基于坝下流场模拟的集鱼系统进口位置选择研究

集鱼系统进口位置的合理选择决定着鱼类能否顺利发现并进入集鱼系统,关系着过鱼设施的运行效果。为选择大坝过鱼设施集鱼系统进口位置,本文以长江流域某水力枢纽工程为例,对坝下尾水河道2.83 km范围内水流流场进行了二维数值模拟,以当地鱼类上溯洄游流速的偏好范围为评判指标,分析了不同发电工况下适宜鱼类上溯的水域范围,并针对不同发电工况给出了集鱼系统进口的适宜布置区域,可为过鱼设施集鱼系统的布置提供依据。研究结果表明:左右岸电站发电机组下泄流量比为1∶0和2∶1时,模拟区域适合鱼类上溯洄游区域的占比较大,这两种工况下,集鱼系统进口应布置在坝下右岸;其他工况下,适合鱼类上溯洄游区域难达坝下,集鱼系统进口或集运鱼船应布置在坝下稍远区域,以保证集鱼系统在不同工况下的集鱼效率。

Study on the optimal positioning of fish collection system based on numerical simulation of reservoir downstream

The suitable design of the entrance position of fish collection system can gurantee that the fish finds and enters into the fish collection system,which is crucial to the function implementation fishpass facility. For guiding the optimal layout of the entrance location of the fish collection system, a hydropower project in the Yangtze River Basin was taken as an example, and 2-D numerical simulation was carried out for the flow field within 2.83km of the tailrace channel. Taking the preference range of the upstream migration velocity of local fish as an indicator,the area suitable for fish upstream under different power generation conditions was analyzed,and the suitable layout area of entrance was given for different power generation conditions,which can provide a basis for the arrangement of fish collection system of fishpass facility. The results show that when the discharge ratio under the power plant on the left and right bank is 1:0 and 2:1, the proportion of the simulated area suitable for fish upstream migration is larger. In these two cases,the entrance of the fish collection system should be arranged near the mainstem of the river to the right bank. In other cases, it is difficult for fish to reach the dam in suitable zone, and the entrance of the fish collection system or the fish barging shall be arranged in the far area of reservoir downstream to ensure the fish collection fulfillment.