Investigations on Pressure Fluctuations in the S-Shaped Region of a Pump–Turbine

Wang, Hongjie; Wang, Jianpeng; Gong, Ruzhi; Shang, Chaoying; Li, Deyou; Wei, Xianzhu

doi:10.3390/en14206683

Cited by 6 publications

(4 citation statements)

References 23 publications

(33 reference statements)

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“…They also found that the dominant frequency of pressure pulsation in the vaneless area was the high-frequency component of the vane frequency, while the dominant frequency of the draft tube vortex zone was lower [24]. Researchers [25][26][27][28][29] considered that the internal flow characteristics were closely related to pressure pulsation, and the reflux and vortex generated in the flow could lead to violent pressure pulsation.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Pressure Fluctuation of a Pump-Turbine with Splitter Blades on Small Opening in Turbine Mode

Xiao,

Chen,

Ren

et al. 2024

Energies

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Unstable flow in a pump-turbine can cause pressure pulsation, and the resulting vibration deteriorates the stability and operating safety of the unit. This study conducted three-dimensional numerical calculations of the overall flow passage of a pump-turbine with splitter blades under the small guide vane opening, and the unsteady flow characteristics of the turbine were investigated. The results showed that the pressure fluctuation was more severe at lower head operating conditions with lower efficiency, especially in the vaneless area (the runner blade passages). Under the lower head condition, the proportion of 12 times the rotational frequency (12 f/fn) increased in the vaneless area, and the amplitude of 1 f/fn as well as 2 f/fn became larger in the runner blade channel, with more space occupied by vortices and reflux areas. A spiral vortex rope formed in the draft tube, increasing the proportion of 0.4 f/fn and 0.7 f/fn pressure pulses.

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Section: Introductionmentioning

confidence: 99%

Analysis of Pressure Fluctuation of a Pump-Turbine with Splitter Blades on Small Opening in Turbine Mode

Xiao,

Chen,

Ren

et al. 2024

Energies

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“…For the study of S-shaped region, Wang et al [4] studied the pressure pulsation mechanism under turbine brake conditions and reverse pump conditions, and found that there are high amplitude and low frequency pressure pulsations under these two conditions, which are caused by reflux and vortex in vaneless space respectively. Kinoue et al [5] studied the start-up process of low specific speed pump turbines and found that the internal flow pattern in S-shaped region was very disordered.…”

Section: Introductionmentioning

confidence: 99%

Study on S-shaped region of pump turbine based on Omega vortex analysis method and entropy production theory

Li,

Zeng,

Wang

et al. 2023

International Journal of Agricultural and Biological Engineering

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In order to comprehensively analyze the operation instability of the pump turbine S-shaped region, this paper uses DDES turbulence model to calculate the model pump turbine from the perspective of the evolution law of runner vortex and draft tube vortex rope and entropy production rate, combined with experiments. The results show that the numerical simulation is in good agreement with the experiment. Omega vortex analysis method is more accurate than other vortex recognition methods because it is not affected by the threshold value. The vortices at the runner region under the runaway condition and the turbine brake condition develop towards the vaneless space and the blade pressure surface respectively, which will cause the flow obstruction and blade separation. The overall vorticity of the reverse pump condition is the largest. The vortex rope of the draft tube under runaway and turbine brake conditions is columnar in shape and has very high rotational strength. The vortex rope under reverse pump conditions is prone to fracture and form scattered vortices, impeding the normal movement of the fluid. The entropy production rate of the spanwise surface near the upper ring and the lower crown is greater than the middle spanwise surface due to the boundary layer effect. And the energy dissipation in the runner under reverse pump conditions is characterized by high at both ends of the runner and low in the middle. The energy dissipation near the wall of the straight cone section of the draft tube is large due to the squeezing effect of the vortex rope on the flow.

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“…For a large amount of high residual pressure liquids in industries such as petrochemical, petroleum processing, seawater desalination, and steel metallurgy, pressure-reducing valves or orifice plates are usually used to reduce these fluids to the required low pressure, which means that large pressure energy in fluids is wasted [1][2][3][4][5][6]. To reduce energy waste, some enterprises use hydraulic turbine devices to recycle and utilize pressure energy [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Influence Analysis of Runner Inlet Diameter of Hydraulic Turbine in Turbine Mode with Ultra-Low Specific Speed

Chen,

Zheng,

Zhang

et al. 2023

Energies

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The hydraulic turbine in turbine mode (HTTM) with an ultra-low specific speed (HTTM-ULSS) has the advantages of a simplified structure, high efficiency, and good stability and has great application value in the industry. However, the influence of the runner inlet diameter (D1) on the performance of HTTM-ULSS has not yet been fully studied. Therefore, the three-dimensional models of Francis runners were established in the ultra-low specific speed range by examining D1 = 0.49 m, 0.5 m, and 0.51 m, and the two-stage hydraulic turbine models were constructed with flow passage components. Then, internal flow and energy characteristics were calculated using Fluent 16.0 software. Further, the influence of D1 on HTTM performance was studied by comparing numerical simulation results. The results show that the water head of the HTTM-ULSS can reach 540.87 m when D1 = 0.51 m, showing its powerful ability to recover the pressure energy in high-pressure water. Moreover, the head and efficiency are closely related to D1; when D1 increases, the circulation at the runner inlet increases, resulting in an enhancement in the ability to recover the water head and decreases in efficiency and in the operating range of the high-efficiency zone; with D1 increasing, the flow pattern inside the runner becomes better, but the high-pressure area of the blade increases. When selecting the D1, attention should not only be paid to the ability to recover the water head but also to the pressure of the runner blades and the internal water flow pattern.

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Investigations on Pressure Fluctuations in the S-Shaped Region of a Pump–Turbine

Cited by 6 publications

References 23 publications

Analysis of Pressure Fluctuation of a Pump-Turbine with Splitter Blades on Small Opening in Turbine Mode

Analysis of Pressure Fluctuation of a Pump-Turbine with Splitter Blades on Small Opening in Turbine Mode

Study on S-shaped region of pump turbine based on Omega vortex analysis method and entropy production theory

Influence Analysis of Runner Inlet Diameter of Hydraulic Turbine in Turbine Mode with Ultra-Low Specific Speed

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