【作者】 高魁东；

【导师】 杜长龙；

【作者基本信息】 中国矿业大学 ， 机械设计及理论， 2014， 博士

【摘要】 薄煤层采煤机滚筒作为机械化薄煤层工作面开采设备的主要工作部件，其性能好坏直接影响采煤机的开采效率。随着薄煤层采煤机双电机并联技术的不断成熟，薄煤层采煤机滚筒的截割性能已基本满足开采要求，而滚筒装煤性能已成为阻碍薄煤层开采效率提高和薄煤层滚筒采煤机推广使用的关键问题。因此，开展薄煤层滚筒采煤机的装煤性能研究对煤矿薄煤层机械化开采技术的发展具有重要意义。本文采用理论分析、模化试验研究和离散元软件仿真的方法，对影响滚筒装煤性能主要结构参数、工作参数、煤层工作面角度、滚筒位置参数和摇臂厚度等因素进行了深入研究。本论文基于散体力学理论和单体力学理论，对抛射装煤机理和推挤装煤机理进行了分析，得到了不同结构参数下煤体轴向速度和切向速度的计算公式；结合薄煤层采煤机滚筒的结构特点和工作特点，分析了滚筒结构参数和工作参数对滚筒装煤性能的影响规律，并给出了滚筒最小和最大理论转速、最大理论截深以及循环煤系数的计算公式，为滚筒的结构设计和工作参数选择提供了依据。以煤岩截割试验台为基础，利用研制的模化滚筒对影响滚筒装煤性能的主要结构参数和工作参数进行单因素模化试验研究和三因素正交模化试验研究。单因素试验研究得到了筒毂直径、叶片螺旋升角、滚筒截深、滚筒转速和牵引速度以及破碎煤体粒度分布对滚筒推挤装煤率和抛射装煤率的影响规律。三因素正交试验研究分别得到了筒毂直径、叶片螺旋升角、滚筒截深与滚筒转速、牵引速度匹配下，各结构参数与滚筒工作参数对滚筒装煤率影响的显著性。模化试验研究结果为薄煤层采煤机滚筒的结构设计和参数选择提供了依据，为后续的仿真试验研究提供了试验验证。基于离散元基本理论，利用PFC3D模拟软件建立了滚筒装煤过程的仿真模型，得到了颗粒参数和墙体参数对滚筒装煤性能的影响规律。以模化试验条件为基础，建立了滚筒离散元仿真准确性的验证模型，并利用该模型进行了多组仿真试验，仿真试验结果与模化试验结果的对比表明在合适的颗粒粒径和颗粒刚度下，滚筒装煤的三维离散元仿真结果与模化试验结果较为相近，证明了三维离散元法用于模拟滚筒装煤过程的可行性和准确性。利用三维离散元软件PFC3D对不同工作面角度下滚筒的装煤过程进行了仿真研究，得到了工作面走向倾角和工作倾角对滚筒抛射装煤率和推挤装煤率的影响规律。仿真结果表明：滚筒抛射装煤率和推挤装煤率在负走向倾角下极低，薄煤层机械化开采工艺设计时应尽量避免负走向倾角的出现；滚筒推挤装煤率随工作倾角的增加呈线性减小趋势，抛射装煤率随工作倾角的增加呈先显著下降后缓慢下降的趋势且滚筒在负工作倾角下的抛射装煤率较水平倾角下的抛射装煤率只有微弱减小。仿真中还对负走向倾角下滚筒抛射装煤的改进措施进行了分析和仿真验证，指出了通过提高颗粒轴向速度和降低颗粒出口位置高度的方法能够在一定程度上增加滚筒抛射装煤率。根据薄煤层采煤机的滚筒结构特点和工作环境，建立了薄煤层采煤机截割部工作过程的仿真模型，得到了滚筒底部距刮板输送机中部槽高度、煤壁与刮板输送机中部槽距离和摇臂壳体厚度对滚筒装煤性能的影响规律，为薄煤层采煤机摇臂、滚筒以及配套设备的设计和工作参数的选择提供了依据和参考。更多还原

