Review of hydrodynamics instabilities in Francis turbine during off-design and transient operations

Goyal, Rahul; Gandhi, Bhupendra K.

doi:10.1016/j.renene.2017.10.012

Cited by 121 publications

(64 citation statements)

References 48 publications

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“…This sacrifice is already recognized in more frequent down times of turbines [6,7]. Furthermore, Goyal et al concluded from laboratory testing that each start and stop procedure causes a fatigue damage equal to 15–20 h of regular operation [8]. Operation in off-design operation points not only causes fatigue to the turbine, the disturbances and stress fluctuations transmit further into the bearing structure, to the first and second stage concretes surrounding the turbine, penstock, spiral, and further [9].…”

Section: Introductionmentioning

confidence: 99%

On the Application of Laser Vibrometry to Perform Structural Health Monitoring in Non-Stationary Conditions of a Hydropower Dam

Klun

Zupan

Lopatič

et al. 2019

Sensors

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This paper presents the first application of the Laser Doppler Vibrometer (LDV) in non-stationary conditions within a hydropower plant powerhouse. The aim of this research is to develop a methodology to include non-contact vibration monitoring as part of structural health monitoring of concrete dams. We have performed in-situ structural vibration measurements on the run-of-the-river Brežice dam in Slovenia during the start-up tests and regular operation. In recent decades, the rapid development of laser measurement technology has provided powerful methods for a variety of measuring tasks. Despite these recent developments, the use of lasers for measuring has been limited to sites provided with stationary conditions. This paper explains the elimination of pseudo-vibration and measurement noise inherent in the non-stationary conditions of the site. Upon removal of the noise, fatigue of the different structural elements of the powerhouse could be identified if significant changes over time are observed in the eigenfrequencies. The use of laser technology is to complement the regular monitoring activities on large dams, since observation and analysis of integrity parameters provide indispensable information for decision making and maintaining good structural health of ageing dams.

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Section: Introductionmentioning

confidence: 99%

On the Application of Laser Vibrometry to Perform Structural Health Monitoring in Non-Stationary Conditions of a Hydropower Dam

Klun

Zupan

Lopatič

et al. 2019

Sensors

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“…However to provide those services, hydraulic machines have to operate under off-design conditions and further deal with transient behavior and fast response times [1]. Regarding Francis turbines, this leads to the occurrence of flow phenomena such as draft tube and channel vortices as well as vortex shedding and cavitation [2,3]. Thereby, strong pressure pulsations interact with the runner and other parts of the machine unit [4].…”

Section: Introductionmentioning

confidence: 99%

Investigation on the Impact of Air Admission in a Prototype Francis Turbine at Low-Load Operation

2019

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Due to significant changes in the energy system, hydraulic turbines are required to operate over a wide power range. In particular, older turbines which are not designed for these environments will suffer under off-design conditions. In order to evaluate whether or not such a turbine could fulfill the new requirements of the energy market, a study about the behavior of a prototype plant in low-load operation is presented. Therefore, prototype site measurements are performed to determine the most damaging operating point by means of acceleration sensors and pressure transducers. Moreover, unsteady computational fluid dynamics (CFD) simulations considering two-phase flow and two hybrid turbulence models are used to analyze the flow conditions inside the turbine. The resulting pressure pulsations are mapped onto the runner blade to obtain stress and further calculate damage factors. Accordingly, the stresses are compared to those obtained by the strain gauge measurement. Moreover, the influence of active flow control by means of air injection on plant behavior and runner lifetime is discussed as well.

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“…[12][13][14] National Energy Administration issued that 80% of HGS' faults are caused by the vibration of the hydraulic-mechanic-electric components. [12][13][14] National Energy Administration issued that 80% of HGS' faults are caused by the vibration of the hydraulic-mechanic-electric components.…”

Section: Introductionmentioning

confidence: 99%

“…Faults in the hydroelectric generation systems (HGS) inevitably result in unexpected safety accidents with enormous maintenance costs. [12][13][14] National Energy Administration issued that 80% of HGS' faults are caused by the vibration of the hydraulic-mechanic-electric components. 15,16 In general, the vibration in the HGS is defined as a drastic reciprocating motion caused by unbalanced forces and uncertain disturbances.…”

Section: Introductionmentioning

confidence: 99%

Bayesian network approach to fault diagnosis of a hydroelectric generation system

Pang

et al. 2019

Energy Science & Engineering

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This study focuses on the fault diagnosis of a hydroelectric generation system with hydraulic‐mechanical‐electric structures. To achieve this analysis, a methodology combining Bayesian network approach and fault diagnosis expert system is presented, which enables the time‐based maintenance to transform to the condition‐based maintenance. First, fault types and the associated fault characteristics of the generation system are extensively analyzed to establish a precise Bayesian network. Then, the Noisy‐Or modeling approach is used to implement the fault diagnosis expert system, which not only reduces node computations without severe information loss but also eliminates the data dependency. Some typical applications are proposed to fully show the methodology capability of the fault diagnosis of the hydroelectric generation system.

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Review of hydrodynamics instabilities in Francis turbine during off-design and transient operations

Cited by 121 publications

References 48 publications

On the Application of Laser Vibrometry to Perform Structural Health Monitoring in Non-Stationary Conditions of a Hydropower Dam

On the Application of Laser Vibrometry to Perform Structural Health Monitoring in Non-Stationary Conditions of a Hydropower Dam

Investigation on the Impact of Air Admission in a Prototype Francis Turbine at Low-Load Operation

Bayesian network approach to fault diagnosis of a hydroelectric generation system

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