【作者】 邓志鹏；

【导师】 秦波涛；

【作者基本信息】 中国矿业大学 ， 安全工程（专业学位）， 2025， 硕士

【摘要】 随着煤矿开采机械化水平提高,在产出大量煤炭资源的同时也造成了严重的粉尘污染。采掘面转载点处因存在高度落差,成为主要产尘源之一。喷雾降尘是目前采掘面转载点采用的常规降尘技术,存在耗水量大、降尘效率低等问题。负压喷雾除尘融合了负压诱导与喷雾降尘机制,相较于普通喷雾降尘效率更高,但目前在转载点的应用较少。因此,本文以转载点负压喷雾装置为研究对象,主要采取理论分析、数值模拟与实验研究相结合的方式对负压喷雾装置降尘机理、不同工况及结构参数下的负压喷雾装置的雾化特性、卷吸特性和降尘特性展开研究,并设计了负压喷雾装置的现场应用工艺,主要研究结论如下:(1)应用ANSYS Fluent针对负压喷雾装置进行了内部流场分析,得到了不同结构参数对装置卷吸性能的影响。选取吸入口位置、喉径、喉管长度及喉嘴距作为研究变量,仿真结果表明:随着吸入口位置远离喉管,装置内部的流场分布发生改变,装置卷吸性能逐渐下降;喉径的增大使得流通截面积增大,减小能量损耗,装置卷吸性能随着逐渐提升;喉管长度改变了空气与水雾射流的作用时间,喉管长度过小会使二者能量交换不充分,喉管长度过大会增大能量损耗,喉管长度为240 mm时装置卷吸性能最佳。随着喉嘴距的增大,装置卷吸性能随之呈现先提升后下降的趋势,喉嘴距为20 mm时最佳。(2)实验探究了水压、喉径及喉嘴距对负压喷雾装置雾化和卷吸特性的影响规律。研究结果表明:水压增大使得水流初速度增大,剪切效应增强,雾滴粒径随之减小,射程、耗水量与卷吸性能均随之提升;随着喉径增大,喉管内流通截面积增大,雾滴粒径随之增大,射程与卷吸性能随之提升,耗水量无明显变化;随着喉嘴距的增大,气液两相流的接触时间增加,雾滴粒径先减小再增大,卷吸性能先提升再下降,喉嘴距为20 mm时取得最小雾滴粒径与最佳卷吸性能,且喉嘴距的改变对有效射程及耗水量无明显影响效应。(3)研究了水压、喉径及喉嘴距对负压喷雾装置降尘特性的影响,确定了最佳组合参数。研究结果表明:对于全尘及呼尘降尘效率而言,各因素主次排序为水压>喉嘴距>喉径。随着水压增大,雾滴粒径减小,卷吸性能增强,全尘与呼尘降尘效率均随之提高;随着喉嘴距的增大,全尘与呼尘降尘效率均先增大后减小,当喉嘴距为20 mm时降尘效率最佳;较小喉径有利于雾滴的破碎使粒径减小,但会减小流通面积增大能量损耗,使得卷吸性能较差,喉径为80mm时降尘效率最佳。在喉径80 mm、喉嘴距20 mm、水压3 MPa的最佳参数组合下,负压喷雾装置全尘降尘效率为85.91%,呼尘降尘效率为76.33%。(4)针对采掘面转载点粉尘防治问题,提出了以负压喷雾装置与密闭罩为核心的现场应用工艺。设计的现场应用工艺以密闭罩约束逸散粉尘,充分利用负压喷雾装置的特点进行高效降尘,具备低水耗、成本低、结构简单、易维护等优势,有效解决了传统喷雾降尘耗水量大、降尘效率低的问题,改善采掘面转载点处的工作环境,保障煤矿企业的安全生产。该论文有图64幅,表12个,参考文献91篇。更多还原

