Key Characteristic Parameters Analysis and Structural Optimization of a Novel Coated Steam Dual Pipe System at 700 °C

This work studied the influence of characteristic parameters on the heat transfer and stress distribution for the thermal barrier coatings used in a novel 700 degrees C dual-pipe system. The finite element sequential coupling method was used on this basis, a structural optimization method for the multilayer heterogeneous coating system was developed by MATLAB and ABAQUS platforms. And the optimal geometric sizes and material properties were identified. Results reveal that the thickness ratio of the ceramic layers, thermal conductivity of the outer ceramic layer, thermal expansion coefficient, cooling steam temperature, and pressure simultaneously have significant effects on the temperature and stress distribution of the coated steam dual-pipe system. The inner surface temperature of P91 steel pipes can be decreased by about 27 degrees C and the maximum Mises stress at the interface between thermal growth oxide and bond coat can be decreased by about 151 MPa, suggesting that the proposed systematic optimization method can be used to automatically determine the optimal key characteristic parameters of multilayer heterogeneous coating systems, resulting in improved thermal management and reduced stress on critical components.