Numerical Simulation Of Sedimentation Tank And Parameter Influence Analysis

The sedimentation tank is an important unit that can't be substituted in the sewage treatment process, which about 25% of the total investment of a sewage water treatment plant is used in. Therefore, the design quality of the sedimentation tank influences directly the whole sewage water treatment system. At present, the design of sedimentation tank mainly bases on three hypotheses of the ideal sedimentation tank, and neglects the influence of the flow pattern to the sedimentation tank, it has a big subjectivity. So, it is hard to achieve the predicted water treatment effect in actually work, thus it is necessary to make further research.Based on the computational fluid dynamics software FLUENT, is used to numerically simulate two-dimensional rectangular sedimentation tank model which was established by Dr. Imam in The University of Windsor of Canada in 1983. Comparing with the numerical result and the experimental data shows that the standard k ?εturbulence model can simulate the hydrodynamics characteristics of water flow in sedimentation tank well.Mathematical model developed previously is used to make an unsteady numerical simulation of the flow field in a rectangular sedimentation tank that this paper selected, with which the distribution of the flow field and concentration field in the rectangular sedimentation tank is found at different time. Furthermore, the mathematic model is applied to calculation of the velocity field of mixture flow, concentration field of suspended solids for rectangular sedimentation tank under different inlet high, different locations of baffles, different granule diameters condition. This paper gets some necessary information about the structure optimization though analysis of the calculated results.Comparison and analysis of the numerical results indicate that variety of inlet height within limits has little influence to the efficiency of the rectangular sedimentation tank. The high of the baffles and size of particles affect removal efficiency of suspended solids very much. For the high of the baffles determine the circulation region and hydraulic retention time in the settling tank, and then...