Hydraulic loss analysis in a pump-turbine with special emphasis on local rigid vortex and shear

Yuan, Zhiyi; Zhang, Yongxue; Zhou, Wei

doi:10.1063/5.0124552

Cited by 14 publications

(3 citation statements)

References 34 publications

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“…Axial-flow pumps working as turbines (pump as turbine, PAT) not only generate clean energy but also generate considerable economic benefits [5]. Compared with traditional turbine units, PATs have a simple structure, low cost, and easy maintenance, making them highly suitable for facilitating the sustainable use of water resources in remote rural regions [7,8]. However, the design and manufacture of axial-flow pumps usually only consider the performance under conventional pump conditions, rather than reverse operating conditions [9].…”

Section: Introductionmentioning

confidence: 99%

Investigation of Non-Uniform Inflow Effects on Impeller Forces in Axial-Flow Pumps Operating as Turbines

Kan,

Zhang,

et al. 2024

Water

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Due to the existence of an inlet elbow, transmission shaft, and other structural components, the inflow of axial-flow pumps as turbines (PATs) becomes non-uniform, resulting in the complexity of internal flow and adverse effects such as structural vibration. In this paper, numerical methods were employed to explore the non-uniform inflow effects on impeller forces and internal flow field characteristics within an axial-flow PAT. The study results indicated that non-uniform inflow caused uneven pressure distribution inside the impeller, which leads to an imbalance in radial forces and offsetting the center of radial forces. With an increasing flow rate, the asymmetry of radial forces as well as the amplitude of their fluctuations increased. Non-uniform inflow was found to induce unstable flow structures inside the impeller, leading to low-frequency, high-amplitude pressure fluctuations near the hub. Using the enstrophy transport equation, it was shown that the relative vortex generation term played a major part in the spatiotemporal evolution of vortices, with minimal viscous effects.

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Section: Introductionmentioning

confidence: 99%

Investigation of Non-Uniform Inflow Effects on Impeller Forces in Axial-Flow Pumps Operating as Turbines

Kan,

Zhang,

et al. 2024

Water

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“…Yuan et. Al [17][18][19] reported the influence of local rigid vortex that the local shear effect was dominant in energy loss in a centrifugal pump.…”

Section: Introductionmentioning

confidence: 99%

Transient vortical structure evolution under part-load condition in a high-power double-suction centrifugal pump based on Liutex method

Deng,

Pei,

Wang

2024

J. Phys.: Conf. Ser.

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In order to investigate the evolution of vortical structures inside a high-power double-suction centrifugal pump, the flow fields were solved numerically by the SST k-ω turbulence mode. After experimental validation, the Liutex/Rortex method was adopted for identifying vortices for each step from the numerical results, and the enstrophy was adopted to present the kinetic energy that vortical structures contained. The vortical structures at different seconds were obtained, and the vortices evolution was figured out. The results indicate that: the wake vortex was the dominant type inside the volute. Vortical structures at the impeller inlet evolve periodically. The interactions between the impeller leading edge with suction ribs and the blade trailing edge and volute tongues were critical factors for vortex evolution. Vortical structures mainly formed at the impeller inlet near the blade suction side. The suction rib would decrease the absolute rotational intensity around it, but the relative local rigid vortex would keep a high intensity. Due to the suction rib and volute tongues, the vortices variated with a period of 1/2T.

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“…Ono et al investigated the relation between the leading edge radius and the S-shaped characteristics and found that the leading edge vorticity causes the inner blade loss [13]. Yuan et al analyzed vortex flow characteristics and vortex control methods in both modes to reduce hydraulic loss [14]. Fu et al used the single-and twophase flow models to demonstrate the influence of cavitation on pressure fluctuation in a pump-turbine [15].…”

Section: Introductionmentioning

confidence: 99%

Numerical Study on the Flow and Structural Characteristics of a Large High Head Prototype Pump-Turbine under Different Operating Conditions

Ru,

Zhang,

Zhou

et al. 2023

Processes

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During the operation of pumped storage power stations, complex operating conditions can lead to different internal flow characteristics, which can cause different vibration characteristics or even damage to the structural components of the pump-turbine units. The time–frequency characteristics of the structural components’ response are of great significance for the safe operation of the unit. In this study, a three-dimensional flow field and structural field model of a large high head prototype pump-turbine is built in order to study the flow and the flow-induced dynamic response characteristics in different turbine operating conditions. The analyzed results show that the maximum deformation occurs at the inner head cover, and the maximum value of stress is located at the fillets on the outlet side of the stay vanes. Under the 50% load condition, the vortices in the runner caused by changes in the opening of the guide vanes result in the main response frequency of 4 fn of the stationary components. The research results can provide references for the structural optimization design of other pump-turbine units.

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Hydraulic loss analysis in a pump-turbine with special emphasis on local rigid vortex and shear

Cited by 14 publications

References 34 publications

Investigation of Non-Uniform Inflow Effects on Impeller Forces in Axial-Flow Pumps Operating as Turbines

Investigation of Non-Uniform Inflow Effects on Impeller Forces in Axial-Flow Pumps Operating as Turbines

Transient vortical structure evolution under part-load condition in a high-power double-suction centrifugal pump based on Liutex method

Numerical Study on the Flow and Structural Characteristics of a Large High Head Prototype Pump-Turbine under Different Operating Conditions

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