Mechanism of low frequency high amplitude pressure fluctuation in a pump-turbine during the load rejection process

Owing to the complexity of the load rejection process, the accompanied complex low frequency pressure fluctuations and their sources have not been determined. Herein, the load rejection transient process of a pump-turbine was simulated with a three-dimensional (3-D) large eddy simulation method and...

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Vydáno v:Journal of hydraulic research Ročník 59; číslo 2; s. 280 - 297
Hlavní autoři: Fu, Xiaolong, Zuo, Zhigang, Chang, Hong, Li, Deyou, Wang, Hongjie, Wei, Xianzhu
Médium: Journal Article
Jazyk:angličtina
Vydáno: Madrid Taylor & Francis 04.03.2021
Taylor & Francis Ltd
Témata:
Amplitude
Amplitudes
Complexity
Components
Finite element method
Fluctuations
Frequency analysis
Frequency dependence
Inlets (waterways)
Large eddy simulation
Load rejection process
Low frequencies
Low frequency
low frequency pressure fluctuation
numerical simulation
Pressure
pump-turbine
Rejection
Reversed flow
Simulation
Time-frequency analysis
Turbine engines
Turbines
Water hammer
ISSN:0022-1686, 1814-2079
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Shrnutí:Owing to the complexity of the load rejection process, the accompanied complex low frequency pressure fluctuations and their sources have not been determined. Herein, the load rejection transient process of a pump-turbine was simulated with a three-dimensional (3-D) large eddy simulation method and a dynamic mesh technology. The simulation results were validated against the experimental data. Through the joint time-frequency analysis of simulated pressure, the complex low frequency pressure fluctuation components were captured, which are generally lower than the rated rotational frequency of the runner. A comprehensive formation mechanism of these complex low frequency pressure fluctuation components was attributed to three transient hydraulic phenomena and their interactions: the water hammer in the pump-turbine, local reverse flow near the runner inlet, and 3-D blocking water ring in the vaneless space. These findings facilitate the elucidation and elimination of complex low frequency high amplitude pressure fluctuations during the load rejection transient process.
Bibliografie:ObjectType-Article-1
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content type line 14
ISSN:0022-1686
1814-2079
DOI:10.1080/00221686.2020.1780488