Calibration of the CVCV-model against quasiclassical trajectory calculations

Abstract

The CVCV-model (Coupled-Vibration-ChemistryVibration) predicts reaction rates in thermal non-equilibrium for different types of reactions, dissociation and exchange reactions. Furthermore, the average internal energies of the molecules removed or gained in a reaction are modelled. Both couplings, the influence of vibrational or rotational energy on reaction rates and the influence of chemical reactions on the vibrational and rotational excitation, have to be considered for hypersonic flow simulations. The two CVCV-model parameters U, describing the preferential reactivity of highly excited molecules, and a, limiting the influence of vibrational energy on the activation energy, were recently adjusted using results of quasiclassica l trajectory calculations presented here. The model was found to be capable of describing reaction rates and average internal energies for both types of reaction. In contrary to previous assumptions, the influence of vibrational energy on the activation energy was found to be low for the second Zeldovich reaction (oc = 0.1) Finally, the adjusted model was applied in a simulation of the second BSUV experiment. NO was found to be created highly excited, confirming strong NO molecular band radiation measured during the flight.