| 摘要 |
<p>The blade (1) has an aerodynamic profile with a convex (4) and a concave (3) side. A hole (2) through the blade takes a wire which rubs against the blade to act as a vibration damper. A raised flange (5, 6) is formed on both the concave and convex sides of the blade round the hole. The flanges are formed integrally with the blade either during casting or forging or by machining afterwards. They form a flat surface (7, 8) round each edge of the hole. The edges of the hole have a radius (9, 10) less than the height of the flange. The outside of the flange is shaped to allow smooth streamline flow past it. The flanges strengthen the blade where it is weakened by the hole.</p> |