【Abstract】 As the main working part of mining mechanization equipment used in thin coal seamface, the drum performance affects the production efficiency of thin coal seam shearerdirectly. With double motor parallel technology of thin coal seam shearer being maturing,the demand of production has been satisfied by the cutting performance of coal seamshearer drum basically. While the poor drum coal-loading performance has become the keyissue of improving the efficiency of thin coal seam mining and popularization of thin coalseam shearer. Therefore, the research on coal-loading performance of thin coal seamshearer drum has great significance for the development of coal mechanization miningtechnology. In this paper, the methods of theoretical analysis, modelling experiment andsimulation by discrete element software are used. The main structural parameters, workingparameters, coal seam working face angles, position parameters of drum and ranging armthicknesses which affecting coal-loading performance of drum were studied deeply.The coal-loading with drum ejection mechanism and coal-loading with drum pushingmechanism have been analyzed based on theories of mechanics of granular media andmonomer mechanics. Then the computational formulas of axial velocity and tangentialvelocity of coal body with different structural parameters are obtained. Combining thincoal seam shearer drum structure and working characteristics, the influences of drumstructure parameters and working parameters on coal-loading performance of drum areanalyzed. The formulas of the minimum theoretical speed, the maximum theoreticalcutting depth, the highest theoretical speed and circular coal coefficient are given,providing references for the structural design and working parameters selection of drum.Based on the coal rock cutting test-bed, the single factor experiment and three factorsorthogonal modeling experiment about drum structure and working parameters whichimpacted coal-loading performance directly are carried out by using the designed modeldrum. The influence law of drum hub diameter, vane helix angle and drum cutting depth,drum rotating speed, drum hauling speed and the distribution of broken coal particle sizeon coal-loading rates of drum ejection and drum pushing are obtained in single factorexperiment research. In three factors orthogonal experimental research, the significantinfluences of structural and working parameters on drum coal-loading rate are acquired,under the matching of drum hub diameter, vane helix angle and drum cutting depth, drumrotating speed and hauling speed. Modeling test results provide references for the structuraldesign and parameter selection of thin coal seam shearer drum, and provide experimental verification for the subsequent simulation experiment research.Based on the basic theory of discrete element, simulation model of drum coal-loadingprocess is established by using simulation software of PFC3D. Then the influence laws ofparticle parameters and wall parameters on drum coal-loading performance are studied.Based on the condition of modeling test, the accuracy verification model of drum discreteelement simulation is established, and several simulation tests are carried out by using theverification model. The comparison of simulation test results and modeling test resultsshows that the simulation and test results are relatively close with the suitable particlediameter and particle stiffness, which proves that the applying of three-dimensionaldiscrete element method in simulating the coal-loading process is feasibility and accuracy.The drum coal-loading processes with different face angles are simulation studied byusing three-dimensional discrete element software of PFC3D, and then the influence laws ofdip angle in mining direction and dip angle in faceline direction on the coal-loading ratesof drum ejection and drum pushing are obtained. The simulation results show thatcoal-loading rates of drum ejection and drum pushing in the negative dip angle in miningdirection are extremely low, which means that the mechanized mining technology designof the thin seam coal should avoid the negative dip angle in mining direction. Coal-loadingrate with drum pushing decreases linearly with the dip angle in faceline direction. Whilecoal-loading rate with drum ejection decreases observably firstly and then decreases slowlywith the increase of dip angle in faceline direction. Meanwhile, coal-loading rate withdrum ejection in negative dip angle in faceline direction decreases weaker than thehorizontal angle. The improvement measure on coal-loading with drum ejection undernegative dip angle in faceline direction is analyzed and verified in simulation. It points outthat the increase of particle axial velocity and reduction of the particle export positionheight can increase drum coal-loading rate with drum ejection in a certain extent.According to the structure characteristic and working environment of the thin coalseam shearer drum, the simulation model of thin coal seam shearer cutting process isestablished, and the influences of height from drum bottom to scraper conveyor chute,distance from the coal wall to the scraper conveyor chute and the ranging arm thickness onthe drum coal-loading performance are obtained, which provides references for the designof thin coal seam shearer ranging arm, drum and the corollary equipment and workingparameters selection.更多还原