干支流垂直交汇下跌水工程下游通航水流条件优化

Navigable flow condition optimization at vertical channel confluence in the downstream of a water drop project

支流入汇往往对干流通航河道流场特性产生影响。在干、支流交汇口支流段上修建水利工程,需优化工程布置以改善其泄流对交汇区通航水流条件的影响。以引江济淮工程派河段某入汇支流跌水为研究对象,通过1∶50比尺物理模型试验,研究跌水泄流以90°角汇入干流时交汇区通航水流条件,提出跌水工程优化布置方案。结果表明:在原布置方案基础上,增大跌水出口段泄槽扩散角度至10°,沿出口扩散段对称布置二级分流墩,并将出口扩散段浚深2 m,在5年及20年一遇洪水工况时,通航水流条件得到显著改善,汇流偏流系数分别为1.13、1.20,交汇区最大横向流速分别为0.15、0.29 m/s,满足规范要求。研究结果可为类似跌水工程布置提供有益参考。

The flow field characteristics of a main stream are always influenced by the inflow of its tributaries.For a water conservancy project built on the tributary at channel confluence,the layout of the project should be optimized to improve the influence of the discharge flow on the navigable flow conditions at the channel confluence.Based on a water drop project on the tributary of the Paihe reach from the Yangtze River to the Huaihe River as a research object,we studied the navigable flow conditions in the confluence area by means of a 1∶50 scale physical model test,where the discharge of water drop project flows into the main stream at a 90°angle,and put forward the optimization scheme of the project layout.The result shows that navigable flow condition can be improved significantly on the basis of the original layout scheme by the optimization scheme of increasing the discharge flume angle of the outlet section to 10°,symmetrically placing two-stage diversion piers along the outlet section and digging 2 m under the outlet section.Under 5-year and 20-year navigable conditions,the water deflection coefficients are 1.13 and 1.20,respectively,and the maximum transverse velocity in the confluence area is 0.15 m/s and 0.29 m/s,respectively,which meets the navigable requirements.The research results can provide a useful reference for the layout of similar water drop projects.