FLOW OF A RAREFIED GAS WITH THERMAL CREEP IN A CIRCULAR TUBE

Abstract

Rarefied gas channel flow at a uniform temperature has been studied both theoretically and experimentally by many investigators. However, the analytical solution demonstrating explicitly the behavior of the gas flow, especially in the transition flow region where the well-known Knudsen minimum occurs, has not yet been obtained because of the complexity of the momentum transport by molecular collisions. Nor has the gas flow induced by the thermal stress been fully researched. In this paper, the problem of rarefied gas flow with thermal creep in a circular tube is studied, with special reference to the effect of thermal creep on the gas flow. The solution of the Boltzmann equation with the BGK model is obtained by use of the iteration procedure which uses the slip continuum solution as the first guess. The volume flow rate of the flow induced by the pressure gradient resulting from the present analysis is in fair agreement with the experimental data in the whole range of the inverse Knudsen number. The solution also gives a fairly good approximation for the thermal creep in consequence of the previous theoretical work.