PARAMETRIC STUDY OF THERMAL AND CHEMICAL NONEQUILIBRIUM NOZZLE FLOW

A numerical analysis of a thermochemical nonequilibrium inviscid nozzle flow was made for two types of wind tunnels. The first one was a French project of an arc jet wind tunnel. The second one was a generic wind tunnel, similar to a future European facility, with higher stagnation conditions than in the first wind tunnel. In the analysis, an equilibrium airflow is assumed up to the throat of the nozzles. Downstream, the calculation is carried out with a quasi-one-dimensional method, taking into account nonequilibrium thermochemistry, with possible vibration-dissociation coupling. There, the airflow is expanded quickly, and departure from equilibrium and then freezing are observed. Different models of chemical, electronic, and vibrational kinetics and different coupling models are studied. Their global influences are analyzed for one test condition for each wind tunnel. Futhermore, for the first nozzle, the computed frozen Mach number compares well with experimental results.