Applicability of molecular dynamics method to the pressure-driven gas flow in finite length nano-scale slit pores

Abstract

This study investigates the applicability of the molecular dynamics (MD) method to the pressure-driven gas flow in finite length nano-scale slit pores. The reflecting particle membrane is introduced to induce a pressure difference between the inlet and outlet. The flow properties are compared with those of the Burnett equations. The inlet and outlet pressures, as well as the mass flow rate in these two simulations are maintained the same by adjusting the tangential momentum accommodation coefficient in the Burnett simulation, which is found to be between 0.4 and 0.5. Qualitative and quantitative agreements are observed between the MD and Burnett simulation results in the bulk of the pore for both streamwise distributions and cross-section profiles. The MD simulation shows an advantage in the near-wall region, in which the wall force field dominates flow behaviour. This study indicates that MD simulation can be used to describe the pressure-driven gas flow characteristics in finite length nano-scale slit pores.