Influence of Purge Ejection Angles and Upstream Wakes/Disturbances on Low Aspect Ratio Turbine Blade Passage Aerodynamics

Abstract

The blade passage aerodynamics of turbine engine can be affected significantly by the purge flow—mainstream interaction. In this paper, aerodynamic behaviour of a turbine blade profile with aspect ratio 1.2 is investigated numerically, in the presence of purge flow and upstream wakes/disturbances. An effort is made to explore the effects of purge ejection angles and upstream wakes over turbine blade passage aerodynamics. Results indicates that purge flow has enhanced the cross passage pressure gradient. Presence of upstream wakes has altered the incidence angle non-uniformly throughout the span. However, strong flow acceleration of purge flow at lower ejection angles has caused significant reduction in the boundary layer cross flow and secondary flow losses. On the contrary higher ejection angles induced tangential and spanwise shifting of the loss core regions at the passage exit. The interaction of purge coolant and upstream wakes with the freestream has enhanced the secondary vortex formations within the blade passage. Additional secondary vortices are originated at the leading edge by the introduction of upstream wakes. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.