The importance of thermal mass diffusion effects in solution of Navier-Stokes equations for some gas mixture problems

A computer code has been developed for numerical computation of compressible turbulent Navier-Stokes equations in general curvilinear coordinates, to solve binary perfect gas mixture flows. The prepared algorithm and the computer code are capable of modeling mixture effects in different fluid flows including viscous and mass diffusion effects. The Roe's numerical scheme is used to discretize the convective terms of governing fluid flow equations and simple upwinding method is used to discretize the equation of continuity of species. A complete model for mass diffusion which consists of ordinary, thermal and pressure terms is employed. The goal of this study is to investigate effects of viscosity, mass diffusion and especially thermal diffusion, on flow fields consisting of different mixtures. It is shown that the thermal mass diffusion can have profound effect on some flow fields, especially when the temperature gradient is not small. However, pressure mass diffusion can be negligible in the most of conventional problems.