Transport coefficients in high-temperature ionized air flows with electronic excitation

Transport coefficients are studied in high-temperature ionized air mixtures using the modified Chapman–Enskog method. The 11-component mixture N2/N2+/N/N+/O2/O2+/O/O+/NO/NO+/e−, taking into account the rotational and vibrational degrees of freedom of molecules and electronic degrees of freedom of both atomic and molecular species, is considered. Using the PAINeT software package, developed by the authors of the paper, in wide temperature range calculations of the thermal conductivity, thermal diffusion, diffusion, and shear viscosity coefficients for an equilibrium ionized air mixture and non-equilibrium flow conditions for mixture compositions, characteristic of those in shock tube experiments and re-entry conditions, are performed. For the equilibrium air case, the computed transport coefficients are compared to those obtained using simplified kinetic theory algorithms. It is shown that neglecting electronic excitation leads to a significant underestimation of the thermal conductivity coefficient at tem...