VISCOUS SHOCK-LAYER STUDY OF THERMOCHEMICAL NONEQUILIBRIUM

A two-temperature, viscous shock-layer (VSL) technique to analyze low- density (slip) effects and vibrational and electronic nonequilibrium f or an Ii-species airflow is presented, This formulation employs recent ly developed physical models, detailed transport and thermodynamic pro perties, and body and shock-slip conditions for multicomponent mixture s. Presently obtained results reproduce examined reentry flight data a cid numerical calculations with a good degree of accuracy over a wide range of conditions, validating its use for the calculation of low-to- high density flows. Detailed stagnation-region calculations along the trajectory of a proposed single-stage-to-orbit vehicle show significan t vibrational and electronic nonequilibrium and slip effects at the hi ghest considered altitude of 85 km. The combined effects of thermal no nequilibrium and slip lower the stagnation-point heating by about 24% at this altitude, These effects are negligible on surface quantities a t 55 km altitude, At this altitude, however, the chemical nonequilibri um effects lower the stagnation heating obtained from chemical equilib rium calculations by about 21% for the Shuttle-like surface. The resul ts provided here demonstrate the use of the VSL technique as a fast ca lculation procedure in a conceptual and preliminary design process, re quiring sensitivity analysis and rapid reanalysis.