关键词: 高超声速飞行器, 热化学非平衡效应, 表面温度分布, 气动热环境, 数值模拟

Abstract: In order to design the thermal protection system of hypersonic vehicles, it is important to simulate non-equilibrium flowfields of high temperature air, and to predict heat transfer rate precisely. In present paper, the simulation methods of coupled surface temperature and heat transfer rate is developed based on the Navier-Stokes equations of non-equilibrium flow-fields, the energy conservation equation at the surface with radiation, catalytic action and ablation, and the unsteady heat conduction equations of heat shield. the numerical simulation code used in this study is the AEROPH_Flow performed by us, which is the flow-field simulation code of numerical code system of aero-physical characteristic of hypersonic vehicle. The numerical simulation results are presented, including a semi-sphere geometries at the altitude of 65km with the free stream velocity of 8km/s and 10km/s, and a sphere-cone geometries at the altitude of 50km with 8km/s, the polycrystalline graphite was selected as the ablative material. The distributions of surface temperature and heat transfer rate are obtained, and the analysis is done for the influence of the surface temperature distribution on heat transfer rate. The results show that the surface temperature distribution have a more important influence on the computational results of heat transfer rate, the factors considered in the high precision prediction of aero-thermal environment are not only thermo-chemical non-equilibrium effect and surface catalytic effect, but also the surface temperature distributions, so the best method for high precision prediction of aero-thermal environment is coupling of surface temperature and heat transfer rate, and it is essential to develop perfect physical models, solving methods and numerical simulation codes of coupled non-equilibrium flow-field, surface catalytic action and ablation, and heat conduction of heat shield, and then, the high precision prediction of aero-thermal environment of hypersonic vehicles will be done greatly under the real flight condition.

Key words: Hypersonic vehicle, thermo-chemical non-equilibrium effect, surface temperature distribution, aero-thermal environment, numerical simulation