Publications Details
Steady isothermal gas mass flow rate in a microscale tube from continuum to free-molecular conditions
Gallis, Michail A.; Torczynski, J.R.
The Direct Simulation Monte Carlo (DSMC) method of molecular gas dynamics is used to simulate the steady flow of an ideal gas through a long thin isothermal microscale tube connecting two infinite reservoirs at different pressures. The tube wall is at the reservoir temperature, and molecules reflect from the walls according to the Maxwell model (i.e., a linear combination of specular reflections and diffuse reflections at the wall temperature). The computed mass flow rates approach the known expressions in the near-continuum and free-molecular regimes and agree reasonably with recent experimental measurements in microscale tubes and channels. Approximate closed-form expressions for the mass flow rate and the pressure profile along the tube are developed and are in reasonable agreement with the DSMC results in all regimes and for all values of the accommodation coefficient. © 2011 by the American Institute of Aeronautics and Astronautics, Inc.