The application of bowing blades in a low aspect ratio integrated inter-turbine duct using splitters

To reduce secondary flow loss within the turbine transition duct, numerical simulations are conducted to improve the performance of low aspect ratio vanes and investigate the impact of blade bowing design within the integrated inter-turbine duct (IITD). The stator row inside the IITD consists of 4 large Struct-Vanes and 12 small Aero-Vanes. Four bowing designs are considered, with bowing angles ranging from 10° to 20° and bowing heights from 10 % to 50 %. A comparative analysis is conducted to explore the mechanisms how different blade bowing schemes control secondary flows and reduce losses within the IITD. Results indicate that the loss distribution is influenced by the aft-loaded blade design and the expanding meridional passage, with primary losses occurring on the lower suction surfaces. The J-type bowing design is the most effective at migrating low-energy fluid, resulting in a decrease in energy loss of up to 5.1 %. However, the design optimization effects of the positive bowing, reverse bowing, and reverse J-type bowing schemes provide weaker optimization or even suboptimal results. Additionally, the J-type designs’ performance is more sensitive to changes in bowing height than in bowing angle, with larger bowing heights promoting radial migration of low-energy fluid in the low aspect ratio IITD.