| 摘要 |
PROBLEM TO BE SOLVED: To prevent cavitation erosion generated near an opening part on a current water surface of a balance hole, reduce hydraulic power axial thrust by the balance hole, and to make differential pressure between pressure acting on an upper part of a runner with an intermediate blade and pressure acting on a lower part of the runner small and reduce hydraulic power axial thrust by the balance hole. SOLUTION: In a Francis type runner, the current water surface side opening parts of the balance holes are formed, for example, in all of or a part of flow passage areas distributed within a range from an inlet diameter to an outlet diameter of a blade (a main wing in Francis type runner with intermediate impeller)of the blade, in a plurality of fluid passages formed between neighboring wings 3. COPYRIGHT: (C)2005,JPO&NCIPI
|
