Molecular Dynamics Simulation of Rarefaction Effect on Shear-driven Gas Flow in Nanochannels

The nanoscale gas flow at normal temperature and pressure varies from the slip flow regime to the transition regime, of which the character length changes across several nanometers to several thousand nanometers. The difference in the degree of rarefaction leads to different rules of the flow in nanochannels. In order to study the influence of rare gas effect on the nanoscale gas flow, we use three-dimensional molecular dynamics method to simulate the shear flow confined by two parallel plate under different Knudsen numbers, and then obtain the distribution of flow velocity, density, normal stress and shear stress, thus calculating and analyzing the variation of the tangential momentum accommodation coefficient. Counting the gas molecules according to the velocity with positive and negative values respectively, we find that the gas flow is decomposed into two independent shear flows, which indicates strong non-equilibrium characteristics in the nanochannel.