Research On Performance Of Special-shaped Drum

In order to improve the recovery rate of coal resources,extend the service life of the mine,and realize the sustainable development of the coal industry,the coal seams that were rarely mined before,such as thin-coal seams,those containing gangues and hard inclusions,must be mined in the future.In the process of coal mining,coal cutting and coal loading performance of a shearer is essential.While the poor drum coal-cutting and coal-loading performance has become the key issues of improving the efficiency of coal seam mining.Therefore,improving the structure of the drum and studying on coal-cutting and coal-loading performance of special-shaped drum has the great significance for the development of coal mechanization mining technology.In this paper,the methods of theoretical analysis,simulation by discrete element software,simulation by finite element software and experiment were used.The cutting performance and loading capacity of special-shaped drum and traditional drum were compared.The research on coal-cutting theory was carried out for current drum.And the coal cutting process of the drum was briefly analyzed.The coal-loading with drum ejection mechanism and coal-loading with drum pushing mechanism have been analyzed based on theories of mechanics of granular media and monomer mechanics.According to the structural characteristics of the drum,the loading capacity of the drum per unit time was used to express the coal loading performance of the drum,and an expression for easily calculating the drum loading capacity was introduced.The 3D simulation model of drum-coal was established and the analysis object was the cutting torque and traction resistance of traditional drum and ladder drum.Research results showed that the cutting torque and traction resistance of ladder drum is less than traditional drum when cutting coal and rock under the same cutting efficiency,but except the first knife,which indicates that cutting performance of the ladder drum is better than traditional drum and provides a reference for design of new type shearer drum.In addition,a further optimized design for the ladder drum structure was carried out.When the diameter of the hub was the same as the diameter of the rear hub,the ladder drum had the best coal-cutting performance.Based on the basic theory of discrete element,simulation model of drum coal-loading process was established and the analysis object was coal loading rate of traditional drum and globoid drum.Research results showed that due to the conical shell,the depth of vane being minimal at the face side increased linearly across the cross-section of the drum,reaching maximum at the discharge point,coal loading rate of globoid drum was higher than traditional drum.In addition,a further optimized design for the globoid drum structure was carried out.When the cone angle of the hub was 80°,the globoid drum had the best coalloading performance.Taking the compressive strength of natural coal samples as the main simulation quantity,the artificial coal wall was configured to provide experimental basis for the research on coalcutting and coal-loading performance of drums.Based on the coal rock cutting test-bed,experiment about coal-cutting and coal-loading performance of the processed special-shaped drum was carried out.And by studying the rock-breaking process and the cutting loads,we found that the results were further validated with experimental data.Based on the analysis of mechanism dynamics,the slotting device was simplified as a linkage mechanism,and the kinematic trajectory simulation analysis was carried out.The research shows that the new rotary drum can theoretically meet the square function of the section after the cutting of a working stroke.The main structure of the rotary drum was subjected to coal-cutting and coal-loading simulations.The study showed that due to the semi-closed state of the rotary drum loading process,coal particles were directly discharged from the rotary drum type notch to the scraper conveyor.The coal loading performance was better than the ordinary type drum.