Thermal creep flow around a spherical particle suspended near a plate

Abstract

Thermophoresis of small particles, like mist, fumes, dust, and so on, floating in a gas, particularly in the vicinity of a solid surface, is of practical interest in aerosol technology and related fields of treating gas molecule-surface interactions. This paper deals with thermal creep flow of a gas around a spherical particle suspended near a plane plate; temperature and flow fields are analyzed by counting the discontinuous rarefaction effects of the gas. In a consequence, the thermal force, as well as the drift velocity of the particle at an arbitrary distance from the plate, but limited to lower Knudsen numbers, are clarified, with thermal and flow fields in the gas being presented for some selected schemes. The thermal force is enlarged by the temperature jump decreased by the momentum slip. It increases as the particle approaches the plate; this increase is very sharp when the particle is closer to the plate. The drift velocity, on the other hand, remains nearly the same as that far away from the plate, but shows a slight decrease in the very vicinity of the plate. © 1998 Scripta Technica. Heat Trans Jpn Res, 27(1): 57–73, 1998