Study on cavitating vortex rope characteristics of reversible pump-turbine under part load turbine condition

Physics of Fluids, Journal Year: 2023, Volume and Issue: 35(8)

Published: Aug. 1, 2023

Pressure fluctuations in the draft tube mainly arise from rotational motion of vortex rope. The formation and development rope are significantly influenced by cavitation. However, precise mechanism underlying progression cavitation its initial weak state to a more severe level remains unclear. objective this study is investigate pump-turbine operating under part load turbine conditions. Numerical simulations were conducted analyze impact coefficient on various parameters, including vapor volume, efficiency, head. With increasing degree cavitation, rope's pattern undergoes transition helical type torch-like type. This consequently leads shift dominant frequency pressure within tube. Furthermore, exhibits higher speed compared rope, thereby causing pronounced effect field. factors contributing morphological explored, with particular emphasis accelerating reverse axial flow reduction tube's circumferential velocity. Additionally, examined swirl number pattern, while also assessing entropy production. These findings provide valuable insight into control pump-turbines Moreover, they carry significant implications for design optimization systems.

Language: Английский

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Evolution mechanism of unsteady internal flow of an ultra-high head pump-turbine in pump mode

Journal of Energy Storage, Journal Year: 2023, Volume and Issue: 74, P. 109309 - 109309

Published: Oct. 18, 2023

Language: Английский

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Numerical simulation and experimental study on hydraulic instability of pump as turbine devices induced by thoma number based on scale-averaged wavelet spectrum

Engineering Applications of Computational Fluid Mechanics, Journal Year: 2025, Volume and Issue: 19(1)

Published: Feb. 12, 2025

Language: Английский

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Simulation analysis of energy characteristics of flow field in the transition process of pump condition outage of pump-turbine

Renewable Energy, Journal Year: 2023, Volume and Issue: 219, P. 119480 - 119480

Published: Oct. 18, 2023

Language: Английский

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Performance characteristics of a contra-rotating pump-turbine in turbine and pump modes under cavitating flow conditions

Renewable Energy, Journal Year: 2024, Volume and Issue: unknown, P. 121605 - 121605

Published: Oct. 1, 2024

Language: Английский

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Analysis of double suction pumps in both pump and turbine modes using entropy factor

Renewable Energy, Journal Year: 2024, Volume and Issue: 237, P. 121555 - 121555

Published: Oct. 9, 2024

Language: Английский

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Variable-Speed Operation of Micro-Hydropower Plants in Irrigation Infrastructure: An Energy and Cost Analysis

Applied Sciences, Journal Year: 2023, Volume and Issue: 13(24), P. 13096 - 13096

Published: Dec. 8, 2023

Micro-hydropower plants have now become a way to decarbonise the power generation system. Older micro-hydropower generally operate at fixed speed. When there is lack of rainfall, these outside their design flow causing various problems (such as occurrence phenomenon cavitation, decreased turbine performance, and operating hours), especially in installed irrigation infrastructure, where priority for water use crops. This study aims carry out comparative evaluation several indicators (cavitation, investment costs, electricity production economic benefit) two types control system on an asynchronous electric generator (a speed (scenario 1) variable-speed 2)) same plant. The Rebolluelo plant (Spain) used this purpose case study. uses semi-Kaplan coupled through gearbox. results show advantages using technology: (i) eliminates possibility (ii) increases output ratio (from 35.87% 93.03%), (iii) benefit 29.31% 108.72%). There are also, course, disadvantages, such 11.96% increase cost. work demonstrated superiority variable technology three four evaluated. could be assistance when making decisions regarding future installations.

Language: Английский

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A Numerical Investigation of Cavitation-Induced Instabilities and its Mitigation Inside a Draft Tube of a Francis Turbine using an Intrusive Structure

Lecture notes in mechanical engineering, Journal Year: 2024, Volume and Issue: unknown, P. 579 - 591

Published: Jan. 1, 2024

Language: Английский

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Unsteady Flow Behaviors and Vortex Dynamic Characteristics of a Marine Centrifugal Pump under the Swing Motion

Machines, Journal Year: 2024, Volume and Issue: 12(10), P. 687 - 687

Published: Sept. 30, 2024

Due to the effects of swing motion, performances and internal flow characteristics marine centrifugal pump undergo some unsteady variations in environment. The hydraulic test system with six degree freedom parallel motion platform is established study performance at different heel angles steady roll position pitch position. head gradually decreases as angle increases. has decreased by 7% reach minimum 15° At same angle, lower than that under rated condition. fluid impeller passage subjected additional inertial force or inducing bias phenomena velocity field. development induces intense vortex shedding dissipation interblade vortices are affected. periodic flow-induced pulsation obviously appear passage. periodicity pressure amplitude influenced due motion. greater excitation fluid-induced vibration amplitude. In addition low frequencies, 20 times shaft frequency evident

Language: Английский

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Study on Suppression of Cavitating Vortex Rope on Pump-Turbines by J-Groove

Published: Jan. 1, 2023

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Language: Английский

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