基于再入轨迹和气动热环境的返回舱烧蚀研究

Research on Ablation for Crew Return Vehicle Based on Re-entry Trajectory and Aerodynamic Heating Environment

针对再入全过程合理预测热防护罩表面材料烧蚀深度和温度的动态变化问题,提出融合再入轨迹、气动热以及Newton-Raphson和三对角矩阵算法(TDMA)构建动态烧蚀的方法。该方法建立直入式和跳跃式三自由度再入轨迹,应用修正的牛顿流体理论估算气动参数,以及修正的Fay-Riddell和Sutton-Grave理论计算驻点区域的热流密度,利用一维非线性热传导方程模拟了热防护材料的烧蚀过程。仿真结果表明:此方法实现了再入全过程热防护材料烧蚀深度和温度连续动态变化的预测,同样适用于更为复杂结构飞行器的动态烧蚀预测,与热平衡积分法(HBI)相比其结果可靠合理,为进一步优化热防护系统(TPS)提供了一定的参考依据。

The ablation of a heat shield subjected to dynamic changes of the surface material depth and temperature can be reasonably predicted in the whole re-entry process. The approach of constructing a dynamic ablation process is presented by combining the reentry trajectory and aerodynamic heat with Newton-Raphson and tridiagonal matrices （TDMA） algorithms. A three degrees of freedom direct and skip re-entry trajectory model is established. The modified Newtonian flow theory,Fay-Riddell and Sutton-Grave theory are adopted to calculate respectively the aerodynamic parameters and stagnation heat flux. A one dimensional nonlinear heat conduction model is employed to simulate the process of thermal protective material abla- tion. The results of ablation prediction demonstrate that continuous dynamic change of the surface material depth and the temperature can be realized. The proposed method can be applied to more complicated structures of the flight vehicles and the results of it are shown to be reliable and reasonable by comparing them with those of the heat balance integral （HBI） method. This study provides a reference for further optimization of the design of thermal protection systems （TPS）.