【作者】 程磊；

【导师】 景国勋；

【作者基本信息】 河南理工大学 ， 安全技术及工程， 2011， 博士

【摘要】 本文基于粉尘爆炸理论,采用试验研究、理论分析、数值模拟三种研究方法,针对煤尘爆炸特性及煤尘爆炸冲击波在单向分岔管道、双向分岔管道、截面积突变管道的传播衰减规律进行了研究,其成果对预防、控制爆炸冲击波的破坏和伤害,煤尘爆炸事故救援决策提供理论与技术支持。在前人研究成果的基础上,对煤尘爆炸特性及爆炸冲击波传播特性进行了分析,详细介绍并论述了煤尘爆炸过程、爆炸冲击波的结构形式、煤尘爆炸两相流、空气冲击波的传播特性以及影响因素。采用20L球形爆炸实验系统,对试验煤样的爆炸特性进行了测试分析,得出了试验煤样的最佳爆炸浓度是500g/m3。通过对煤样进行工业分析,得出挥发分的95%、固定碳的80%参与了燃烧反应。对爆炸前后煤尘样进行微观分析发现,爆前煤尘样表面布满裂隙,而爆后样品表面较平滑无裂隙。通过能谱分析表明,爆后煤样中C、O元素的质量分数分别减少了7%、9%,Na、Mg、Al、Si等无机元素的质量分数增加。利用自行设计制作的煤尘爆炸传播实验系统,研究了一般空气区内煤尘爆炸冲击波在单向、双向分岔管道、截面积突变管道内的传播规律。试验结果表明,衰减系数也随初始压力增大而增大,但增幅较小;单向分岔管道内直线段内冲击波超压衰减系数随分岔角度的增大而减小,支线段内的衰减系数随分岔角度的增大而增大,增幅大于减幅;双向分岔管道内,单条分岔管道的衰减系数随其分岔角度的增加而增大,两条分岔因各自分岔角度的变化呈反方向互相影响,随两条分岔夹角的增加,其总衰减系数也增大。截面积管道内的冲击波超压衰减系数随初始超压、载面积变化率的变化而变化。基于流体动力学基本原理,对分岔管道内煤尘爆炸传播过程进行适当简化与合理假设,根据质量、动量、能量守恒定律,建立了巷道内压力计算公式,得出在分岔巷道内冲击波传播衰减规律公式,在给定初始压力、分岔角度、入射冲击波强度后就可计算出各分岔巷道内的冲击波超压衰减系数。与试验结果对比,推导的公式与试验结果相吻合。对一般空气区内煤尘爆炸冲击波在分岔管道、截面积突变管道内的超压变化规律进行了数值模拟模拟分析,得出了在分岔管道、截面积突变管道内的冲击波超压传播过程中的压力分布情况、测点的超压峰值及衰减系数。模拟结果与试验结果相吻合,说明了数值模拟结果的可靠性,为今后进行更深入研究提供了一种新方法。数值模拟结果也对试验研究、理论分析中的一些现象与结果作了合理的解释,起到了有益的补充。更多还原

【Abstract】 Based on the dust explosion theory, adopting methods of experimental study, theoretical analysis, numerical simulation, the dissertation studies characteristics of coal dust explosion and the propagation law of shock wave of coal dust explosion in one-way, two-way bifurcation pipeline and cross-section pipeline. The results offer important theoretical and technological support for preventing and controlling the damage of explosion shock wave and decision-making in coal dust explosion accidents.On the basis of former researches, the characteristics of coal dust explosion and the propagation character of explosion shock wave were analyzed, and the process of explosion, structure of the explosion shock wave, the propagation law and factors of two-phase flow of gas and solid when detonation and air shock wave in coal dust explosion were introduced and discussed in detail.The 20L spherical explosion test apparatus was adopted to test and analyze characteristics of test coal explosion, and the perfect concentration was confirmed to be 500g/m3. By making a proximate analysis on coal dust sample, it is concluded that 95% of the volatile and 85% of fixed carbon participate in the combustion. With a microscopic analysis, it is found that the surface of the text coal was covered with fracture before the explosion, while after the explosion the surface was smooth. The energy spectrum analysis showed that the mass of carbon and oxygen reduced by 7% and 9%, correspondingly, the mass of inorganic elements, such as Sodium, Magnesium, aluminum, silicon increased.By adopting the self-designed-and-manufactured coal-dust explosion propagation experiment system, the propagation law of shock wave in general air area of coal dust explosion in one-way or two-way bifurcation pipeline and cross-section pipeline was studied. The results showed that attenuation coefficient raised with the increase of initial pressure, but the increase was slight. In one-way bifurcation pipeline, the coefficient decreased with the increase of angle in the straight line, and the increase was bigger than the decrease. In two-way bifurcation pipeline, the attenuation coefficient of each bifurcation raised with the angle increasing, and the two branches interacted in the opposite direction because of the difference of angle of each branch. The final attenuation coefficient raised with increase of the angle between the two branches. In cross-section pipeline, the attenuation coefficient varied with initial pressure and the variation rate of load area changing.Based on hydrodynamics, according to mass, momentum and energy conservation, by simplifying properly and reasonably hypothesizing propagation progress of the dust explosion in pipeline, the formulas of the overpressure in different pipeline was established. With the initial pressure, the bifurcation angle and the intensity of the incident shock wave being given, the shock wave pressure could be calculated, and the propagation law of shock wave in the bifurcation entry could be got. And the results based on the formulas conformed to the experiment results.By making numerical simulation analysis on the law of overpressure change of dust shock wave in bifurcation pipeline and cross-section pipeline in general air zone, pressure distribution diagram and the overpressure peak of each measured point in the propagation progress of shock wave were obtained. The simulation result was identical with the experiment result, which showed that the result of numerical simulation was correct, therefore a new method was provided for the further study. The simulation results, as a beneficial supplement, also settled some phenomena and results in the experimental study and theoretical analysis.更多还原