Grid convergence and influence of wall temperature in the calculation of thermochemical non-equilibrium heat flux

Abstract

In order to accurately simulate the aerothermal environment of hypersonic vehicles, research on the grid convergence and influence of wall temperature is conducted in this paper. Two kinds of gas models are utilized for numerical simulations, namely the thermochemical non-equilibrium gas model and the perfect gas model. A typical hypersonic vehicle—the Orbital Reentry Experiment capsule—is used as the simulation object. After designing a series of coarse and refined grids, numerical simulations are conducted with the two gas models under different wall temperatures. Results indicate that the heat transfer prediction is very sensitive to normal grid spacing at the wall. Grid convergence for the two gas models is basically the same. When the grid is convergent in the hypersonic flow heat flux calculation, the required normal height of the first layer is smaller for the low wall temperature condition, compared with the high wall temperature case. Moreover, when the grid-convergence requirement is met, the heat flux increases with the reduction of wall temperature for all of the simulated flight conditions.