综采工作面尘雾场离散颗粒流细观污染-凝并机理基础研究

In view of the deficient dedusting effect of traditional macro spraying dust reduction method in fully-mechanized mining face, theoretical analysis, numerical simulation, experimental measurement and system construction are synthetically adopted in this project, and the research for the pollution-coagulation mechanism of dust-droplet field by the method of discrete particles from the microscopic view is carried out. Firstly, based on the experimental data of airflow and dust in production site, the fractal dimension, fractal character and fractal description of dust particles' parameters are obtained by fractal theory and experimental analysis of dust particles' characteristics. Secondly, macro spreading law of dust group and meso dispersion law of single dust particle are simulated numerically with the method of CFD-DEM in order to find out the macro-meso diffusion law of dust with high concentration. Then, with the airflow-dust-droplet simulation experiment platform based on the laser Doppler interference method, the spatial distribution characteristics of particle size-velocity-concentration of dust-droplet field before and after releasing dust source are analyzed to determine the quantitative coupling relationship among the parameters of dust and droplet. In addition, computational particle fluid dynamics software-Barracuda, is used to simulate and analyze the collision and coagulation between dust particle and droplet, which reveals the mechanism of droplet capturing dust particle at the mesoscopic scale and develops the spraying dust reduction theory. Finally, according to the above theoretical and experimental results, an atomizing dust control and removal system with local area closure method for fully-mechanized mining face is established.

针对综采面传统宏观喷雾降尘方法除尘效果不佳的问题，本项目运用理论分析、数值模拟、实验测定、体系构建相结合的综合研究手段，采用离散颗粒方法从细观角度对尘雾场污染-凝并机理进行探究。首先，根据生产现场风流、粉尘实测数据，结合粉尘颗粒特性实验分析，利用分形理论得到粉尘颗粒参数分形维数、分形特征和分形描述。其次，运用计算流体力学（CFD）-离散元（DEM）方法对粉尘团宏观扩散规律和单个尘粒细观逸散规律进行数值模拟，摸清综采面高浓度粉尘宏细观弥散机制。再则，通过激光多普勒风流-粉尘-雾滴仿真实验台，对释放尘源前后粉尘-雾滴场粒度-速度-浓度大小空间分布特性进行分析，明确尘雾场各参数间定量耦合关系。此外，应用计算颗粒流体动力学软件Barracuda，进行尘粒-雾滴碰撞、凝并模拟分析，从介观角度揭示雾滴捕尘机理，发展喷雾降尘理论。最后，依据上述理论、实验成果，形成综采面局部区域封闭式雾化控除尘方法体系。

本项目采用理论分析、数值模拟、实验测定、体系构建相结合的综合研究方法，首先，根据生产现场风流、粉尘实测数据，结合粉尘颗粒特性实验分析，推导粉尘的粒度、粒径分布、比表面积、孔隙体积、孔径分布等颗粒特性分形维数计算方法，得到粉尘的分形特征、分形描述。其次，根据综采面不同尘源产尘特点，依据计算流体力学（CFD）和离散元模型（Discrete Element Method，DEM）理论，建立适用于综采面的风流－粉尘离散颗粒流数学模型，一方面，对粉尘颗粒团宏观扩散规律进行数值模拟，得到综采面高浓度粉尘污染特点；另一方面，对不同粒径单个颗粒随风流的沉降、扩散规律进行模拟分析，从细观角度摸清综采面不同尘源粉尘弥散规律。再则，利用激光多普勒（PDI）相位干涉喷雾降尘仿真实验平台，对释放尘源喷雾降尘前后不同类型单喷嘴及不同组合形式多喷嘴在多种实验条件下的雾滴场雾化参数、尘粒分布特性、粉尘－雾滴运动状态进行深入研究。然后，应用计算颗粒流体动力学软件 Barracuda，进行风流-雾滴-尘粒三相耦合条件下的尘粒-雾滴碰撞、凝并模拟分析，从介观角度揭示雾滴捕尘机理。最后，依据上述理论、实验成果，形成综采面局部区域封闭式雾化控除尘方法体系。