排沙漏斗悬移质泥沙运动数值模拟

排沙漏斗是一种利用立轴旋涡实现水沙分离的二级排沙设施。为了探明排沙漏斗悬移质泥沙运动特征和排沙机理,采用欧拉-拉格朗日方法模拟了排沙漏斗水气沙三相流动,其中水相和气相采用雷诺应力模型(RSM)和VOF方法描述,悬移质泥沙用颗粒轨道模型描述。通过对计算的悬移质含沙量垂向分布与实验结果的对比,验证了数学模型的可靠性。计算结果表明:在漏斗室外侧区域含沙量分布整体上较均匀,在漏斗室内侧区域的近底部存在一个明显的高浓度带。作者认为,上述排沙漏斗悬移质泥沙含沙量分布特征主要是由排沙漏斗内的二次流引起的。

Numerical study on suspended sediment transport in a vortex settling basin

The vortex settling basin is a hydraulic structure which used a vertical vortex to exclude sedi-ment particles from diverted water. In order to ascertain the suspended sediment transport characteristics and the sediment removal mechanism in a vortex settling basin,an Euler-Lagrange method is used to simu-late the air-water-sediment multiphase flow in the device. In this method,the turbulent flow of gas and liq-uid is modelled using the Reynolds stress model (RSM) and the Volume of fluid (VOF) interface tracking technique. A discrete particle model is adopted to calculate suspended sediment motion. The calculation re-sults of the mean suspended sediment concentration distribution are in good agreement with measured re-sults. The calculation results show that the sediment concentration distribution in the outer region of the ba-sin is more uniform, and that there is a significantly high concentration zone near the bottom in the inner region of the basin. The authors hold that the sediment concentration distribution is mainly caused by the secondary flow within the vortex settling basin.