高溜井粉尘产运机理与时空分布特征及控制技术研究

发布时间：2018-07-10 12:03

本文选题：高溜井 + 冲击气流　；参考：《北京科技大学》2017年博士论文

【摘要】：金属矿山广泛采用溜井转运矿石,因矿石下落过程形成强大的冲击气流,粉尘随冲击气流扩散至采场,严重污染井下作业环境。本文以李楼铁矿采场高溜井为研究背景,采取理论分析、现场实测、相似实验、数值模拟及现场应用相结合的研究方法,对高溜井卸矿时冲击气流的产生和粉尘的扩散规律进行了研究,并对其影响因素进行了分析。通过研究气水喷雾降尘机理,提出了适用于高溜井的气水喷雾降尘系统并予以现场实施。通过分析矿石颗粒和粉尘在溜井内运动的受力分析,揭示了高溜井卸矿时粉尘的产生机理及影响因素,建立了冲击气流产生及粉尘运动的气固耦合三维数学模型;根据相似原理,推导出了高溜井卸矿时冲击气流产生和粉尘时空分布的相似准则数,建立了高溜井相似模型,并对不同卸矿条件下的冲击气流和粉尘的分布情况进行了实验研究。结果表明:最大冲击风速和粉尘平均浓度随卸矿流量及卸矿高度的增大而增大;矿石粒径范围及溜井阻力系数越大冲击气流越小,粉尘浓度也越小;粉尘浓度随含水率的增大迅速下降,含水率达到3.31%以上时,下降趋势不明显;同时卸矿的中段越多,冲击气流会产生叠加而增大。依据气固耦合相关理论,将矿石颗粒按离散体系处理,通过牛顿定律求解每个颗粒的运动,将气体按连续介质处理,通过求解Navier-Stokes方程得到气流的运动,采用DEM-CFD耦合的方法对溜井卸矿过程冲击气流和粉尘浓度的时空分布特征进行了数值模拟,对比现场实测结果,验证了该方法的准确性和适用性。结合相似实验和数值模拟对各影响因素的分析,在现有高溜井结构参数基础上,气水喷雾是控制高溜井卸矿粉尘最便捷有效的方法。本文通过实验研究了气水喷嘴的雾化特性,得出气水喷嘴的最佳气水流量比约为100-150。在溜井卸矿口及联巷内安装气水喷雾降尘系统,通过现场测定数据表明,喷雾降尘系统平均降尘效率可以达到80%以上,有效改善了采场的作业环境。
[Abstract]:It is widely used in metal mines to transfer ore through a well, and the dust diffuses into the stope as a result of the falling process of the ore, which seriously pollutes the underground working environment. In this paper, based on the research background of the high pass well in the stope of Lilou Iron Mine, a research method combining theoretical analysis, field measurement, similarity experiment, numerical simulation and field application is adopted. In this paper, the generation of impingement airflow and the diffusion of dust during unloading of high pass well are studied, and the influencing factors are analyzed. Based on the study of the mechanism of gas-water spray dust control, a gas-water spray dust control system suitable for high pass wells is put forward and implemented on the spot. Based on the analysis of the movement of ore particles and dust in the slide well, the mechanism of dust generation and the influencing factors are revealed, and the gas-solid coupling mathematical model for the generation of impingement airflow and the movement of dust is established. According to the similarity principle, the similarity criterion number of impact airflow generation and dust spatial and temporal distribution during unloading of high pass well is deduced, and the similarity model of high pass well is established. The distribution of impact airflow and dust under different unloading conditions was studied experimentally. The results show that the maximum impact velocity and the average dust concentration increase with the increase of the discharge rate and the unloading height, the larger the ore particle size range and the resistance coefficient, the smaller the impact air flow and the smaller the dust concentration. The dust concentration decreases rapidly with the increase of water content. When the water content is above 3.31%, the decreasing trend is not obvious, and the more the middle part of unloading ore, the more the impingement airflow will be superimposed and increased. According to the theory of gas-solid coupling, the ore particles are treated as discrete system, the movement of each particle is solved by Newton's law, the gas is treated as continuous medium, and the gas flow is obtained by solving the Navier-Stokes equation. Using DEM-CFD coupling method, the temporal and spatial distribution characteristics of impact air flow and dust concentration in the unloading process of pass well are numerically simulated, and the accuracy and applicability of the method are verified by comparing the field measured results. Based on the analysis of the influence factors of the similar experiment and numerical simulation, the gas-water spray is the most convenient and effective method to control the discharging dust of the high pass well on the basis of the existing structural parameters. In this paper, the atomization characteristics of gas-water nozzle are studied experimentally, and the optimum gas-water flow ratio is about 100-150. The air-water spray dust control system is installed in the unloading gate of the pass well and the joint roadway. The field data show that the average dust control efficiency of the spray dust control system can reach more than 80%, which effectively improves the working environment of the stope.
【学位授予单位】：北京科技大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TD714.4

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