Aerodynamic influence of rim seal purge flow injection on the main flow in a 1.5-stage axial turbine with nonaxisymmetric end wall contouring

This paper presents an investigation of the aerodynamic influence rim seal purge flow injection on main in a 1.5-stage turbine with non-axisymmetric end walls and bowed stator using experimental measurements unsteady RANS simulations. The study focuses secondary vortex structures formed rotor passages axial rig. Through performance map measurements, it was found that efficiency gain configuration is partially eliminated by flow. Numerical investigations, which are supported detailed five-hole probes hot-wire probes, revealed air intensifies near hub, thereby generating additional losses. These resulting highly similar both axisymmetric baseline result jet-like vortices emerging from cavity. From these findings, can be concluded contour no longer provides any benefit hub. Only casing, where not affected flow, optimized continues to improve rig homogenizing outflow thus reducing passages.