Life prediction of liquid rocket engine thrust chamber liner wall

To understand the failure mechanism and predict the life of thrust chamber liner wall, fluid-thermo-structural coupled numerical simulation was carried out for the thrust chamber. The thermal and mechanical loading of thermo-structural coupled analysis were provided by fluid-thermal coupled analysis; for thermo-structural coupled model, a two-dimensional plane strain finite element analysis of the nonlinear deformation of the thrust chamber liner wall was performed. Through computation, the stress-strain distribution of thrust chamber liner wall at different stages of each cycle and the deformation process under cyclic loading were obtained, and a post processing method is applied to predict the life of the thrust chamber liner wall. The results show the fluid-structural coupled method can accurately carry out the loading data exchange from fluid-thermo coupled module to thermo-structureal coupled module and provide the accurate boundary conditions for structural analysis. The liner wall is under tensile stress during the pre-cooling, post-cooling and relaxtion phases, while under compression stress during the hot run phase. The residual stress and strain are increasing with the operate cycle increasing. The cyclic thermal and mechanical loading cause the liner wall to bulge and thin, and finally lead to the failure of the cooling channel. The analysis model is able to simulate the deformation of the thrust chamber liner wall under cyclic thermo and mechanical loading and predict the cycle life.