Simulation Study Of Integrated Oxidation Ditch With Vertical Circle

the Integrated Oxidation Ditch with Vertical Circle use the mutual conversion of potential energy and kinetic energy to save energy consumption By means of push flow and intermittent aeration,the Integrated Oxidation Ditch with Vertical Circle reduces the floor area by half compared with the traditional integrated oxidation ditch.The oxidation ditch has good water quality treatment and stable operation.As a new type of integrated oxidation ditch,the current research is mostly the experimental research of small-scale test model,which has limitations on the scale of oxidation ditch and has limited help for the practical engineering application.The hydraulic conditions in the operation process can not be optimized only by the value of traditional oxidation ditch and integrated oxidation ditch design code.Therefore,the Integrated Oxidation Ditch with Vertical Circle is studied.With the help of CFD numerical simulation method,This paper analyzes the internal flow field of the Integrated Oxidation Ditch with Vertical Circle to research the effects of the distance of the guide plate and the depth of submergence and the distance of the ejector and the direction and the depth on the flow pattern and the overall reaction efficiency of each part of the reaction zone were studied through the analysis of the internal flow field map of different parts of the monitoring section in the reaction zone of the three-dimensional circulation integrated oxidation ditch with different actual scale to optimize the size of the reaction zone of the main ditch by hydraulic method.The simulation results are analyzed as follows:(1)The velocity distribution is more uniform and the energy distribution is more reasonable and the average velocity is closer to the optimal velocity when the installation direction of the flowmaker is opposite to the direction of the incoming flow.(2)The effect of water treatment is obvious when the position of the flowmaker is changed when other structural dimensions are fixed.The optimal location is behind the bend diversion wall in the lower anaerobic zone.The best position of the flowmaker depends on the scale,The best position of the flowmaker with the scale of 8000m3/d,10000m3/d,11000m3/d,12000m3/d,13000m3/d,14000m3/d,and 17000m3/d is 8m-12 m behind the diversion wall of the upstream bend,The best position of the flowmaker with a scale of 150000m3/d,is 8m behind the downstream diversion wall.(3)The variation of the installation height of the flowmaker mainly affects the velocity distribution inside and outside the guide wall of the bend The higher the height of the flowmaker from the bottom of the oxidation ditch,the more uneven the velocity distribution inside and outside the guide wall of the bend,and the lower the average velocity in the reaction zone.The best height of the flowmaker is 350 mm from the bottom.(4)The paper set baffles behind the aeration turntable in order to improve the uneven velocity distribution in the downstream of the aeration turntable in the aerobic area.When the baffles is 2.8-3.0m downstream of the middle axis of the aeration turntable,the velocity distribution is more uniform and the hydraulic effect is better.The simulation results have certain reference value for the engineering design and operation of the Integrated Oxidation Ditch with Vertical Circle...