Thermo-structural behavior of thermal barrier coatings for thrust chamber applications

Abstract

The investigation of the failure mechanism is essential for the application of thermal barrier coating in the thrust chamber of liquid rocket engines. In this work, a four-layer thermal barrier coating system in a typical regeneratively-cooled thrust chamber was simulated by finite element method, and the interface morphology between layers was represented by an ideal cosinusoidal curve. A thermo-structural analysis, the boundary conditions of which were calculated by a fluid-thermal coupling method, was carried out to study the influence of the interface roughness and thermally grown oxide on the temperature and stress distributions under thermal cycles. Elasto-plastic deformation and creep behavior were also taken into consideration. The computed results reveal that the roughness parameters including interface amplitude and wavelength as well as the thermally grown oxide thickness have limited effects on the temperature distribution in the thrust chamber wall, but a significant impact on the residual stress distribution in thermal barrier coatings. As these parameters grow, the magnitude of residual stress generally increases, meanwhile, the dangerous regions transform in a complicated way. Much attention should be paid to the interface of thermal barrier coatings in thrust chambers.