Pump as turbine cavitation performance for both conventional and reverse operating modes: A review

Kan, Kan; Binama, Maxime; Chen, Huixiang; Zheng, Yuan; Zhou, Daqing; Su, Wen-Tao; Muhirwa, Alexis

doi:10.1016/j.rser.2022.112786

Cited by 102 publications

(37 citation statements)

References 186 publications

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“…In these schemes, the y + on average in the runner and guide vanes is less than 5, which meets the calculation requirements. [26][27][28] Scheme 5 is selected for numerical simulation.…”

Section: Mesh Generation and Numerical Calculation Settingsmentioning

confidence: 99%

Vortex structure and pressure fluctuation of a pump-turbine in pump mode using large Eddy simulation

Zhang

Jiang

Wang

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part A:

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Pump-turbines are usually used to ensure the stability of power system frequency and make up for the shortcomings of the intermittent nature of new energy such as wind energy. They are an important part of modern power systems. The Large Eddy Simulation (LES) method is used to study the vortex characteristics and pressure fluctuation intensity of the model pump-turbine working in pump mode. Results show that the wake vortex of the impeller has a great influence on the internal flow field of the pump-turbine, which is developed from the vortex structure near the suction surface of the blade. The distribution of trailing edge shedding vortex of guide vanes and shock vortex around tongue is closely related to the wake vortex of impeller. The wake vortex is divided into α and β according to the distribution range along the blade height. Their motion law and dissipation rate are different, and the influence of the α vortex on the flow field is greater. The distribution of pressure fluctuation intensity near the wall corresponds to the vortex structure, which indicated that the vortex is an important factor in pressure fluctuation. It is of great significance to improve the vortex structure inside the pump-turbine for safe and stable operation. The research in this paper can provide reference for the stable operation of the pump-turbine.

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“…In these schemes, the y + on average in the runner and guide vanes is less than 5, which meets the calculation requirements. [26][27][28] Scheme 5 is selected for numerical simulation.…”

Section: Mesh Generation and Numerical Calculation Settingsmentioning

confidence: 99%

Vortex structure and pressure fluctuation of a pump-turbine in pump mode using large Eddy simulation

Zhang

Jiang

Wang

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part A:

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“…When the pump draws energy from the fluid, it is known as pump as turbine (PAT). The interest in this type of turbomachine is because power generation is less expensive in equipment than a conventional turbine for low power ranges [1][2][3][4][5][6][7][8]. Even though the use of PATs may be the best option for harnessing small hydro resources [9], especially in rural and remote areas with power supply problems [7,8], the study of this type of turbomachines has not been extensive.…”

Section: Introductionmentioning

confidence: 99%

“…Cavitation is an important source of instabilities, so it was included in the same query as instabilities. In this group, the following topics are addressed: geometry, efficiency, cavitation [4,[7][8][9][10][11][12][13][14][15][16][17][18][19][20][21], flow structures [8,[22][23][24][25], pressure fluctuations [16,21,26,27], vortex rope [27], energy losses when switching from pump to turbine mode [28], and application of entropy production theory for energy losses [29]. None of them addresses the measurement of instabilities.…”

Section: Introductionmentioning

confidence: 99%

Periodic Instabilities in a Specific Low-Speed Pump Working as a Turbine

Bolaños¹,

Botero²

2023

Advances in Turbomachinery

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The hydrodynamic instabilities in a turbomachine can be divided into two main groups: periodic (or quasi-periodic) and nonperiodic. And the total instability, calculated from a statistical parameter with linear characteristics, such as variance, can be defined as the sum of periodic and nonperiodic instabilities. Based on the above, the main objective of the study was to estimate the periodic instabilities in a pump operating as a turbine. For this purpose, pressure fluctuation signals from sensors installed on the turbomachine volute and spaced 135° apart were used. The signals were analyzed in the time and frequency domain to identify, initially, the periodic instabilities and their relationship with the spectral components and, subsequently, to estimate the magnitude of these instabilities as the variance of the filtered series in the spectral band related to the periodic instability. In addition, the study aims to establish the contribution of periodic instabilities to total instability.

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“…Wei et al 19 studied the influence of the diameter change of seal ring behind the impeller and balance hole on the fluid flow property of the balance chamber, and found the variation law of the pressure and axial force in the balance chamber. Kan et al 20 studied the cavitation phenomenon in reverse-operated pumps due to local low pressure, it was found that the reverse mode is more likely to cavitation, and the cavitation performance can be significantly improved by modifying the geometric design parameters of the reverse-operated pump. In addition, domestic and foreign scholars have carried out many studies on the influence of factors such as the leakage of port ring gap and the leakage flow of the balance hole on the axial force.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the axial force distribution characteristics of multistage pumps and its correlation with hydraulic property

Chen

Lihuan

Zhipeng³

et al. 2022

Advances in Mechanical Engineering

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As the centrifugal pump is running, the fluid usually flows into the impeller along pump shaft, and the fluid flows out radially by the force of the impeller. The force is mutual, so the impeller is also subjected to the reaction force of the fluid, but the distribution of this force on the blades is uneven. In addition, the front and rear shrouds of the impeller are asymmetric, which are the main causes of axial force. This paper adopts numerical calculation method studying the mechanism of axial force of impeller at all stages of multistage pump at various working conditions, and exploring the formation mechanism of shroud pressure differential force and blade twisting axial force and its variation laws of similarities and differences, analyzing the steady state and transient characteristics between axial force and hydraulic property of double-casing multistage pump. The results show that the rotational angular velocity of the fluid in the front and rear pump chamber at each stage impeller is distributed along the axial direction in three regions, the regions are pump body boundary layer, core region, and impeller boundary layer. The working surface and back surface of the blade twist have the high and low axial force area, and its distribution is staggered, at the same number of stages, the greater the flow rate, the smaller the blade twisting axial force. The shroud pressure differential force with the increase of impeller stages presents a linear increasing trend, conforms to the principle of linear superposition of cover pressure differential force. The total axial force pulsation of multi-stage pump is related to the number of secondary impeller blades, its primary frequency coincides with the secondary impeller blade frequency, increasing the flow rate can reduce the multi-stage pump axial force pulsation amplitude. The pulsation period of single-stage impeller head and efficiency are related to the number of impeller blades, the smaller the number of impeller stages, the stronger the pressure dynamic, and static interference effect of the impeller inlet and outlet. Rotation of the secondary impeller causes dynamic and static interference, which is the main reason for the pulsation of the axial force coefficient in double-casing multistage pumps, the pulsation intensity is related to the periodic generation and shedding of the blade vortex. The results of the study can be used as a reference for optimizing the axial force of double-casing multistage pumps.

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Pump as turbine cavitation performance for both conventional and reverse operating modes: A review

Cited by 102 publications

References 186 publications

Vortex structure and pressure fluctuation of a pump-turbine in pump mode using large Eddy simulation

Vortex structure and pressure fluctuation of a pump-turbine in pump mode using large Eddy simulation

Periodic Instabilities in a Specific Low-Speed Pump Working as a Turbine

Analysis of the axial force distribution characteristics of multistage pumps and its correlation with hydraulic property

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