Influence of blade lean together with blade clocking on the overall aerodynamic performance of a multi-stage turbine

In the present work, an in-house flow solver for multi-stage turbomachines is first applied to compute the unsteady flows in a subsonic 1.5-stage axial turbine with different clocking configurations. The influence of the wake location of the first stator on the overall adiabatic efficiency is presented and analyzed, demonstrating the possibility to improve the aerodynamic performance of the turbine by properly leaning the stator blade. Four different blade lean schemes are then configured based on the given clocking configuration with peak efficiency at 50% span. The overall adiabatic efficiency and the spanwise distributions of aerodynamic performance parameters of different lean configurations are presented and compared to those of the baseline configuration. The adiabatic efficiency of the optimal lean configuration is about 0.35% larger than that of the baseline configuration, while the maximum adiabatic efficiency difference among different clocking configurations is only 0.086%. The improvement on the overall aerodynamic performance of the multi-stage turbine contributed by blade lean is significantly remarkable. The blade lean and blade clocking can be carefully assembled in the unsteady flow regime during the design or optimization phases of multi-stage turbomachines.