The Numerical Simulation Study Of Perforated Swirl Flocculation Tank With Adding Grid Plate

In recent years,due to the deterioration of water quality and large number of expansion and new sewage treatment plants,a corresponding increase in treatment costs and construction costs.Therefore,in order to improve the flocculation effect to save energe,it is necessary to select proper water treatment structure and optimize it.Flocculation as an integral part of water treatment,the flocculation effect will impact the follow-up treatment effect.As a common flocculation structure in small waterworks,perforated swirl flocculation tank have the advantages of simple structure,convenient construction and low cost.However,the main disadvantage is that the flocculation effect can not be guaranteed when the amount of water changes greatly,and the flocculation effect is unsatisfactory.Reference the grid flocculation tank,consider adding a grid plate in the shaft of the perforated swirl flocculation tank to enhance the spoiler and enhance its flocculation effect.We choose turbulent kinetic energy dissipation rate???and vortex velocity gradient?G₀?as the evaluation index of flocculation in this paper?Using the method of numerical simulation of CFD to simulate the front and middle sections under the conditions of the number of grid plates,the spacing and the mesh size was different.Based on this,the optimal parameters are obtained and a more economical and reasonable optimization plan is proposed.The result of numerical simulation shows that:?1?Perforated swirl flocculation tank with grid plate can effectively improve the flocculation effect.?2?The optimal number of grid layers in the front section is 4 layers per shaft,and the optimal grid spacing is 400mm?3?The optimal number of grid layers in the middle section is 3 layers per shaft,and the optimal grid spacing is 400-500mm?4?The optimal mesh size increases with the increase of scale.The front section is60-70mm;middle section is 80-100mm.The simulation results in this paper have certain reference value to improve the flocculation pool and the design of practical engineering.