Influence of non-axisymmetric endwall contouring parameters on the aerodynamic and cooling performance-numerical simulation and PSP experimental verification

High secondary flow losses and severe thermal loads present major challenges for the high-efficiency cooling design of turbines. Non-axisymmetric endwall contouring (NEC) can effectively suppress secondary flow losses in the endwall region, while the contouring parameters of NEC significantly influence endwall cooling efficiency. This study investigates the coupled effects of endwall contouring parameters (period α , phase angle b and contour amplitude H ) on aerodynamic properties and cooling performance through a combination of numerical simulations and pressure-sensitive paint experimental validation. It analyzes the influence of different NEC configurations and the Baseline endwall on the film cooling effect of film cooling holes. The results indicate that at a period α = 1.0, the aerodynamic-cooling performance can be synergistically improved. The positive phase b can significantly suppress aerodynamic losses and, at b = 30°, the area-averaged film cooling effectiveness increases by 16.9% compared with the Baseline; a contour amplitude H = 3% effectively reduces flow distortion at the outlet of the cooling hole. NEC suppresses the generation and development of secondary flow vortices, including horseshoe vortices, channel vortices and corner vortices. Experiments show that the NEC-(COS) configuration has significant synergistic control advantages at low to medium inflation ratios, while NEC-(SIN) is more suited for high blowing ratios with strong jet characteristics. When using the parameter combination α = 1.0, b = 30° and H = 3%, the mixing effect of secondary flows is significantly weakened, resulting in a significant reduction in aerodynamic losses and secondary kinetic energy, as well as improved average film cooling efficiency. These findings provide a solid theoretical basis and reliable experimental data to support the efficient optimization design of turbine endwalls.