气动加热环境下超高温陶瓷热化学氧化烧蚀机理与建模

The proposal focuses on the mechanisms of the coupled interactions between aerodynamic heating environments and ultra-high temperature ceramics (UHTCs). Based on the principle of high temperature gas dynamics, the thermochemical ablation of UHTCs composed of zirconium diboride and silicon carbide under aeroheating conditions (aeroheating rate around 500~3500 kW/m2, stream enthalpy around 5000~20000kJ/kg) will be investigated. The chemical ablation, dynamic evolution of oxidant scales and thermal response mechanisms will be especially concerned. A quantitatively model and computational method which can reflect the active to passive oxidation transition of Si-containing compounds, the growth/recession and blowing/mechanical erosion of oxidant scales will be established. The model will also be verified and validated by the experimental results obtained from arc-jet wind tunnel tests. Finally, a prepared tool will be developed to predict the thickness of oxidation layer and thermal response of UHTCs in aerothermal heating conditions.

本项目面向气动加热环境与超高温陶瓷材料之间的复杂相互作用关系，从高温气动热力学基本原理出发，建立二硼化锆/碳化硅基超高温陶瓷在气动加热环境（热流密度500~3500kW/m2，气流焓值5000~20000kJ/kg）下的热化学烧蚀模型，重点研究材料的表面热化学烧蚀机理、氧化膜结构的动态演化规律和综合热响应机制，揭示硅基组分的主被动氧化转变、氧化膜生长与结构演变及机械剥蚀等因素对超高温陶瓷性能影响的作用机理。利用电弧风洞地面模拟试验数据完成对所建立氧化及热响应模型的校验和验证，最终获得超高温陶瓷在气动加热条件下的氧化烧蚀及热响应预测工具。

项目针对气动加热环境与超高温陶瓷材料之间复杂的物理化学相互作用，利用高温静态氧化与高焓风洞动态氧化两种实验手段，基于热力学平衡与热化学烧蚀模型建立了二硼化锆/碳化硅基超高温陶瓷的氧化烧蚀模型。获得了静态氧化环境下700ºC~1800ºC温度范围内材料的氧化层结构及氧化烧蚀机理,完成了超高温陶瓷材料在热流密度5.84MW/m2~8.39MW/m2，气流总焓24.2~31.4MJ/kg等离子电弧风洞状态下的氧化烧蚀实验，并对发展的氧化烧蚀传热模型进行了验证与确认。项目揭示了超高温陶瓷材料的表面热化学烧蚀机理、氧化膜结构的动态演化规律和综合热响应机制，阐明了硅基组分的主被动氧化转变、氧化膜生长与结构演变及机械剥蚀等因素对超高温陶瓷性能影响的作用机理，获得超高温陶瓷在气动加热条件下的氧化烧蚀及热响应预测模型。