Effect of transients on Francis turbine runner life: a review

Trivedi, Chirag; Gandhi, Bhupendra K.; Michel, Cervantes J.

doi:10.1080/00221686.2012.732971

Cited by 213 publications

(109 citation statements)

References 14 publications

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“…In order to do this, Hydro-Québec decided to use the data from their measurement campaigns on Francis and propeller runners to identify and validate dynamic models that will represent the turbines behavior and enable start-up optimization. This paper follows previous work conducted at Hydro-Quebec by Gagnon et al [1][2][3], and by other researchers [4,5], on the impact of a transient operation on Francis runners, and builds on the review on fatigue damage mechanisms in hydro turbines [6].…”

Section: Introductionmentioning

confidence: 94%

Modeling the dynamic behavior of turbine runner blades during transients using indirect measurements

Diagne

Gagnon

Tahan

2016

IOP Conf. Ser.: Earth Environ. Sci.

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Abstract. Turbine start-up transients are induced by the wicket gates opening sequence and generate high amplitude stress cycles. These stress cycles have a detrimental effect leading to faster crack growth in the runner blades. Using a series of direct measurements taken on a prototype runner in order to find the optimal start-up parameters exposes both the runner and the instrumentation to a series of successive damaging transient events during the optimization process. To solve this, finding sensors strongly correlated to strain gauges and whose signals can be easily obtained to identify a model to predict the strain, instead of directly measuring it, would reduce the risk, cost and downtime associated with a measurement campaign. This paper shows that turbine shaft torsion measurements is highly correlated to the strain at a runner blade hotspot, and we demonstrate that the ARMAX model can be used to represent the dynamic system in order to minimize the strain on blades.

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Section: Introductionmentioning

confidence: 94%

Modeling the dynamic behavior of turbine runner blades during transients using indirect measurements

Diagne

Gagnon

Tahan

2016

IOP Conf. Ser.: Earth Environ. Sci.

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“…The exerted unsteady fluctuations during the transients are a challenge for the turbine designers and power plant owners because they are difficult to predict during the design stage. Hydraulic turbines are subject to cyclic stresses, asymmetric forces on the runner, wear and tear during transient operations; each of them may affect the components lifetime [4]. From a controlling point of view, the turbines behavior varies significantly with unpredictable loads, mainly because of the turbines complexity as non-linear and nonstationary multivariable systems.…”

Section: Introductionmentioning

confidence: 99%

“…Most of the studies are focused on the steady state operation of the turbines and more studies on transient operation of the turbines are required as presented in the review paper prepared by Trivedi et al, [4]. Gagnon and Leonard [2] investigated runner blades deformation of two hydropower plants during load rejection.…”

Section: Introductionmentioning

confidence: 99%

Effects of load variation on a Kaplan turbine runner

Amiri¹,

Mulu

Cervantes

et al. 2016

International Journal of Fluid Machinery and Systems

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Introduction of intermittent electricity production systems like wind and solar power to electricity market together with the deregulation of electricity markets resulted in numerous start/stops, load variations and off-design operation of water turbines. Hydraulic turbines suffer from the varying loads exerted on their stationary and rotating parts during load variations since they are not designed for such operating conditions. Investigations on part load operation of single regulated turbines, i.e., Francis and propeller, proved the formation of a rotating vortex rope (RVR) in the draft tube. The RVR induces pressure pulsations in the axial and rotating directions called plunging and rotating modes, respectively. This results in oscillating forces with two different frequencies on the runner blades, bearings and other rotating parts of the turbine. This study investigates the effect of transient operations on the pressure fluctuations exerted on the runner and mechanism of the RVR formation/mitigation. Draft tube and runner blades of the Porjus U9 model, a Kaplan turbine, were equipped with pressure sensors for this purpose. The model was run in off-cam mode during different load variations. The results showed that the transients between the best efficiency point and the high load occurs in a smooth way. However, during transitions to the part load a RVR forms in the draft tube which induces high level of fluctuations with two frequencies on the runner; plunging and rotating mode. Formation of the RVR during the load rejections coincides with sudden pressure change on the runner while its mitigation occurs in a smooth way.

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“…Solar and wind, typical renewable energies, are examples of intermittent energy sources and may cause unstable operation of the power grid (Trivedi et al 2013). Hence, pumped storage power plants (PSPP) are widely believed as having great potential in storing large amounts of electrical energy and adjusting the variations.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Simulation in Guide Vane Opening Process of a Pump-Turbine in Pump Mode

Han

Wang

Gao

et al. 2017

JAFM

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During the process of switching conditions in pump-turbine, unstable flow would take place and seriously impact on the stability and safety. This paper deals with the guide vanes' moving process in pump mode through unsteady numerical simulations. Dynamic mesh methodology is used for simulations in which GVO (Guide Vane Opening) from 9mm to 26mm. Simulation results approve that, there are many complex vortex structures and flow blockages phenomena under small GVO condition. Through the mathematical method of Fast Fourier Transform (FFT) and Short-Time Fourier Transform (STFT), the dominant pressure fluctuation frequencies are from runner blade passing frequency (BPF) and its harmonic frequency, as well as some other low frequencies are from unsteady flow states. Furthermore, the flow states are more unstable and complex under small guide vanes moving process. Compared with fixed GVO position, the flow states are more unstable and complex under guide vanes moving process, while the amplitude of main frequencies becomes higher.

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Effect of transients on Francis turbine runner life: a review

Cited by 213 publications

References 14 publications

Modeling the dynamic behavior of turbine runner blades during transients using indirect measurements

Modeling the dynamic behavior of turbine runner blades during transients using indirect measurements

Effects of load variation on a Kaplan turbine runner

Dynamic Simulation in Guide Vane Opening Process of a Pump-Turbine in Pump Mode

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