Failure analysis of a Francis turbine runner

Frunzăverde, Doina; Muntean, Sebastian; Mărginean, Gabriela; Campian, Viorel Constantin; Marșavina, Liviu; Terzi, Radu; Şerban, Viorel Aurel

doi:10.1088/1755-1315/12/1/012115

Cited by 67 publications

(52 citation statements)

References 3 publications

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“…Seven regimes corresponding to the Francis turbine operation were investigated yielding equivalent Von Mises stress distributions on the runner blade. As a general observation all stress levels are below the yield strength of the blade material (T10CuNiCr180), [15].…”

Section: Resultsmentioning

confidence: 87%

“…The failure under fatigue of the runner blades of the Francis turbines [11][12][13] is focused on the region of the weld seems located at the junction between blade-crown and bladeband because those regions present a higher risk to initiate cracks leading to the catastrophic failure under fatigue [14][15][16]. Several authors have investigated only the junctions between the blade-crown and the blade-band considering a simplified geometry of T-joint [17][18][19][20] because of the stress concentration is located in these critical regions.…”

Section: Introductionmentioning

confidence: 99%

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Numerical assessment of stress concentration in Francis runner blade — crown/band junctions

2019

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The paper presents the results of numerical investigation for stress distribution near runner blade-crown/band junctions. Starting with the geometrical investigation of the geometries for a real turbine, different junction geometries were identified. Eight different junction geometries were numerically investigated in order to determine the stress distribution. The applied load for structural analysis was the pressure distribution, obtained from a Computational Fluid Dynamics analysis of the runner blade. The results of the stress distribution will allow to quantify the effect of different junction geometry on stress concentration and integrity of the runner.

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Section: Resultsmentioning

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Numerical assessment of stress concentration in Francis runner blade — crown/band junctions

2019

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“…Xiao et al [18] studied the dynamic stresses in a Francis turbine runner based on fluid-structure interaction analysis, and indicated that the dynamic stresses caused by the hydraulic forces during off-design operating points are one of the main reasons for the fatigue and cracks in the runner blade. Frunzaverde et al [19] studied the failure of a Francis turbine runner. The investigations led to the conclusion that the cracking of the blade is caused by fatigue.…”

Section: Introductionmentioning

confidence: 99%

A Review of the Transient Process and Control for a Hydropower Station with a Super Long Headrace Tunnel

Guo

Zhu

2018

Energies

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The hydropower station with a super long headrace tunnel is a significant development type for hydropower energy. By constructing a super long headrace tunnel, the huge natural water fall head can be utilized to generate more electricity. With the development of hydropower energy, a hydropower station with a super long headrace tunnel becomes more and more competitive. Compared with a hydropower station with a short headrace tunnel, the transient process and control for a hydropower station with a super long headrace tunnel is much more complicated and becomes an intractable challenge. It is well known that the transient process and control is the basis of the design and operation of a hydropower station. To overcome the challenge of the transient process and control, much research has been carried out. This paper provides a systematic review on the latest research progress of the transient process and control for hydropower stations with a super long headrace tunnel. Firstly, two key issues for the transient process and control, i.e., hydraulic design optimization of the surge tank and operation control of unit, are illuminated. Secondly, for both single surge tanks and surge tanks with special types or combinations, the hydraulic design optimization methods are described. The most disadvantageous design and advantageous operation of surge tanks under combined operating conditions are discussed. Thirdly, the stability and regulation quality of the hydro-turbine governing system under isolated and grid-connected operation conditions are presented. Finally, some trends and recommendations for future research directions are made. A research thought for establishing the complete theory and application system of the transient process and control for hydropower stations with a super long headrace tunnel from the perspective of multi-slice and multi-scale is proposed.

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“…Lifetime estimation of the structural components is essential for the safety of a hydroelectric turbine. Dynamic loads during the service life of a hydraulic turbine runner can cause failure and, therefore, represent a significant risk related to the structural reliability of the turbine . The turbines used for hydropower are chosen on the basis of the height of standing water to drive them, and the Francis turbines are very common.…”

Section: Introductionmentioning

confidence: 99%

“…Dynamic loads during the service life of a hydraulic turbine runner can cause failure and, therefore, represent a significant risk related to the structural reliability of the turbine. [1][2][3][4][5][6][7] The turbines used for hydropower are chosen on the basis of the height of standing water to drive them, 8 and the Francis turbines are very common. A Francis hydraulic turbine has hot-formed blades that are welded to both band and crown by double-fillet welds (Fig.…”

Section: Introductionmentioning

confidence: 99%

Simplified analysis of fracture behaviour of a Francis hydraulic turbine runner blade

Vantadori

Scorza

2013

Fatigue Fract Eng Mat Struct

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Each welded connection between blades and band or crown of a Francis hydraulic turbine runner can be considered as a T‐joint subjected to pure bending induced by the water action. A semi‐elliptical crack is assumed to exist at the surface of one of the aforementioned welded connections. The actual geometry of the T‐joint can be simplified, that is, only the cracked plate (representing the blade) under a given stress distribution acting on the defect faces is examined. A numerical procedure already proposed by the authors to compute the stress‐intensity factor (SIF) along the crack front is here applied by introducing some changes to simplify such computations. The obtained values of SIF are compared with some results available in the literature.

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Failure analysis of a Francis turbine runner

Cited by 67 publications

References 3 publications

Numerical assessment of stress concentration in Francis runner blade — crown/band junctions

Numerical assessment of stress concentration in Francis runner blade — crown/band junctions

A Review of the Transient Process and Control for a Hydropower Station with a Super Long Headrace Tunnel

Simplified analysis of fracture behaviour of a Francis hydraulic turbine runner blade

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