High-temperature vibrational relaxation and decomposition of shock-heated nitric oxide: II. Nitrogen dilution from 1900 to 8200 K

This work investigates the high-temperature vibrational relaxation and decomposition of nitric oxide (NO) diluted in nitrogen (N2) to target NO–N2 rates relevant air, thereby building off argon (Ar) experiments investigated Part I. [J. W. Streicher et al., “High-temperature shock-heated oxide. Argon dilution from 2200 8700 K,” Phys. Fluids 34, 116122 (2022)] Again, two continuous-wave ultraviolet laser diagnostics were used obtain quantum-state-specific time histories NO shock-tube experiments, including absorbance (α) ground state NO, translational/rotational temperature (Ttr), number density (nNO). The probed mixtures 2% 0.4% either pure N2 (NO/N2) or an equal parts N2/Ar mixture (NO/N2/Ar). NO/N2 spanned initial post-reflected-shock conditions 1900–7000 K 0.05–1.14 atm, while NO/N2/Ar 1900–8200 0.11–1.52 atm. leveraged times I (τVTNO−Ar τVTNO−NO) extended measurements include vibrational–translational vibrational–vibrational with (τVTNO−N2 τVVNO−N2). Similarly, this four rate coefficients (kdNO−Ar, kdNO−NO, kfN2O, kzNO−O) dissociation (kdNO−N2). A few studies have directly inferred these current data differ common model values. In particular, τVTNO−N2 differs slightly Millikan White correlation, τVVNO−N2 is slower than Taylor al.'s inference, kdNO−N2 Park two-temperature model. unique experimental study significantly improve understanding air.