Modeling of Nitrogen Monoxide Formation and Radiation in Nonequilibrium Hypersonic Flows

Abstract

The interaction between nitrogen vibrational-translational relaxation with different chemistrymodels in a hypersonic shock is studied. The vibrational-translational transition models considered include the Larsen–Borgnakke, Schwartz- Slawsky-Herzfeld, and forced harmonic oscillator models; and the nitrogen monoxide formation reaction was studied using the total collision energy chemistry model and reaction cross sections obtained from quasi-classical trajectory simulations. Using direct simulation Monte Carlo solutions that incorporate these models, improved nitrogen monoxide spectral radiation modeling was performed by employing quenching rates from recent experiments. Comparisons of electronic state populations and the corresponding radiative spectra for the different vibrational-translational and chemistry models are presented, and it is shown that the vibronic spectral structure of the nitrogen monoxide radiation could provide a way to test the fidelity of the internal energy transfer and chemistry models.