Investigations of a turbine pre-swirl system with high temperature drop efficiency through the design of a novel vane-shaped receiver hole

The pre-swirl system, a vital system responsible for supplying cooling gas to the turbine blades. However, the pre-swirl system involves rotor-stator matching and intricate power-heat conversion challenges, which has led to a bottleneck in the development of its temperature drop potential. This study investigates the traditional pre-swirl system structure to identify factors limiting its temperature drop performance. A novel design idea is proposed to enhance the temperature drop performance by reducing the power consumption in the pre-swirl system. Subsequently, the structure optimization and performance improvement for pre-swirl system are conducted through the design of four vane-shaped receiver hole models. To assess the effectiveness of these enhancements, the thermodynamic and aerodynamic characteristics of the pre-swirl system before and after optimizations are evaluated using numerical simulations. Finally, the system temperature drop characteristics equipped with optimal receiver holes are thoroughly evaluated by experimental test analysis. The findings reveal that the new type of pre-swirl system, featuring a leading-edge vane-shaped receiver hole design and the removal of the cover-plate cavity, surpasses traditional designs. It exhibits a remarkable 35.3 % improvement in the receiver hole discharge coefficient, a 39.7 % reduction in system entropy increase, and a 6.36 kW/(kg/s) decrease in specific power consumption. Significantly, experimental verification demonstrates a 10 % increase in the nozzle pressure ratio, the temperature drop of pre-swirl system increased by 53.6 % from 23.5K to 36.1K, and the temperature drop efficiency of pre-swirl system increased from 0.567 to 0.872. Therefore, this study offers valuable insights for the design of high-performance pre-swirl systems, contributing to the overall improvement of turbine efficiency.