Slip Coefficients for Gaseous Mixtures

Abstract

To take into account a moderate gas rarefaction without solving the Boltzmann kinetic equation the slip boundary conditions are applied to the hydrodynamic equations. Moreover, some phenomena, e.g. thermal creep, can be calculated applying the Navier‐Stokes equation with the slip boundary conditions, while the non‐slip conditions do not provide such phenomena. So, the slip coefficients have the same importance in continuum mechanics as the transport coefficients such as the viscosity, thermal conductivity, diffusion coefficient, etc. In the present work, some numerical results on the viscous, thermal and diffusion slip coefficients for a binary gaseous mixture are obtained on the basis of the McCormack model of the Boltzmann equation, which is solved by the discrete velocity method. A comparison of the present results with those obtained from the exact Boltzmann equation showed that the McCormack model equation provides reliable results with modest computational efforts.