风流扰动下煤炭装载冲击粉尘运移规律与抑尘技术研究

Study on the transport law of coal loading impact dust and dust suppression technology under airflow disturbance

煤炭装载冲击是露天煤矿主要的产尘环节之一,尤其在自然风流的作用下容易造成大面积的粉尘污染。针对内蒙古地区露天煤矿地域气象风力强劲、装车冲击粉尘浓度高、粉尘扩散污染严重等问题,采用Realizableκ-ε湍流模型,结合数值模拟分析不同风速扰动下装载冲击产尘运移规律,探究抑尘运移方法及其防治粉尘污染的作用效果,结合内蒙古白音华三号露天煤矿装车站现场,设计优化阻尘技术并进行现场应用与效果分析。研究结果表明:流经装车涵洞的过堂风、背风面形成的涡旋风流是促使下风侧粉尘颗粒运移的主要原因;随着风速的增大,装车站风流的不均匀性不断加剧,粉尘颗粒在风流的夹带作用下向下风侧区域扩散;粉尘扩散污染路径装设抑尘网可实现对粉尘运移的有效阻隔,且随着抑尘网高度的增加,装车站下风侧区域内的风速值出现显著降低,并在装车涵洞出口处形成一条风速值分布较为均匀的低速带,进而降低了粉尘颗粒的逃逸速度,有效控制了粉尘的扩散范围;此外,抑尘网安装高度对于风流场与粉尘运移的影响存在阈值,基于模拟研究结果,优选网高为7 m的防风抑尘网进行现场应用。现场粉尘浓度测定结果表明:抑尘网内外粉尘降低效率达到82.51%以上,有效降低了装车站粉尘扩散范围,对矿区周边的环境保护具有重要意义。

Coal loading impact is one of the main dust-producing links in open-pit coal mine,especially under the action of natural wind flow,it is easy to cause large-scale dust pollution.Aiming at the problems such as strong meteorological wind,high concentration of loading impact dust and serious dust diffusion pollution in open-pit coal mines in Inner Mongolia,Realizableκ-εturbulence model and numerical simulation are used to analyze the law of loading impact dust migration under different wind speed disturbances,and to explore the method of dust migration and its effect on preventing and controlling dust pollution.Based on the installation site of Baiyinhua No.3 open-pit mine in Inner Mongolia,the dust suppression technology is optimized and the application and effect analysis are carried out.The results show that the main reason for the migration of dust particles on the downwind side is the vortex wind flow through the loading culvert.With the increase of wind speed,the inhomogeneity of air flow at loading station becomes more and more serious,and the dust particles spread to the downwind area under the entrained action of air flow.The installation of dust suppression net in the dust diffusion pollution path can effectively block the dust migration,and with the increase of the height of the dust suppression net,the wind speed in the downwind area of the loading station decreases significantly,and a low-speed zone with more uniform distribution of wind speed is formed at the exit of the loading culvert,thus reducing the escape velocity of dust particles and effectively controlling the dust diffusion range.In addition,there is a threshold for the influence of the installation height of the dust suppression net on the air flow field and dust migration.Based on the simulation results,the wind and dust suppression net with a net height of 7 m is preferred for field application.The dust concentration measurement results show that the dust reduction efficiency inside and outside the dust suppression net is more than 82.51%,which effectively reduces the dust diffusion range of the loading station,and has great significance for the environmental protection around the mining area.