Numerical Simulation Of Inclined Plate Sedimentation Tank Based On CFD

Theoretically,the core of the ideal inclined plate sedimentation tank is to measure the sedimentation effect by the average flow rate,and the influence of the uneven threedimensional flow field is not considered.In terms of design,there is uncertainty in the designed sedimentation tank due to the wide parameter range and other reasons.Therefore,the optimization of the hydraulic characteristics and removal rate of the sedimentation tank has been the subject of many researches.However,solving the problem by experimental means has limitations and takes a long time.With the development of CFD simulation technology,the use of Fluent to simulate sedimentation tanks has gradually emerged as a way of saving time and costs by simulating the flow state of the fluid in the tank,and also allowing observation of the particle distribution inside the tank while changing the design parameters,thus facilitating the analysis and optimisation of the parameters and ultimately generating a retrofit This makes it easier to analyse and optimise the parameters,and ultimately to generate a retrofit solution,achieving a win-win situation for both economics and technology.In this thesis,the two-phase flow transient simulation of the inclined plate sedimentation tank is carried out based on CFD theory,using the standard k-ε model and Mixture mixing model with the Beijing Super Cloud Computing Centre as the research object,and the simulation results after the calculation are analysed.The results are as follows:(1)when changing the height of the water distribution area of the sedimentation tank: due to the increase in the height of the water distribution area,the swirl formed within the water distribution area is larger and more obvious.The turbulent kinetic energy and the turbulent kinetic energy dissipation value also increased slightly with the height of the water distribution area within the range of about 2m in the sedimentation tank height,so that the water flow in this range of mixing to strengthen,the particles are not easy to precipitate.However,in the area above the inclined plate the turbulence decreases and the particles gradually sink.It was found that increasing the height of the distribution zone increases the turbulent energy and the rate of water dissipation between the inclined plates,which is not conducive to particle settling.The height of the distribution zone does not have a significant effect on the pressure and velocity fields,and the variation between the four conditions is small.(2)When changing the spacing between the sloping plates in a sedimentation tank:when the spacing between the sloping plates is smaller,the flow of water between the plates is more uniform and there are fewer small eddies.In terms of turbulence,the smaller the spacing between the sloping plates,the less turbulent the sedimentation tank is,the less mixed the water is and the more easily the particles settle.When the turbulent kinetic energy value and the turbulent kinetic energy dissipation value are more than2 m in the sedimentation tank height,the value of the sedimentation tank with a small distance between the inclined plates is lower,and the small distance between the inclined plates is more conducive to particle sedimentation.According to the comparison of the curves of turbulent power and consumption rate of the water flows between the inclined plates,a smaller distance between the inclined plates is more favourable to reduce the turbulence of the water.For the pressure and velocity fields,the spacing between the inclined plates has less influence.(3)When varying the size of the particulates suspended in the sedimentation tank:the effect on the internal velocity range,the pressure range and even the turbulence of the sedimentation tank is relatively small.However,due to the different particle diameters in the sedimentation tank,the flow trajectory of the water flow is less different,especially above the inclined plate,the flow is in the outflow direction,and the water flow with a particle size of 60μm is closer to the horizontal.