Pressure Pulsation and Energy Dissipation Mechanism of a Pump-Turbine Considering Runner Blade Leading Edge Effect

Efficiency and stability significantly determine the operating quality of a pump-turbine, and the runner blade leading edge angle (BLEA) is a critical factor influencing these performance indicators. In this study, numerical simulations were conducted to investigate the pressure pulsation characteristics and energy dissipation mechanisms within a pump-turbine under three different runner blade leading edge angles (standard, +15°, and −15°). The findings indicate that the blade angle has little effect on efficiency, with the maximum relative difference of 0.5%. When compared to the original blade geometry, the variant whose blade inclines 15° toward the rotational direction in turbine mode demonstrates superior performance both in terms of efficiency and in reducing pressure pulsations, under both turbine and pump operational modes. Additionally, it was observed that energy dissipation locations vary notably depending on the flow direction: when operating as a turbine, prominent dissipation occurs within the runner region, while in pump mode, significant energy losses are primarily concentrated in the stay vanes and guide vanes. The insights presented in this work provide beneficial guidance for optimizing pump-turbine designs, enhancing efficiency and stability, and ultimately contributing to sustainable development in pumped-storage power plants.