Experimental investigation on characteristics of cavitation-induced vibration on the runner of a bulb turbine

Feng, Jia; Liu, Boxing; Luo, Xingqi; Zhu, Guangming; Li, Kang; Wu, Guangkuan

doi:10.1016/j.ymssp.2023.110097

Cited by 12 publications

(3 citation statements)

References 26 publications

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“…The use of VMD for vibration signals at V1 and V2 yields 4 signal components with varying main frequencies. For the wideband vibration signal x(t), the RMS can reflect the energy of the signal [30]. RMS of the vibration signal x(t) is calculated as follows: As shown in Fig.…”

Section: Analysis Of Cavitation-induced Vibrationmentioning

confidence: 99%

Correlation analysis of cavitation-induced pressure pulsation and vibration in a bulb turbine

Li,

Feng,

Zhu

et al. 2023

J Hydrodyn

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Cavitation is one of the primary factors leading to the destabilisation of tubular turbines. To enhance their stability, this study examines the effects of runner cavitation on draft tube pressure fluctuations and vibration in tubular turbines through experimental methods. With varying cavitation coefficients, a synchronous test system, including a high-speed camera, vibration acceleration sensors and pressure pulsation sensors, is applied to obtain cavitation images of the runner, and vibration and internal fluid pressure pulsation data of the draft tube. The results show that the correlated component of pressure pulsation signals during the cavitation process is the synchronous pressure pulsation of 16 fn. With the development of cavitation, the amplitude of synchronous pressure pulsation increases first and then decreases. Cavitation enhances the high-frequency vibration of the runner chamber wall and the RMS of the vertical vibration component IMF3 and the horizontal vibration components IMF2 and IMF4 are linearly negatively correlated with the cavitation coefficient. The associated component between cavitation-induced vibration and pressure pulsation signal is 16 fn and its harmonics. In the process of cavitation, pressure pulsation plays a leading role in vibration.

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Section: Analysis Of Cavitation-induced Vibrationmentioning

confidence: 99%

Correlation analysis of cavitation-induced pressure pulsation and vibration in a bulb turbine

Li,

Feng,

Zhu

et al. 2023

J Hydrodyn

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show abstract

“…Luo [8] performed simulations for a tidal bulb turbine to find out the relationship between pressure pulsations, operation mode and water head, and the results indicated that the intensity of dominant frequency was influenced by gravity effect depending on the specific operation mode and location while the amplitudes was ruled by head change in ebb and flood modes. In case of condition conversion, Additionally, Chen and Feng et al [9,10] conducted numerical method to investigate the transient characteristics of load injection and runaway process as well as reveal the variation of discharge, torque and axial force with rotation speed and opening degree during steady state and transient process. On the other hand, some researchers [11,12] presented hydro-dynamic properties and fatigue characteristics analysis in prototype bulb turbines combining with CFD and FEM to find out possible causes of the structure failure and bring out prevention and treatment measurements, which can be of great help to maintain the stability and reliability.…”

Section: Introductionmentioning

confidence: 99%

Investigation on hydraulic characteristics of a model and prototype bulb turbine based on similarity criteria

Zhou,

Luo,

Wang

et al. 2024

J. Phys.: Conf. Ser.

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From the perspective of the world hydropower utilization trend, the medium and high head hydraulic resources are gradually decreasing, and along with much more attention to the ecological environment and land resource constraints, low-head hydropower plants have been becoming particularly prevalent. Benefit from compact structure, less investment, high capacity and wide operation range, bulb tubular turbines have come up to be the optimal option for the development and exploitation of low-head energy resources and been widely applied. In this paper, based on measurement data and CFD simulation results of model and prototype, scale effect which derived from similarity law was picked up to investigate the hydraulic performance and operating properties. Through comparison and analysis, it’s concluded that distinct from high-head application similarity conversion turns out to be more complicated for bulb turbines in case of flow characteristics, and it’s recommended that this conversion be further modified considering different boundary conditions. Such achievements will be of great help to look into the mechanism of ratio effect and accelerate research progress.

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“…It can gradually develop into a multiphase, multiscale state that includes small-scale cavity growth and collapse behavior, as well as large-scale cavitation evolution behavior. Meanwhile, cavitation typically results in vibration [1] , erosion [2] , and noise [3] , which can significantly impede the advancement of technology and equipment in high-speed hydrodynamic fields such as underwater weapons, underwater launch, aerospace, fluid machinery, and national defense. Therefore, accurately capturing the bubble structure at various scales and analyzing the transformation Based on high-speed water tunnels and high-speed camera technology, numerous experimental studies have shown that cavitation patterns gradually develop from incipient to sheet, cloud, and supercavitation as the Reynolds number increases or the cavitation number decreases.…”

Section: Introductionmentioning

confidence: 99%

Multi-scale characteristics investigation of sheet/cloud cavitation

Tian

et al. 2023

IOP Conf. Ser.: Mater. Sci. Eng.

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Sheet and cloud cavitation involve the formation of large-scale cavities and microbubbles across a wide range of length scales. In this study, a two-way coupling Eulerian-Lagrangian algorithm was utilized to simulate the cavitating flow around a NACA66 hydrofoil at an incidence of 8 degrees and a cavitation number of 1.2. The large eddy simulation (LES) and volume of fraction (VOF) methods are used to capture the large scale vapor structures in Eulerian frame. Meanwhile, the discrete bubble model (DBM) and simplified Rayleigh-Plesset equation are implied to solve the dynamic of Lagrangian microbubbles smaller than local grid scale. The results indicate that large-scale cavities are periodically shed downstream, influenced alternatively by the re-entrant jet and shock wave mechanisms, resulting in periodic variations of both the number and Sauter mean diameter of microscale bubbles. During the quasi-periodic evolution process of sheet/cloud cavitation, the microbubbles scatter around the large scale cavities where have strong turbulence intensity and high vorticity, and the probability density function of discrete bubble diameter similarly conforms to Gamma distribution with the dominant bubble size between 30 and 70μm. During the growth of an attached cavity, the number density of bubbles follows a power-law scaling with a value of -5/3 on radius. For the other stages, the bubble size spectrum of smaller microbubbles exhibits a -2/3 power-law scaling when the diameter of the microbubble is less than 200 μm. For larger bubbles with a diameter greater than 300 μm, the bubble density is proportional to the bubble radius to the power of -6.

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Experimental investigation on characteristics of cavitation-induced vibration on the runner of a bulb turbine

Cited by 12 publications

References 26 publications

Correlation analysis of cavitation-induced pressure pulsation and vibration in a bulb turbine

Correlation analysis of cavitation-induced pressure pulsation and vibration in a bulb turbine

Investigation on hydraulic characteristics of a model and prototype bulb turbine based on similarity criteria

Multi-scale characteristics investigation of sheet/cloud cavitation

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