基于有限元方法的防热瓦损伤分析

防热系统是可重复使用运载器安全飞行的重要保障,而对受损防热结构进行传热特性分析是实现其健康监控的基础.本文针对典型的可重复使用陶瓷防热瓦,建立其有限元传热学分析模型,在考虑气动加热、辐射散热以及防热瓦与飞行器蒙皮之间的传热三种因素的基础上,分别模拟了单片防热瓦在正常情况和发生表面涂层损伤或冲击损伤情况下的传热情况,并进一步分析了两种损伤对于防热瓦温度分布的影响.结果表明,冲击损伤对防热瓦的影响比表层损伤明显严重,可能导致防热瓦底层结构的温度过高而产生严重后果.本文在讨论相应的损伤监测的测点布置原则后建议对防热系统进行多层次的温度监测.

Analysis of TPS Damage Based on Finite Element Method

Thermal Protection System is of great importance in a safe flight of Reusable Launch Vehicle,while the health monitoring of it must be based on the characterization of heat transfer within damaged TPS structure.In this paper,a finite element model of reusable ceramic TPS tiles is built,and heat transfer within a tile is computed on condition that the tile be perfect,surface-cracked or impacted,with aerodynamic heating,radiation,and heat conduction through the tile and vehicle skin considered,on the basis of which the influence of both damages on temperature distribution is analyzed.The result indicates that impact is a much more significant influence than surface-crack and may result in great threat by heating the back structure.Finally,sensor placement for damage detection of Thermal Protection System is discussed and a multilayer temperature monitoring principle is suggested.