Influence of Boundary Conditions and Chemical Reactions on the Rayleigh-Bénard Convection of a Rarefied Gas Mixture

摘要

In this paper we investigate the long time behavior (final state) of the Rayleigh-Bènard convection by using Direct Monte Carlo Simulation (DSMC) method in the following cases:1) The upper (cold ) or lower (hot) diffuse reflecting plate is moved with a constant velocity (case of one component gas);2) Presence of a second gas component (case of neutral binary gas mixture). An analysis of the influence of the admixture on the flow stability is presented;3) Case of a chemically reacting gas mixture. An analysis of the influence of a bimolecular chemical reaction on the convection flow stability is presented.In general, the numerical results show that when changing some parameters of the chemical reaction, species concentration and wall velocity one can control the flow and transform it from a pure heat-conduction regime to a stable convection vortex regime or a convection in form of running waves.