Gas flow through a slit into a vacuum in a wide range of rarefaction

Abstract

Gas flow through a two-dimensional slit into a vacuum is investigated by a direct simulation Monte Carlo method. Results for the mass flow rate are obtained as a function of the rarefaction parameter, which is inversely proportional to the Knudsen number. The distributions of density, temperature and mass velocity, and streamlines are presented. In the free molecular flow regime and in the hydrodynamic limit, our results agree with theoretical asymptotes, and in the transition regime, they compare well with numerical simulations by other authors.