Study On The Flow Characteristics Of Sepiolite Powder Particles In Jet Classification Zone

The sepiolite powder particles classifier based on the principle of jet Coanda effect,which makes sepiolite powder particles have different motion trajectories in the jet classification zone and realizes size classification of sepiolite powder particles,according to the strength of the Coanda effect of sepiolite powder particles with different particle sizes on the wall of Coanda block in the classifier.Based on this theoretical basis,the effects of the main structural parameters(the curvature radius of the Coanda block)and process parameters(jet velocity and outlet pressure)of the classifier on the classification of sepiolite powder particles are discussed respectively by numerical simulation and experimental research.This dissertation mainly discusses the following aspects:(1)The physical characteristics of sepiolite powder particles are measured.The physical characteristics of sepiolite powder particles are measured by SU5000 field emission scanning electron microscope,Mastersizer2000 laser particle size analyzer and volumetric method,which provide the necessary data for the establishment of the mechanical model and numerical simulation of sepiolite powder particles in the jet classification zone.(2)The jet mechanics model of sepiolite powder particles is established.The force analysis of sepiolite powder particles in the jet classification zone is carried out and the jet mechanics model is established by the boundary layer theory and Coanda effect of gas-solid mixed flow of sepiolite powder particles,which provide theoretical basis for numerical simulation of sepiolite powder particles flow characteristics.(3)The flow characteristics of sepiolite powder particles in jet classification zone are analyzed and the collection zones are divided.Based on the discrete phase model of computational fluid dynamics software Fluent,the influence of the curvature radius of Coanda block,the jet velocity and the outlet pressure on the flow characteristics of sepiolite particles in the jet classification zone is analyzed,and the optimal parameters are obtained,which provide a theoretical basis for the division of collection intervals of sepiolite powder particles with different particle sizes.(4)The experimental research on jet classification of sepiolite powder particles is carried out.The experimental platform is built,and the single factor control method is used to perform jet classification experiments on sepiolite powder particles with different particle sizes from the three factors of Coanda block curvature radius,jet velocity and outlet pressure,to verify the numerical simulation results.Theoretical analysis and experimental results show that the classifier based on the jet Coanda effect improves the classification accuracy and classification effect of sepiolite powder particles,and the suitable curvature radius of Coanda block,jet velocity and outlet pressure are helpful to improve the classification effect of sepiolite powder particles.