【作者】 徐龙江；

【导师】 杜长龙；

【作者基本信息】 中国矿业大学 ， 机械设计及理论， 2012， 博士

【摘要】 矸石是煤炭开采的伴生物，其在地面大量堆积形成矸石山，对人体健康和矿区环境均造成不利影响。如从根源上消除矸石排放和堆集造成的危害，其理想方法是在井下实现煤和矸石的分离，并进行矸石的井下填充。根据煤和矸石的物理机械特性差异并结合已有井下煤矸分选设备的结构特点，提出一种新的井下煤矸分离设备—井下鼠笼式选择性煤矸分离装备。该设备对于煤和矸石的井下选择性破碎分离，实现煤矿的绿色开采具有重要意义。为此，本论文采用理论分析、仿真与实验研究相结合的方法，对井下鼠笼式选择性煤矸分离装备的关键技术进行研究。针对鼠笼式选择性煤矸分离装备的结构特点和破碎过程，基于赫兹理论和铁摩辛柯理论，建立了煤矸颗粒之间、煤矸颗粒与破碎杆及煤矸颗粒与筒壁的接触碰撞动力学模型，以此为基础，推导出煤矸颗粒冲击破碎速度的理论表达式。该表达式为分离装备结构参数及运动参数的选取提供了理论指导。采用离散单元法进行了单颗粒煤岩材料的冲击破碎行为仿真研究，建立了单颗粒煤岩材料冲击破碎的离散元仿真模型，并通过实验验证了模型的正确性；采用有限元和离散元相结合的方法对煤岩颗粒冲击破碎机理进行了研究，分析了冲击速度对煤岩破碎形态的影响规律；利用单颗粒煤岩材料冲击破碎离散元模型研究了煤岩特性参数、破碎杆截面形状参数对煤岩冲击破碎行为的影响规律。研究结果表明：煤岩冲击破碎速度与材料抗压强度、弹性模量和密度均成幂函数关系，仿真结果与理论结果具有较好的一致性，由此证明冲击破碎速度理论公式的正确性；破碎杆截面形状及参数对煤岩冲击破碎速度及冲击载荷也有较显著的影响，对于三角形破碎杆，煤岩冲击破碎速度随破碎杆截面角度的增加而减小，冲击载荷随截面角度的增加而增大；对于圆柱形破碎杆，煤岩冲击破碎速度随圆柱半径的增大而减小，冲击载荷随圆柱半径的增大而增大。开展了选择性煤矸分离的实验研究，揭示了滚筒数量、煤矸性质、滚筒结构参数、滚筒运动参数及落料高度等因素对煤和矸石选择性破碎效果的影响规律。研究表明，三滚筒结构形式的分离装备能较好的满足煤和矸石的选择性破碎分选要求；不同硬度煤和矸石具有不同的最佳转速，煤矸破碎率与自身所占比例成二次函数变化关系；在滚筒结构参数中，破碎杆杆径对煤矸破碎效果影响较小，破碎杆数目对煤矸破碎率影响较显著；煤矸破碎率与滚筒转速成线性关系，其受落料高度的影响较小。利用离散单元法开展了分离装备内颗粒群的动力行为研究。建立了煤岩颗粒与破碎杆的接触数学模型，并通过正交实验法对影响煤矸破碎率的相关因素进行了显著性分析。分析表明，单颗粒煤岩冲击破碎杆时，滚筒转速、破碎杆间距和入料口位置对破碎率的影响较为显著。采用离散元法研究了在不同滚筒、破碎杆间距及入料口位置情况下，滚筒内颗粒群的动力学行为及煤矸破碎率，研究发现：颗粒在分离装备中的碰撞行为主要发生在破碎滚筒与分离装备壳体之间的区域；中间滚筒冲击颗粒产生的速度幅值较小，而上滚筒和下滚筒冲击颗粒产生的速度幅值则较大；当滚筒拥有六根破碎杆时，煤和矸石的选择性破碎效果最佳。对分离装备滚筒上破碎杆的可靠性开展了仿真研究，分析了破碎杆杆径、杆长等几何参数对破碎杆的固有频率、动态应力等动力学特性的影响规律，为破碎杆结构的设计和改进提供了参考。更多还原

