Non-equilibrium chemistry model of an air plasma flow behind strong normal shock waves

A non-equilibrium air chemistry model is developed to study the shock layer around fast moving objects. It is based on an augmented Dunn-Kang model [1] that includes elastic scattering, vibrational relaxation, species diffusion, transport model and surface reactions. The air chemistry is coupled to a normal shock wave model and a one-dimensional stagnation line model. It provides the electron and gas temperatures, species densities, species and thermal fluxes. At temperatures below about 5,000 K the leading species and power fluxes are due to vibrationally excited nitrogen molecules, while at higher temperatures the nitrogen and oxygen molecules are dissociated and the fluxes of atomic species (oxygen and nitrogen) dominate. The adiabatic parameter γ decreases with gas temperature increasing and approaches its limiting value of 1 at high gas temperatures [2].

[1]. M. G. Dunn and S. Kang, “Theoretical and experimental studies of reentry plasmas”, NASA-CR-2232, NASA Langley Research Center (1973)

[2]. Tz. B. Petrova, G. M. Petrov, and J. R. Peñano, “Transport properties of high Mach number hypersonic air plasmas”, submitted for publication in Plasma Sources Sci. Technol.