| 摘要 |
<p>A draft tube (2) of hydraulic machinery according to the present invention suppresses generation of a horseshoe vortex in a junction of the upstream-side end (4) of the pier (3) and the inner wall of the draft tube (2) and reduces energy loss in the draft tube (2). The draft tube of hydraulic machinery includes a water-flow control part (30, 31 or 32) suppressing generation of stagnation on the upstream side of the junction. Preferably, the water-flow control part is formed such that the angle between the upstream-side end of the pier (3) and an upper surface of the water-flow control part (30, 31 or 32) is equal to or greater than 90° in a plane including a cross-section of the pier (3) viewed from a side surface of the draft tube. Preferably, the water-flow control part (30, 31 or 32)is formed such that the length from the inner wall of the draft tube (2) to the surface of the water-flow control part (30, 31 or 32) along an extended line of the upstream-side end (4) of the pier (3) toward the inner wall is equal to 0.1D or more, where D denotes the maximum thickness of the pier.</p> |
