Numerical Simulation On Flow Field And Structural Design Of Hydrocyclone Separator

Water is the resource of all things.Proper sewage treatment can not only reduce pollution,but also alleviate the current situation of water shortage.Hydrocyclone separator is one of the most common equipment of sand-removal process in sewage treatment plants.It has lots of advantages,such as simple construction,small cover of area,simple operation and high separation efficiency.Now with the industrial development,the sewage discharge of cities and towns is increasing.So the existing hydrocyclone separator is difficult to meet the needs of sewage treatment plants.The sewage disposal capacity of sewage treatment plants needs to be improved urgently.So it is very important for industrial development to develop a cost-effective type of hydrocyclone separator.In this paper,the hydrocyclone separator is taken as the research object,and numerical simulation of flow field has done on it.The research work on external operation parameters and internal structural parameters of the hydrocyclone separator is carried out.The fluid motion in the hydrocyclone separator is complex turbulent motion and the volume concentration of particle phase is low.So the numerical simulation of flow field is divided into two stages.The first stage is to simulate the flow field of liquid phase,using VOF model and RSM model.In the second stage,DPM model is added to simulate the solid-liquid two-phase flow field on the basis of the convergence of the liquid phase.The main results are as follows:(1)The three-dimensional velocity characteristics of flow fluid and the volume concentration distribution of particle phase are studied.The influence of operation parameters on the performance of the hydrocyclone separator is analyzed.The results show that tangential velocity and axial velocity have greater influence on the flow fluid of the hydrocyclone separator.For small particle size of 0.075-0.1mm,the separation efficiency of the hydrocyclone separator decreases with the increase of inlet velocity;it fluctuates between 20%and 60%.And for large particle size of 0.15-0.2mm,the separation efficiency of the hydrocyclone separator increases first and then decreases with the increase of inlet velocity;it fluctuates between 40%and 90%.The separation efficiency of the hydrocyclone separator is greatly affected by inlet velocity and particle size.And it is less affected by the volume concentration of particle phase.At low inlet velocity,the separation efficiency decreases first and then increases with the increase of particle volume concentration.At high inlet velocity,the separation efficiency increases first and then decreases with the increase of particle volume concentration.(2)The influence of structural parameters on the flow field,pressure drop,split ratio and separation efficiency is analyzed under proper condition.The results show that it is better for improving the performance of the hydrocyclone separator to change the column height,cone angle,inlet section angle and center cone height properly.It can improve the pressure drop and the split ratio,and the separation efficiency of the hydrocyclone separator can be increased to more than 80%.