Exact equations and transport coefficients for a multicomponent gas mixture with a partially ionized plasma

Abstract

Molecular transport processes are governing in many problems associated with-the flow of high-temperature multicomponent gas mixtures. Thus, a flow with a partially dissociated and ionized multicomponent gas is realized in problem of viscous heat-conducting gas flow around bodies in practically the whole flow domain outside the bow shock on the most heatstressed section of the trajectory, where convective heat transfer predominates, during entry in the atmosphere of planets of the solar system. Molecular transport processes in such a mixture govern directly the molecular heat and mass fluxes, the viscous friction force, as well as the rate of thermochemical destruction of the streamlined surface [i]. Transport processes play an important role in the flow of a weakly ionized plasma in a MHD generator [2], gas-phase nuclear reactors [3], and other problems. Consequently, a sufficiently rigorous and complete study of the behavior of the transfer coefficients in a broad temperature and pressure range is a problem of practical importance, and even more so since experimental investigations of multicomponent plasmas at high temperatures are related to great complexities in the diagnostics. It is also important to note that a study of all the necessary properties of a complete set of transfer coefficients has not been performed up to now because of the complexity of the appropriate formulas given by the kinetic theory of gases in the exposition in [4]. Of the experimental papers, [5-7] should be noted, in which the investigation of certain transfer properties of air, nitrogen, hydrogen, and argon was performed (mainly the heat conduction and viscosity coefficients only). Numerical computations were carried out in [8-11] for the transport properties of ionized gases by kinetic theory methods [4] with high approximations taken into account in a polynomial expansion of the distribution functions in Sonin polynomials. However, for flows of chemically equilibrium hightemperature gases for which effective coefficients are introduced in the hydrodynamics equations with additional terms associated with component transfer, heat liberation in reactions, and the use of quasineutrality conditions of the ionized mixtures taken into account (a strict determination of the complete set of effective transfer coefficients is given in [12, 13]), computations of all the effective coefficients in the hydrodynamics equations have never been performed successively. Up to now there is not sufficient information in the literature about the influence of any coefficient in any element temperature, pressure, and concentration range, nor about the role of taking account of high approximation in the computation of the transport coefficients for determining the heat flux, the component diffusion fluxes, and the viscous friction force [14].