Investigations on Pressure Fluctuations in the S-Shaped Region of a Pump–Turbine

Investigations on Pressure Fluctuations in the S-Shaped Region of a Pump–Turbine

Hydraulic pumped storage is a special power generation and electricity shortage technology, which is usually operated with thermal power and nuclear power units, and plays a key role in ultra-high voltage and smart grid. Pressure fluctuations are the main reasons for the instability of the S-shaped...

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Bibliographic Details
Published in:Energies (Basel) Vol. 14; no. 20; p. 6683
Main Authors: Wang, Hongjie, Wang, Jianpeng, Gong, Ruzhi, Shang, Chaoying, Li, Deyou, Wei, Xianzhu
Format: Journal Article
Language:English
Published: Basel MDPI AG 01-10-2021
Subjects:
Electricity distribution
Fluctuations
frequency characteristic
High voltage
Hydraulics
Life span
Nuclear energy
Pressure
pressure fluctuation
Propagation
Pumped storage
pump–turbine
Rotation
S-shaped region
Simulation
Thermal power
Turbines
Turbulence models
Vortices
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Summary:Hydraulic pumped storage is a special power generation and electricity shortage technology, which is usually operated with thermal power and nuclear power units, and plays a key role in ultra-high voltage and smart grid. Pressure fluctuations are the main reasons for the instability of the S-shaped region of pump–turbines, which seriously affects their lifespan and operation stability. To reveal the mechanism and propagation law of pressure fluctuations in the S-shaped region as well as numerical simulations at the turbine, the braking and the reverse pump operating conditions of a pump–turbine were carried out. Numerical results were validated using the performance experiments, and the generation mechanism and propagation law of pressure fluctuation were analyzed in detail. The analyses show that high-amplitude pressure fluctuations mainly occur in the braking and reverse pump operating conditions. Under the braking condition, a 0.49-fn low-frequency pressure fluctuation was captured, which is caused by the rotation of the backflow in the vanes. Under the reverse pump condition, a 0.19-fn low-frequency pressure fluctuation was confirmed, which is caused by the periodic rotation of the vortex between the vaneless space. This study has important guiding significance for practical engineering application.
ISSN:1996-1073
1996-1073
DOI:10.3390/en14206683