Thermodynamic and Transport Properties for Induction Plasma Modeling

Abstract

The development at the von Karman Institute of an inductively heated plasma wind tunnel has brought a need for theoretical and numerical investigation of high-temperature gases (plasmas) of different types. The thermodynamic properties of individual species are computed using statistical thermodynamics formulations based on the rigid rotator and harmonic oscillator model. A discussion is made about cut-off criteria for the electronic levels, low-temperature corrections to the partition function and anharmonicity considerations. It is shown that sufficient accuracy is obtained for practical applications of chemical equilibrium without complex cut-off criteria and anharmonicity corrections. The mixture thermodynamic properties are computed at chemical equilibrium reactions approach. An efficient formulation has been obtained for mole fraction or mass fraction computation which allows the reduction of the system of unknowns to a size equal to the number of basic nuclei types. The method is illustrated by 3-species argon and 13-species air plasma computations. Finally, transport properties are computed from kinetic theory of gases. The underlying mixture rules and the collisional data used is input are discussed and results are shown for a 13-species air plasma.