Research On Numerical Simulation Of Internal Flow Field Of Grid Flocculation

Along with the implementation of the new drinking water quality standards, the effluent turbidity of most of the water supply plants with conventional treatment process can not meet the new standard less than1NTU requirements. Therefore we need to seek an effective measure to renovate and upgrade the original waterworks, to ensure that the waterworkswater quality can meet the new standards. Generally such water plant renovation project will improve it by two aspects:increase the depth of processing and enhanced flocculation. From comparisons concluded that enhanced flocculation method is more cost-effective than the reinforced flocculation method, the main problem is how to improve the efficiency of the flocculation of the flocculation tank. This article is mainly focused on the research of Grid flocculation tank, through the analysis of the dynamics of flocculation and this flocculation pool internal flow field flow state numerical simulation to determine the flow pattern changes on the flocculation effect.The main content of this research project:(1)On the basis of the flocculation kinetic theory, using computing software to calculate the FLUENT simulation of the grid flocculation tank through the fluid to explore this internal flow field situation;(2) Simulate the Turbulence Characteristics over the gate of the grid flocculation tank, various influencing factors, as well as double-gate plate numerical simulation study, to analyze the flocculation tank internal flow field changes, as well as optimal conditions;Simulate the turbulent flow characteristics of the grid flocculation tank over the gate, single gate panels, dual-gate numerically, use the evaluation indicators to measure the numerical simulation of flocculation efficiency, the following analysis can be drawn:(1) Numerically study the turbulent flow characteristics of the grid flocculation tank over the gate, to determine the gate board can effectively improve the water flow field, and improve the flocculation;(2) trash rack spacing, the thickness of the grid plate, the inflow velocity and trash rack width of the flow field have varying degrees of effect, of which the most prominent role is the trash rack spacing;(3) Numerically simulation the double gate plate to determine the spacing of the grid plate has the range of600～700mm, which is the scope of rational design and engineering specifications match; At the same time by increasing the flow rate through the gate approach can effectively improve the grid flocculation tanks, flocculation effect.This article limited analysed the flow pattern distribution law and the characteristics of the flow field, and analyse the simulation results to guide the design of research work, which also provide a new method for design work.