Compressible effects in microchannel flows [MEMS]

The direct simulation Monte Carlo (DSMC) method is used for airflow simulation in many micro-electro-mechanical-systems (MEMS). In this application, due to the breakdown of the continuum assumption, traditional methods such as CFD, etc., failed even under standard conditions. However, DSMC is a successful tool when applied to the micro-scale geometry related to MEMS devices. In this paper, simulations of the gaseous flow passing though microchannels in the slip-flow regime are compared with an analytical solution using the Navier-Stokes equations with slip velocity boundary condition. Excellent agreements have been achieved in the fully developed flow region. By way of further investigation, the effects of the pressure ratio are examined. The pressure gradient along the channel direction dominates the flow motion.