Simulations of Non-Equilibrium Air Chemistry Compared To Hypersonic Wind Tunnel Experiments

Computational fluid dynamics simulations of hypersonic flow over a finite-span cylindrical test article are presented and compared to laser absorption spectroscopy measurements obtained in a high-enthalpy reflected shock tunnel. The experimental dataset consists of simultaneous measurements of rotational temperature, vibrational temperature and mass density of nitric oxide in the freestream and post-shock region surrounding the test article. The partially measured freestream along with computational fluid dynamics simulations of the shock tunnel nozzle are used to characterize the un-measured freestream properties required to set the boundary conditions for the test article simulations. Synthetic measurements are post-processed on the simulation results to convert simulation flow field data into a form that is more appropriate for comparison with the experimental line of sight laser diagnostic measurements. The computational fluid dynamics simulations use the Modified Marrone-Treanor nonequilibrium chemical kinetics model and new vibrational relaxation time constants for five species air that are based on quantum chemistry calculations.