综放工作面非稳态脉冲粉尘团产生机理及逸散规律基础理论研究

Aiming at the thick coal seam, high mechanization degree and large mining intensity which lead to problems such as high-concentration of nonsteady pulsing dust regiments and low efficiency of reducing dust in major dust producing sources like coal cutting, advancing support and coal caving of the fully mechanized caving face, this research item is put forward. First, the generation mechanism of the high-concentration dust regiments in fully mechanized caving face is discussed in order to lay a foundation for the subsequent theoretical research. On the basis of analyzing settlement, planktonic and diffusion laws of dust under various dynamic action and according to multiphase flow theory, fluid mechanics mathematical model which is suitable for instantaneous point source and continuous point source of nonsteady pulsing dust regiments in fully mechanized caving face is established and numerical simulation is carried out. Combining with the field measured results, dispersion law of dust regiments in production field in fully mechanized caving face will be made clear. The dust suppression with high pressure spraying experimental platform in the national key laboratory of mining disaster prevention and control is used to carry out simulation experiment on coupling relationship between dust field and droplet field, so as to find out the quantitative mathematical relationship between droplet and the captive dust particles, and to provide basis for the nozzle optimization, rational design and optimal placement of the combined atomizing dust removal device. Through the above theoretical analysis and experimental research, the generation mechanism and dispersion law of nonsteady pulsing dust regiments are put forward, so as to indicate the direction for the overall control of dust concentration in fully mechanized caving face.

本项目是针对目前煤层厚、机械化程度高、开采强度大而导致的矿井综放面割煤、移架、放煤等主要尘源非稳态脉冲粉尘团浓度高、降尘效率低等问题而提出的。首先对综放面高浓度粉尘团的产生机理进行探讨，为后续理论研究奠定基础。根据对粉尘在各种动力作用下沉降、浮游、扩散规律的分析，基于多相流理论，建立适合于综放工作面瞬时点源和连续点源非稳态脉冲粉尘团的流体力学数学模型，并进行数值模拟，结合现场实测结果，进而摸清综放工作面生产现场粉尘团的弥散规律。采用矿山灾害预防控制国家重点实验室高压喷雾降尘实验平台，对粉尘场与雾滴场之间耦合关系进行模拟仿真实验，找出雾滴与其捕获尘粒之间的定量数学关系，为组合式雾化降尘装置的喷嘴优选、合理设计和优化布置提供理论依据。通过上述理论和实验研究，提出综放工作面非稳态脉冲粉尘团的产生机理与弥散规律，从而为全面控制综放工作面粉尘浓度指明方向。

本项目是针对综放工作面割煤、移架、放煤等主要尘源非稳态脉冲粉尘团浓度高、降尘效率低等问题而提出的。首先，对综放工作面非稳态脉冲粉尘团产生机理进行了研究，并采用Winner99显微颗粒图像分析仪、Winner3001干粉激光粒度分析仪、JS94H型微电泳仪、DSA100型视频光学接触角测量仪等现代测试仪器对粉尘团的理化特性进行了测定分析，为后续的数值模拟与现场工程应用提供了基础数据。其次，建立了基于Eulerian-Eulerian与Eulerian-Lagrangian模型相结合的气体－颗粒两相流动的流体力学数学模型，并对综放工作面喷雾降尘过程尘雾场进行了数值模拟。再则，采用自行设计制作的高压喷雾降尘仿真实验台，利用喷雾激光粒度分析仪、显微颗粒图像分析仪对不同类型喷嘴所成雾场与粉尘场的耦合关系进行了实验，得到了雾滴与其捕获尘粒之间的定量变化规律。最后，依据综放工作面粉尘团与雾滴场数值模拟与耦合实验结果，针对兖矿集团东滩煤矿1303综放面不同生产工序的产尘粒度特点，优选了不同尘源处的喷嘴并对喷雾降尘装置进行了优化设计，取得了很好的喷雾降尘效果。