综采面风流—呼尘宏细观流动—弥散污染规律数值模拟研究

发布时间：2018-11-09 13:14

【摘要】：综采工作面在我国矿井中普遍存在,随着采煤技术及设备的发展,一次性采全高的采煤工艺被广泛应用,这使得综采工作面的采煤设备体积更大、功率更高,从而导致现场粉尘浓度大大提高,与此同时,复杂的采煤空间诱导风流发生复杂流动,这使得高浓度粉尘发生难以预测的弥散污染,进而导致降尘设备难以达到满意的降尘效果,居高不下的粉尘尤其是呼尘严重威胁着矿井的安全生产和井下工人的生命安全。由此可见,研究确定综采面呼尘弥散污染规律,进而优化设计一套行之有效的煤尘清洁系统势在必行,同时,对于科学指导现场粉尘治理、职业病防治、设备研发以及高效生产均具有十分重要的意义。鉴于此,本文采用理论分析、实验测试、数值模拟及现场应用相结合的方法,从宏细观层面对综采工作面的呼尘弥散污染规律进行了较为深入的研究,并结合呼尘污染特性和现有的除尘措施和方法,优化了煤尘清洁系统,并进行了工程应用,从而逐步展开了“综采面风流-呼尘宏细观流动-弥散污染规律数值模拟研究”的课题。首先建立了风流-呼尘运动数学模型,结合SolidWorks、DesignModeler等CAD软件对综采工作面进行了等比例的精细化几何建模,同时根据工作面尘源特点将综采工作面划分为移架完成区、采煤区以及未采区。根据流体及粉尘弥散流动特点,通过ANSYS ICEM CFD对不同的区域设定个性化网格划分参数,从而实现对重点污染区域的精确求解。接着,在现场相应尘源附近布置多个采样点,采集尘源处的全尘及呼尘颗粒,通过对采样粉尘进行显微颗粒图像分析,得到各尘源的粉尘粒径频率分布等参数,发现在呼尘范围内2 ～4 μm的粉尘占比最大,是呼尘污染防治的重中之重,所得数据将作为数值模拟粉尘参数设定的科学依据。然后,利用ANSYS Fluent软件数值模拟研究了风速对综采工作面呼尘弥散污染行为的影响,得到了呼吸带高度呼尘质量浓度和风速之间的拟合函数,研究发现其最佳通风除尘风速范围为1.5～2.0m/s,完善了风速对呼尘弥散影响的相关理论。与此同时,结合最佳风速条件进行数值模拟,借助风流流线和呼尘迹线研究确定了最高风速区及高浓度呼尘团的性质与成因。在此基础上,结合呼尘颗粒细观弥散情况,首次从细观层面对综采工作面呼尘弥散污染规律进行了数值模拟研究,并从细观层面探究了三大呼尘颗粒在时间尺度下的空间位置、速度、沉降、弥散时间等参数的演化规律。最后,根据呼尘的扩散污染特性优化设计了综采工作面新型煤尘清洁系统,并在大柳塔煤矿52305-1综采工作面进行了现场应用,应用后的现场粉尘浓度大大降低,全尘及呼尘的平均降尘率分别达到90.10%、90.03%,降尘效果明显,工作面的环境和劳动卫生条件有一定的改善。
[Abstract]:With the development of coal mining technology and equipment, the fully high mining technology of one-off mining is widely used, which makes the coal mining equipment of fully mechanized mining face larger in volume and higher in power. Therefore, the dust concentration in the field is greatly increased, and at the same time, the complicated coal mining space induces the complicated air flow, which makes the high concentration dust have the unpredictable dispersion pollution. Therefore, it is difficult for dust control equipment to achieve satisfactory dust lowering effect. The high dust, especially the exhaling dust, is a serious threat to the safety of mine production and the life safety of underground workers. It can be seen that it is imperative to study and determine the law of dust dispersion in fully mechanized coal face, and then to optimize and design a set of effective coal dust cleaning system. At the same time, it is imperative to scientifically guide the field dust control and occupational disease prevention. Equipment research and development and efficient production are of great significance. In view of this, this paper uses the methods of theoretical analysis, experimental test, numerical simulation and field application to study thoroughly the law of dust dispersion pollution in fully-mechanized mining face from macro and meso level. Combined with the pollution characteristics of exhaling dust and the existing measures and methods of dust removal, the coal dust cleaning system was optimized, and the engineering application was carried out. Thus, the subject of "numerical simulation study on the law of air flow, macro flow and dispersion pollution in fully mechanized coal face" has been carried out step by step. Firstly, the mathematical model of air-flow-exhalation movement is established, and the geometric modeling of the fully mechanized coal face is carried out in equal proportion with CAD software such as SolidWorks,DesignModeler. At the same time, according to the characteristics of dust source in the working face, the fully mechanized mining face is divided into the complete area of moving frame. Mining areas and unmined areas. According to the characteristics of fluid and dust dispersion flow, the individualized grid parameters are set up for different areas by ANSYS ICEM CFD, so that the accurate solution of the key polluted areas can be realized. Then, a number of sampling points are arranged near the corresponding dust sources in the field to collect all dust and exhaled dust particles in the dust source. By analyzing the microscopic particle image of the sampled dust, the particle size and frequency distribution parameters of each dust source are obtained. It is found that the dust in the range of 2 ~ 4 渭 m is the most important in the prevention and control of dust pollution. The obtained data will be used as the scientific basis for the setting of dust parameters in numerical simulation. Then, the influence of wind speed on the dispersion of dust in fully mechanized coal mining face is studied by using ANSYS Fluent software, and the fitting function between the mass concentration and wind speed of breathing zone height is obtained. It is found that the best ventilation and dust removal velocity range is 1.5 V 2.0 m / s, which improves the theory of the influence of wind speed on the dispersion of respiratory dust. At the same time, combined with the optimal wind speed conditions, the properties and causes of the highest wind speed and high concentration dust mass were determined by the study of the flow streamline and the air flow trace. On this basis, combined with the micro-dispersion of exhaling dust particles, the first numerical simulation of dust dispersion in fully mechanized coal mining face is carried out from the meso level, and the spatial position of the three large dust particles in time scale is explored from the meso level. The evolution law of velocity, settlement, dispersion time and so on. Finally, a new coal dust cleaning system is designed optimally according to the diffusive pollution characteristics of exhaling dust in fully mechanized coal mining face, and it is applied to 52305-1 fully mechanized coal mining face of Daliuta Coal Mine. The dust concentration in the field is greatly reduced after the application. The average dedusting rate of all dust and exhaling dust was 90.1010 and 90.03 respectively. The dust control effect was obvious and the working environment and working hygiene conditions were improved to some extent.
【学位授予单位】：山东科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD714

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