Conjugate Heat Transfer Analysis of Film Cooling and Thermal Barrier Coatings under Non-Uniform Steam-Temperature Inflows in Hydrogen-Fueled Gas Turbines

The operational efficacy of hydrogen-fueled gas turbines is constrained by severe thermal management challenges arising from the interplay between high-temperature, steam-rich combustion products and inherent flow non-uniformities generated by modern swirl combustors. This study systematically investigates the conjugate heat transfer characteristics of turbine vane film-cooling systems under such conditions through a rigorous computational framework implementing three canonical combustor-exit patterns (Uniform, Central Core, and Dual-Core Flow) on a flat-plate configuration. Our approach innovatively integrates entropy generation rate analysis with conventional thermal performance metrics to quantify both aerodynamic losses and cooling effectiveness under non-uniform steam concentration and temperature distributions. It is demonstrated that the Dual-Core Flow configuration achieves optimal cooling performance across all streamwise locations, with coupled cooling effectiveness increasing substantially at higher blowing ratios. Notably, the non-uniform inflow pattern asymmetrically modulates the heat transfer coefficient by altering the vortex structure in the shear layer. Meanwhile, the presence of steam suppresses irreversible thermal entropy generation while enhancing irreversible viscous entropy generation, particularly near wall boundaries where entropy production surpasses mixing-zone levels by significant margins. The maximum local irreversible heat transfer dissipation caused by water vapor reaches 8.4%. Furthermore, substrate temperature homogeneity proves most sensitive to Uniform Flow conditions, with ceramic top coat thickness exhibiting negligible influence on temperature uniformity. This work provides fundamental insights for advancing thermal barrier coating integration strategies in hydrogencombustion environments, establishing a critical foundation for optimizing next-generation turbine cooling architectures against complex thermo-fluid interactions characteristic of zero-carbon power systems.