Thermophoresis of a Micro-Particle in Gaseous Media with Effect of Thermal Stress Slip

Abstract

The present article pertains to a theoretical analysis for thermophoresis of a micro-particle in rarefied gas environment. Different from the conventional analyses, thermal stress effect in velocity slip boundary condition is taken into account. This interfacial thermal characteristic is always ignored in previous theoretical studies. The present theory with consideration of the thermal stress slip provides an appropriate modification and thus agrees well with the measured data of thermophoretic mobility of various particles. Order-of-magnitude analysis also qualitatively demonstrates enhancement of the thermal stress slip with reducing particle size or increasing characteristic temperature gradient. Finally, a parametric analysis shows that the thermal stress slip effect becomes more pronounced at conditions of high particle thermal conductivity and high Knudsen number as well.