Research On Three Dimensional Numerical Simulation Of Horizontal Swirl Sedimentation Tank

The precipitation process in the sewage treatment process,as an important part of the technology,mainly takes advantage of gravity sedimentation effect to remove a lot of suspended solids in sewage.Its purification effect determines the complexity and operating costs of the whole sewage treatment system.According to the theory of fluid mechanics,in addition to the importance of precipitation gravity toward suspended solids in the sedimentation tank,there are other forces that play a very important role in operational characteristics of suspended solids as well,such as: Basset force,Saffman force and Magnus force etc.The reasonable internal flow field can effectively change the hydraulic characteristics of the sedimentation tank,which has a great impact on the sedimentation effect.Based on the fluid mechanics principle,the current study constructed a new swirl sedimentation tank,analyzed its hydraulic characteristics and the motion of suspended particles,and carried out the numerical simulation towards hydraulic characteristics of both the newly constructed swirl sedimentation tank and the current radial flow sedimentation tank.The operating characteristics of solid particles in the settling tank were analyzed and compared as well.The results showed that,under the same water flow conditions,compared to the current radial flow sedimentation tank,the precipitation of swirl sedimentation tank has higher efficiency while in equivalent volume;under the same sedimentation efficiency conditions,the swirl sedimentation tank could dispose a greater amount of sewage while in equivalent volume.The current study provides new ideas and theoretical supports for the further improvement of the suspended sediment removal capacity,which is also significant in the optimal design of sedimentation tank.