Thin Seam Shearer Under Different Cutting Conditions Simulation Study On Drum Working Performance

In view of the complex and changeable geological conditions of thin coal seam,shearer drum needs to regularly cut the complex coal rock which is difficult to cut,such as top and bottom,dirt and rock layer.Therefore,in view of the problems of insufficient cutting ability and low loading performance in thin coal seam mining,the research group developed a new thin coal seam shearer with inclined drum arrangement,taking this as the research object to cut pure coal,cut roof and cut floor under different cutting conditions,and conducted in-depth analysis from three aspects:theoretical model,numerical simulation and experimental research.According to the relative position of coal stratum and drum,the motion trajectory and velocity equation of single pick of shearer drum under different cutting conditions are constructed.Based on this,the theoretical model of three-way load for cutting the crushed coal rock with additional grinding action is derived.On this basis,the factors affecting the three-way load on the coal rock are considered,such as the thickness change of coal rock,different loose coefficient,friction coefficient and cutting impedance,etc.,and the three-way load theoretical model is determined by piecewise accumulation calculation.By using discrete element EDEM software,the simulation tests of cutting pure coal,cutting roof and cutting floor with conventional arrangement and inclined arrangement of drum are established.The load characteristics of a single cutter and the whole drum are investigated by using single factor variable control method.The theoretical values are calculated according to the theoretical model and compared with the simulated load.The errors are in line with the actual engineering requirements,and the accuracy of the theoretical model is verified.Based on the theoretical model of coal loading with conventional drum arrangement,the theoretical model of coal loading performance of cut composite coal rock is further established,considering the influence of inclined drum arrangement on coal loading performance,and on this basis,the theoretical model of coal loading performance after inclined drum arrangement is derived.The theoretical loading performance value and simulated loading test value are calculated and compared,and the accuracy of theoretical calculation is verified.Based on the multi-gear rotary cutting test bench,the measurement of coal and rock parameters provides a theoretical basis for the simulation of coal wall parameters and the setting of coal and rock parameters in discrete element software.Based on the experimental equipment,the experimental study of single factor rotary cutting coal and rock is carried out,and the changing law of load characteristics of cutting coal and rock with different parameters is explored.Furthermore,the errors of theoretical,simulated and experimental loads under different coaxial inclination anglesθand different cutting thicknesses h_max are analyzed,and the accuracy of the theoretical model and numerical simulation is verified.The load characteristics and loading performance of the drum under different cutting conditions are analyzed from theoretical model,numerical simulation and experimental research,which provides practical engineering application value for improving the cutting ability and loading efficiency of the drum shearer in thin coal seam.