截齿工作角度布置及水射流辅助截割头破岩研究

发布时间：2018-04-08 21:54

本文选题：截齿工作角度　切入点：空间力学模型　出处：《中国矿业大学》2015年硕士论文

【摘要】：掘进机作为煤矿井下巷道掘进的关键装备,其截割头性能的好坏直接决定了掘进机性能的优劣,为安全高效地开采煤炭资源,应当对掘进机截割头的截齿破岩进行研究和改进,使其钻进性能和截割性能提高。基于此,本文对截齿工作角度和高压水射流辅助破岩进行了研究,并根据研究结果,研发了截齿工作角度优化的高压水射流辅助破岩截割头,利用煤岩截割试验台对其进行试验研究。以岩石的结构特性和物理机械性质为基础,对截齿截割破岩机理进行了分析。基于实际制造中定位截齿轴线和齿座底面的角度安装工艺,建立了钻进工况条件下截割头截齿的空间力学模型,基于此,分析了截齿工作角度对截齿受力的影响,建立了截割头钻进工况条件下所受载荷模型。以单齿直线破岩数值试验为基础,验证ANSYS/LS-DYNA数值模拟截齿破岩的准确性。通过已验证的数值模拟方法研究单齿钻进破岩过程,根据仿真结果修正截齿空间力学模型,通过对不同仰角、倾斜角条件下单齿钻进工况研究得到:截齿所受截割阻力和斜率随着仰角、倾斜角的增大而增大;截齿所受进给阻力和斜率随着仰角的增大而增大,随着倾斜角的增大而减小;仰角的合理选取范围应大于齿尖锥角的0.5倍小于50°,倾斜角的合理选取范围是20°~50°。以高压水射流冲击破岩机理为基础,建立了水射流破岩的流固耦合作用方程。通过对水射流喷嘴的流场特性仿真分析指出:水射流由核心段、破裂段和水滴段组成,水射流轴线上的速度逐渐衰减;对水射流的两相混合分布规律进行了分析,在喷嘴内部,流体的介质为水,在喷嘴外部,流体的介质为两相混合,距喷嘴轴线越近,水射流的主要介质水的体积含量越高。对水射流冲击作用下岩石变形和水射流辅助截齿破岩进行了仿真分析,得到水射流作用的应力波具有明显的局部效应,截齿在水射流应力波作用范围内进行破岩,当水射流辅助截齿破岩时,水射流提前于截齿破坏岩石单元,并改变岩石单元所受应力。相比较于无水射流辅助截齿破岩,当水射流压力为20MPa时,截齿最大值受力减小率为15.77%,均值减小率为27.34%,说明水射流辅助截齿破岩具有较好的效果。基于截齿工作角度对单齿钻进工况条件下载荷研究和高压水射流辅助截齿破岩仿真研究,根据当前截割头截齿的布置参数,优化截割头截齿角度并设置高压水射流喷嘴,从而研发了截齿工作角度优化的高压水射流辅助破岩截割头。通过对优化前后截割头钻进破岩试验结果的对比分析,得到截割头截齿工作角度优化有效地降低截割头载荷;钻进工况条件下截割头的扭矩以及进给阻力都与水射流压力、转速、进给速度呈指数关系,随着水射流压力的增大而减小,随着转速的增大而减小,随着进给速度增大而增大。
[Abstract]:As the key equipment of roadway driving in underground coal mine, the performance of cutting head directly determines the performance of roadheader. In order to exploit coal resource safely and efficiently, it is necessary to study and improve the broken rock of cutting head of roadheader.The drilling performance and cutting performance are improved.Based on this, the working angle of tooth cutting and high pressure water jet assisted rock breakage are studied, and based on the research results, a high pressure water jet assisted rock breaking head with optimized tooth cutting angle is developed.The coal and rock cutting test bench is used to test and study it.Based on the structural and physical mechanical properties of rock, the mechanism of cutting rock is analyzed.Based on the angle installation technology of the position gear axis and the bottom surface of the base in the actual manufacture, the spatial mechanical model of the cutting head is established under the condition of drilling. Based on this, the influence of the working angle of the cutter on the force of the cutter is analyzed.The load model of cutting head drilling is established.On the basis of single tooth linear rock breaking numerical test, the accuracy of ANSYS/LS-DYNA numerical simulation is verified.The rock breaking process of single tooth drilling is studied by using the verified numerical simulation method. According to the simulation results, the spatial mechanical model of truncated teeth is modified, and different elevation angles are obtained.The research on the working conditions of slotting angle shows that the cutting resistance and slope increase with the elevation angle, the feed resistance and slope increase with the elevation angle, and decrease with the increase of the inclination angle.The reasonable range of elevation angle should be less than 50 掳and the reasonable range of elevation angle should be less than 50 掳than that of cusp angle, and the reasonable range of inclination angle should be 20 掳~ 50 掳.Based on the rock breaking mechanism of high pressure water jet, the fluid-solid coupling equation of water jet rock breaking is established.Through the simulation analysis of the flow field characteristics of the water jet nozzle, it is pointed out that the water jet is composed of the core section, the rupture section and the water droplet section, and the velocity on the axis of the water jet decreases gradually, and the distribution law of the two phase mixing of the water jet is analyzed.The medium of the fluid is water, and outside the nozzle, the medium of the fluid is a two-phase mixing, the closer it is to the axis of the nozzle, the higher the volume content of the water in the main medium of the water jet is.In this paper, the rock deformation and the water-jet assisted cutting rock are simulated and analyzed. The results show that the stress wave of water jet has obvious local effect, and the cutting tooth breaks rock in the range of water jet stress wave.When the water jet assists to break the rock, the water jet destroys the rock unit ahead of the tooth cutting, and changes the stress of the rock unit.Compared with the water-jet assisted cutting rock, when the water jet pressure is 20MPa, the maximum force reduction rate is 15.77 and the mean value reduction rate is 27.34, which shows that the water-jet assisted cutting rock has a better effect.Based on the working angle of the cutter, the load research under the condition of single tooth drilling and the simulation study of the rock cutting with the aid of high pressure water jet are carried out. According to the layout parameters of the cutting head, the angle of the cutting head is optimized and the high pressure water jet nozzle is set up.A high pressure water jet assisted cutting head with optimized working angle was developed.By comparing and analyzing the test results of cutting head drilling before and after optimization, it is obtained that the optimization of cutting head tooth cutting angle can effectively reduce the load of cutting head, and the torque and feed resistance of cutting head under drilling condition are all with water jet pressure.The speed of feed is exponentially related, which decreases with the increase of the pressure of water jet, decreases with the increase of speed, and increases with the increase of feed speed.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD421.5

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