Dynamic model for hydropower generators with floating rotor rim

Rondon, David; Aidanpää, Jan-Olov; Gustavsson, Rolf; Lundin, Urban; Jeppsson, Peter

doi:10.1016/j.ymssp.2022.109645

Cited by 3 publications

(12 citation statements)

References 25 publications

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“…The generator rim is discretized by 21,236 ten-node tetrahedral elements and is modeled as isotropic, linear elastic steel with the material properties defined in Rondon et al (2023) [20]. The outer surface of the rim connects to the poles.…”

Section: Rotor Rimmentioning

confidence: 99%

“…Gustavsson et al (2012) [19] measured the deformation of the rotor rim due to the effect of an elliptical stator on its shape. Rondon et al (2023) [20] developed a model of a generator with a flexible rotor rim and rigid stator to estimate the dynamics of the machine. They compared its results to the measurements by Gustavsson et al (2012) [19].…”

Section: Introductionmentioning

confidence: 99%

“…The focus of this model is to study the deformation of the rotor rim at a constant operating speed while the stator is rigid and undeformed. The model's results are compared to the model proposed by Rondon et al (2023) [20], and the ring theory and the influence of the poles and connecting plates on the natural frequencies and modes of vibration are studied. This study focuses solely on in-plane vibrations and does not consider the influence of shaft tilting.…”

Section: Introductionmentioning

confidence: 99%

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Three-Dimensional Modeling for Mechanical Analysis of Hydropower Generators with Floating Rotor Rim

Rondon,

Pääjärvi,

Aidanpää

et al. 2024

Machines

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Hydropower generators withstand multiple forces from diverse sources during operation. To ensure their stability and safe performance, numerical tools are developed to characterize their dynamic properties. Traditionally, generators are assumed to be rigid in rotordynamic analyses. However, the measurements in power stations challenge this assumption. This article proposes a novel approach to modeling hydropower generators with floating rotor rims using a three-dimensional (3-D) Finite Element Method, aiming to study their dynamic performance and properties, including natural frequencies, the modes of vibrations, and expansion due to centrifugal and electromagnetic forces, with the goal of improving the reliability of modern designs. Both this approach and employing a two-dimensional (2-D) model using curved beams result in similar in-plane natural frequencies and the expansion of the rotor rim due to centrifugal forces. However, the 3-D model can be used to calculate the out-of-plane natural frequencies and modes, to model the dynamics of complex geometries, and to perform stress evaluation and fatigue analysis.

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Section: Rotor Rimmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Three-Dimensional Modeling for Mechanical Analysis of Hydropower Generators with Floating Rotor Rim

Rondon,

Pääjärvi,

Aidanpää

et al. 2024

Machines

Self Cite

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“…In many studies, governing equations have been extracted based on the different effects of eccentric rotation. 4,[13][14][15] By incorporating the inertial forces caused by eccentric rotation, Maretic 4 and Yu et al 13 formulated governing equations using the classical Kirchhof plate theory and the lumped-parameter method, respectively. Rondon et al 14 derived the governing equation of an eccentrically rotating rotorstator system using the Lagrange equations, where the effects of eccentric rotation were reflected in the centrifugal softening matrix and centrifugal force.…”

Section: Introductionmentioning

confidence: 99%

“…4,[13][14][15] By incorporating the inertial forces caused by eccentric rotation, Maretic 4 and Yu et al 13 formulated governing equations using the classical Kirchhof plate theory and the lumped-parameter method, respectively. Rondon et al 14 derived the governing equation of an eccentrically rotating rotorstator system using the Lagrange equations, where the effects of eccentric rotation were reflected in the centrifugal softening matrix and centrifugal force. Liu et al 15 extracted the governing equation of an eccentrically rotating cylindrical shell using Hamilton's principle, where eccentricity affected the kinetic energy, potential energy, and virtual work.…”

Section: Introductionmentioning

confidence: 99%

Dynamic instability of an eccentrically rotating ring-shaped structure

Wei,

Wang,

Wang

2024

Proceedings of the Institution of Mechanical Engineers, Part C:

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Ring-shaped structures are widely used in engineering. However, their rotation axes are typically not coincident with the geometric axes, thus resulting in a rotational centrifugal force and significant vibration. This study focuses on the dynamic instability caused by constant and time-varying eccentricities. An analytical model is established using Hamilton’s principle and the Galerkin method, in which the rotational centrifugal forces resulting from constant and time-varying eccentricities are incorporated. Based on this model, the effects of rotation, revolution, eccentricity ratio, and damping on instability behaviors are examined. The instabilities caused by constant eccentricity are predicted using eigensolutions, whereas those caused by time-varying eccentricity with single- and multifrequency components are estimated by applying the Floquét theory. The results show that the instability domains from the multifrequency eccentricity are not a simple superposition of those from the single-frequency eccentricity but contain more instability domains originating from their combinations. The instability suppressions imposed by damping and gyroscopic effects are compared. Finally, the instability domains from constant and time-varying eccentricities are verified via numerical calculations.

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