Resonance observation of pump-turbine runners from the stationary frame: analytical-numerical model for the natural mode splitting of submerged rotating disc-blades-disc structures
With the growing adoption of renewable energy sources such as wind and solar power, pumped storage technology is flourishing in several developing countries. Based on the widespread vibration issues faced by pumped storage units, particularly in their runners and top covers, this paper aims to inves...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2025 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/443473 |
| Acceso en línea: | https://hdl.handle.net/2117/443473 https://dx.doi.org/10.1016/j.ymssp.2025.113292 |
| Access Level: | acceso abierto |
| Palabra clave: | Pump-turbine Bladed disk Resonance Multi-frequency vibration Mode splitting Numerical simulation Àrees temàtiques de la UPC::Matemàtiques i estadística::Anàlisi numèrica::Modelització matemàtica Àrees temàtiques de la UPC::Matemàtiques i estadística::Anàlisi numèrica::Mètodes en elements finits |
| Sumario: | With the growing adoption of renewable energy sources such as wind and solar power, pumped storage technology is flourishing in several developing countries. Based on the widespread vibration issues faced by pumped storage units, particularly in their runners and top covers, this paper aims to investigate the natural mode splitting of complex rotating structures and the observation of this phenomenon from the stationary reference frame. The finite element method (FEM) is employed to analyze the characteristics of the diametrical mode shape of a disc-blades-disc (DBD) structure, which is representative of pumped turbine runners. An analytical approach is utilized to investigate the formation mechanism of these diametrical components, thereby predicting the rules governing the mode shape splitting of underwater rotating structures. The imposed modal motion method, based on computational fluid dynamics (CFD), is used to predict the natural frequency splitting and hydraulic damping splitting of the DBD structure. Building on these studies, a combined approach of analytical methods, CFD, and FEM is employed to predict the resonance characteristics of the rotating structure on the stationary reference frame, as well as the resulting pressure pulsations and the vibrations of the stationary casing. Results reveal that the relationship between the diametrical components of the natural modes of the DBD structure is strictly related to the number of blades. When the structure rotates in water, its diametrical modes split into two independent travelling wave modes, each containing multiple diametrical components (i.e., travelling wave components), with the difference between these components equaling the number of blades. The model predicts that if a travelling wave mode is excited, a ’multi-frequency’ feature, with frequency differences equal to the product of the number of blades and the rotational frequency, will be observed on the stationary frame. These findings are consistent with the multi-frequency vibration phenomena observed in some real cases, providing a foundation for further understanding the vibration mechanisms in pump-turbines and similar mechanical structures. |
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