大采高综采工作面截割湍流风对煤尘侧向逸散的影响机制

    Influence mechanism of cutting turbulent wind on coal dust lateral dispersal in large mining height fully mechanized mining face

    • 摘要: 大采高工作面内大尺寸的采煤机滚筒在截割煤体时产生更为明显的湍流风,使得工作面局部风速发生变化,粉尘颗粒向人行道区域发生横向扩散。为了明晰大采高工作面截割湍流风对粉尘质量浓度沿程分布的影响机制,针对三道沟85219工作面,运用数值模拟方法构建了风流-粉尘两相耦合数学模型,对工作面风流分布、粉尘运移、呼吸带高度粉尘质量浓度分布进行研究。结果表明;相较于仅系统通风作用下的流场,前后滚筒处及移架处在截割湍流风扰动下横向偏移分速度明显增大,在滚筒附近产生了横向偏移分速度约为−1.06 m/s的“风流偏移区”;在截割湍流风扰动下,前后滚筒处质量浓度超过151.85 mg/m3的粉尘团向人行道区域发生横向逸散,在顺风割煤状态下前滚筒处截割湍流风对截割煤尘横向逸散的诱导能力高于后滚筒处,前滚筒附件人行道呼吸带区域粉尘质量浓度相较于仅系统通风状态下提升了64.77%;将模拟数据与现场实测数据进行比对,相对误差小于12.57%,模拟数据相对准确。基于此,提出一种采煤机含尘气流控尘装置,在现场进行应用并检测其防控尘效果,在工作面人员作业区域呼尘降尘效率超过78.31%,全尘降尘效率超过89.93%。

       

      Abstract: The large size shearer drum in the large mining height working face generates more obvious turbulent wind in cutting the coal body, which causes the local wind speed of the working face to change, and the horizontal diffusion of dust particles to the sidewalk area. In order to clarify the influence mechanism of cutting turbulent wind on the dust mass concentration distribution along the working face with large mining height, a coupled mathematical model of airflow and dust was constructed by numerical simulation method for 85219 working face, and the airflow distribution, dust migration and dust mass concentration distribution at the height of the breathing zone were studied. The results show that, compared with the flow field under system ventilation only, the partial velocity of negative drift increases significantly at the front and back of the drum and at the moving frame, and a “wind drift zone” with negative drift wind velocity value of -1.06 m/s is generated near the drum. Under the disturbance of cutting turbulent wind, dust masses with a mass concentration of more than 151.85 mg /m3 at the front and back rollers have transverse dispersion to the sidewalk area. In the state of downwind coal cutting, the ability of cutting turbulent wind at the front rollers to induce transverse dispersion of cutting coal dust is higher than that at the back rollers. The dust mass concentration in the breathing zone of the sidewalk near the front roller was increased by 64.77% compared with the condition of system ventilation only. The comparison between the simulated data and the field-measured data shows that the relative error is less than 12.57%, and the simulated data is relatively accurate. Based on this, a dust-bearing air flow dust control device shearer is proposed, which is applied in the field and its dust control effect is tested. The dust removal efficiency in the working area of the working face is more than 78.31%, and the total dust removal efficiency is more than 89.93%.

       

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