【Abstract】 Gangue, the accompanying mineral of coal mining, is always transported to theground and accumulated as hillock, and the human health and the mining environment areall influenced by it. Achieving separation for coal and gangue underground and backfillinggangue in situ is the method that can radically solve the environmental problems producedby discharge and accumulation of gangue. According to the differences in physical andmechanical properties of coal and gangue and combined with the structural characteristicsof the existing separation equipment for coal and gangue underground, put forward a newseparation equipment for coal and gangue underground—the Squirrelcage SelectivitySeparation Equipment for coal and gangue Underground.It has great significance on theselectivity separation for coal and gangue and the realizability of the coal green mining.Therefore, the theoretical analysis, numerical simulation and experiments are combined toinvestigate the key technology of the Squirrelcage Selectivity Separation Equipment forcoal and gangue Underground.According to the structure character and the crushing process of the SquirrelcageSelectivity Separation Equipment for coal and gangue, the mechanics models of the impactbetween the particles for coal and gangue, the particles and the crashing rod, the particlesand the drum wall were built, which based on the the Hertz Theory and the TimoshenkoTheory. And the theoretical formula of the impact velocity of the coal and gangue wasdeduced, which provides the theoretical guidance for the selectivity of the structureparameters and motion parameters of the equipment.The simulation of the impact crushing of single coal particle was done by discreteelement method, and the simulation model was proved by experiment. The influence of theimpact velocity to the crushing model of single coal particle was analyzed, which utilizesthe finite element and the discrete element methods. And the influence of the characteristicparameters of the coal and section style of the impact rod to the coal crushing was acquiredby researching on the single coal particle crushing. The results indicate that: therelationships among the impact velocity and the compressive strength, the elasticity, thecoal density are all power exponent. And the simulation results and the theoretical resultshave good uniformity, which proves the theoretical formula of impact velocity is correct.The influence of the section style and parameters of the crashing rods to the impactvelocity and the impact load of the coal is remarkable. The impact velocity of the coaldecreases with the increases of the section angle of the crashing rod, the impact load increases along with the section angle when the section of crashing rod is triangle; theimpact velocity decreases along with the radial of crashing rod increases, while the impactload increases along with the rod radial increases when the rod section is cylindrical.The influence rules of the drum numbers, the characteristics of coal, the drumstructure parameters, the drum mechanical parameters and the blanking height to thecrashing effect of the coal and gangue were researched based on the experiments. Theresults indicate that: the separating equipment with three drums is better to satisfy therequirement of the selective crashing separation of the coal and gangue. The best crashingrotary speed of different compressive strength for coal and gangue is different; In thestructure parameters of the drum, the influence of the radial of the crashing rod to thecrashing effect is small, the numbers of the crashing rod is remarkable; and the relationshipbetween the crashing ratio and the drum rotary speed is linearly, which influenced by theblanking height is small.Dynamic characteristic of the particle group in the separation equipment wasresearched by utilizing the discrete element method. The contact model of the coal particleand crashing rod was built, and the significance tests were done on the influenced factorsof the coal crushing rate by orthogonal experiment. The tests indicate that: the influence ofthe drum rotary speed, the rod space, the coal feed position on the crushing rate isremarkable. The discrete element method was used to research on the dynamiccharacteristic of the particle in the drum and the crushing rate of the coal and gangue werestudied under the condition of different drum, different rod space and different materialfeed position. The results indicate that: the crashing behavior happens between the drumand the shell of the equipment; the velocity amplitude caused by the impact between themiddle drum and the particles is small, while the velocity amplitude caused by up drumand down drum are bigger; and the crashing effect is best when the drum with six rods.The simulation was done on the reliability of the crashing rod, the natural frequencyand the dynamic stress of the crashing rod were analyzed for different rod diameter anddifferent rod length, which provides the design parameters for the improvement of thecrashing rod.更多还原