高超声速再入体表面热解烧蚀效应数值模拟

表面防热材料热解与烧蚀效应研究在高超声速飞行器总体设计中具有重要应用价值。以热解烧蚀效应对飞行器目标特性及通信性能影响的预测评估为背景，从化学非平衡气体动力学方程及固体热传导方程出发，建立了气-固交界面上热解烧蚀壁面边界条件的一般形式及热物理化学模型，发展了高超声速再入体绕流流场与表面材料内部温度场耦合求解的数值模拟方法，并对计算模型和数值方法的可靠性进行了验证分析。在此基础上针对复杂外形再入体及表面硅基防热材料，开展了典型再入条件下再入体绕流及尾流流场的数值模拟，重点分析了表面材料热解烧蚀效应对流场等离子体分布的影响。研究表明：在表面材料中不含碱金属杂质的情况下，热解与烧蚀效应对流场中等离子体分布影响较小，而在含有微量碱金属杂质的情况下，热解与烧蚀效应对流场中等离子体分布及化学组分分布具有很大影响，由此对再入目标特性与电磁通信性能带来的影响不容忽视。

Numerical Simulation on Pyrolysis and Ablation Effects for Surface Material of Hypersonic Reentry Body

It is important to study the effects of pyrolysis and ablation of heat protection material in integrated design of hypersonic vehicles. In order to predict and assess the material pyrolysis and ablation effects on target signatures and microwave communication, based on chemical nonequilibrium gas dynamic equations and solid heat transfer equations, the general surface conditions to couple flowfield with heat shield and the thermophysical and chemical models were set up. The method to solve governing equations for hypersonic flowfield and ablator heat transfer was established, and the feasibility of such model and method was validated. In addition, the flowfield and wake over reentry body with complex shape and silicon-based heat protection material were simulated numerically and the influence of the material pyrolysis and ablation on plasma distribution were analyzed. The study shows that the effects of pyrolysis and ablation on plasma distribution are small in the absence of alkali metal element in the surface materials, and the effects on plasma distribution are significant in the case of containing trace amounts of alkali elements. For the latter case, its influence on reentry target signatures and microwave communication can not be ignored.