Viscous velocity, diffusion and thermal slip coefficients for ternary gas mixtures

Abstract

An approach is presented to determine the viscous velocity, diffusion and thermal slip coefficients for three-component gaseous mixtures. The gas is described by the McCormack linearized kinetic model. It is shown that two diffusion slip coefficients exist for a ternary mixture. The boundary problem is solved by the discrete velocity method. The slip coefficients are calculated and tabulated for He–Ar–Xe mixture at various values of the mole fractions for the hard-sphere and experimental potentials. It has been found that the diffusion and thermal slip coefficients are more sensitive to the interaction potential than the viscous one. Representative velocity profiles of the Knudsen layer are also shown. Furthermore, a test calculation is presented for pressure and mole fraction driven flows in a tube. The flow rates obtained by the slip solution are compared to the kinetic results. It is revealed that the slip flow approximation provides a relatively good estimation of the flow rates at higher rarefaction parameters. The present methodology and the tabulated data can be useful to determine the gaseous flow in the slip region for the ternary mixture.