Aerodynamic response of endwall contouring to blade bowing variations in turbine cascade

Despite the widespread implementation of non-axisymmetric endwall contouring and three-dimensional blade shaping for secondary flow attenuation, the integration of these two techniques remains a further exploration. Blade bowing modifies the endwall loading distribution, thereby redistributing the secondary loss structure. This study utilizes validated RANS simulations to systematically characterize the aerodynamic response of endwall contouring (EW-B1) and its integrated design with section profiling (EW-SP) under diverse bowing configurations. Findings reveal that increasing the bowing angle induces a transition in the dominant loss structure from the horseshoe vortex (HV) to the passage vortex (PV), which offsets the net benefits of EW-B1 and EW-SP. To address this, an adapted endwall configuration is developed for positive bowed blades. This approach emphasizes minimizing the entirely secondary vortex dissipation rate over localized vorticity redistribution, achieving a substantial reduction in PV-related losses with marginal HV-related impact. Such insights provide guidance for the coupled design of blades and endwalls in complex aerodynamic environments.