小长宽比鱼道池室水力学试验研究

鱼道水流条件是影响其过鱼效果的重要因素。在分析鱼道类型及其特点的基础上,针对应用最为广泛的竖缝隔板式鱼道,通过1∶4的大比尺局部物理模型试验,研究了各级水池长宽比小于1.0条件下的隔板布置及竖缝宽度,对比了3种布置方案,分析评价了竖缝流速指标以及池室流速分布、流态和消能特性,提出了适合小长宽比池室条件下的鱼道隔板布置型式。通过1∶12.5的鱼道整体水力学模型试验,对运行水力指标进行了验证分析,确立了减小隔板前局部水位壅高及提高竖缝流速沿程均匀性的设计原则;为适应鱼道进、出口水深的变化,从生态明渠引水补充鱼道流量,最小补水流量为0.22 m~3/s。试验结果表明,这种鱼道布置型式可推广应用到其他类似鱼道工程中。

Hydraulic model tests of fishway with small sized pond

Fishway flow condition is an important factor affecting the fish passing effect. Based on the analyses of structural types and corresponding characteristics of the fishway, a partial hydraulic physical model with a large scale of 1∶ 4 is established for a vertical slot fishway, which is widely used in the water conservancy projects. The layout of the baffle and the vertical slot are studied under the conditions that a ratio of every pool’s length to width is less than 1.0. Three layout schemes are comparied in the experiments. Velocities of the vertical slot and velocity distribution, flow patterns and energy dissipation of the pool are tested and analysed. The baffle type is put forward suitable for the fishway with a small ratio of the pool’s length to width. Besides, the hydraulic characteristics are validated by an overall integral hydraulic physical model test which has a scale of 1∶12.5 when the fishway operates. The design rules are worked out to reduce local backwater of the baffles and enhance velocity uniformity of the vertical slots along the fishway. In order to suit the changes in water depth at the entrance and exit of the fishway, the studies of water supplement measures from an ecological open channel into the fishway are also carried out, showing that the minimum supplement discharge should be 0.22 m3/s. The test results show that the suggested baffle type can be applied to other similar fishway works.