The CFD-based design tool is applied to investigate and improve the flow matching relationship and the hydraulic performance of Francis turbine components for a turbine rehabilitation project. At first numerical analysis of spiral casing with stay vanes was performed, the discharge angle distribution at the spiral casing outlet was obtained and according to the discharge angle distribution, the stay vanes were divided into 5 groups to correspond with the spiral casing discharge angle distribution. The circumferential relative position relationship between the stay vanes and the guide vanes was numerical investigated by altering the circumferential position of the stay vane, and the optimal matching relationship between the stay vane outflow angle and the guide vane inflow angle was obtained. Systemic measures of adopting negative rake angle blades, increasing blade number, increasing blade wrap angle, thickening blade exit edge, and reducing optimum unit speed were used to develop a new runner that replaced existing runner to damp the vibration of turbine units. And the model test comparison in the same conditions of the new runner and existing runner was carried out and the results showed that the severe vibration of the power building floor was eliminated.

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