【Abstract】 With the improvement of the mechanization level of coal mining,a large amount of coal resources are produced,and serious dust pollution is also caused.Due to the height drop at the transfer point of the mining face,it has become one of the main dust sources.The spray dust reduction is a conventional dust reduction technology used in the transfer point of the mining face at present,which has the problems of large water consumption and low dust reduction efficiency.Negative pressure spray dust removal combines the mechanism of negative pressure induction and spray dust reduction,which is more efficient than ordinary spray dust reduction,but it is currently less applied at the transfer point.Therefore,this thesis takes the negative pressure spray device at the transfer point as the research object,mainly adopts the combination of theoretical analysis,numerical simulation and experimental research to study the dust reduction mechanism of the negative pressure spray device,the atomization characteristics,entrainment characteristics and dust reduction characteristics of the negative pressure spray device under different working conditions and structural parameters,and designs the field application process of the negative pressure spray device.The main research conclusions are as follows:(1)ANSYS Fluent was used to analyze the internal flow field of the negative pressure spray device,and the influence of different structural parameters on the entrainment performance of the device was obtained.The position of the suction port,the throat diameter,the length of the throat and the distance between the throat and the mouth are selected as the research variables.The simulation results show that as the position of the suction port is far away from the throat,the flow field distribution inside the device changes,and the entrainment performance of the device gradually decreases.The increase of throat diameter increases the flow cross-sectional area,reduces the energy loss,and the entrainment performance of the device gradually increases.The length of the throat tube changes the action time of the air and water mist jet.If the length of the throat tube is too small,the energy exchange between the two will be insufficient.If the length of the throat tube is too large,the energy loss will be increased.When the length of the throat tube is 240 mm,the entrainment performance of the device is the best.With the increase of throat-mouth distance,the entrainment performance of the device increases first and then decreases,and the best throat-mouth distance is 20 mm.(2)The effects of water pressure,throat diameter and throat-to-mouth distance on the atomization and entrainment characteristics of negative pressure spray device were investigated.The results show that the increase of water pressure increases the initial velocity of water flow,enhances the shear effect,decreases the droplet size,and improves the range,water consumption and entrainment performance.With the increase of throat diameter,the flow cross-sectional area in the throat increases,the droplet size increases,the range and entrainment performance increase,and the water consumption does not change significantly.With the increase of throat distance,the contact time of gas-liquid two-phase flow increases,the droplet size decreases first and then increases,and the entrainment performance increases first and then decreases.When the throat distance is 20 mm,the minimum droplet size and the best entrainment performance are obtained,and the change of throat distance has no obvious effect on the effective range and water consumption.(3)The effects of water pressure,throat diameter and throat distance on the dust reduction characteristics of the negative pressure spray device were studied,and the optimal combination parameters were determined.The results show that for the total dust and respirable dust reduction efficiency,the primary and secondary order of each factor is water pressure>throat mouth distance>throat diameter.With the increase of water pressure,the droplet size decreases,the entrainment performance increases,and the total dust and respirable dust reduction efficiency increase.With the increase of the distance between the throat and the mouth,the dust reduction efficiency of the whole dust and the respirable dust increases first and then decreases.When the distance between the throat and the mouth is 20 mm,the dust reduction efficiency is the best.The smaller throat diameter is conducive to the fragmentation of droplets and the decrease of particle size,but it will reduce the flow area and increase the energy loss,which makes the entrainment performance worse.When the throat diameter is 80 mm,the dust removal efficiency is the best.Under the optimal parameter combination of throat diameter of 80 mm,throat mouth distance of 20 mm and water pressure of 3 MPa,the total dust reduction efficiency of negative pressure spray device is 85.91%,and the respirable dust reduction efficiency is 76.33%..(4)Aiming at the problem of dust prevention and control at the transfer point of mining face,a field application process with negative pressure spray device and airtight cover as the core is proposed.The designed field application process uses a closed cover to restrain the fugitive dust,and makes full use of the characteristics of the negative pressure spray device for efficient dust reduction.It has the advantages of low water consumption,low cost,simple structure and easy maintenance.It effectively solves the problems of large water consumption and low dust reduction efficiency of traditional spray dust reduction,improves the working environment at the transfer point of mining face,and ensures the safe production of coal mine enterprises.The thesis contains 64 figures,12 tables and 91 references.更多还原