plates have potential applications in aerospace science and technology. The radiometric force acting on a circular thin plate with surface temperatures much higher than the environment was studied with the aid of direct simulation Monte Carlo (DSMC). Dimensional analysis showed that the scaled radiometric force depended on the scaled temperatures of both sides of the plate and the Knudsen number. Statistical analysis of the gas–plate interactions demonstrated that the gas around the plate was in a thermal non-equilibrium state. The radiometric force acting on the plate could change its direction along the radius for small Knudsen numbers, which was thought to be a combined effect of rarefied and continuum flow. Furthermore, a dimensionless expression was proposed for the radiometric force for a wide a range of surface temperatures and for radius-based Knudsen numbers equal to or larger than 0.05. The radiometric force varied non-linearly with the temperature difference, and dependence of the radiometric force on the perimeter and the mean free path for small Knudsen numbers was between those predicted by the theories of Einstein and Sexl. This work improves the understanding of radiometric flow at small Knudsen numbers and can be applied to aerospace technology.