Coal Loading Process Simulation Of The Shearer And Research On Coal Loading Efficiency

As the major actuator of shearer,besides cutting coal,spiral drum’s another main function is to load the coal into scraper conveyor.In the past decades,the coal loading efficiency has always been the focus in the field,especially the thin seam shearer.Based on analyzing the coal loading theory,some factors affected the coal loading efficiency such as the main structure parameters,motion parameters,comprehensive parameters of coal rock as well as forms of drum structure were analyzed with discrete element method.Based on the coal loading mechanism of shearer drum,force analysis and kinematic analysis were conducted on one coal particle on the blade,the coal loading efficiency formulation was calculated to obtain the main factors affected the coal loading efficiency including drum structure parameters such as diameter of drum,blade and hub,thickness and number of the blade,spiral angle,drum width,and motion parameters such as speed and velocity of the drum,as well as other parameters such as the mining height,full coefficient,friction angle and the loosening coefficient of the coal flow.Combining above factors together with coal loading theory,these factors affected the coal loading efficiency were further analyzed,which provides theoretical basis for further research on coal loading efficiency.Based on the fundamental theory of discrete element,discrete element software PFC3D was used to establish the coal wall and the middle trough of scraper conveyor model,drum model established in the UG software was imported in the PFC software,forming a simulation model of coal loading.A certain type thin seam shearer was taken as research object,the blade spiral angle,speed and velocity of the drum were taken as the main design variables,the coal loading process of drum clockwise an reverse was simulated,coal loading efficiency and velocity,number of particles in the drum were calculated to analyze the effects of the three factors on the coal loading efficiency and the optimized matching.The speed of the drum was taken as the major research point to analyze its effect on the velocity of X,Y,Z direction.The results provided reference value for the drum design and motion parameters,selection.In accordance with the coal loading mechanism and working features of the shearer,effects of the coal property parameters on coal loading efficiency including dampness,fraction coefficient,density and granularity of the coal were analyzed.With discrete element simulation method,the friction coefficient of coal,the coefficient of friction between coal and blade,and granularity of coal particle size were taken as the major object to research the effect on the coal loading efficiency of the drum,which provide experimental basis to further improving the coal loading theory.Through discrete element method,traditional spiral drum,cone spiral drum,spiral drum with variable slop angle and spiral drum with axial slop blade with the same specification were taken as research object,starting from axial velocity and axial throw distance of the coal flow,the motion track of coal flow and microscopic mechanism between coal flow and blade were analyzed,simulation results show that:when the drum rotates reversely,spiral drum with variable slop angle and spiral drum with axial slop blade can raise the coal loading efficiency;when the drum rotates clockwise,spiral drum with axial slop blade shows better coal loading result and mechanical analysis was conducted on these two structure.Finally,the author proposed that drum design in the future should take following aspects into consideration:reducing fraction between coal flow and blade,shortening motion time of coal inside the drum and raising the acceleration of coal flow inside the drum.