硅橡胶基防热涂层烧蚀机理及热解/传导耦合模型  

Ablation mechanism and coupling pyrolysis/conduction model of a silicone rubber matrix thermal protection coating

作　　者：时圣波 张云天[2] 胡励 房光强 崔新芳 SHI Shengbo;ZHANG Yuntian;HU Li;FANG Guangqiang;CUI Xinfang(Shanghai Key Laboratory of Spacecraft Mechanism,Shanghai 201108,China;China Shaanxi Aerospace Flight Vehicle Design Key Laboratory,School of Astronautics,Northwestern Polytechnical University,Xi’an 710072,China;Beijing System Design Institute of Electro-Mechanic Engineering,Beijing 100854,China)

机构地区：[1]上海市空间飞行器机构重点实验室,上海201108 [2]西北工业大学航天学院陕西省空天飞行器设计重点实验室,西安710072 [3]北京机电工程总体设计部,北京100854

出　　处：《航空动力学报》2023年第9期2049-2061,共13页Journal of Aerospace Power

基　　金：国家自然科学基金(12172296);上海市空间飞行器机构重点实验室基金(2021XGD)。

摘　　要：采用同步热分析仪,开展了热失重实验,确定了防热涂层热分解反应的温度区间、活化能和反应机理函数。利用石英灯辐射加热平台,开展了高温环境考核实验,揭示了防热涂层高温环境下的微结构演化规律和能量耗散机理。基于能量守恒原理,充分考虑热解反应吸热、热解气体扩散换热以及质量引射效应等引起的能量转换关系,建立了防热涂层的热解/传导耦合模型,预报了典型热环境工况下硅橡胶基防热涂层的质量烧蚀率及温度响应规律。烧蚀后涂层表面基本保持平整,背面温度为151.4℃,质量烧蚀率为0.28 g/s。质量烧蚀率的模型计算值与实验测量值的偏差仅为7.1%,满足实际工程中热防护设计需求。研究表明,硅橡胶基防热涂层中等热流环境下具有良好的耐烧蚀和隔热性能,是航空航天装备大面积防热区域的理想候选方案。Thermogravimetric analysis was carried out by using synchronous thermal analyzer.The temperature range,activation energy and reaction mechanism function for the thermal decomposition reaction of the coating were determined.Thermal exposure experimental tests were conducted using a quartz lamp radiant heating platform.The mechanism of microstructure evolution and energy dissipation of thermal protection coating at high temperatures were revealed.Based on the principle of energy conservation,a coupling model for predicting the pyrolysis and thermal conduction of the thermal protection coating was established.The energy conversion relationships,which were caused by pyrolysis reaction,thermal diffusion of decomposition gas and mass ejection effect,were considered.The mass loss and temperature response of the silicone rubber matrix thermal protection coating under a typical thermal environment were calculated.After thermal exposure,the specimen surface remained basically flat,and the temperature at back surface was 151.4℃while the mass loss rate was 0.28 g/s.The deviation between the calculated mass loss rate and its measured value was only 7.1%.This can meet the requirements of thermal protection design in engineering applications.The results showed that the silicone rubber matrix thermal protection coating has good ablation resistance and thermal insulation properties in medium heat flux environment,so it has excellent potential for the large area thermal protection application of aerospace vehicles.

关 键 词：硅橡胶基防热涂层 烧蚀 热分解 热解/传导模型 热影响层 隔热性能 

分 类 号：V45[一般工业技术—材料科学与工程]