Transport properties of gases and plasma mixtures for gasdynamics simulation

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Transport coefficients of high-temperature gas mixtures in the new expressions of molecular flux is investigated on the base of kinetic theory and the Chapman-Enskog method with high orders of Sonine's polynomial expansion. The heat flux equation as well as the mass diffusion flux of molar species are resolved with respect to the gradients of temperatures and species fractions. The new form of transport coefficients make possible to numerical investigating gases and plasma molecular properties in the wide ranges. The new simplified expressions for hightemperature mixtures of gases and plasma are deduced. The data base for molecular transport properties, collision integrals, cross sections and potential functions is worked out. Introduction Molecular transport processes in various thermophysical states of matters is a subject of interest in the such problems, as atmosphere pollution by industrial spent gases, burning flows in channels, ablation processes, the space flights at high altitudes and so on. The numerical simulation in these scientific fields based on the system of hydrodynamic equations (mass diffusion, heat flux, pressure tensor expression). They require that all coefficients in the equations to be known, and just coefficient reliability (including transport coefficients) is responsible for the modeling agreement. The ordinary Data Bases of transport coefficients due to direct experiment measurements are strongly confined nowadays to temperature and pressure ranges. Such, the well-known Data Bases as NBS, NIST don't exceed the limit of 20002500K usually, and there is no idea, that the ranges of experiments could be considerably extended. The well-known Russian Hand Books of Vargaftic B.N. [1], Kikoin I.K. [2] don't contain transport properties data at high temperature more than 6000K. The theoretical data have been calculated in some works. From the latest, which have been calculated in high orders of Sonine's polynoms expansion are Abbaoui M., et.all [3], Capitelli M. [4], Kuratani K., et.al [5], and some others. But they are not completed. Thus, the theoretical models and calculations are of importance to full filling transport properties data base. The main object of our investigations is: (1) over-covering wide temperature and density ranges by reliable data to satisfy numerous applications, while describing chemical-physical processes in atmosphere, solving gasdynamic and heat transfer problems, and other others; (2) simplification of the kinetic theory expressions to the practical useful ones without loss of accuracy; (3) accumulation data of transport coefficients, collision integrals, cross sections and potential function into the computerized library, providing light access to consumer. The New Exact Molecular Fluxes Expressions Molecular kinetic formalism and the ChapmanEnskog method with Sonine's polynomial expansions [6] gives expressions for the molecular fluxes (transport terms in hydrodynamic equations) and the transport coefficients in them. The new ones are derived as the explicit molecular flux via the gradients of hydrodynamic American Institute of Aeronautic And Astronautic Copyright© 1997, American Institute of Aeronautics and Astronautics, Inc. variables, due to direct solution of system of algebraic equations of the Chapman-Enskog method [7]. Transport coefficients coincide with the molecular flux expressions, correspondingly. In ordinary used standard procedure of ChapmanEnskog method [6] the molecular diffusion flux of species Jj and the heat flux Jq are expressed via the mass diffusion forces dj. In this case the evaluation of the transport properties is a very cumbersome procedure, which requires to exclude the vectors of diffusions forces dj. The new molecular fluxes contains the transport coefficients which order of the determinant matrix is lowered on the number N equal to the whole number of species in mixture. The heat flux equation is, as follows where X(£) is the translation thermal conductivity coefficient, A,int is the thermal conductivity due to exited internal modes. The diffusion flux of species J i are derived by the Stefan-Maxwell equations, as the following ff = VAAi (2) where kj-,is the thermodiffusion ratio; the binary diffusion coefficient,./^) is the correction due to high Sonine' polynom expansion,