Study On Separation Performance Of Small Diameter Hydrocyclone

It is one of the main research hotspots of hydrocyclone to classify and separate fine solid particles from the liquid phase by the small diameter hydrocyclone.More experimental researches are demanded to verify whether the influence of optimum proportion of insertion depth and wall thickness of the vortex finder of the small hydrocyclone on its performance is similar to that of the large ones.Therefore,it is urgent to study the separation behavior of the fine particles in the small diameter hydrocyclone.In addition,most scholars focused on local improvement and optimization of the hydrocyclone,but the innovative design is scarce.Therefore,it has become an urgent problem that should be solved to explore,develop and design a new hydrocyclone,which could promote the separation efficiency of fine particles in the small hydrocyclone.The separation of the fine particles in a small hydrocyclone with the diameter of 50 mm was studied in this work.The optimum proportion of the insertion depth of the vortex finder to the diameter of the hydrocyclone,the wall thickness of the vortex finder and the flow rates were obtained by using the method of orthogonal design.On the basis of the optimal size,two kinds of vortex finders with tube-in-tube structure were designed,and the influence of vortex finders with tube-in-tube structure on the separation efficiency in the small hydrocyclone was investigated.In addition,the relationships of the separation efficiency,the modified separation efficiency and the pressure drop and the split ratio were discussed according to the optimal structure.Finally,the optimal structure of hydrocyclone was obtained by the analysis of separation efficiency and particle size separation efficiency.The experimental results showed that the cylindrical part of the hydrocyclone plays an important preliminary separation role.Additionally,a thin vortex finder which is extended to the junction between the cylindrical and the conical parts is beneficial to the separation efficiency when the fine particles are separated.The results showed that the optimum proportion of the vortex finder insertion depth to the hydrocyclone diameter in the small hydrocyclone is bigger than those in the big ones,and it is indicated that there is a remarkable difference of separation between them.Based on the traditional hydrocyclone with the diameter of 50 mm,a hydrocyclone with a vertical groove was designed.Numerical simulations of the separation behavior of two kinds of hydrocyclones with different structures under the same conditions were carried out by FLUENT.The velocity,pressure and volume fraction of solid distribution were compared.The results showed that the existence of the vertical groove has little influence on the velocity field and the pressure field inside the hydrocyclone.However,it has a certain guiding effect on the flow of the heavy medium,which is favorable to the separation of solid particles.