Effect investigation of interaction between upstream wake and film cooling on the flowfield dynamics of high-pressure turbine blade

The upstream wake periodically modifies the spatiotemporal flow characteristics around downstream blades, influencing their dynamic responses. However, existing studies rarely examine this interaction from the perspectives of fluid frequency and coherent flow structures, particularly in engine-representative high-pressure turbine (HPT) where wake-film cooling interactions occur. After all, film cooling not only redistributes temperature but also increases flow complexity by interacting with the upstream wake and mainstream gas. Understanding these effects is critical for accurate blade dynamic response analysis. Using the E3 single-stage HPT model, we establish and compare two numerical configurations: with and without film cooling. On-blade pressure and temperature are analyzed via fast Fourier transform (FFT) and proper orthogonal decomposition (POD). The results demonstrate that upstream wake induces periodic pressure/temperature fluctuations, primarily at the leading edge, dominated by the first four rotor-passing frequency harmonics. The coolant jet attenuates the first harmonic's impact while promoting downstream migration or phase-shifting of large-scale coherent structures. Additionally, high-speed coolant can cut mid-scale coherent structures, mitigating corner vortex blockage and improving trailing-edge load distribution. This study provides significant insights for cooling hole arrangement, flow field reduction, and dynamic response prediction in HPT blades.