Modelization and Simulation of Francis Turbine Inter-blade Vortices in Partial Load Conditions

Bouajila, Sofien; Brammer, James; Flores, Emmanuel; Ségoufin, Claire; Maı̂tre, Thierry

doi:10.1007/978-981-10-7218-5_66

Cited by 2 publications

(2 citation statements)

References 4 publications

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“…The closer it is to the upper crown position, the closer the vortex structure is to the runner inlet. The same phenomenon was found in related experiments [20] and CFD simulations [21][22][23].…”

Section: Test Results Of Different Sectionssupporting

confidence: 86%

Particle Image Velocimetry Test for the Inter-Blade Vortex in a Francis Turbine

Jin²,

et al. 2021

Processes

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Hydropower units are usually operated in non-design conditions because of power grid requirements. In a partial-load condition, an inter-blade vortex phenomenon occurs between the runner blades of a Francis turbine, causing pressure pulsation and unit vibration, which hinder the safe and stable operation of power stations. However, the mechanism through which the inter-blade vortex generation occurs is not entirely clear. In this study, a specific model of the Francis turbine was used to investigate and visually observe the generation of the blade vortex in Francis turbines in both the initial inter-blade and vortex development zones. Particle image velocimetry was used for this purpose. In addition, we determined the variation law of the inter-blade vortex in the Francis turbine. We found that the size and strength of the inter-blade vortex depend on the unit speed of the turbine. The higher the unit speed is, the stronger the inter-blade vortex becomes. We concluded that the inter-blade vortex of such turbines originates from the pressure surface or secondary flow and stall of the blade at the inlet side of the runner at high unit speeds, and also from the backflow zone of the suction surface of the blade at low unit speeds.

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Section: Test Results Of Different Sectionssupporting

confidence: 86%

Particle Image Velocimetry Test for the Inter-Blade Vortex in a Francis Turbine

Jin²,

et al. 2021

Processes

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show abstract

“…Magnoli et al [22] identify three independent vortical structures in a runner with numerical simulations, and the experimental measurements confirm that the pressure oscillation amplitude is drastically increased due to the set-in and development of inter-blade vortex. Besides, some investigations towards inter-blade cavitation vortex are performed by Kurosawa et al [23], Bouajila et al [24] and Liu et al [25].…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of inter‐blade cavitation vortex for a Francis turbine at part load conditions

Sun

Guo

Luo

2021

IET Renewable Power Gen

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Inter‐blade cavitation vortex at part load has raised significant concerns about operation stability for Francis turbines due to tremendous development and integration of renewable energy resources into power grid. The principal objective of this study is to investigate the flow characteristics of inter‐blade cavitation vortex and its influence on pressure fluctuations for a low‐head Francis model turbine. Unsteady numerical simulations are carried out using shear stress transport turbulence model and Zwart cavitation model. Numerical results yield to a good validation with the experimental data. The findings show that inter‐blade cavitation vortices highlighted by cavitation structure and vortex structure are extremely different at the points adjacent to the incipient line of inter‐blade cavitation vortex. The location of inter‐blade cavitation vortex development in the runner is more sensitive to rotating speed than that to guide vane opening. The formation mechanism of inter‐blade cavitation vortex is attributed to flow separation in the vicinity of the runner hub. Pressure fluctuations induced by inter‐blade cavitation vortex are directly associated with the evolution of vapour volume in the runner and feature wide‐band and low‐frequency characteristic, and the fluctuations on the suction side of the runner blade are significantly magnified because of the presence of inter‐blade cavitation vortex.

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Modelization and Simulation of Francis Turbine Inter-blade Vortices in Partial Load Conditions

Cited by 2 publications

References 4 publications

Particle Image Velocimetry Test for the Inter-Blade Vortex in a Francis Turbine

Particle Image Velocimetry Test for the Inter-Blade Vortex in a Francis Turbine

Numerical investigation of inter‐blade cavitation vortex for a Francis turbine at part load conditions

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