Dynamic Simulation in Guide Vane Opening Process of a Pump-Turbine in Pump Mode

Han, Lina; Wang, H. J.; Gao, Yang; Li, Deyou; Gong, Ruzhi; Wei, Xianzhu

doi:10.18869/acadpub.jafm.73.242.26983

Cited by 7 publications

(4 citation statements)

References 16 publications

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“…Su et al 28 used STFT to analyze the pressure pulsation signals in different components of the pump turbine. Han et al 29 used STFT to analyze the pressure pulsation signal in the process of guide vane movement of the pump turbine in pump mode. It was found that the main pressure pulsation frequency came from the blade passing frequency and its harmonic frequency.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation on the transient gas–liquid flow in the rapid switching process of pump turbine

Zhang

Zhu

Xiao

et al. 2023

Energy Science & Engineering

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The frequent switching of pump mode and turbine mode of the pump turbine leads to frequent transient phenomena. To ensure the safe and stable operation of the unit, a detailed study on the exhaust and pressurization process when the unit switches from turbine mode to the pump mode has been carried out. Based on the Shear Stress Transfer model (SST) k–ω turbulent model, the numerical simulations are processed both in a steady and unsteady state. The visualization results of gas–liquid two phases distribution in the dynamic process of exhaust and pressurization are given, and the characteristic references of each stage are also carried out. The transient characteristics of the torque, axial, and radial force of the runner and guide vane are analyzed by combining the short‐time Fourier transform. The results show that the main frequencies in this transient process are the blade passing frequency and its harmonic frequency. This process also presents a high amplitude band at all frequency values, which may be caused by the entrainment and centrifugal action of the runner on the free liquid surface.

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Section: Introductionmentioning

confidence: 99%

Numerical investigation on the transient gas–liquid flow in the rapid switching process of pump turbine

Zhang

Zhu

Xiao

et al. 2023

Energy Science & Engineering

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“…The vortex core region also reached the maximum area and number at a moment during the start-up process. Han et al [25] numerically studied the transient characteristics of pump turbines under pumping conditions with different guide vane openings based on the dynamic mesh technology. Compared with the constant guide vane opening condition, the flow in the pump was more unstable under moving guide vane conditions, and there were complex vortex structures and flow blocking phenomena with small guide vane openings.…”

Section: Introductionmentioning

confidence: 99%

Numerical Modeling of the Hydrodynamic Performance of Slanted Axial-Flow Urban Drainage Pumps at Shut-Off Condition

et al. 2022

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Increasing extreme rainfall events caused by global climate change have had a significant impact on urban drainage systems. As a critical component of a pumping station, a large-scale slanted axial-flow pump (SAFP) featuring high specific speed plays a critical role in mitigating urban flooding and waterlogging. In this study, to reveal the transient characteristics of a SAFP at shut-off conditions, a computational fluid dynamics (CFD) based approach with dynamic mesh was proposed. Multiple shut-off conditions with various shut-down speeds of the sluice gate (SG) were modeled. Our analysis demonstrated that both the shut-off conditions and the slanted structure have conspicuous impacts on the hydrodynamic performance of a SAFP. Reducing the shut-down speed leads to a greater reverse flow rate and higher runner speed. The water hammer effect was simulated with different shut-down speeds, increasing the water head by 5.07–10.42 m, the axial force by 163.46–297.06 kN∙m, and the axial moment by 116.05–224.01 kN∙m. Compared with the axial direction, moments in the radial directions were found with more obvious oscillation as a result of stronger rotor–stator interaction. Due to the gravitational effect of the slanted structure, the fluctuation of the runner in vertical direction presented an off-axis characteristic compared with the horizontal one. As the SG speed increased, pressure fluctuations gradually decreased at various locations across the SAFP.

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“…At present, numerical simulation technology has been widely used in the prediction of turbine pressure fluctuations (Iovănel et al 2019). Dynamic mesh methodology was used for simulations in which GVO (Guide Vane Opening) of a pumpturbine from 9mm to 26mm by Han et al (2017). Yan et al (2010) investigated the influence of water compressibility on pressure fluctuations induced by rotor-stator interaction (RSI) in hydraulic machinery, using the commercial CFD solver ANSYS-CFX.…”

Section: Introductionmentioning

confidence: 99%

Effect of Guide Vane Pitch Circle Diameter on Pressure Fluctuation in Vaneless Zone of Francis Turbine

2020

JAFM

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In a Francis turbine, the guide vanes are arranged in the direction of flow behind the stay vanes. And as it is generally believed that the outlet angle of water after it flows through the spiral case and stay vanes is fixed, the flow and flow circulation are altered by changing the opening of the guide vanes so as to change the output of the turbine. The rotor-stator interaction effect induced by the interaction between the guide vanes and the runner of the Francis turbine was one of the main causes of the pressure fluctuation. The effect of guide vanes placement on pressure fluctuation in vaneless zone of Francis turbine was studied. In this study, the commercial software ANSYS CFX16.0 was used for the three-dimensional numerical simulation of the whole flow passage of a Francis turbine model in a power station. The turbulence model used in the calculation was the shear stress transport (SST) model. The independence between the total number of computational meshes and the timestep was verified to ensure the reliability of the calculation results. Five schemes with different diameters of the guide vanes distribution circle were proposed including D0/D1 (guide vane pitch circle diameter /diameter of runner inlet) equaling to 1.119, 1.128, 1.138, 1.144, and 1.15. The steady calculation results showed that, when the turbine was operating under the design condition, D0/D1 increased from 1.119 to 1.15, and the turbine efficiency and output showed a monotonically increasing trend, with the efficiency increased by 0.17 percentage point and output increased by 3.91kw. Twenty monitoring points were set up in the vaneless zone between the guide vanes and the runner to collect pressure fluctuation signals in the vaneless zone. By analyzing the characteristics of unsteady pressure fluctuations in the vaneless zone under design conditions of the five schemes, the optimal position of the guide vanes was determined. The numerical results showed that the pressure fluctuation amplitude at monitoring points in the same axial direction increased gradually from the top cover to the bottom ring. When the unit operated under the design conditions, by increasing the guide vane pitch circle diameter, the rotor-stator interaction between the guide vanes and the runner domain was weakened, and the pressure fluctuation amplitude in the vaneless zone between the guide vanes and the runner was reduced, thereby the stability of unit operation was improved.

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Dynamic Simulation in Guide Vane Opening Process of a Pump-Turbine in Pump Mode

Cited by 7 publications

References 16 publications

Numerical investigation on the transient gas–liquid flow in the rapid switching process of pump turbine

Numerical investigation on the transient gas–liquid flow in the rapid switching process of pump turbine

Numerical Modeling of the Hydrodynamic Performance of Slanted Axial-Flow Urban Drainage Pumps at Shut-Off Condition

Effect of Guide Vane Pitch Circle Diameter on Pressure Fluctuation in Vaneless Zone of Francis Turbine

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