Nonequilibrium effects in high enthalpy gas flows expanding through nozzles

An approach based on the direct simulation Monte Carlo method is proposed to model a core flow in converging–diverging nozzle. The area of applicability this defined by Boltzmann equation, which allows fully kinetic models that accurately capture thermal and chemical nonequilibrium be applied gas flows where regime rapidly changes from continuum transitional. validated through comparison with available experimental data. examination reaction rate effects for Caltech's T5 shock tunnel condition has shown little impact but demonstrated significant sensitivity nitric oxide (NO) density all exchange NO recombination rates. use most recent theoretical rates results factor two lower at nozzle exit as compared conventional Park rates, indicates re-visiting latter may necessary. Multi-parametric study conditions not provided an explanation large drop free-stream temperature over time, under constant velocity, observed recently T5. Modeling High Enthalpy Shock Tunnel Göttingen considerable between vibrational modes N2, NO, O2; it also vibration–dissociation coupling strongly influences mole fractions O2.