Two-temperature thermodynamic and transport properties of argon–hydrogen and nitrogen–hydrogen plasmas

Two-temperature thermodynamic and transport properties of argon–hydrogen and nitrogen–hydrogen plasma mixtures are presented, chemical equilibrium being achieved. The calculations of transport properties are carried out using the Chapman–Enskog method up to the third order; when electron temperature differs from that of heavy particles, calculations are performed following both a recent two-temperature theory by Rat et al that retains the coupling between electrons and heavy particles and a simplified decoupling theory proposed by Devoto. No relevant discrepancies between results obtained using these two approaches have been found, allowing the simplified method of Devoto to be still used in the computation of non-equilibrium transport properties like thermal conductivity, electrical conductivity and viscosity, with the exception of some diffusion coefficients. Results for composition, mass density, specific heat, thermal conductivity, electrical conductivity and viscosity of atmospheric pressure plasmas in the electron temperature range 300–40 000 K are reported.