A representative transonic turbine stage TTM (constructed by the University of Graz) was selected as the research object to investigate the effects of circumferential multiple grooves (CMG) design parameters on the efficacy of tip leakage flow (TLF) control. A validated high-fidelity numerical methodology was employed to analyze the impact of key design parameters, including the width of the shaping area (WSA), the number (N), and distribution ratio (P) of CMG, on both the control efficacy and underlying mechanisms of TLF control within the TTM turbine stage. The findings demonstrate that across all investigated design parameters, the introduction of CMG significantly enhances the aerodynamic performance of the baseline turbine configuration. The analysis reveals that N exerts a more dominant influence than both P and WSA parameters. Flow field visualization reveals that CMG implementation induces substantial complexity in turbine rotor blade tip clearance flow structures. Following CMG implementation, the flow losses caused by the tip leakage vortex are significantly attenuated downstream of the rotor blade middle location, while losses from the upper passage vortex increase moderately. Since the TLF through the CMG (CMG-TLF) is in the opposite direction to the original TLF, the introduction of a CMG with appropriate parameters can reduce the net leakage flow rate across the rotor blade tip region significantly, resulting in enhanced turbine stage efficiency. When the design parameters of the CMG are set to WSA10P0.8N2, the flow rate of the TLF is reduced by 89.76% and the turbine stage efficiency increases by 0.53%.
Shi et al. (Mon,) studied this question.