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| Finite element analysis of stress, deformation and modal of head cover in axial-flow hydro-turbine |
| YAO Tingting1, ZHENG Yuan2* |
| College of Energy and Electrical, Hohai University, Nanjing, Jiangsu 210098, China |
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Abstract One-way fluid-structure coupling computations were carried out on the head cover of an axial-flow hydro-turbine under different working conditions. Firstly, an accurate hydraulic pressure distribution on the head cover was secured with ANSYS CFX at different operating points. Then finite element analysis was performed on the head cover in ANSYS Workbench by loading the pressure distribution onto the wet surface of the cover. Finally, the static stress and deformation distributions in the head cover were obtained under each working condition. Additionally, modal analyses of the head cover with and without prestress were launched, and its natural frequency and mode shape were realized. The results show that under different working conditions all the maximum static stress and displacement appear in the area between two ribs in the bottom plate and rise with increasing hydraulic head. The natural frequencies of the head cover in prestressed state are less than 0.5% higher than those without prestress, as such the prestress effect can be neglected. Compared with various frequencies of hydraulic exciting forces, the natural frequencies of the head cover differ from them significantly, suggesting a less possibility of resonance. The results provide an effective basis for stress and vibration examinations of the head cover in axial-flow hydro-turbines and offer a reference for structural optimization design of the cover.
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Received: 06 July 2018
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