Suppression of cavitation in the draft tube of Francis turbine model by J-Groove

Chen, Zhenmu; Choi, Young‐Do

doi:10.1177/0954406218802310

Cited by 16 publications

(5 citation statements)

References 21 publications

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“…The CFD analysis process is directly connected to the optimum design process. The CFD analysis method was adopted from previous studies [33][34][35].…”

Section: Cfd Methodologymentioning

confidence: 99%

A CFD-Based Shape Design Optimization Process of Fixed Flow Passages in a Francis Hydro Turbine

Shrestha

Choi

2020

Processes

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In recent times, optimization began to be popular in the turbomachinery field. The development of computational fluid dynamics (CFD) analysis and optimization technology provides the opportunity to maximize the performance of hydro turbines. The optimization techniques are focused mainly on the rotating components (runner and guide vane) of the hydro turbines. Meanwhile, fixed flow passages (stay vane, casing, and draft tube) are essential parts for the proper flow uniformity in the hydro turbines. The suppression of flow instabilities in the fixed flow passages is an inevitable process to ensure the power plant safety by the reduction of vortex-induced vibration and pressure pulsation in the hydro turbines. In this study, a CFD-based shape design optimization process is proposed with response surface methodology (RSM) to improve the flow uniformity in the fixed flow passages of a Francis hydro turbine model. The internal flow behaviors were compared between the initial and optimal shapes of the stay vane, casing, and the draft tube with J-Groove. The optimal shape design process for the fixed flow passages proved its remarkable effects on the improvement of flow uniformity in the Francis hydro turbine.

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“…The CFD analysis process is directly connected to the optimum design process. The CFD analysis method was adopted from previous studies [33][34][35].…”

Section: Cfd Methodologymentioning

confidence: 99%

A CFD-Based Shape Design Optimization Process of Fixed Flow Passages in a Francis Hydro Turbine

Shrestha

Choi

2020

Processes

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“…The swirling flow was eliminated by controlling the angular momentum of flow by using the hollows named j-grooves. The jgroove structures were also explored by Wei et al, [3] and Chen and Choi [4]. It was observed that the structures decreased the quantity of vortex structures.…”

Section: Introductionmentioning

confidence: 97%

Vortex breakdown in discharge cone of the Francis Turbine

Semerci¹,

Yavuz

2023

Journal of Energy Systems

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Hydraulic turbines are usually operating at high efficiencies around 90%. It is possible to increase the efficiency by preventing flow characteristics such as failure, cavitation and vortex rope in the draft tube. In some cases, such as partial loads or overloads, pressure pulsations and vortex rope would occur in the draft tube. These undesired events would damage the components of the turbine and that also causes the efficiency to decrease. To eliminate these artifacts, it is decided to design a new component. Vortex Preventing Element, which is designed to eliminate vortex structures and pressure fluctuations, is located at the inlet of draft tube. Computational Fluid Dynamics analyses are performed for different designs having several stage numbers of vortex preventing elements. The preliminary results showed that the one stage vortex preventing element design creates more uniform flow in the draft tube and also increases the efficiency about 3%. Since more studies about the vortex preventing element are in progress, it could be said that the vortex preventing element can handle vortex phenomena in the draft tube and effects the efficiency of the Francis turbines.

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“…The pressure pulsations in the leafless region all show a dynamic and static interference phenomenon, and the main frequency is the blade passing frequency. Chen et al , considered the impact of J-Groove on pressure pulsation at nondesign operating points through experimental methods and numerical simulations. The results show that J-Groove can improve performance and reduce internal unsteady flow.…”

Section: Introductionmentioning

confidence: 99%

Study on the Unsteady Characteristics and Radial Force of a Single-Channel Centrifugal Pump

Wang

et al. 2023

ACS Omega

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To research the internal flow characteristics of a single-channel centrifugal pump, the computational fluid dynamics method is used in this study. Several monitoring points are set on the volute to analyze the change of pressure pulsation and radial force when the impeller rotates at different angles. The results show that the pressure pulsation in the single-channel pump volute is induced by the rotor–stator interaction and its harmonics. The monitoring points close to the separation tongue along the rotation direction of the impeller are more affected by the flow rate.

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Suppression of cavitation in the draft tube of Francis turbine model by J-Groove

Cited by 16 publications

References 21 publications

A CFD-Based Shape Design Optimization Process of Fixed Flow Passages in a Francis Hydro Turbine

A CFD-Based Shape Design Optimization Process of Fixed Flow Passages in a Francis Hydro Turbine

Vortex breakdown in discharge cone of the Francis Turbine

Study on the Unsteady Characteristics and Radial Force of a Single-Channel Centrifugal Pump

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