液体火箭发动机推力室壁瞬态加载三维热结构分析

Three Dimensional Transient Loading Thermomechanical

关键词:  液体火箭发动机  再生冷却  推力室  瞬态导热  热应力  结构分析  流固耦合

Key words:  Liquid rocket engine  Regenerative cooling  Thrust chamber  Transient heat transfer  Thermal stress  Structural analysis  Fluid-structure interaction

摘要:

为了预测再生冷却液体火箭发动机推力室壁的应变分布，研究内壁失效机理，使用有限元法对推力室壁进行了三维瞬态热分析，在瞬态热分析结果的基础上采用多线性随动硬化模型对推力室壁进行了三维弹塑性结构分析。计算结果表明，多线性随动硬化模型能够准确地模拟推力室内壁材料的应力-应变关系；内壁温度达到稳态的时间相比外壁要短得多，在预冷、试车和后冷开始约0.1s后内壁温度便已经接近稳态；瞬态加载三维热结构分析能够确定推力室内壁最先失效的危险点的位置在喉部上游冷却通道中心；推力室壁瞬态加载三维热结构分析得到的最大残余应变比稳态加载大15.7%。

Abstract:

To predict the strain distribution of regeneratively cooled LRE thrust chamber wall，and to study the failure mechanism of inner wall，three dimensional transient thermal analysis of thrust chamber wall is carried out，with finite element method，and three dimensional transient loading elastic-plastic structural analysis using multilinear kinematic hardening model is presented further. The calculated results indicate that multilinear kinematic hardening model can accurately model the stress-strain response of thrust chamber inner wall. The time to reach steady state of inner wall temperature is much shorter than that of outer wall temperature，about 0.1s later after pre cooling，hot run and post cooling phase. The inner wall temperature already approaches steady state. Three dimensional transient loading thermomechanical analysis demonstrates that the failure position of thrust chamber inner wall is located at the center of cooling channel，upstream of the throat. The calculated maximum residual strain based on transient loading is about 15.7% larger than that based on steady loading.