State-Specific Study of Air in the Expansion Tunnel Nozzle and Test Section

Thermochemical nonequilibrium in expansion tunnel nozzles is investigated numerically using a state-to-state description one dimension for representative air conditions. Limiting the multiquantum jumps of vibration–vibration–translation (VVT) transitions to three both and can accurately simulate nozzle flow. The reduction VVT vibration–translation works well. State-to-state modeling an actual condition yielded agreement with measured static pressure. A study on influence different thermochemical excitations freestream at test section shows that postshock radiation emissions differ by more than 50%. However, non-Boltzmann distributions have no influence. An evaluation discrepancy between two-temperature models former generally predicts faster relaxation. Furthermore, results indicate that, general, molecular species all vibrational temperature.