复杂气动传热问题的参数辨识与可辨识性判据研究

The successful design of the Thermal Protection System(TPS) of the hypersonic flight vehicle relies to a great extent on the effective estimation of both the surface heat flux during the flight and the thermal properties of the TPS material. So, this project is to carry out deep studies focusing on some basic problems in the aero-thermodynamic parameter estimation research and engineering application. Firstly, the inverse estimation problems for complicated aero- thermodynamic heat transfer cases such as ablation and hyperbolic heat transfer phenomenon in multilayer and porous material of TPS are concerned. One side, the now available estimation mechanism and algorithm for the carbon-based ablative materials is improved and modified to meet the needs of treating the heterogeneous thermal protection material and the 'foaming' effect of the material, which makes the estimation problem closer to the flight circumstances and improves the precision of the estimation result. On the other side, the theoretical origin of the ill-posedness of the hyperbolic heat conduction problem and parabolic/hyperbolic coupled heat conduction problem is analyzed and corresponding estimation method is developed, extending the application area of the estimation method. Secondly, the identifiability criterion for the surface heat flux is deeply investigated. The now available criterion is re-examined and extended to suit for the following complicated heat transfer cases of the thermal parameter being a function of temperature, TPS material ablation, and conduction/radiation coupled heat transfer. Furthermore, based on the identifiability analysis results, the precision prediction method of the estimated result of heat flux can be founded, which provides a theoretical ground for the design of the thermal measurement system and the effectiveness evaluation of measurement results.

高超声速飞行器防热系统的成功设计在很大程度上依赖于对飞行器表面热流密度和防热材料性能的有效辨识。本项目针对目前气动热参数辨识研究和实际应用中出现的一些应用基础问题开展深入研究。首先针对防热材料烧蚀、多层多孔材料内部存在双曲型导热等复杂气动传热问题，进一步改进完善现有的碳基材料烧蚀机理，建立起适于处理非均匀防热材料、材料"起泡"等复杂烧蚀问题的辨识方法，使其更接近飞行实际情况，提高表面热流辨识结果的精度；分析双曲型传热逆问题、抛物型/双曲型耦合热传导逆问题不适定性的机理，建立辨识方法，拓展现有辨识方法的应用范围。同时，对复杂传热情况下的表面热流密度可辨识性问题进行深入研究，对现有的可辨识性判据进行改进与完善，推广用于热物性参数是温度的函数、考虑烧蚀、考虑传导/辐射耦合等复杂传热情况，并建立起辨识结果精度的分析预测方法，为飞行器测热系统设计、试验结果有效性分析提供理论支持。

高超声速飞行器防热系统的成功设计在很大程度上依赖于飞行器气动热参数的有效辨识。本项目针对目前气动热参数辨识研究和实际应用中出现的一些应用基础问题开展深入研究。针对防热材料烧蚀、多层多孔材料内部存在双曲型导热等复杂气动传热问题，建立了适于处理非均匀防热材料、材料“起泡”等复杂烧蚀问题的辨识方法，使其更接近飞行实际情况；分析了双曲型传热逆问题、抛物型/双曲型耦合热传导逆问题不适定性，建立了辨识方法，拓展了现有辨识方法的应用范围。此外，建立了基于系统响应的可辨识性分析方法，用于热物性参数是温度函数、考虑烧蚀、考虑传导/辐射耦合等复杂传热情况的可辨识性分析。还揭示了频率组合热流情况下的辨识结果偏差规律。通过这些研究，提高了飞行器表面热流密度辨识方法的有效性和鲁棒性，能更好地为高速飞行器防热系统精细设计提供参考。目前，相关辨识方法已在多个工程飞行器的气动热环境分析、飞行试验测试系统设计与数据分析中得到了实际应用。项目培养毕业硕士研究生1人，发表期刊和国际学术会议论文9篇，其中SCI检索1篇，EI检索4篇。