DSMC Simulation of Pressure Driven Binary Rarefied Gas Flows Through Short Microtubes

Binary gas flows driven by pressure gradient through short microtubes are studied by using an upgraded version of the Direct Simulation Monte Carlo (DSMC) method. Two types of mixtures, He/Xe and Ne/Ar, are examined. Several values of the channel length to radius ratio, the downstream to upstream pressure ratio and a wide range of the gas rarefaction are considered. Results are presented for the species and total flow rates and for the axial distributions of the macroscopic quantities. There is a pronounced difference of the flow behavior of the two mixtures due to the different molecular mass ratios. The flow rate of the He/Xe mixture for very short channels and large pressure drops is increased with increasing gas rarefaction, while the flow rate of the Ne/Ar mixture shows a different rarefaction dependence. The obtained results can be useful in optimal design of microfluidic or vacuum devices.