甲烷—空气爆炸火焰传播的微观研究

发布时间：2018-12-09 13:25

【摘要】：可燃气体的爆炸是我国工业生产行业中爆炸危害频发的主要事故之一，其中尤以煤矿瓦斯爆炸事故最为常见，极大损害了劳动人民的生命和财产安全，爆炸的频发与严重后果使受害群众身体和心理上都蒙受巨大阴影。因此，研究管道内气体爆炸火焰传播特性及其机理将能使企业更好地预防和控制管道内气体爆炸灾害的发生和发展。近年来，对气体爆炸火焰传播过程的研究越来越受到人们的重视，研究内容也更加广泛。本论文利用中北大学防火防爆安全工程技术研究中心自制的透明管道气体爆炸测试装置，采用高速摄像技术测试气体爆炸过程火焰传播的情况，对常温、常压下甲烷空气混合气体的燃烧爆炸过程进行了一定的试验研究，得出相关结论如下： (1)建立了可燃气体爆炸火焰的微观试验系统，利用高速摄像机测定了甲烷爆炸火焰在水平管道中动态的微观传播过程，用MATLAB软件编写程序计算出火焰阵面即时传播速度。 (2)试验研究了管道内甲烷浓度在7%-13%范围内变化时火焰的出现、结束以及持续时间等传播情况，分析了甲烷在不同浓度下的火焰传播速度、火焰微观结构，得到其影响规律。试验结果表明，，甲烷浓度在7-8%之间时速度没有明显变化，最大时约70m/s，增加浓度后火焰速度迅速上升，当量浓度时最大速度约130-140m/s，之后火焰速度开始减慢，在12%时略有回升，整体呈下降趋势。当量浓度下甲烷火焰出现时间在点火后32ms处，火焰传播很快，持续时间较短，约30ms。火焰出现时，以均匀的类球面向前传播，之后规则形状终止，转变为管壁方向分别加速，火焰面倾斜变形，50ms时最终生成郁金香状火焰；8%浓度和12%浓度的甲烷火焰出现时间均超过100ms，持续时间略长，分别为60和80ms。火焰形状的变化与当量浓度时类似。 (3)试验研究了1.3m、2.3m、3.3m三个不同管道长度时火焰传播特性，分析不同管道长度时火焰传播速度、火焰结构的变化规律。结果表明，火焰传播受管长的影响较大，表现为管长从1.3增加至2.3m时，爆炸更为剧烈，爆炸声更响亮，火焰亮度更强，火焰阵面扭曲变化激烈，火焰传播速度较短管中也增大；而继续增加管道长度至3.3m，所有浓度的甲烷均未发生爆炸，只有10%浓度时有微弱燃烧现象。加长管道后，火焰出现时间提前到早于80ms，持续时间约80ms。
[Abstract]:The explosion of combustible gas is one of the most frequent accidents in industrial production in China, especially in coal mine, which greatly damages the life and property safety of the laboring people. The frequent and severe consequences of the explosion have greatly overshadowed the victims, both physically and psychologically. Therefore, studying the characteristics and mechanism of gas explosion flame propagation in pipeline will enable enterprises to better prevent and control the occurrence and development of gas explosion disaster in pipeline. In recent years, more and more attention has been paid to the flame propagation process of gas explosion. In this paper, the flame propagation in the process of gas explosion is measured by using the self-made transparent pipeline gas explosion test device made by the fire and explosion safety engineering research center of Central North University, and the flame propagation during the gas explosion process is measured by high speed camera technology. The combustion and explosion process of methane air mixture under atmospheric pressure has been studied, and the relevant conclusions are as follows: (1) the micro test system of combustible gas explosion flame is established. The microcosmic propagation process of methane explosion flame in horizontal pipe was measured by high speed video camera. The real time propagation velocity of flame front was calculated by MATLAB software. (2) the appearance, end and duration of flame in the range of 7% to 13% of methane concentration in the pipeline were studied, and the flame propagation velocity and flame microstructure of methane at different concentrations were analyzed. The law of influence is obtained. The results showed that there was no significant change in the velocity of methane between 7-8%, the maximum concentration was about 70 m / s, the flame velocity increased rapidly after increasing the concentration, the maximum velocity at the equivalent concentration was about 130 ~ 140 m / s, and then the flame velocity began to slow down. At 12, a slight rise, the overall downward trend. When the methane flame appears at the 32ms after ignition at the equivalent concentration, the flame propagates quickly and the duration is shorter, about 30 Ms. When the flame appears, it propagates forward with a uniform spherical surface, then the regular shape terminates and changes into the tube wall direction to accelerate separately, the flame surface is inclined to deform, and finally the tulip flame is formed during 50ms. The emergence time of methane flame at 8% concentration and 12% concentration was more than 100 msand lasted a little longer (60 and 80 msrespectively). The change of flame shape is similar to that of equivalent concentration. (3) the flame propagation characteristics of three different pipe lengths of 1.3mL 2.3mand 3.3m have been studied, and the flame propagation velocity and flame structure have been analyzed. The results show that the flame propagation is greatly influenced by the tube length. When the tube length increases from 1.3 to 2.3 m, the explosion is more intense, the sound of the explosion is louder, the flame brightness is stronger, and the distortion of the flame front is intense. The flame propagation velocity also increases in the short tube. However, when the length of the pipe was increased to 3.3 m, no explosion occurred in all concentrations of methane, and only 10% of the concentration had a weak combustion phenomenon. The flame appears earlier than 80 Ms and lasts about 80 Ms after the lengthening of the pipe.
【学位授予单位】：中北大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：X932

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