Results 11 to 20 of about 9,992 (233)
Active flow control of the vortex rope and pressure pulsations in a swirl generator
Engineering Applications of Computational Fluid Mechanics, 2017 The vortex rope and pressure pulsations caused by a radial pressure gradient in the conical diffuser of a swirl generator is controlled using continuous slot jets with different momentum fluxes and angles injected from the runner crown.
Ardalan Javadi, Håkan Nilsson
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Vortex rope mitigation with azimuthal perturbations: A numerical study
IOP Conference Series: Earth and Environmental Science, 2021 Abstract A novel method to mitigate the rotating vortex rope is investigated numerically on a propeller turbine using ANSYS CFX. Pulsating momentum is injected in a horizontal plane in the diffuser cone from four evenly spaced jets. Three mitigation strategies are tested; M1 in which the momentum is injected perpendicular to the axial ...
Holmström, H +2 more
openaire +2 more sources
Applied Sciences, 2021 The flow in a Francis turbine at full load is characterised by the development of an axial vortex rope in the draft tube. The vortex rope often promotes cavitation if the turbine is operated at a sufficiently low Thoma number.
Jean Decaix +4 more
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Energies, 2021 The inter-blade passage vortex, the vortex rope of the draft tube, and the vortex in the guide apparatus are the characteristics of flow instability of the Francis turbine, which may lead to fatigue failure in serious cases.
Tao Guo, Lihui Xu, Wenquan Wang
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Machines, 2022 The flow characteristics of the draft tube of a Francis turbine have a significant influence on turbine stability. Numerical simulations were performed for a Francis turbine under three different output conditions of 20%, 100%, and 120% at the rated and ...
Lei Ji +7 more
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Manipulation of the swirling flow instability in hydraulic turbine diffuser by different methods of water injection [PDF]
EPJ Web of Conferences, 2018 Vortex rope, which induces substantial pressure pulsations, arises in the draft tube (diffuser) of Francis turbine for off-design operating conditions.
Rudolf Pavel +3 more
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Hydraulic Vibration and Possible Exciting Sources Analysis in a Hydropower System
Applied Sciences, 2021 To understand the hydraulic vibration characteristics in a traditional hydropower system and identify possible exciting sources that may induce serious hydraulic vibrations in the flow passage, experimental tests and numerical calculations were conducted
Aili Shen +5 more
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Energies, 2022 The vortex rope in the draft tube is considered as the major contributor to pressure pulsation at partial load (PL) conditions, which causes the hydro unit to operate unstably.
Zhumei Luo +4 more
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Machines, 2023 The existence of vortex ropes inside the draft tube significantly impacts hydraulic efficiency and operational stability, and few studies on the formation mechanism of vortex ropes and hydraulic loss problems have been explored.
Haobo Wang +3 more
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Suppressing the Vortex Rope Oscillation and Pressure Fluctuations by the Air Admission in Propeller Hydro-Turbine Draft Tube [PDF]
Journal of Applied Fluid Mechanics, 2023 For the purpose of automatic generation control (AGC), a portion of the propeller hydro-turbine units in China is adjusted to operate within a restricted range of 75%-85% load using computer-controlled AGC strategies.
H. Wu +9 more
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