Numerical Investigation of the Performance Impact of Stator Tilting Endwall Designs on a Mixed Flow Turbine

This paper numerically investigates stator endwall designs for a mixed flow turbine. One key design parameter studied is the tilting angle of endwall. By examining with different angles, aim this to improve efficiency turbine at low velocity ratio working conditions. The performance curve speed was chosen comparison between baseline and tilted designs. First, numerical predictions were validated experimental data. Then, understand mechanism variation designs, internal field analyzed in detail. It found that could form geometric “kink” profiles. On shroud side, certain such kink caused local separations upstream rotor leading edge. separation have effect reducing intensity tip leakage vortex exit kinetic energy losses outlet may also exhaust diffuser. As result, peak shifted toward lower ratio. If stage incorporated downstream diffuser, optimal study showed shift point from 0.62 0.60 compared baseline. maximum improvement 1.3% points, which occurred Meanwhile, 0.2% points higher than diffuser removed, similar observed but less gain achieved condition. A preliminary unsteady simulation conducted study.