State-to-state approach in the kinetics of air components under re-entry conditions

A state-to-state vibrational kinetics for air components including recombination-dissociation processes as well as the formation of NO through the reaction between vibrationally excited nitrogen molecules and atomic oxygen has been inserted in a monodimensional fluid dynamic code, describing the boundary layer surrounding a body under re-entry conditions. The results show that the formation of NO is strongly enhanced by the nonequilibrium vibrational distribution of N-2 formed during the recombination process. This kind of distribution is responsible for the non-Arrhenius behavior of dissociation constants of N-2 and O-2 as well as the NO formation rate as a function of instantaneous temperature.