A review of non-equilibrium dissociation rates and models for atmospheric entry studies

The appropriate simulation of vibrational exchange and dissociation processes in high-temperature (above 1000 K) plasmas mandates the application of more detailed state-to-state models, when compared with those based on first-order theories, utilized for the simulation of low-pressure plasmas. Such can be achieved through the application of approaches such as the forced harmonic oscillator model, or the quasi-classical trajectory model. This allows obtaining multiquantum state-resolved rates significantly more accurate at high temperatures, as compared with rates issued from first-order perturbation theories. This work reviews the more recent high-temperature datasets proposed by several groups, including our own. Such datasets have then been applied to the simulation of dissociation processes in high-temperature shock-heated nitrogen flows, and a comparison against traditional multi-temperature models has been carried out, for post-shock temperatures ranging from 20 000–100 000 K. Differences between the results predicted by the state-resolved and macroscopic models are significant, except in the high-temperature limit.