Influence of multi-parameter dispersion on thermal conductivity of CMCs and thermal performance of turbine blades

Abstract Ceramic matrix composites (CMCs) are increasingly utilized in aero-engine blades owing to their exceptional mechanical and thermal properties. However, variability in material components and processing technologies leads to dispersion in equivalent performance, potentially affecting the reliability of CMC turbine blades. Focused on unidirectional fiber-reinforced CMCs, the present study integrates numerical simulations and neural network models to investigate the influence of mesoscale geometric and thermal parameter variabilities on the dispersion of the equivalent thermal conductivity (ETC). Based on the obtained probability density function of ETC, further quantitative analysis is conducted to assess the effect on the maximum surface temperature, high-temperature area proportion, temperature variation range, and temperature standard deviation of turbine blades. The results indicate that the ETC is most predominantly sensitive to the fiber diameter. The coefficient of variation for the axial-direction ETC remains identical to the input parameters while that for the normal-direction ETC is significantly amplified under the nonlinear heat transfer features. The ETC dispersion induces a 14% fluctuation in the high-temperature area proportion at the blade surface and a maximum temperature variation over 10 K at the leading edge region.