Effect of runner blades-guide vanes combination on a prototype pump-turbine pressure pulsation characteristics in turbine mode with special emphasis on rotor–stator interaction

The study of pressure pulsation in pump-turbines is vital for comprehending hydraulic stability and optimizing system design, and the combination of runner blades and guide vanes plays an important role in pressure pulsation characteristics, which is not sufficiently studied. This paper carried out a numerical and experimental study on the pressure pulsation characteristics of a prototype pump-turbine in turbine mode under three typical guide vanes-runner blades combinations: case A: 20 GVs-9 RBs, case B: 20 GVs-11 RBs, and case C: 16 GVs-10 RBs (consisting of five long blades and five short blades). The synergistic effect of runner blades and guide vanes on pressure pulsation patterns with special emphasis on rotor–stator interaction (RSI) was analyzed. The results show that the combination of GVs-RBs has complex mechanisms on pressure pulsation, and case A: 20 GVs-9 RBs shows better performance in many conditions, while the runner with splitter blades has better flow stability in part-load conditions. The results in this paper offer strategies for suppressing RSI-dominated pulsations through combination design, thereby providing crucial theoretical guidelines for optimizing prototype pump-turbine design and operational maintenance.