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| Effects of guide vane opening on stress and strain of Francis turbine runner |
| SHI Guangtai1,2*, ZHU Yuzhi1,2, LIU Zongku1,2, LI Jin1,2 |
| 1. Key Laboratory of Fluid and Power Machinery, Ministry of Education, Xihua University, Chengdu, Shchuan 610039, China; 2. School of Energy and Power Engineering, Xihua University, Chengdu, Sichuan 610039, China |
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Abstract In order to study the stress and strain of Francis turbine runner, the theory of one-way fluid-structure interaction was adopted, and the Workbench platform was employed to carry out numerical simulations of this one-way fluid-structure interaction. In the simulation process, firstly, the ANSYS CFX software and the standard k-ε turbulence model were used to calculate the three-dimensional flow pattern in the turbine. Secondly, the flow field static pressure was transmitted to the runner solid surfaces by static structural module, and then a coupling simulation was performed, and the stress and deformation distribution rules of the runner were obtained. Finally, the numerical results were validated with the experimental results. The results show that at 100% opening, from the lowest head to the rated head, and from the rated head to the highest head, the maximum principal stress and equivalent stress of the runner increase by 9.8% and 15.9%, respectively. In addition, at different guide vane openings, the transient larger deformation, maximum principal stress and maximum equivalent stress of the turbine runner are mainly concentrated in the junction of the blade trailing edge and the cone(hub)and at the trailing edge near the shroud. Specially, with increasing guide vane opening, these values are amplified gradually, particularly, at the trailing edge near the shroud. Because that location is thinner, a fatigue failure is prone to occur there under the repeated action of an alternating stress; nevertheless, cracks and fractures are more likely to appear there as well.
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Received: 05 June 2019
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