关键词: 水泵水轮机;内流特性;涡带;压力脉动;动静干涉;模态分析;

Abstract: In order to study the stability of pump turbine unit under different head turbine conditions, the ANSYS Workbench platform is utilized to conduct a full channel numerical simulation, in which the mechanism of pressure pulsation, as well as the prestress modal analysis of the pump turbine are investigated, and the simulated results are verified with the experimental results.The calculation results indicate that the flow state of the pump turbine unit in the rated condition is sufficient, the water pressure pulsation is closely related to the occurrence of the vortex zone phenomenon, and the pressure pulsation of each component's monitoring point presents a certain periodicity.Moreover, the main frequency of pressure pulsation is rotating frequency and its frequency doubling, whereas the rotor-stator interference under the interaction between the runner and movable vane is the main source of pressure pulsation.Furthermore, the natural frequency of the prestressed runner is far away from the hydraulic excitation frequency of each component, so the resonance is less likely to occur.The results can provide a reference for the causes of vibration and the operational stability of pump turbine units considering various head turbine conditions.

Key words: pump turbine; internal flow characteristics; vortex; pressure pulsation; dynamic and static interference; modal analysis;