基于CFD−DPM模型的挡煤板控尘机理研究

    Research on dust control mechanism of coal baffle based on CFD-DPM model

    • 摘要: 综采工作面是矿井粉尘污染最严重的区域之一,大采高工作面开采时落煤高度较大,采煤机割煤时产生的粉尘容易扩散至人行道,对矿工的身体健康造成严重威胁。为深入探究大采高工作面截割工序中挡煤板对粉尘的防控机理,以陕北张家峁煤矿15211工作面为研究对象,建立了三维数值模型,采用计算流体动力学−离散相模型(CFD−DPM)的数值模拟方法,分析了不同挡煤板高度下综采工作面的风流特性、紊流分布和粉尘运移轨迹、分布范围及粒径分布变化。结果表明:随着挡煤板高度的增加,其对气流的分隔效应愈发显著,导致人行道区域气流流线减少,风速逐渐降低,而滚筒附近的风速则急剧上升,风速超过了2.5 m/s;当挡煤板高度达到1.6 m时,采煤机前方形成了长达30 m的高风速区域,增强的气流效应与物理阻隔相结合,有效改变了粉尘的运移路径与分布格局,显著抑制了粉尘的横向扩散,缩短了粉尘的暴露时间及运移距离;人行道内侧的粉尘污染区域显著减小,粉尘质量浓度降至50 mg/m3,大部分粉尘被有效地限制在了人行道外侧,对粒径大于40 μm的粉尘拦截效果尤为明显;对比挡煤板为0.8 m与1.6 m时的粉尘质量浓度分布,随着挡煤板高度的增加,人行道呼吸带处的粉尘质量浓度显著降低,降尘率达50.2%;将数值模拟结果与现场实测数据进行比对,平均误差为6.9%,进一步验证了模拟的准确性和可靠性。

       

      Abstract: The fully mechanized mining face is among the most critical areas for dust pollution within a mine, in large mining height faces, the elevated coal fall height during the mining process facilitates the dispersion of particulate matter from the coal cutting machinery into the pedestrian walkway, thereby posing a significant health risk to miners. To elucidate the dust control mechanism of coal buffle in large mining faces during the shearing process, a three-dimensional numerical model was constructed using 15211 working face of Zhangjiamao Coal Mine in northern Shaanxi as a case study. Computational Fluid Dynamics-Discrete Phase Model (CFD-DPM) numerical simulation techniques were utilized to analyze the airflow characteristics, turbulence distribution, dust transport trajectories, distribution range, and particle size distribution under varying coal baffle heights. The findings reveal that an increment in the coal baffle height intensifies its air flow partitioning effect, resulting in a reduction of airflow streamlines in the pedestrian walkway, a progressive decrease in wind velocity, and a precipitous increase in wind velocity near the drum, exceeding 2.5 m/s. When the height of the coal buffle reaches 1.6 meters, a 30-meter-long high wind speed area is formed in front of the coal shearer. The combination of enhanced airflow effect and physical barrier effectively changes the migration path and distribution pattern of dust, significantly suppresses the lateral diffusion of dust, and shortens the exposure time and migration distance of dust. The dust pollution area on the inner side of the sidewalk has been significantly reduced, with the dust mass concentration dropping to 50 mg/m3. Most of the dust is effectively confined to the outer side of the sidewalk, and the interception effect on dust with a particle size greater than 40 μm is particularly obvious. By comparing the dust concentration distribution when the coal buffle was 0.8 m and 1.6 m, the dust concentration at the breathing zone of the sidewalk decreased significantly, with a dust reduction rate of 50.2%. The numerical simulation results were compared with the on-site measured data, and the average error was 6.9%, further verifying the accuracy and reliability of the simulation.

       

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