Behavior of Two-Temperature Model in Intermediate Hypersonic Regime

Abstract

Shock standoffdistancefora sphereis calculated to examine thebehavioroftheexisting two-temperature model in theintermediate hypersonic e ow regime. Calculations are carried outforthreebinary scaling parametervalues, corresponding to nearly frozen, nonequilibrium, and nearly equilibrium e ows, respectively. The obtained shock standoff distances are compared with the experimental data obtained in a ballistic range. It is shown that the two-temperature model reproduces the shock standoff distances in the intermediate hypersonic e ows fairly well but tends to lose its accuracy where vibrational excitation occurs but chemical reactions are nearly frozen. Nomenclature M = collision partner in dissociation/recombination reactions p1 = static pressure in the test section, Pa q = power on the vibrational temperature in the dee nition of Ta, 0<q <1 R = nose radius of a sphere, m T = translational temperature, K Ta = rate-controlling temperature for dissociation reactions, T 1 iq T q v , K Tv = vibrational temperature, K U1 = e ight velocity, m/s ° = specie c heat ratio Ω1 = freestream density, kg/m 3