| With the growing concern of environmental protection by the society and the implementation of national energy conservation policy,it has been increasingly recognized that Using CFD (Computational Fluid Dynamics) technology to simulate the flow of sewage treatment system in the sewage treatment plant design and renovation process.The study using the Unitank process operation and management data of a sewage treatment plant in Shanghai as the initial conditions to model and analy the solid and fluid two phase flow in Unitank side-tank in different stage.Based on the comprehensive study on the basis of extensive literature,proposed using CFD technology to simulate the sewage and sludge two phase flow in Unitank side-tank. According to the Unitank process of a sewage treatment plant in Shanghai,Split the system by time and space,established three dimensional models of solid-liquid two-phase flow of three stages.According to the literature on solid and fluid two phase flow and hydrodynamic characteristics of secondary settling tank,transform the operation and management data of the sewage treatment plant as the initial conditions for the CFD modelling.Validated the model by sampling planned at monitoring points and comparing the calculated results with the actual measured values.The result showed that inclined tube layer had a great influence on the distribution of flow rate and sludge concentration at the feeding and stirring stage. Secondly at the effluent stage, bottom flow rate was faster than the middle and top,and there was a clear water-sludge interface at the height 3.5m to the bottom,sludge concentration by the side was thicker than that in the middle in the middle and top of the tank, and sludge concentration was positively correlated with the flow rate.Thirdly at the feeding stage, the was a counterclockwise circulation in the tank,and the influent at 4 different points flowed differ from each other,and there was not much correlation between flow rate and sludge concentration.
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