Numerical study of hydraulic axial force of prototype pump-turbine pump mode’s stop with power down

Mao, Zhongyu; Tao, Ran; Bi, Huili; Luo, Yongyao; Wang, Zhengwei

doi:10.1088/1755-1315/774/1/012094

Cited by 6 publications

(3 citation statements)

References 9 publications

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“…The numerical method which depends on solving the three dimensional flow field could obtain the pressure distribution on the runner surface and then the hydraulic thrust could be determined. 8 Jin et al 9 studied the axial force of a centrifugal pump, and the reliability of the numerical method was verified by the experimental data. Obviously, the numerical method could obtain the time variation law of the hydraulic thrust, and the relationship between the hydraulic thrust and the operating condition can be determined with less cost.…”

Section: Introductionmentioning

confidence: 96%

Effect of the pressure balance device on the flow characteristics of a pump-turbine

Luo

Wang

2022

Proceedings of the Institution of Mechanical Engineers, Part A:

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Pump-turbine plays a significant role in the pumped storage station, and it is troubled by unreasonable hydraulic thrust. Some pressure balance devices have been adopted to ensure the safety of the pump-turbine unit, but the effect mechanism has not been numerical studied. This paper establishes the CFD model of the flow passage of a pump-turbine, wherein the crown gap, band gap, pressure balance pipe, and the discharge ostium are considered. Then, the flow characteristics of the pump-turbine at four typical operating conditions in turbine mode are calculated in transient scheme, and the numerical results agree with the experimental results. Finally, the effect of the pressure balance pipe and the discharge ostium on the pressure pulsation and the hydraulic thrust is discussed. The results show that the pressure balance pipe causes the direction of the axial hydraulic thrust to change from downward to upward, and the discharge ostium helps reducing the axial hydraulic thrust to a reasonable range. The pressure balance pipe and the discharge ostium have little effect on the radial hydraulic thrust. The pressure pulsation analysis provides a basis for revealing the mechanism of the hydraulic thrust frequency, and the rotor-stator interaction frequency exists in the axial hydraulic thrust. This paper provides a deeper knowledge of the impact mechanism of the pressure balance pipe and discharge ostium on the flow characteristics of the pump-turbine, which could contribute to future designs of the pump-turbine units, and is helpful for improving the safety of the pumped storage unit.

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Section: Introductionmentioning

confidence: 96%

Effect of the pressure balance device on the flow characteristics of a pump-turbine

Luo

Wang

2022

Proceedings of the Institution of Mechanical Engineers, Part A:

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“…Obtaining the time history of axial hydraulic thrus through experimental testing is difficult, but numerical simulation methods can offer a valuable IOP Publishing doi:10.1088/1742-6596/2752/1/012091 2 alternative. By solving the 3D flow field, the numerical approach can provide the pressure distribution on the runner surface, enabling determination of the axial hydraulic thrust and radial force characteristics exerted on the runner [9]. Notably, CFD calculations performed by Wu et al [10] show that the runner clearance significantly impacts the characteristics of axial hydraulic thrust in the unit.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation on the flow characteristics of a pump-turbine in load rejection process

Cao,

Liu,

Zeng

2024

J. Phys.: Conf. Ser.

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Pumped storage plays a crucial role in maintaining the stability of the power grid, with the pump-turbine being the key component. The flow characteristics of the pump-turbine during transient processes have a significant impact on the unit’s safety, particularly in load rejection scenarios. In this study, a 1D transient simulation is conducted to analyze the flow characteristics of a pump-turbine during load rejection using the Quasi-static method. The study focuses on the flow patterns and axial hydraulic thrust. The results indicate that the unit operates in turbine, braking, and pumping modes during load rejection, with the streamline becoming chaotic. This complex flow pattern also leads to notable variations in the axial hydraulic thrust, ranging from -92t to 405t. The findings presented in this paper are valuable for ensuring the safety of pump-turbines and can serve as a reference for their optimization and operation.

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“…In recent years, the joint 1D/3D simulation method combining 1D pipeline calculation with 3D unsteady flow calculation of turbines [14][15][16][17] has been mostly used to study the transient processes of hydraulic turbine units. The 1D/3D joint simulation method can more accurately calculate key parameters such as rotational speed, flow rate and guide vane opening of the turbine unit and achieve valuable results for hydropower engineering applications.…”

Section: Introductionmentioning

confidence: 99%

Fluid–Structure Coupling Analysis of the Stationary Structures of a Prototype Pump Turbine during Load Rejection

Huang²,

Yang³

et al. 2022

Energies

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During the load rejection transient process of the prototype pump turbine units, the pressure fluctuations of the entire flow passage change drastically due to the rapid closing of guide vanes. The extremely unsteady pressure distribution in the flow domains including the crown chamber and the band chamber may cause a strong vibration on the stationary structures of the unit and result in large dynamic stress on the head cover, stay ring and bottom ring. In this paper, the numerical fluid dynamic analysis of the entire flow passage of a reversible prototype pump turbine during load rejection was performed. The flow characteristics in the runner passage, crown chamber, band chamber, seal labyrinths and balance tubes are analysed. The corresponding unsteady flow-induced dynamic behaviour of the head cover, stay vanes and bottom ring was investigated in detail. The analysed results show that the total deformation of the inner edge of the head cover closed to the main shaft is larger than that of other stationary structures of the unit during the load rejection. The maximum stress of the stay ring is larger than that of the head cover and the bottom ring and the maximum equivalent stress is located at the fillet of the stay vane trailing edge. The fluid–structure coupling calculation method and the analysed results can provide guidance for the design of stationary components of hydraulic machinery such as pump turbines, Francis turbines and centrifugal pumps with different heads.

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Numerical study of hydraulic axial force of prototype pump-turbine pump mode’s stop with power down

Cited by 6 publications

References 9 publications

Effect of the pressure balance device on the flow characteristics of a pump-turbine

Effect of the pressure balance device on the flow characteristics of a pump-turbine

Numerical simulation on the flow characteristics of a pump-turbine in load rejection process

Fluid–Structure Coupling Analysis of the Stationary Structures of a Prototype Pump Turbine during Load Rejection

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