Static and dynamic calculation of a Francis turbine runner with some remarks on accuracy

Dubas, M.; Schuch, M.

doi:10.1016/0045-7949(87)90081-2

Cited by 8 publications

(10 citation statements)

References 16 publications

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“…A few publications give some general data (Tanaka, 1990) but there are no detailed publications indicating the influence of the water on the modal characteristics of hydraulic runners. Other publications (Dubas and Schuch, 1987;Du et al, 1998;Xiao et al, 2001;Cao and Chen, 2002) present only results of numerical simulations without comparison with experiments.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation of added mass effects on a Francis turbine runner in still water

Rodríguez¹,

Egusquiza²,

Escaler³

et al. 2006

Journal of Fluids and Structures

104

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The mechanical design of hydraulic turbines is conditioned by the dynamic response of the runner that is usually estimated by a computational model. Nevertheless, the runner has complex boundary conditions that are difficult to include in the computational model. One of these boundary conditions is the water in which the runner is submerged. The effect of the added mass and damping of water can modify considerably the natural frequencies of the runner. An experimental investigation in a reduced scale model of a turbine runner, using modal analysis, was carried out. Several impact tests with the runner freely suspended in air and in water were done. The response was measured with accelerometers located in different positions of the runner. From the modal analysis, the natural frequencies, damping ratios, and mode-shapes were determined. The same mode-shapes obtained in air were obtained in water but with lower natural frequencies and higher damping ratios in water. The difference in the natural frequencies is shown to be dependant basically on the added mass effect of the water and not on its added damping. This difference also depends on the geometry of the mode, presenting different values for different mode-shapes. Using nondimensional values, the reduction in the natural frequencies can be extrapolated to other Francis runners presenting similar geometrical characteristics. r

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Section: Introductionmentioning

confidence: 99%

Experimental investigation of added mass effects on a Francis turbine runner in still water

Rodríguez¹,

Egusquiza²,

Escaler³

et al. 2006

Journal of Fluids and Structures

104

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show abstract

“…For a structure with a complex geometry, such as a hydraulic turbine impeller, there is a limited number of studies available, performed in Francis impellers in air and in water but with simplified boundary conditions [4]. Other publications have presented detailed experimental and numerical analysis considering the effect of surrounding mass of water [5][6][7] but in a reduced scale model and without taking into account the boundary conditions of the casing.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the dynamic response of pump-turbine impellers. Influence of the rotor

Egusquiza

Valero

Presas

et al. 2016

Mechanical Systems and Signal Processing

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a b s t r a c tThis paper deals with the dynamic response of pump-turbine impellers. A pump-turbine impeller is a complex structure attached to a rotor and rotating inside a casing full of water with very small clearances between the rotating and the stationary parts. The dynamic response of this type of structures is very complex and it is very much affected by the connection to the rotor as well as by the added mass and boundary conditions. As a consequence its calculation presents several uncertainties.First, the dynamic response of pump-turbine impellers is introduced. Second an experimental investigation in a real impeller attached to the rotor and inside the machine was carried out. For this investigation, the impeller of an existing pump-turbine unit with an installed power of 110 MW and a diameter of 2.87 m was studied. For a better analysis of the experimental results a numerical model using FEM was also built-up. Frequencies and mode-shapes were identified numerically and experimentally and the characteristics of the structural response analyzed.To determine the influence of the rotor and supporting structures on the impeller response the results were compared with the ones obtained with the same impeller but suspended (non-connected to the rotor). Experimental and numerical simulation were also used for this case. The changes in the dynamic response due to the rotor connection were determined.Finally the results obtained are compared with the results from other pump-turbine impellers of different designs and general conclusions about the dynamics of this type of structures are given.

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“…But for more complex structures such as impellers or runners, finite element models must be used. In this sense, a numerical simulation of a real Francis turbine was carried out by Dubas and Schuch [9] [10] and Liang et al [11] who measured and simulated respectively the added mass effect on a Francis turbine reduced scale runner. Nevertheless, the geometry of a pump-turbine impeller differs from that of a Francis runner.…”

Section: Introductionmentioning

confidence: 99%

Modal behavior of a reduced scale pump-turbine impeller. Part 1: Experiments

Escaler

Hütter

Egusquiza

et al. 2010

IOP Conf. Ser.: Earth Environ. Sci.

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Static and dynamic calculation of a Francis turbine runner with some remarks on accuracy

Cited by 8 publications

References 16 publications

Experimental investigation of added mass effects on a Francis turbine runner in still water

Experimental investigation of added mass effects on a Francis turbine runner in still water

Analysis of the dynamic response of pump-turbine impellers. Influence of the rotor

Modal behavior of a reduced scale pump-turbine impeller. Part 1: Experiments

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