Experimental and numerical study of a prototype Francis turbine startup

Unterluggauer, Julian; Sulzgruber, Verena; Doujak, Eduard; Bauer, Christian

doi:10.1016/j.renene.2020.04.156

Cited by 30 publications

(17 citation statements)

References 10 publications

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“…For example, grid sizes of about 6 million cells were used for the investigation of transient processes in the low-load region [30] for hydropower plant 2. In the case of transient processes (e.g., STU), a mesh with approximately 13 million cells [34] was created and for the investigations of air injection and vortex shedding at the trailing edge of the runner, the existing mesh had to be refined again to approximately 37.5 million cells [35].…”

Section: Computational Fluid Dynamics (Cfd)mentioning

confidence: 99%

Fatigue Strength Analysis of a Prototype Francis Turbine in a Multilevel Lifetime Assessment Procedure Part II: Method Application and Numerical Investigation

et al. 2022

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Part I of the publication series addressed the fundamentals of lifetime assessment of prototype Francis turbines. This paper (Part II) focuses on the numerical part of the procedure. The essential steps and requirements shall be presented (background). The starting points for the numerical considerations are the pressure fields of the transient CFD simulations, which are exported per time step and applied to the existing structure via a fluid–structure interaction. That enables a transient mechanical stress calculation to be conducted, resulting in the fatigue analysis of the component to estimate the remaining lifetime. The individual model requirements should be represented accordingly and applied to the prototype facility (method). The results obtained from this application should be discussed and evaluated. It has to be mentioned that the validation of the numerical results will be performed at Part IV of this publication series (results). The present paper will end up discussing the results and conclusions about further data processing (Conclusion).

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Section: Computational Fluid Dynamics (Cfd)mentioning

confidence: 99%

Fatigue Strength Analysis of a Prototype Francis Turbine in a Multilevel Lifetime Assessment Procedure Part II: Method Application and Numerical Investigation

et al. 2022

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“…Swirl intensity, also known as vortex intensity, is used to evaluate the vortex characteristics of the draft tube with or without J-grooves under different vortex conditions. It is the ratio of the axial flux of angular momentum to the axial flux of axial momentum [29]. Swirl intensity is expressed by S num , as shown in Equation (10).…”

Section: Influence Of J-grooves On Swirl Intensitymentioning

confidence: 99%

The Effect of J-Groove on Vortex Suppression and Energy Dissipation in a Draft Tube of Francis Turbine

Luo

Cong

et al. 2022

Energies

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The vortex rope in the draft tube is considered as the major contributor to pressure pulsation at partial load (PL) conditions, which causes the hydro unit to operate unstably. Based on the prototype Francis turbine HLA551-LJ-43 in the laboratory, J-grooves are designed on its conical section in this paper. We used numerical simulation to study the effect of the J-grooves on vortex suppression and energy dissipation in the draft tube. Four typical operating conditions were chosen to analyze the vortex suppression; the corresponding flow ratios Q* are 100%, 82%, 69%, and 53%, respectively. Entropy production theory is used to calculate the energy losses and assess the effect of the J-groove on energy dissipation under part-load conditions. By comparing entropy production, circumferential and axial velocity components, swirl intensity, pressure pulsation, and vortex distribution in a draft tube with and without J-grooves at different operating conditions, it can be concluded that the entropy production on the wall containing a conical section with J-grooves is obviously smaller than that without J-grooves, the effects of J-grooves on reducing circumferential velocity component Vu, pressure pulsation, and weakening vortex intensity and vortex rope in the conical section are obvious, especially at part load and deep part-load operating conditions. Using J-grooves shows better performance on vortex control and energy dissipation in the draft tube of a Francis turbine at partial load conditions.

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“…In recent decades, experimental strain gauges have been significantly improved [26,40,[42][43][44][45]. However, the widespread use of this method as part of a stationary diagnostic system for aging hydraulic units is not available due to serious technical and economic problems:…”

Section: Prospects For Development Of Diagnostic and Prognostic Systemsmentioning

confidence: 99%

Limitations of Modern Diagnostic and Prognostic Systems for a Hydraulic Unit’s Health

Georgievskaia

2021

Eng

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Modern diagnostic systems for the hydraulic unit’s health play an important role in ensuring the reliability and safety of the hydroelectric power plant (HPP). However, they cannot provide timely detection of such dangerous operational defects as fatigue cracks. This article reflects two main reasons for this problem. The first one is a high level of the individuality of hydraulic units, which does not allow the effective use of statistical methods of information processing, including BIG DATA and MACHINE LEARNING technologies. The second is the fundamental impossibility to identify cracks in some key components of hydraulic units only on the basis of data analysis from a standard diagnostic system usually used at the HPP. Developed computational studies on the example of Francis turbines confirmed this. It is proposed to supplement the functionality of standard diagnostic systems with a prognostic block for an individual analytical forecast of the unit’s residual lifetime based on the calculated assessment of fatigue strength. This article presents the developed conceptual diagram and the demonstration version of the proposed analytical predictive system. The comparison of the standard vibration diagnostic system and the proposed solution as a tool for the early detection of cracks in a Francis turbine runner shows some advantages of the proposed approach.

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Experimental and numerical study of a prototype Francis turbine startup

Cited by 30 publications

References 10 publications

Fatigue Strength Analysis of a Prototype Francis Turbine in a Multilevel Lifetime Assessment Procedure Part II: Method Application and Numerical Investigation

Fatigue Strength Analysis of a Prototype Francis Turbine in a Multilevel Lifetime Assessment Procedure Part II: Method Application and Numerical Investigation

The Effect of J-Groove on Vortex Suppression and Energy Dissipation in a Draft Tube of Francis Turbine

Limitations of Modern Diagnostic and Prognostic Systems for a Hydraulic Unit’s Health

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