| 摘要 |
PURPOSE:To reduce the stress concentration at the outlet edge of a crown side vane by suppressing the reduction of pressure at the inlet edge of a band side vane by forwardly tilting the inlet edge of the band side vane in the direction of revolution of a runner with respect to the inlet edge of the crown side vane. CONSTITUTION:As for a Francis type turbine, vanes 4 are installed at equal intervals between the crown 2 and band 3 of a runner 1. In this case, the edge part 4b on the band 3 side of the vane 4 is tilted forwardly in the direction of revolution of the runner 1, with respect to the edge part 4a on the crown 2 side. Therefore, the pressure in the vicinity of the inlet on the band 3 side of the vane 4 is suppressed, and the inlet cavitation characteristic is improved. Further, the generation of counter-current along the high pressure surface in the vicinity of the edge part 4a on the crown 2 side of the vane 4 is suppressed, and the flow passage swirl cavitation characteristic is improved. Further, the stress concentration in the vicinity of the outlet of the vane 4 on the crown 2 side can be improved.
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