再生冷却推力室热障涂层系统的热结构分析

Thermomechanical Analysis of a Regeneratively-Cooled Thrust Chamber with Thermal Barrier Coatings

关键词:  液体火箭发动机  推力室  再生冷却  热障涂层  有限元法  温度场  应变场

Key words:  Liquid rocket engine  Thrust chamber  Regenerative cooling  Thermal barrier coating  Finite element method  Temperature field  Strain filed

摘要:

为了设计和优化适用于液体火箭发动机推力室的热障涂层，应用ANSYS的热-结构分析功能，对再生冷却推力室-热障涂层系统进行了热结构有限元分析，得到在不同涂层覆盖下，推力室壁中的温度场和应变场，并通过对热障涂层中应变场的分析，研究不同涂层发生分层剥落的关键位置以及主要驱动力。结果表明，陶瓷层厚度较大的YSZ+NiCrAlY涂层拥有更优异的性能，使推力室壁在热试阶段的最大应变量减少约36.1%；工作循环中，涂层与推力室壁的接触面上会产生较大的应变量，最终有可能导致涂层剥落失效；粘结层能缓解涂层与推力室壁间的热膨胀系数不匹配，使陶瓷层在热试阶段的最大应变量减少约80%。

Abstract:

To design and optimize the thermal barrier coating (TBC) for LRE thrust chamber， finite element analysis of TBC system in regeneratively-cooled thrust chamber is carried out， by the thermomechanical analysis function in ANSYS. The temperature and strain fields of different coatings are computed. Based on the strain fields， dangerous regions and driving forces leading to failure in TBC are determined. The results show that YSZ coatings with a thick ceramic layer and a NiCrAlY bond layer provide better protection， making the maximum strain in thrust chamber wall 36.1% lower in hot test. The failure position of TBC is located at the interface of coating and thrust chamber wall. Bond layer mitigates the mismatched thermal expansion coefficient between coating and thrust chamber wall， making the maximum strain in ceramic layer 80% lower in hot test.