Numerical investigation on aerothermal performances of film cooled high pressure turbine vane under inlet non-uniformities

Abstract

Lean-premixed combustion technologies have been widely adopted in advanced civil turbofan engine to reduce NOx emission. There exist hot streak (HS) and swirl simultaneously at the exit of lean-premixed combustor. Current paper presents a numerical investigation on the aerothermal performances of film cooled high pressure turbine (HPT) nozzle guide vane (NGV) subjected to HS and swirl. Current investigation was carried on the stage one film cooled NGV of GE-E3 HPT, which took into consideration the realistic clocking position of HPT NGV relative to the fuel injector in combustor. The effects of swirl orientations on the migration of HS and film coolant and the aerothermal performances on NGV surface were examined. Results demonstrates that, swirl and its induced incidence angle effect turn over some film coolant from pressure side (PS) to suction side (SS), or vice versa. Such effects also dominate the radial migration of film coolant. The redistributions of film coolant show significant effect on the film cooling effectiveness on NGV surface. Compared with no-swirl case, the greater film cooling effectiveness appears at the region where film coolant accumulates, and as expected, the smaller film cooling effectiveness arises at the region covered by less film coolant. As for heat transfer coefficient (HTC), swirl affects HTC on NGV surface mainly through redistributing film coolant and the hot fluid from HS. The migrations of film coolant and hot fluid keep step with each other on the NGV surfaces directly impinged by inlet HS and swirl, so that the HTC distributions on these surfaces are not significantly affected by swirl. The radial momentum of film coolant endowed by the film hole with radial incidence angle can partly offset the swirl's induced incidence angle effect, which reduces the variations in film cooling effectiveness and heat transfer coefficient due to swirl.