岸边取水口导沙坎防沙效果数值模拟研究

Numerical Analysis of the Sediment Prevention Effect of the Sediment Deflecting Sill at the River Intake

为解决岸边取水口前泥沙淤积问题,探究不同导沙坎防沙效果。基于RNG k-ε湍流模型和质量粒子模型,建立了雅砻江锦屏二级水电站取水口区域的水流和泥沙运动三维数学模型,模拟结果与现场实测结果吻合较好。进一步模拟了设置单一导沙坎和组合式导沙坎后取水口区域的水流和泥沙运动过程,结果表明:在取水口前加设单一导沙坎能够改变底层水流流向,但防沙效果有限;加设组合式导沙坎后,河流底部大部分水流流向下游,中层和表层水流竖轴回流消失,进入取水口的水流宽度显著增加。组合式导沙坎能够生成连续较强的螺旋流,可以有效防止河床泥沙颗粒向取水口运动,同时将上层清水引入取水口,达到较为理想的引清、防沙效果。本研究可为岸边取水工程的设计提供参考。

To address the problem of sediment accumulation in the intake area of the river intake and to explore the effectiveness of different sediment trapping structures,a three-dimensional mathematical model for flow and sediment transport are established in the intake area of the Jinping Second-Level Hydropower Station in the Yalong River.The model is based on the RNG k-εturbulence model and the mass particle model.The simulation results are in good agreement with field measurements.The study simulates the flow and sediment transport processes in the intake area after the installation of a single sediment deflecting sill and a combined sediment deflecting sill.The results indicate that the addition of a single sediment deflecting sill in front of the intake can alter the flow direction at the bottom layer of the river,but its effectiveness in sediment control is limited.On the other hand,the installation of a combined sediment deflecting sill redirects most of the flow downstream at the riverbed,eliminates the vertical-axis recirculation of the middle and surface layers,and significantly increases the flow width entering the intake.The combined sediment deflecting sill can generate a continuous and strong helical flow,effectively preventing sediment particles from reaching the intake and introducing clear water from the upper layer,thus achieving desirable sediment control and water intake effects.The findings of this study can provide valuable insights for the design of river intake projects.