| 摘要 |
PROBLEM TO BE SOLVED: To provide a Francis type runner for restraining the occurrence of a hydraulic loss in an undesigned point caused by a secondary flow without increasing a friction loss in a design point. SOLUTION: This Francis type runner is formed by arranging a plurality of runner blades 10 in the peripheral direction between a crown 8 fixed to a rotary shaft and a ring-shaped band 9. At least either one of a band side edge line and a crown side edge line on the rear edge of the runner blades in a meridian cross section, exists on the upstream side more than a line vertically erected to an inner surface of the band or the crown in an intersection between the edge line 10a and the band or an intersection between the edge line 10a and the crown, and is formed in a concave curved shape toward the downstream side. COPYRIGHT: (C)2007,JPO&INPIT
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