Patent ID: 8118558
Filing Date: 2012-02-21
Classification: F03B,F05B,Y02E,Y10T

Abstract:
1. A runner vane having no fillet at a tip in a back surface thereof in an axial-flow hydraulic machine configured by: obtaining a plurality of circumferential sections of the runner vane by cutting the runner vane from a root to the tip of the runner vane with a plurality of coaxial cylindrical surfaces having centers on an axis of the runner, circumferentially dividing respective streamlines, indicating a front surface and the back surface of the runner vane in the respective circumferential sections of the runner vane, into parts of equal lengths from an leading edge and to a trailing edge of the runner vane, respectively, obtaining a plurality of radial sections of the runner vane extending from the root to the tip of the runner vane, by cutting the runner vane with radial sections respectively extending along lines connecting respective edge points of the parts of equal lengths in the respective streamlines in the circumferential sections of the runner vane, forming the front surface and the back surface of the runner vane such that a radius ρp of curvature of the front surface and a radius ρs of curvature of the back surface meet a condition expressed by the following inequality, by forming a camber line of the respective radial sections of the runner vane so as to have a curved part thereof convex toward the front surface of the runner vane near the tip of the runner vane.