Coupled thermal–mechanical analysis of film cooling performance under different blowing ratio considering the effects of curvature

Due to the varying curvature across different regions of turbine blades, identical film cooling hole designs exhibit different cooling effectiveness when applied to different areas. However, under realistic turbine-blade curvatures and complex thermally induced gradients, the nonlinear creep-damage mechanisms in the vicinity of cooling holes remain insufficiently elucidated. In this study, the CHT module is independently validated by infrared-thermography measurements of the surface cooling effectiveness on a dedicated film-cooling test rig. Based on these measurements, a conjugate heat transfer (CHT) model is established to simulate the temperature distribution within film cooling holes. The resulting thermal field is then integrated into a crystal plasticity finite element method (CPFEM) framework to evaluate creep damage evolution. Meanwhile, the CPFEM creep–damage predictions are calibrated and validated by benchmarking the simulated responses against corresponding experimental measurements. Nine substrate geometries, including flat, convex, and concave models, are systematically analyzed under blowing ratios of 0.5, 1.0, and 1.5. The results indicate that increasing convex curvature improves cooling coverage and delays damage initiation. These insights suggest that positioning film cooling holes away from low-curvature regions on the pressure side can optimize both cooling effectiveness and component durability.