Nitrogen nonequilibrium vibrational distributions and non-Arrhenius dissociation constants in hypersonic boundary layers

A ladder-climbing model including V-V (vibration-vibration) and V-T (vibration-translation) energy exchange processes linked to state-to-state dissociation-recombination kinetics has been developed and inserted in the fluid dynamics equations, describing the boundary layer surrounding a noncatalytic surface hit by a hypersonic flow of atomic and vibrationally excited molecular nitrogen. The results show a strong overpopulation of vibrational levels with respect to Boltzmann distributions along the coordinate perpendicular to the surface and the corresponding non-Arrhenius behavior of dissociation constants.