Abstract: A new treatment of pressure boundary condition for DSMC method is proposed.With the new method,the computational divergence of traditional "number flux method" can be avoided and a higher convergence speed than the "averaged at inlet" method is obtained.The flows in micro-channels driven by different pressure drops are investigated using the new method.Comparison between DSMC results and continuum-based results has also been made.

Key words: pressure boundary condition, micro flow, DSMC