水泵水轮机反水泵工况下活动导叶压力脉动分析OA

As the largest form of energy storage,pumped storage power station units are prone to entering the S-characteristic region during startup under turbine operating conditions,leading to increased vibrations and failure to synchronize to the grid.This study takes a model pump turbine as the research subject and employs the dynamic mode decomposition method to analyze the unsteady characteristics of the flow field under reverse pump conditions.The dis-tribution of flow field eigenvalues and the relationship between modal energy and frequency across different modes are clarified.The results show that the counterclockwise high-speed water rings formed in the vaneless space,along with periodically evolving vortex structures in the guide vane passages such as separation vortices and horseshoe vortices,collectively cause low-energy flow passages to propagate circumferentially at 0.2 times the rotational frequency,resulting in significant uneven energy distribution.The pressure fluctuations in the vaneless space are dominated by the rotor-stator interaction frequency of 9fn,which exhibits high amplitude and uniform circumferential distribution.Within the guide vane flow passages,the dominant frequencies shift to low-frequency fluctuation at 1.2fn induced by the periodic evolution of secondary separation vortices with amplitude exhibiting a non-uniform and alternating cir-cumferential distribution.Dynamic mode decomposition further confirms the periodic and stable nature of the flow field.The dominant modes accurately correspond to the basic steady-state structure,rotor-stator interaction,and internal flow instability characteristics.The periodic evolution of vortex structures within the guide vanes is identified as the root cause of low-frequency pressure fluctuations and uneven energy distribution across the flow passages.