Pressure Analysis in the Draft Tube of a Pump-Turbine under Steady and Transient Conditions

Yang, Jing; Lv, Yue; Liu, Dianhai; Wang, Zhengwei

doi:10.3390/en14164732

Cited by 10 publications

(4 citation statements)

References 16 publications

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“…Ardizzon et al (2016) simulated the low-frequency components caused by the rotating stall phenomenon at low flow rates and found that the draft tube flow-state change is significant when the operating load is small. The vortex rope rotation frequency is generally 1/3-1/5 of the rotation frequency (Wang et al, 2017;Yang et al, 2021). Guo et al (2021) found that the smaller the guide vane opening, the more disordered the vortex generated in the mixed-flow turbine, thus affecting the efficient and stable operation of the turbine.…”

Section: Introductionmentioning

confidence: 99%

Effect of wave disturbance on the fluid dynamics of the pump turbine in a seawater pumped storage hydroplant

Wang

Song

et al. 2023

Front. Earth Sci.

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Compared with conventional pumped-storage hydroplants, seawater pumped-storage hydroplants are constructed in a complex marine environment. The wave disturbance may affect the safety operation of the pump turbine in the seawater pumped hydroplant via affecting the level of the free water surface. To explore the effect of wave disturbance on the operation of the pump turbine in a seawater pumped-storage hydroplant, assuming that the wave disturbance follows a sine function, on the basis of Airy’s micro-amplitude wave theory and the comprehensive characteristic curve of a pump turbine, we use sliding grid technology and the SST k–ω turbulence model to simulate the dynamics of fluid in a full-flow channel. In this study, the unsteady flow field, Q-criterion vorticity, relative pressure pulsation amplitude, and frequency of pressure pulsation are analyzed to determine the internal flow field and pressure pulsation under different wave disturbance conditions and operating loads. The results show that both the pressure pulsation in the pump turbine and its frequency domain are affected by the wave disturbance. In addition, the turbulent flow with a large flow rate tends to produce higher relative pressure pulsation under wave disturbance. Due to the large flow rate and strong static and dynamic interference in the vaneless area, the relative amplitude of the pressure pulsation is significantly affected by wave disturbance. Furthermore, the low-frequency pressure pulsation of the draft tube is superimposed with the wave disturbance frequency.

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Section: Introductionmentioning

confidence: 99%

Effect of wave disturbance on the fluid dynamics of the pump turbine in a seawater pumped storage hydroplant

Wang

Song

et al. 2023

Front. Earth Sci.

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“…Wang and Cavazzini simulated the pressure fluctuation in the S-shaped region of a pump turbine and captured the low-frequency component caused by the rotating stall phenomenon at a low flow rate, which was induced by the rotating stall phenomenon [17,18]. By analyzing the pressure difference between the inner wall of the draft tube center and the inner wall, Yang et al determined the relation between the pressure pulsation values of the inner wall and that of the center wall of a draft tube [19]. Guo et al found that the smaller the opening of the guide vane, the more disordered the vortex generated by each part of the turbine, and the more unstable the flow field.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study of the Internal Fluid Dynamics of Draft Tube in Seawater Pumped Storage Hydropower Plant

Wang

Meng

et al. 2023

Sustainability

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Pumped storage hydropower plants are renewable energy systems that are effective in saving energy and solving electricity peak-on shortage. Seawater pumped storage hydropower plants are a novel type of pumped storage hydropower plant specifically supplying electric power for ocean islands with the support of solar energy and wind energy. Compared with traditional pumped storage hydropower plants that are constructed on the mainland, seawater pumped storage hydropower plants should take the influence of the complex marine environment, such as extreme waves and winds, into consideration. Taking the characteristics of waves near islands in the East China Sea as an example, we explored the transient hydraulic characteristics in the draft tube of a pump turbine under wave disturbance using a sliding grid interface and the detached eddy simulation (DES) turbulence model. By analyzing the characteristics of unsteady flow in the draft tube, the vortex characteristics under the Q criterion, the frequency characteristics of the pressure pulsation, the evolution law of the internal fluid, and the propagation law of the pressure pulsation were explored. For the situation without wave disturbance, an obvious eccentric vortex in the straight cone section of the draft tube was observed in the case where the opening of the guide vane was small. With the increase in the opening of the guide vane, the eccentric vortex gradually dissipated. For the situation with wave disturbance, the main frequency of the draft tube equaled the frequency of the wave disturbance, the maximum pressure pulsation at the selected monitoring points increased 5 to 15 times, and the superposition of the wave pressure pulsation signals and the draft tube pressure pulsation produced more low-frequency, high-amplitude pressure pulsation signals. Even though the pressure pulsation frequency spectrum varied a lot, the frequency domain of the pressure pulsation without wave disturbance still existed. In addition, the wave disturbance merely varied with the pressure of the draft tube. The influence of wave disturbance on the pressure distribution in the draft tube was relatively small. The results can provide a reference for the operation of seawater pumped storage hydropower plants.

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“…Zhao et al [18] studied the stability performance of PSH generation systems during the transition from condensing to generating mode, developed a mathematical model to describe this dynamic transition process, and effectively predicted the dynamic response of the system parameters. Finally, Yang et al [19] studied the relationship between the pressure pulsation value in the center of the pump-turbine draft tube and the wall pressure pulsation value using the CFD method. The study provided the critical value of the wall pressure pulsation when cavitation occurred, providing a reference for determining the cavitation phenomenon using the wall pressure pulsation value in practical engineering.…”

Section: Introductionmentioning

confidence: 99%

Research on Energy Loss Characteristics of Pump-Turbine during Abnormal Shutdown

Deng¹,

Xu²,

Li³

et al. 2022

Processes

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Pumped-storage hydropower (PSH) stations are an efficient emission-free technology to balance renewable energy generation instabilities. The pump-turbine is a core component of PSH stations requiring frequent start-up, shutdown, and working conditions for regulation tasks, making it prone to instabilities. Based on entropy production theory and vortex dynamics, we analyzed the energy loss characteristics for three working conditions of the pump, pump brake, and turbine when shutting down the pump-turbine. The results showed that the entropy production and vorticity of the spiral casing and draft tube remain almost constant, while the entropy production and vorticity of the runner region substantially change from the late pump braking to the late turbine condition. The entropy production and vorticity are derived from the guide vane transitioning to the runner flow channel through the vaneless space. The change law of energy loss through entropy production agrees with the change law of internal flow turbulence through vorticity. The entropy production analysis can quantify the energy loss and mark its location, while the vorticity analysis can quantify the degree of flow disturbance and show its location. The entropy production theory and vortex dynamics combination provide insights into the connection between undesirable flow phenomena and energy loss.

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Pressure Analysis in the Draft Tube of a Pump-Turbine under Steady and Transient Conditions

Cited by 10 publications

References 16 publications

Effect of wave disturbance on the fluid dynamics of the pump turbine in a seawater pumped storage hydroplant

Effect of wave disturbance on the fluid dynamics of the pump turbine in a seawater pumped storage hydroplant

Numerical Study of the Internal Fluid Dynamics of Draft Tube in Seawater Pumped Storage Hydropower Plant

Research on Energy Loss Characteristics of Pump-Turbine during Abnormal Shutdown

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