过渡阶梯体型对一体化消能工水力特性的影响

Influence of transitional ladder on the hydraulic characteristics of integrated energy dissipator

宽尾墩+阶梯溢流坝+消力池的一体化消能工有效地解决了我国高坝泄洪建筑物在高水头、大单宽流量下的高速水流问题,但仍然存在空蚀破坏的问题。通过对三种过渡阶梯与阿海原工况共4种方案下Y型宽尾墩+阶梯溢流坝+消力池一体化消能工进行水工模型试验,对比分析其水力特性,结果表明:(1)各方案反弧段内的最大时均压强出现在方案一中,相比有过渡衔接方式的三种方案的最大时均压强增加了3.3%;(2)过渡阶梯体型对台阶面负压影响较大,最大负压均出现在第二台阶立面凸角上缘,四个方案中,方案三最大负压最小,为-0.33 k Pa;(3)从消能方面来看,方案一的消能率最低,为51.71%,方案三的消能率最高,为52.77%,比方案一增加了2.05%。

Application of energy dissipators combining flaring gate piers, a stepped steep chute and a stilling basin is an effective way of solving the major problems of high-velocity flows that occur on high dams under large discharges per unit width and high working heads. But cavitation damage remains a possible threat to such overflow structures. In this study, we conduct scale model tests on a dissipator of this new type and compare its four design schemes, focusing on the hydraulic characteristics of Y-type flaring gate piers, stepped chutes and stilling basins. Scheme 1 has a steep chute with a regular staircase shape, and schemes 2-4 have a stepped chute section for transition of the step size. The results show that 1） Among the four schemes tested, the time-average pressure on the flip bucket scheme 1 is the highest, 3.3% higher than the other three schemes with a transition section. 2） The transitional shapes of the stepped chute produces greater effect on the negative pressure occurring on the step surface, and its value around the edge of the second step is the largest. The largest negative pressure （-0.33 kPa） of scheme 3 is the lowest of the four schemes. 3） In energy dissipation of all the schemes, the lowest dissipation rate is 51.71% in scheme 1 and the highest 52.77% in scheme 3.