Endwall design and loss mitigation for incidence-tolerant turbine blading

Modern aero-engine turbines operate over a wide range of incidence angles, with endwall regions experiencing variations of up to 40 deg or more. These variations significantly alter secondary flow structures, posing challenges for loss control and aerodynamic performance. This study investigates the endwall loss mechanisms of turbine cascades under wide incidence conditions by comparing front-loaded and aft-loaded blade profiles. Dissipation-based analysis and vortex visualization reveal that front-loaded profiles exhibit favorable loss characteristics under negative incidence but suffer from increased loss near the leading edge under positive incidence due to the formation of horseshoe vortices. To address this, a design strategy combining front-loaded blade loading with three-dimensional endwall contouring is proposed. The endwall profiling effectively suppresses horseshoe vortex formation under positive incidence while maintaining low loss under negative incidence. The results demonstrate that this combined approach can improve endwall aerodynamic performance across a wide range of incidence angles, providing a promising guideline for turbine endwall design under off-design conditions.