Impact of Electronic Excitation on the State-to-state Vibrational-Chemical CO Kinetics

Dissociation of carbon monoxide in shock heated flows is studied with emphasis to the phenomenon of dissociation induction. Different kinetic schemes are implemented, both neglecting and including electronic excitation; various vibrational and electronic state-resolved models of dissociation rate coefficients are assessed. Vibrational-electronic relaxation coupled to dissociation behind the shock front is simulated in the frame of the state-to-state approach for several test cases with varying initial pressure, temperature, mixture composition and shock velocity. It is found that dissociation delay may appear regardless taking into account electronic excitation; the incubation time is mainly governed by mixture composition and initial pressure. Electronic excitation noticeably influences the overall dissociation rate. Recommendations for using specific dissociation models are given for different test cases.