井下煤尘爆炸特性及降尘抑爆技术研究

发布时间：2018-06-28 08:22

本文选题：煤尘爆炸 + Fluent　；参考：《中北大学》2017年硕士论文

【摘要】：作为井下五大自然灾害之一,煤尘不仅危害工人的身体健康,而且存在爆炸的危险。随着煤炭资源开采的机械化、自动化程度越来越高,煤尘的产生量也越来越多,开展对煤尘爆炸理论的研究,以及对煤尘防治装置的改进,变得更为急迫。本文首先介绍了文章的研究背景与意义,并对国内外的煤尘爆炸机理、煤尘爆炸传播规律和煤尘防治技术进行了分析和总结。之后描述了煤尘爆炸的基本过程,从热爆炸理论和自由基原理两个角度简述了煤尘爆炸的化学反应机理并说明了煤尘爆炸威力的影响因素,然后简单解释了煤尘爆炸冲击波在不同类型的巷道中衰减原因,为下文的数值仿真奠定了理论基础。为研究煤尘爆炸的冲击波在不同初始条件下的传播规律,建立了直巷道模型,并利用CFD仿真软件Fluent分析了不同瓦斯含量、煤尘浓度和煤尘粒度时,直巷道内冲击波超压的变化趋势。结果表明:煤尘混合物爆炸冲击波的超压值以及压力值的上升速度随着瓦斯含量的增加呈现先增大后减小的趋势;冲击波超压值随煤尘浓度的增大而先增大后减小;煤尘粒径的变化对爆炸冲击波超压和火焰温度及其速度的影响显著,粒度越小,火焰速度和温度越高。为研究复杂巷道中煤尘爆炸冲击波的传播规律,建立了不同角度的拐弯巷道、分岔巷道和变截面巷道模型,同样利用Fluent软件,在典型位置设置观测点,分析了各种情况下的超压值变化。结果表明:巷道拐弯的弯角越大,拐弯之后的直巷道中的压力值越小,拐弯角度的增大有利于冲击波的压力衰减;单向分岔巷道中,分岔角度增大时,下游直巷道的超压值随之增大,而分岔支巷道中的压力值则逐渐减小;变截面巷道中,当冲击波由窄巷道传播至宽巷道时,冲击波超压发生明显降低,且宽巷道的截面越大,这种衰减越明显。基于水雾对煤尘的吸附和沉降机理的分析,设计了一种可降尘、抑爆的主动装置。该系统将多传感器方案其他安保系统联合,做到信息共享,可以有效的保证对危险源辨识的准确度;设计了基于提醒和危险两种结果的对应,尤其在危险回路中,额外增加了机械触发的快速喷雾回路,具有成本低廉和安装简易的优点,且增加了系统可靠性。
[Abstract]:As one of the five natural disasters, coal dust not only endangers the health of workers, but also has the risk of explosion. With the mechanization of coal resource exploitation, the degree of automation is becoming higher and higher, and the production of coal dust is more and more. It is more urgent to carry out the research on the theory of coal dust explosion and the improvement of coal dust prevention and control device. In this paper, the background and significance of the research are introduced, and the mechanism of coal dust explosion at home and abroad, the propagation law of coal dust explosion and the prevention and cure technology of coal dust are analyzed and summarized. Then the basic process of coal dust explosion is described, the chemical reaction mechanism of coal dust explosion is briefly described from the view of thermal explosion theory and free radical principle, and the influencing factors of coal dust explosion power are explained. Then the attenuation reason of coal dust explosion shock wave in different types of roadways is briefly explained, which lays a theoretical foundation for the numerical simulation below. In order to study the propagation law of shock wave of coal dust explosion under different initial conditions, a straight tunnel model is established, and the different gas content, coal dust concentration and coal dust particle size are analyzed by CFD simulation software fluent. The change trend of shock wave overpressure in straight tunnel. The results show that the overpressure value and the rising speed of blast wave of coal dust mixture increase first and then decrease with the increase of gas content, and the value of shock wave overpressure increases first and then decreases with the increase of coal dust concentration. The change of coal dust particle size has a significant effect on the explosion shock wave overpressure, flame temperature and velocity. The smaller the particle size is, the higher the flame velocity and temperature are. In order to study the propagation law of coal dust explosion shock wave in complex roadway, different angle models of bend roadway, bifurcation roadway and variable section roadway are established, and the observation points are also set up in typical position by using fluent software. The change of overpressure value under various conditions is analyzed. The results show that the greater the bend angle, the smaller the pressure value in the straight roadway after turning, and the greater the bend angle is in favor of the pressure attenuation of shock wave, while in the unidirectional bifurcation roadway, when the bifurcation angle increases, The overpressure value of the downstream straight roadway increases, while the pressure value in the branched roadway decreases gradually, while in the variable section roadway, the shock wave overpressure decreases obviously when the shock wave propagates from the narrow tunnel to the wide roadway, and the larger the section of the wide roadway is, The more obvious this decay is. Based on the analysis of adsorption and settling mechanism of coal dust by water mist, an active device for dust suppression and explosion suppression is designed. The system combines other security systems of the multi-sensor scheme to share information, which can effectively guarantee the accuracy of hazard source identification, and designs the correspondence based on the warning and hazard results, especially in the dangerous loop. It has the advantages of low cost and easy installation, and increases the reliability of the system.
【学位授予单位】：中北大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD714.5

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