Separation Performance Study Of The Hydrocyclone With Double Vortex Finder

Aiming at the problems of low accuracy and wide products particle size in current hydrocyclone classification and separation,the paper attemps to achieve narrow-scale fine grading by using a hydrocyclone with double vortex finder.Three kinds of products,including the underflow,inner-overflow and outer-overflow can be obtained.By combining the method of numerical simulation,laboratory tests and industrial verification,the separation process of the hydrocyclone are studied in depth,meanwhile the separation mechanism of the hydrocyclone are explained in detail,which has important theoretical significance and engineering application value for the research and development of fine classification multi-hydrocyclone equipment.In this paper,the flow fields of the hydrocyclone with double vortex finder and conventional hydrocyclone have been simulated and compared.The results show that,compared with the conventional hydrocyclone,the internal pressure drop of the hydrocyclone with double vortex finder is smaller,the tangential velocity is larger and the gradient of variation is obvious.The axial velocity and redial velocity get smaller.The turbulent flow field is relatively sTable The inner overflow has fine and uniform particle size which is obviously finer than the ordinary overflow,achieving the goal of obtaining narrow-grain products.Taking the concentration and yield of each product,the production capacity of the hydrocyclone and the comprehensive classification efficiency as evaluation indexes,a series of single factor tests have been carried out to study the separation performance of the Φ150mm hydrocyclone with double vortex finder.The influence factors include pressure,cone angle,apex diameter,inner vortex finder diameter and insertion depth.The results show that,the pressure has great influence on the production capacity.The larger the cone angle is,the stronger the internal swirling effect becomes,then the inter-overflow yield and the particle size become larger accordingly.The apex diameter seriously affects various indexes of underflow products.Under the test conditions,the optimum range of apex diameter is 20-22 mm.As the inner vortex finder diameter increases,the yield of the inner-overflow and the cut size of the hydrocyclone increase.When the insertion depth of the inner vortex finders is 30-60mm longer than the outer vortex finder,the finest inner overflow product can be obtained,but when it is 30-60mm shorter than the outer vortex finder,the best classification performance can be obtained.The L9(34)orthogonal tests have been designed and performed.Taking the hydrocyclone production capacity,the inter overflow yield and the comprehensive classification efficiency as evaluation indexes,the primary and secondary factors which affect the classification performance of the hydrocyclone with double vortex finder have been analyzed.The factors include pressure,cone angle,apex diameter and inner vortex finders diameter.Finally the best combination of classification parameters are selected.Based on the above research results and the field conditions,a Φ381mm flat-bottom hydrocyclone with double vortex finder has been designed and fabricated for industrial verification.The results show that the comprehensive classification efficiency of the hydrocyclone increase by 12.03%compared with the original system after improvement.The inner-overflow yield accounts for 30.1%of the total yield of overflow products,which greatly reduces the load of the vibrating screen and the whole sand return amount,improving the comprehensive performance of the grinding and separation system.