Experiment and simulation analysis of material crushing and classification of ultrafine pulverizer

MEI Xiao; TIAN Yuan; LIU Xiangwei

doi:10.13732/j.issn.1008-5548.2023.06.007

Abstract：In order to obtain the best crushing effect of the ultrafine pulverizer and ensure the fine and uniform discharge parti-cles,the ultrafine pulverizer was used for crushing experiments under a certain cutter head speed.In order to optimize the feeding frequency,the influence of different feeding frequency on the crushing effect of cutter head was analyzed.By comparing the parti-cle size distribution of experimental samples,the crushing and grading effect of cutter and grading wheel were analyzed.Fluent software was used to visualize the flow field inside the ultrafine pulverizer,and the mass flow rate distribution of materials at the discharge port and the flow field state in the grading region were analyzed under different grading wheel speeds.The result shows that when the cutter speed is 1 232 r/min,the feeding frequency has little influence on the particle size distribution,and the opti-mal feeding frequency is 20 Hz.The rotating speed of the grading wheel has greater effects on the grading effect when the particle size is more than 40 μm,but has less effects when the particle size of is from 0.5 to 40 μm.With the increase of the rotation speed of the grading wheel,the content of fine particles at the outlet of the material increases and the particle size decreases.When the cutter speed is 1 232 r/min and the grading wheel speed is 900 r/min,the velocity contour distribution in the crush-ing chamber is the most uniform and the fluid flow is stable,the symmetry of tangential velocity and pressure distribution is the best,and the air flow shows an overall upward movement in the axial direction,which is conducive to the stable discharge of materials.The optimal rotational speed of the grading wheel is 900 r/min.