Pressure boundary treatment in micromechanical devices using the direct simulation Monte Carlo method

Abstract

Two numerical procedures in the Direct Simulation Monte Carlo (DSMC) method, applying particle flux conservation at inflow/outflow pressure boundaries, have been developed to treat the two most important boundary conditions encountered in micromechanical devices involving gaseous flows. The first one is for both specified pressures at inlet and exit; while the second one is for specified mass flow rate and exit pressure. Both numerical procedures have been tested on short and long microchannels in the slip and transitional regimes. Excellent agreement has been found between the current results and the previous reported numerical results as well as the experimental data for the first type of boundary conditions. Finally, the developed numerical procedures have been applied to backward-facing micro-step gaseous flows to demonstrate its general applicability in more complicated flows.