Research on aerodynamic noise control technology of an ultra-high expansion ratio turbine

To address the need for aerodynamic noise control of an ultra-high expansion ratio turbine, we discuss the effect of the non-uniform outflow of the nozzle and a tip leakage vortex on the aerodynamic noise characteristics of the turbine. We put forward three kinds of aerodynamic noise control methods, including adding an axial gap between the rotor and stator; nozzle-down, bilateral repair and trailing edge blowing, and tip-leakage flow control. We then optimized a one-stage ultra-high expansion ratio turbine with respect to the suggested aerodynamic noise control methods. The results show that the aerodynamic noise of the single-stage ultra-high expansion ratio turbine is significantly reduced after the proposed noise-control optimization, and this optimization has little impact on the turbine's aerodynamic performance.