MULTIFLUID DESCRIPTION OF RAREFIED GAS MIXTURE FLOWS

In the present contribution attention is focused to extend the application of multifluid descriptions to rarefied conditions for the first time. To this aim, a multifluid Maxwell model and a multifluid Smoluchowski model are proposed for near wall behavior of the constituents of a rarefied gas mixture. Afterwards, multifluid balance equations in conjunction with these boundary conditions are solved for some slip flows of binary gas mixtures between parallel plates. The corresponding results are compared with those of a previously developed Navier–Stokes solver. Inspection of the results indicates that while the Navier–Stokes equations may lose their accuracy under high rarefaction, non–equilibrium features are properly captured by developed multifluid description. This successful method is thereafter utilized to discuss the consequences of velocity–slip, the tangential–momentum–accommodation coefficient, and mass disparity of the mixture constituents on the degree of non–equilibrium between the constituents of the gas mixtures between parallel plates.