Discrete element simulation analysis on the wear characteristics of drum in coal seam with gangue

During its working process,the spiral drum completes two functions of coal-cutting and coal-loading. The load on the spiral drum of a shearer working under complex coal seam conditions has nonlinearity,time-varying,impact and strong coupling. Therefore,the wear problem of drum is inevitable,which seriously affects its working performance and production efficiency. Based on the virtual prototyping technology,the discrete element numerical simulation method was used to study the wear characteristics of drum in coal seam with gangue,so as to improve its cutting performance and prolong its service life. Based on the coal-rock cutting mechanism and the discrete element method,the interaction relationship between drum and coal-rock and the wear model of drum were analyzed. Taking the MG2×55 /250-BWD shearer spiral drum as an example,and the Hertz-Mindlin with bonding model was used as the contact model between particles,the Hertz-Mindlin with Archard Wear model was used as the contact model between coal-rock and drum,the coupling model was established for drum cutting in the coal seam with gangue by Pro / E and EDEM. The influence trend of the traction speed,the drum rotation speed,the spiral angle and the compressive strength of coal-rock on the drum wear was analyzed by using the orthogonal test method,and the evaluation models of pick and blade wear depth were obtained through a multiple regression analysis. Based on the actual working condition,the cutting ratio energy consumption,load fluctuation coefficient and productivity were comprehensively considered,the multi-objective optimization function was constructed and solved by MATLAB to obtain the optimal working parameters of the drum.The results show that the drum assembly has different degrees of wear,and the wear of the local contact area of the pick tip is the most serious. The main wear area of the blade is near the pick root of the tail piece. The compressive strength of coal-rock and the traction speed increase,the wear of pick and blade is intensified. The drum rotation speed increases,the pick wear depth decreases,the blade wear depth increases first and then decreases. The spiral angle increases,the pick wear depth increases first and then decreases,the blade wear depth gradually decreases. The compressive strength of coal-rock is the main factor causing the wear of pick and blade. When the compressive strength of coal-rock is 30 MPa,and the traction speed is 5. 66 m / min,the drum rotation speed is 80. 40 r/ min,and the spiral angle is 11. 35°,the drum performance is optimal. The cutting ratio energy consumption is 0.713 2 kW·h / m3,the load fluctuation coefficient is 0.0819, the wear depth of pick, blade and end plate are 1.595 μm,1.0617 nm and 0. 907 nm,respectively,and the productivity is 315. 4655 t / h. The distribution of the drum wear in the discrete element simulation results is consistent with the actual wear of the drum under the field condition,which verifies the feasibility of the simulation model and process. The quantitative analysis of the drum wear problem can be realized using the research method,which can greatly reduce the test cost and contribute to the research and development of efficient,powerful and wear-resistant drum.