Research And Discrete Element Simulation On Rotary Coal Cutting Process Of Conical Pick

At present,with the implementation of the production capacity and the strategy of new-old kinetic energy conversion,the coal industry is developing from the pursuit of speed,efficiency and high productivity to the pursuit of quality,green and intensive.The improvement of coal cutting efficiency and quality relates to the transformation of the coal industry,and the shearer,as the core device of fully mechanized mining machinery,of which coal mining process is directly related to the coal cutting efficiency.Therefore,the coal cutting mechanism of conical pick on the shearer has become the focus in recent years.In this paper,the rotary cutting coal process of conical pick driven by the traction speed of shearer and the angular velocity of drum was studied.(1)The rotary cutting coal process was analyzed,then the variation of cutting angle and cutting thickness with cutting radius,angular velocity and traction speed in coal cutting process was calculated based on the derived equation.Where the cutting thickness was most affected by the traction speed,the cutting angle was most affected by the cutting radius,and the cutting angle had a sudden change when the pick was cutting to the position of maximum cutting thickness.(2)On the basis of coal cutting model of Evans,a rotary cutting mechanical model was proposed by analyzing the rotary cutting coal process,from which could be concluded that variation of cutting force in coal cutting process with different traction speed,angular velocity and cutting angle,where the cutting force was quite small when cutting angle is 46-47°.(3)According to the stress-strain curve of coal that obtained from three axis compression test,the discrete element software PFC2D was used to simulated the three axis compression experiment to perform the parameter calibration,the microscopic mechanical parameters that needed for coal model are obtained.(4)Aimed at the different cutting parameters,the discrete element coal model were established to do the research on rotary cutting coal process of conical pick,the variation of cutting force with different angular velocity,traction speed and installation angle was concluded,and the crack propagation process of coal in coal cutting process at different cutting parameters was analyzed.(5)In view of the distribution of coal structure surface,the discrete element coal model with different joint and bedding were build and simulated,the variation of cutting force and crack number with different joint angle,joint spacing and joint strength was concluded,and the crack propagation process in coal cutting process at different coal structure surface was analyzed.