Effects of air curtain dust control parameters on dust pollution in fully mechanized mining faces
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摘要: 气幕控尘效果受压抽风及径向分风多要素影响,而现有研究多局限于某单一要素对气幕控尘的影响规律。为掌握气幕控尘参数对综掘工作面粉尘污染的影响,对不同径向分风流量和负压控尘流量条件下的风流场演变和粉尘场扩散开展了数值模拟研究。结果表明:① 径向分风流量主要影响轴向射流场的卷吸效应,负压控尘流量主要影响工作面的抽风负压作用,当径向分风流量与压风总流量比值≥0.8、压风总流量与负压控尘流量比值<1.0时,气幕运移至射流区域时转变为轴向运移,形成厚度≥1.4 m的轴向控尘流场。② 径向分风流量及负压控尘流量越大,巷道压抽风侧风流流量及风速分布越均匀,粉尘扩散距离越小,掘进机司机处粉尘质量浓度越低。在此基础上,确定了综掘工作面气幕控尘优化参数:径向分风流量为288 m3/min(径向分风流量与压风总流量比值为0.9),负压控尘流量为426 m3/min(压风总流量与负压控尘流量比值为0.75)。经现场实测,应用气幕控尘优化参数后,掘进机司机处降尘率达93.5%,人员作业环境得到明显改善。Abstract: The effectiveness of air curtain dust control is influenced by various factors, including suction ventilation and radial airflow distribution. Existing research is largely limited to the effects of single factors on air curtain dust control. To understand the impact of dust control parameters on dust pollution in fully mechanized mining faces, numerical simulations were conducted to investigate the evolution of airflow and dust dispersion under different conditions of radial airflow distribution and negative pressure dust control. The results indicated that: ① Radial airflow distribution primarily affected the entrainment effect of the axial jet field, while negative pressure dust control flow mainly influenced the negative pressure effect of suction at the working face. When the ratio of radial airflow distribution to total air supply was not less than 0.8 and the ratio of total air supply to negative pressure dust control flow was less than 1.0, the air curtain transitioned to axial movement in the jet region, forming an axial dust control flow field with a thickness of not less than 1.4 m. ② As radial airflow distribution and negative pressure dust control flow increased, the airflow quantity and speed distribution on the suction side of the tunnel became more uniform, leading to reduced dust dispersion distance and lower dust mass concentration at the operator's position. Based on these findings, the optimized parameters for air curtain dust control in fully mechanized mining faces were determined: radial airflow distribution at 288 m³/min (with a ratio of radial airflow distribution to total air supply of 0.9) and negative pressure dust control flow at 426 m³/min (with a ratio of total air supply to negative pressure dust control flow of 0.75). Field measurements showed that after applying the optimized air curtain dust control parameters, the dust reduction rate at the operator's position reached 93.5%, significantly improving the working environment.
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表 1 颗粒相基本参数
Table 1. Basic parameters of particle phase
参数 设置 注入方式 表面喷射 质量流率/(kg·s−1) 0.002 8 最小粒径/m 8.2×10−7 中位粒径/m 4.83×10−6 最大粒径/m 2.65×10−5 扩散系数 3.5 表 2 风流运移实测与模拟结果对比
Table 2. Comparison of measured and simulated results of airflow migration
测点 风速 断面距工作面距离/m 2 5 7 a 实测值/(m·s−1) ¤, 0.41 ¤, 0.47 ¤, 0.51 模拟值/(m·s−1) →, 0.42 ¤, 0.49 ¤, 0.52 相对误差/% 3.95 3.72 2.14 b 实测值/(m·s−1) →, 0.46 ¤, 0.51 ¤, 0.54 模拟值/(m·s−1) ¤, 0.49 ¤, 0.54 →, 0.55 相对误差/% 7.27 5.65 1.86 c 实测值/(m·s−1) ↑, 0.44 ¤, 0.45 ¤, 0.49 模拟值/(m·s−1) ↑, 0.47 ¤, 0.47 ¤, 0.51 相对误差/% 6.03 5.32 3.26 表 3 不同环节各测点粉尘质量浓度及降尘率
Table 3. Dust mass concentration and dust reduction rate at different measuring points in different stages
环节 数据类型 距工作面距离/m 3 7 25 50 100 Ⅰ 粉尘质量浓度/
(mg·m−3)705.3 501.2 326.5 255.3 208.6 Ⅱ 粉尘质量浓度/
(mg·m−3)251.3 163.4 125.2 100.8 84.9 降尘率/% 64.4 67.4 61.7 60.5 59.3 Ⅲ 粉尘质量浓度/
(mg·m−3)231.5 32.4 25.1 20.7 17.1 降尘率/% 67.2 93.5 92.3 91.9 91.8 -
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