Computational Simulation of Reentry Flows over Hypersonic Vehicles Using Nonlinear Coupled Constitutive Relations

The accurate prediction of the aerodynamic and aerothermodynamic data for a reentry vehicle at high altitudes is often an important guidance for the design of the thermal protection system. During the reentry process, the hypersonic vehicles will intensively experience complicated physical and chemical phenomena, primarily including the real gas effects and rarefied gas effects. In this study, the model of nonlinear coupled constitutive relations (NCCR) is introduced for the numerical simulations of hypersonic reentry flows with the effects of thermochemical nonequilibrium and rarefaction nonequilibrium, as well as Gupta's chemical kinetic model and Park's two-temperature model are employed. Two numerical examples, including hypersonic flows around the ELECTRE vehicle at 54.3 km and the Orion command model at 105 km, are used to examine the performance of the present solution. It is found that the results computed by NCCR model, especially the heat flux distributions along the solid surface, are in better agreement with those of direct simulation Monte Carlo or flight data than the conventional Navier-Stokes equations.