Low-pressure vane of counter-rotating turbine with J-type bowing design: A numerical study of aerodynamic performance considering sealing flow

Counter-rotating turbine technology is widely applied in advanced aeroengines due to its superior aerodynamic performance. Ensuring safe operation typically requires a substantial supply of sealing air to prevent the intrusion of high-temperature mainstream gas into the turbine disk cavity. However, the introduction of sealing flow significantly intensifies secondary flow structures in the hub region, thus limiting further aerodynamic improvements. Therefore, this study investigates the impact of different J-type bowing designs on the aerodynamic performance of low-pressure guide vanes in a counter-rotating turbine. Initially, the bending structure of the blade hub region in the J-type bowing designs was modified by varying the bowing angle and bowing height. Subsequently, numerical simulations and topological analysis methods were utilized to investigate the effects of bowing design on the hub region flow field. Numerical results based on different J-type bowing designs demonstrate that the reverse J-type bowing design exhibits superior aerodynamic performance, effectively delaying horseshoe vortex formation and reducing its scale. A 4.23% reduction in the streamwise size of the leading-edge horseshoe vortex validates the effectiveness of the proposed design approach. The results of this study effectively address the challenge of high aerodynamic losses within the vane passage of the counter-rotating low-pressure turbine guide vanes and provide an effective approach for controlling hub region losses under the influence of sealing flow.