On the vibrational state-specific modeling of radiating normal shocks in air

Abstract

A comprehensive state-to-state (StS) model for air was formed, including vibration–vibration–translation (VVT) reactions. The generated VVT reaction rates were compared with available first-principles calculations, and reasonable agreement was obtained. The influence of multiquantum transitions revealed that the possible reduction on the number of VVT transitions depends on the application. The influence of VV transitions revealed that the vibrational excitation becomes too fast if VVT transitions are reduced to VT transitions, invalidating this approximation. Comparisons were made with existing NO emission measurements in the ultraviolet and mid-infrared spectrum. At velocities of 3–4 km/s, some of the current O2 dissociation rates may be inaccurate. At a higher velocity of 6.81 km∕s, the NO mole fraction predicted by the StS model is around an order of magnitude greater than that predicted by the two-temperature model. Finally, recommendations were given on the further development of the StS model.