基于CFD的网格絮凝池内水流紊动协同效应分析

Synergetic Analysis of Water Flow Turbulence in Grid Flocculating Tank Based on CFD

借助CFD方法对网格絮凝池内的流场进行数值模拟,并结合紊流涡旋理论和絮体多级成长模型,从水流速度分布、紊动能和紊动能耗散率等角度考察不同网格板的开孔率和间距以及过水孔洞的尺寸等条件下整个池内水流紊动的相互作用.研究发现,前述各因素对流场的影响均局限于一定的区域范围,但考虑到絮凝任何阶段水动力学环境的变化都会导致最终形成絮体性能的差异,故在实际构筑物设计时,应充分利用不同分段水流紊动间的协同效应,通过确定适宜的设计参数组合来实现絮凝效果的优化.

According to turbulence vortex theory and floc multi-level growth model, turbulent interactions of water flow were explored under different perforation ratios and distances of grid plates as well as different physical dimensions of the water opening.For comparison purposes, the velocity distribution, turbulent kinetic energy and dissipation rate of turbulent kinetic energy of water flow, derived from flow-field simulations by the Computational Fluid Dynamics （CFD） method, were used.The results showed that each factor may only affect the flow field within a certain regional range of the tank.However, as the morphological characteristics of the resultant floc are highly related to the hydrodynamic environments in any part of flocculating tank, an appropriate combination of design parameters of actual structures would be determined by responsibly taking into account synergetic effects of water flow turbulence in different parts of the whole tank, in order to realize the optimization of flocculation effect.