Assessment of the Thermochemical Model for a Super-orbital Reentry Flow

We assessed the effect of the thermochemical models for a super-orbital reentry flow, on which the experiment was performed using a super-orbital expansion tube X2 at University of Queensland. The flow velocity achieved by the expansion tube is 10.3 km/s. Our numerical code is based on AUSM-DV scheme and simplified diagonal implicit method. The thermochemical model used in our numerical code is based on Park’s two-temperature model for thermal non-equilibrium and Park’s chemical reaction model for 11 air species. Our numerical results were compared with experimental data and numerical results obtained by the Langley Aerothermodynamic Upwind Relaxation Algorithm (LAURA). In the thermal equilibrium region inside the shock layer, the flow properties, such as temperature, electron number density, and total density, are in good agreement with experimental and numerical results. On the other hand, in the thermal nonequilibrium region, a large discrepancy is observed. The discrepancy is considered to arise from the difference of thermochemical models, especially, the models related to the thermal non-equilibrium. Thus we should pay attention to the energy relaxation processes for thermal nonequilibrium to understand the super-orbital flow and the problems related to it. ∗Research Associate, Member AIAA., E-mail:thootu@ipc.shizuoka.ac.jp. Phone: +81-53-478-1078, Fax: +81-53-478-1078 †Associate Professor, Associate Fellow AIAA. ‡Research Associate, Member AIAA. §Professor, Associate Fellow AIAA. Nomenclature e = total energy per unit mass eV = vibrational-electronic energy per unit mass Fj = flux vector S = vector of source term T = translational-rotational temperature TV = vibrational-electronic temperature uj = velocity U = vector of conserved quantities xj = coordinate directions ρ = total density