CFD Simulation Of Parameters And Operating Condition Effects On De-oiling Hydrocyclone Efficiency

In view of the increasingly serious problem of oily wastewater treatment, this paper encompasses development structure parametric and operating condition of deoiling hydrocyclone by CFD simulation. It aimed on the effect of different structure sizes and operating conditions on hydrocyclone flow field, separation performance and energy loss effect, and optimized structure parameters by response surface.In this paper, the main results of simulation analysis are as as follow:① It has compared the F hydrocyclone with the optimization hydrocyclone on the flow field characteristics, analyzed the velocity field, pressure field, separation performance and energy loss in the hydrocyclone, and found that the optimization model has improvement on low energy consumption and high separation efficiency.② when the deoiling hydrocyclone with nominal diameter(Dc)of 25 mm and other structure and operating parameters are constant, the single factor simulation experiment of structure parameters was carried out.which inclueds the inlet size, the diameter of the overflow pipe,the overflow pipe insertion depth, the swirl chamber diameter, the swirl chamber length,the big angle, the small angle,the underflow pipe diameter and the underflow pipe length.Results show that the change of any structure size about the hydrocyclone will only affect the size of the tangential velocity and axial velocity variation, but will not change its distribution. Moreover,it has got the change of structure parameters size on the influence of the pressure drop and separation efficiency.③With the constant of structure parameters about the deoiling hydrocyclone,CFD analysis of operating parameters and fluid properties,including inlet flux, split ratio,inlet pressure, inlet inlet oil volume fraction,oil diameters,which effects on the deoiling hydrocyclone efficiency and the pressure drop has been studied. Results show that The optimal treatment scope of inlet flux varies from5.5 m3/h to 6.5m3/h for this deoiling hydrocyclone. Moreover,The fitting result of pressure drop and inlet flux is1483.20094.0i=DQP.it shows a agreement with other scholars.O il droplets size d50 is approximately equal to 40 microns. And when d > 100 microns, the separation efficiency of oil droplets can reach 98%.④ It has been optimized structure parameters of the deoiling hydrocyclone by the response surface.Results show that the swirl chamber diameter and the small cone angle are the main factors which effects the separation performance of the deoiling hydrocyclone.And other structure parameters which influences on separation efficiency are relatively small. The inlet size, underflow pipe diameter and small cone Angle are the main factors which effects the pressure drop of the bottom flow. And other structure have little impact on the pressure drop of the bottom flow.And the prediction model of the separation efficiency and the pressure drop about the deoiling hydrocyclone have been established. It can comprehensively reflect the deoiling hydrocyclone structure parameters effect on the separation efficiency and the pressure drop which will help to optimize the design of the deoiling hydrocyclone.