Effects of incidence angle on endwall convective transport within a high-turning turbine rotor passage

Effects of incidence angle on the endwall convective transport within a high-turning turbine rotor passage have been investigated. Surface flow visualizations and heat/mass transfer measurements at off-design conditions are carried out at a fixed inlet Reynolds number of 2.78 × 10⁵ for the incidence angles of −10°, −5°, 0, 5°, and 10°. The result shows that the incidence angle has considerable influences on the endwall local transport phenomena and on the behaviors of various endwall vortices. In the negative incidence case, convective transport is less influenced by the leading edge horseshoe vortex and by the suction-side corner vortex along their loci but is increased along the pressure-side corner vortex. In the case of positive incidence, however, convective transport is augmented remarkably along the leading edge horseshoe vortex, and is much influenced by the suction-side corner vortex. Moreover, heat/mass transfer is enhanced significantly along the pressure-side leading edge corner vortex. Local endwall convective transport in the area other than the endwall vortex sites is influenced significantly by the cascade inlet-to-exit velocity ratio which depends strongly on the incidence angle.