Numerical analysis of the mixing of two gases in a microchannel

Institut Jean le Rond d’Alembert, Université Pierre et Marie Curie, CNRS, UMR 7190, 75005 Paris, France

^a Corresponding author: cedric.croizet@upmc.fr

Received: 8 April 2012
Accepted: 14 November 2013

Abstract

We present the results of a numerical simulation of a mixing process of two parallel streams of nitrogen (N₂) and carbon monoxide (CO), in a microchannel with a splitter plate mounted at the inlet. As an attempt to enhance mixing efficiency, bumps are added on the channel walls, downstream the splitter. Typically, in such a passive micro device, the gas flow is laminar, rarefied, and characterized by a Knudsen number in the range of about 0.01 to 0.5, that is in the transition flow regime. The Direct Simulation Monte Carlo (DSMC) method is employed to explore the influence of the bumps and the splitter plate, and to analyze the sensitivity of the gas mixing length to parameters such as the inlet velocity as well as the height and location of the bumps. For a selected range of parameters, quantitative analytical and numerical results are in very good agreement.