Numerical Simulation Of Medium Particle Distribution In Three-product Dense Medium Cyclone Based On CFD

In the coal preparation process,the dense medium process has strong adaptability to coal quality,wide selection of particle size range,high separation efficiency,high separation accuracy,easy to realize coal preparation process automation,large processing capacity and better integrated with other coal preparation processes,have become the leading coal preparation method in China.The three-product dense medium cyclone is widely used in coal preparation plants in China because of its advantages of small size,large processing capacity,no moving parts,high separation efficiency,and only one set of dense medium system.There are many factors influencing the separation density of the three-product dense medium cyclone,but its two-stage dense medium density adjustment is more difficult,and the first-stage separation density and the second-stage separation density are difficult to meet the process requirements at the same time.Therefore,it is of great significance to study the distribution characteristics and influencing factors of the particle volume fraction in the cyclone.In this paper,the WTMC1200 / 850 pressureless three-product dense medium cyclone is selected as the research object,using CFD technology,mixed multiphase flow model(Mixture),combined with the Reynolds stress model(RSM),with dense medium particles 0.01mm(4.00%),0.02mm(3.40%),0.03mm(1.90%),0.04mm(1.50%),0.05mm(1.30%),0.08mm(1.10%)constitute the suspension,using statistical principles,using the time average to characterize the results,research its internal pressure distribution,to investigate its stability issues;study the characteristics of density distribution,and compare with the distribution law of particle volume fraction,discuss the relationship between particle distribution and density distribution,and conclude that the effect of particles of different particle sizes on density distribution is not the same.The structural parameters of a cyclone such as the diameter of overflow of the first section,the depth of insertion of overflow pipe of the first section,the shape of the medium inlet(aspect ratio)and the shape(aspect ratio)and area of the outlet(connecting pipe)of the first section and operating parameters such as the inlet velocity of the cyclone and the distribution of particles of different particle sizes in the inlet suspension are selected,and a single factor analysis was carried out to analyze the significance of its influence on the stability and density distribution,and through the particle distribution to explore the particle size that causes the densitydistribution to change.Finally,through analysis,it is found that changing the distribution of particles with different particle sizes in the inlet suspension has the greatest influence on the density distribution of the cyclone,which is an effective method of density compensation and adjustment.