DSMC Simulation: Validation and Application to Low Speed Gas Flows in Microchannels

A direct simulation Monte Carlo method (DSMC) solver, adapted to the subsonic microflow, is developed under the object-conception language (C++). Some technical details critical in these DSMC computations are provided. The numerical simulations of gas flow in a microchannel are carried out using the developed DSMC solver. Streamwise velocity distributions in the slip flow regime are compared with the analytical solution based on the Navier–Stokes equations with the velocity slip boundary condition. Satisfactory agreements have been achieved. Furthermore, the domain of the validity of this continuum approach is discussed. Simulations are then extended to the transitional flow regime. Streamwise velocity distributions are also compared with the results of the numerical solutions of the linearized Boltzmann equation. We emphasize the influence of the accommodation coefficient on the velocity profiles and on the mass flow rate. The simulation results on the mass flow rate are compared with the experimental data, which allow us to validate the “experimental” technique of the determination of the accommodation coefficient.