入池流量与倾角对鱼鳃式沉沙池内水沙二相流的影响分析

Impact Analysis of Flow Rate and Inclination Angle on Two-Phase Flow of Water and Sand in a Fish Gill-Type Sedimentation Tank

为提高沉沙池的除沙效果,提出了一种新型除沙措施即鱼鳃式沉沙池。鱼鳃式沉沙池在池室内部布设多组倾斜的过滤网片,利用滤网拦截泥沙,提高泥沙沉降效率。采用物理模型试验和数值计算方法,分析不同流量和滤网角度下的流场分布和除沙效果,以此得到较优的结构型式,为该类沉沙池的工程设计和技术推广提供理论参考。结果表明,植入鱼鳃装置后沉沙池的泥沙截除率提高了12.5%~22.0%。数模计算进一步揭示,鱼鳃式沉沙池内流速变化分为五个区域,含沙量变化沿程呈现四个不同阶段。在泥沙沉积量计算中,最大泥沙沉积区出现在第一、二片滤网底部,建议增大鱼鳃装置前部的滤网孔径,使鱼鳃装置设置更加合理。

To improve the sand removal efficiency of the sedimentation tank,a novel sand removal measure has been proposed,namely the fish gill-type sedimentation tank.The fish gill-type sedimentation tank is equipped with multiple sets of tilted filter screens inside the tank room,which intercept sediment using filter screens and improve sediment settling efficiency.Physical model tests and numerical calculation methods were used to analyze the flow field distribution and sand removal effect under different flow rates and filter screen angles so as to obtain an optimal structural design,which provide theoretical references for engineering design and technology promotion for this type of sedimentation tank.The results show that the sediment removal rate of the sedimentation tank increased by 12.5 to 22.0%after the fish gill device was implanted.Numerical modeling further reveals that the flow rate change in the fish gill-type sedimentation tank was divided into five regions,and sediment concentration changes showed four different stages along the way.In sediment deposition calculations,the maximum sediment deposition zone appeared at the bottom of the first and second filter screens.Thus,it suggests that the mesh size of the filter screens in the front of the fish gill device should be increased for more reasonable placement.