Flow excitation mechanisms of unbalanced impeller forces after pump power-trip of ultra-high head pump-turbines  

作　　者：FU XiaoLong LI DeYou LV JingWei YANG Biao WANG HongJie WEI XianZhu 

机构地区：[1]School of Energy Science and Engineering,Harbin Institute of Technology,Harbin,150001,China [2]State Key Laboratory of Hydro-Power Equipment,Harbin Institute of Large Electrical Machinery,Harbin,150040,China

出　　处：《Science China(Technological Sciences)》2024年第5期1602-1611,共10页中国科学（技术科学英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.52079034,and 52209108);the Sichuan Science and Technology Program(Grant No.2023YFQ0021);the China Postdoctoral Science Foundation(Grant Nos.2022M720948,and 2023T160162);the Natural Science Foundation of Heilongjiang Province,China(Grant No.HL2023E058)。

摘　　要：To elucidate the dynamic mechanisms of unbalanced impellers in ultra-high head pump-turbines(PTs),this study employed a one-and three-dimensional coupled method to simulate the pump power-trip(PPT)process of an ultra-high head PT.The investigation revealed two novel pulsation frequency components,denoted as fDVand fINFT,associated with impeller forces.The pulsation intensities of these components were markedly higher than those of rotor-stator interaction frequency components in ultra-high head PTs.Notably,the fDVcomponents exhibited pulsations at 1–2 times the rated rotation frequency of the impeller,spanning the entire transition period.Meanwhile,the fINFTcomponents constituted a complex frequency band with various frequency values,primarily occurring near conditions(Q=0,n=0,M=0,and d M/dt=0).These two pulsation frequency components were predominantly linked to the unsteady evolution of dean vortices inside the volute and complex transitions of the flow pattern within the impeller,respectively.It is crucial to note that these unbalanced flow-induced impeller axial forces can elevate the risk of accidents where the rotor is subjected to significant upwind axial forces.These findings offer valuable insights into mitigating the risk of rotor lifting due to axial forces during PT events in ultra-high head PTs.

关 键 词：ultra-high head pump-turbine pump power-trip unbalanced impeller forces pressure pulsations flow pattern transitions 

分 类 号：TV136.1[水利工程—水力学及河流动力学]