Prediction of hydro-acoustic resonances in hydropower plants by a new approach based on the concept of swirl number

Favrel, Arthur; Pereira, João Gomes; Landry, Christian R.; Alligné, Sébastien; Andolfatto, Loïc; Nicolet, Christophe; Avellan, François

doi:10.1080/00221686.2018.1555556

Cited by 14 publications

(8 citation statements)

References 19 publications

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“…Important variations in head would require the selected Francis turbines to operate in part-load and full conditions, which can cause several vibrations and induce dangerous cavitation phenomena [63][64][65]. Figure 11 illustrates the three phases in which three turbines are operating until the lower load limit is reached, then only two turbines, and, eventually, a single Francis turbine is in function.…”

Section: Turbomachinery Selectionmentioning

confidence: 99%

“…Therefore, the first hypothesis of this scenario is to shut down the first turbine (turbine I as depicted in Figure 8) after a variation of ∆H = 105 m to the gross head of the power plant, which corresponds to a variation in the available head of each turbine equal to the 26% of the nominal head. The turbines would operate in part-load condition, but only for a limited time, about 900 s, which corresponds to the 6% of the operating time and this is not critical for the machine safety [64]. After the stop and by-pass of the turbine I, the turbines II and III would experience an increase of the head and discharge allowing the machines to leave the part-load condition until the second horizontal gallery is reached, which corresponds to the nominal operating condition for both machines.…”

Section: Turbomachinery Selectionmentioning

confidence: 99%

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Underground Pumped Storage Hydropower Case Studies in Belgium: Perspectives and Challenges

et al. 2020

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To avoid the geographical and topographical prerequisites of the conventional pumped hydro energy storage, the use of underground cavities as water reservoirs allows countries without steep topography, such as Belgium, to increase the potential of the energy storage capacity. Belgium abounds in disused mines and quarries convertible into water basins. In this article, two Belgian case studies are presented and discussed for their singularity. A slate quarry in Martelange is discussed in technical aspects proposing three operating scenarios. Moreover, a preliminary economic analysis of the underground pumped storage system and a greenhouse gas emission evaluation for the storage system’s lifetime are presented. The analysis for a 100 MW power plant estimates a total initial investment of over 12 million euros and two million of CO2 avoided over its lifetime. This article also proposes the use of the coal mine 500 m deep of Pérronnes-lez-Binche. The mine representation discussed here offers a high energy capacity, but the substantial head drop (from about 500 to 200 m) challenges the selection of the hydraulic turbomachinery. A 1D simulation computed in SIMSEN draws out the behaviour of the unusual hydraulic configuration of turbines in series.

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Section: Turbomachinery Selectionmentioning

confidence: 99%

Section: Turbomachinery Selectionmentioning

confidence: 99%

Underground Pumped Storage Hydropower Case Studies in Belgium: Perspectives and Challenges

et al. 2020

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“…The operation at PL resonance is undesirable and should be avoided for as long as possible. Favrel et al [7,23,24,25,26] studied this phenomenon in detail for the reduced-scale model of the Francis turbine selected for this study.…”

Section: Operating Regimes In Francis Turbinesmentioning

confidence: 99%

“…Cavitation, turbulence or vortex rope are some of the hydraulic phenomena that usually appear in Francis turbines. In addition, those phenomena can lead to hydro-acoustic or mechanical resonances [7,8,9]. The flow-rate is easily controllable in Francis turbines by changing the angle of the guide vanes, however, the head is given by upstream and downstream water levels.…”

Section: Introductionmentioning

confidence: 99%

Detection of Hydraulic Phenomena in Francis Turbines with Different Sensors

Valentín

Presas

Valero

et al. 2019

Sensors

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Nowadays, hydropower is demanded to provide flexibility and fast response into the electrical grid in order to compensate the non-constant electricity generation of other renewable sources. Hydraulic turbines are therefore demanded to work under off-design conditions more frequently, where different complex hydraulic phenomena appear, affecting the machine stability as well as reducing the useful life of its components. Hence, it is desirable to detect in real-time these hydraulic phenomena to assess the operation of the machine. In this paper, a large medium-head Francis turbine was selected for this purpose. This prototype is instrumented with several sensors such as accelerometers, proximity probes, strain gauges, pressure sensors and a microphone. Results presented in this paper permit knowing which hydraulic phenomenon is detected with every sensor and which signal analysis technique is necessary to use. With this information, monitoring systems can be optimized with the most convenient sensors, locations and signal analysis techniques.

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“…This paper suggested that the only way to successfully solve the instability problem is to consider the generation and pumping modes simultaneously, and insist that a lot of research is still needed for that. Favrel et al [15] investigated the prediction of hydro-acoustic resonances by a new approach based on the concept of swirl numbers. The hydro-acoustic parameters of the draft-tube cavitation flow under off-design conditions were determined by using onedimensional numerical models.…”

Section: Introductionmentioning

confidence: 99%

A Comparative Study of the Scale Effect on the S-Shaped Characteristics of a Pump-Turbine Unit

et al. 2021

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S-shaped characteristics in turbine mode are prone to instabilities in associated transient processes. A single value of the speed factor corresponds to multiple values of the discharge factor, having the possibility of changing the operating point among the turbine, turbine brake, and reverse pump modes. Because of this characteristic, the S-shaped curves induce instability in transient processes. Understanding the hydraulic behavior of a turbine on the four-quadrant characteristic is important since it provides detailed performance information through the whole discharge range of the turbine. This study was numerically and experimentally investigated the scale effect on the S-shaped characteristics in the turbine transition region. The four-quadrant characteristic curves (full- and laboratory-scale) in the turbine mode were predicted by numerical simulations. To verify the predicted results, a laboratory-scale experiment was performed in the turbine, turbine brake, and reverse pump modes. Although the full-scale experiment was performed in the normal operating head range, the scale effect can be validated by comparing steady operating points between the two models. Based on the verified results, the internal flow and pressure pulsation characteristics were determined at the operating point in a specific transition region.

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Prediction of hydro-acoustic resonances in hydropower plants by a new approach based on the concept of swirl number

Cited by 14 publications

References 19 publications

Underground Pumped Storage Hydropower Case Studies in Belgium: Perspectives and Challenges

Underground Pumped Storage Hydropower Case Studies in Belgium: Perspectives and Challenges

Detection of Hydraulic Phenomena in Francis Turbines with Different Sensors

A Comparative Study of the Scale Effect on the S-Shaped Characteristics of a Pump-Turbine Unit

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