Determination of slip coefficient for rarefied gas flows using direct simulation Monte Carlo

TLDR: In this paper, a qualitative analysis was carried out to determine the slip coefficient as a function of two dimensionless parameters, and an intensive computation using the direct simulation Monte Carlo method was then performed to simulate the Couette flows between two walls for different gas, number density, wall (plate) velocity, wall temperature, and distance between the two walls.

Abstract: A qualitative analysis is first carried out to determine the slip coefficient as a function of two dimensionless parameters. An intensive computation using the direct simulation Monte Carlo method is then carried out to simulate the Couette flows between two walls for different gas, number density, wall (plate) velocity (Uw), wall temperature (Tw) and distance between the two walls. Numerical results show that the slip coefficient is proportional to the mean free path gw of molecules colliding with the wall, which is affected by the number density, the wall temperature and gas mass. The slip coefficient is finally found to be 1.125 gw. This slip coefficient is verified for five gases, and validated under the conditions of Uw300 m s-1 and Tw500 K. This slip coefficient is very useful for slip flow analysis in micro-electro-mechanical systems using N-S equations.