飞行器热解炭化材料烧蚀产物对等离子体流场的影响规律

高速飞行器表面防热材料在气动加热产生的高温下会热解烧蚀，烧蚀产物进入空气边界层流场后，与流场中的高温空气发生复杂化学反应，对飞行器周围空气流场中组分浓度和等离子体分布产生影响。基于求解热化学非平衡Navier-Stokes方程，建立耦合烧蚀壁面的三维等离子体流场计算方法。理论预测电磁衰减测量项目第2次飞行试验（RAMC-II）的等离子体流场，并与飞行试验数据进行比较，验证方法的可靠性。针对升力体飞行器，分析表面材料烧蚀对等离子体流场的影响规律。结果表明：升力体头部流场的电子数密度最高，飞行器身部区域的电子密度相比头部会降低约2~3个量级，对等离子体流场贡献最重要的离子是NO⁺和N⁺；烧蚀产物进入流场会使激波的脱体距离变大，等离子体层厚度增加；随着流动向下游发展，飞行器身部的烧蚀速率降低，但烧蚀产物对等离子体流场的影响范围变大，飞行器身部流场的电子数密度会有一定升高；随着马赫数增大，烧蚀速率变大，壁面材料烧蚀影响更加显著，其中驻点线的峰值电子数密度改变较小，但飞行器身部对称面的电子数密度会显著增大；对于成分存在差异的同一类型防热材料，烧蚀产物进入流场后对激波脱体距离和峰值电子数密度的影响存在差异。

Influence of Ablation Products of Aircraft Pyrolytic Carbonized Material on Plasma Flow Field

The heat-resistant material on the surface of high-speed aircraft will decompose and ablate at the high temperature generated by aerodynamic heating. After entering the flow field，the ablation products react with the high-temperature air in the flow field， thus affecting the component concentration and plasma distribution in the air flow field around the aircraft. Based on solving the thermochemical non-equilibrium Navier-Stokes equations，a three-dimensional plasma flow field calculation method coupling the ablated wall surface is established. The plasma flow field of RAMC-II is predicted and compared with the flight test data to verify the reliability of the proposed method. The influence of material ablation on plasma flow field of lifting body aircraft is analyzed. The results show that the electron density in the flow field on the head of the aircraft is the highest， the electron density in the body area is reduced by two or three orders of magnitude，and NO⁺ and N⁺ contribute most to the electron number density in the flow field. The ablation products injected into the flow field increase the separation distance of shock wave and the thickness of plasma layer. With the development of the flow downstream，the ablation rate of the aircraft body decreases， but the influence range of ablation products on the plasma flow field becomes larger， and the electron number density of the body flow field increases to a certain extent.With the increase in Mach number， the ablation rate of wall increases， and the influence of ablation products is more obvious. The peak electron density on stagnation line changes little， but the electron number density on symmetrical surface of body increases significantly. For the same kind of ablative materials with different components， the influences of ablated products of different materials entering into the flow field on the shock wave separation distance and the peak electron number density are different.