Numerical analysis of non-axisymmetric flow characteristic for a pump-turbine impeller at pump off-design condition

Zhao, Xiaoran; Xiao, Yexiang; Wang, Zhengwei; Luo, Hao; Ahn, Soo-Hwang; Yangyang, Yao; Fan, Honggang

doi:10.1016/j.renene.2017.06.088

Cited by 34 publications

(11 citation statements)

References 21 publications

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“…It showed that the accident was caused by large pressure pulsation. Zhao et al 4 found significant differences in pressure fluctuations in different channels under a pump off-design condition. Herbert et al 5 studied the fluid dynamics of the pump-turbine in turbine mode.…”

Section: Introductionmentioning

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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Section: Introductionmentioning

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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show abstract

“…The pump performance was evaluated when the diffuser blade height was 0 (no blade), 0.5, 0.6, 0.8, and 1 time the diffuser width. Xiaoran et al (2018) employed the CFD tool to analyze the asymmetric flow characteristics in a reversible turbine pump operating in pump mode, taking the relationship between pressure fluctuations and unsteady flow pattern in the impeller as the premise of analysis. Wang, Wang, Kong, Gou, and Yang (2017) proposed changes in the blade profile of a pump impeller so that it could operate as a turbine with good performance.…”

Section: Introductionmentioning

confidence: 99%

Comparison between CFD simulation and affinity laws and analysis of the degree of reaction.

Rosa,

Brito,

Tibiriça

et al. 2023

Acta Sci Technol

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Computational Fluid Dynamics (CFD) is a modern technology used to study fluid flow. Experimental methods for predicting the turbomachinery performance involve greater time consumption and financial resources compared to the CFD approach. For the centrifugal pump the impeller is the main component, as it transfers energy to the fluid. The pump flow rate and the total head are directly associated with the impeller rotation speed. The purpose of this paper is to present the analysis and comparison of numerical simulation results using Computational Fluid Dynamics of a centrifugal pump impeller under three different rotation speeds: 3500 rpm (nominal), 3100 rpm and 2700 rpm. The software used was ANSYS-CFX®, the turbulence model adopted was the Shear Stress Transport (SST). Eight operating points were simulated for each rotation. The simulation provided the characteristic curves, pressure distribution, and total and static pressure at the inlet and the outlet of the impeller. The degree of reaction was calculated. The results were compared by application of affinity laws, and showed agreement with them. The results also showed that the degree of reaction increased with increasing flow rate, and it was coherent with the backward curved blade impeller. The simulations show that the energy portions that make up the total energy transferred by the impeller agree with the affinity laws.

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“…For example, L. Minakov et al [7] performed numerical simulation of the flow in a Francis turbine at startup condition. Zhao et al [8] conducted the steady and unsteady simulations of the pressure fluctuations in a pump-turbine with the SAS SST-CC turbulence model. Although the flow excitation characteristics in hydraulic turbine can be studied by the numerical methods, the researches have still need to be verified by the experiments.…”

Section: Introductionmentioning

confidence: 99%

An on-line monitoring method for the flow excitation in francis hydraulic turbine based on dynamics

Li¹,

Zhang²,

Liu³

et al. 2022

J. vibroeng.

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During the operation of hydraulic turbine, the vibration often exceeds the standard due to flow excitation, which affects the safe and stable operation of the hydraulic turbine. In this paper, an on-line monitoring method for the flow excitation in Francis hydraulic turbine is proposed based on the dynamic characteristics of Francis hydraulic turbine. Firstly, based on the flow excitation characteristics in Francis hydraulic turbine and the dynamic equation of main shaft system, the internal relationships between the dynamic response of turbine bearing and the flow excitation in the Francis hydraulic turbine are clarified. Secondly, according to these relationships, a method based on wavelet transform (WT), particle swarm optimization (PSO), and variational mode decomposition (VMD) is proposed for extracting the flow excitation features in Francis hydraulic turbine. Then, by this method, the flow excitation features are acquired. Based on the obtained flow excitation features, the flow excitation can be monitored on-line. Finally, the proposed on-line monitoring method for the flow excitation in Francis hydraulic turbine is verified by experiments. Based on the results, the flow excitation components in the signal extracted by this method are about 35 % more than those extracted by the previous methods. The results show that the on-line monitoring method proposed in this paper is convenient and effective.

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Numerical analysis of non-axisymmetric flow characteristic for a pump-turbine impeller at pump off-design condition

Cited by 34 publications

References 21 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

Comparison between CFD simulation and affinity laws and analysis of the degree of reaction.

An on-line monitoring method for the flow excitation in francis hydraulic turbine based on dynamics

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