导　　师： 罗振敏

学科专业： 081903

授予学位： 硕士

作　　者： ;

机构地区： 西安科技大学

摘　　要： 气体在不受控条件下的燃烧与爆炸给人们带来了巨大的生命、财产损失。基于可燃气体爆炸的巨大破坏性，研究其引发破坏模式、燃烧爆炸传播机制以及相应的抑制方法，提出防灾减灾措施显得愈发迫切。 本文结合可燃性气体爆炸、传播相关机理，运用XKWB-S型气体爆炸火焰传播特性测试系统和专业气体爆炸模拟软件FLACS，对小尺寸爆炸管道内不同浓度甲烷爆炸特性及CO2抑爆过程进行了实验和数值模拟研究。 结果表明，内径88mm、长1600mm/(L//D=18/)的石英玻璃管道内甲烷爆炸极限为4.95/%~12.65/%；爆炸感应期随着甲烷浓度的增加而缩短，甲烷被引燃后的火焰生成过程显现出球形火焰的生长和内焰的拉伸与前移两个过程，火焰长度随着爆炸传播距离的增大而增加，且甲烷越接近当量浓度，其爆炸传播过程中的火焰长度和火焰传播速度越大。甲烷爆炸传播过程中，爆炸超压经历压力积聚-传播-泄压-负压回流-震荡并恢复常压等阶段；温度在爆炸发生后迅速上升，随着爆炸火焰的传播受到壁面作用的影响而有所下降，泄爆后，敞口端气体在负压回流的作用下向管道封闭端运移导致封闭端温度有所回升。 体积分数9/%的CH4在6~18/%CO2作用下仍会爆炸，随着CO2添加量的增大爆炸压力减小，火焰的强度、亮度均逐步降低，传播速度逐渐递减。由于受到爆炸传播过程中产生的湍流影响，火焰传播速度出现波动。各组分混合气体爆炸压力和气体运动速度由于压力波、反射压力波和壁面作用的影响均呈现一定的波动，且受到爆炸传播过程中以及泄爆之后管道内部的压力梯度变化的影响，二者没有同时达到最大值。CO2添加量增至18/%时，9/%CH4爆炸压力峰值降低约77/%，压力峰值到达时间延长约3.35倍。21~27/%的CO2完全抑制了9/%CH4的爆炸。 Burning and explosion caused by gas under uncontrolled conditions can bring enormouslife and property losses. Based on the huge destructive effect of flammable gas explosion, it isincreasingly urgent to study its destructive patterns, mechanism of explosion andcorresponding suppression method, so as to put forward the measures of disaster preventionand mitigation. In this paper, combining with the relevant mechanism of combustible gas explosion andspread, XKWB-S gas explosion flame propagation characteristics test system and professionalgas explosion simulation software FLACS were employed to study the explosioncharacteristics of methane in different concentration of small size explosive pipe and processof CO2to suppress the explosion. The result shows that the explosion limitation of methane in the quartz glass pipe is4.95/%~12.65/%, which its inner diameter of88mm and1600mm long /(L//D=18/). Inductionperiod of methane shortens with the increase of concentration. After methane being ignited,the production process of flame can be divided into the two parts,which is the spherical flameand inner flame stretching and moving forward. The thickness and the speed of flameincreases with the increase of the spread distance of explosion, and the closer theconcentration of methane gets to its equivalence, the greater the thickness of the flame in theexplosive propagation process. During the explosive propagation process of methane, theexplosive overpressure goes through the pressures of build-up, spread of pressure, pressurebackflow, shocking and recovery of normal pressure stage; Temperature rises rapidly after theexplosion, then fell down as the explosion flame propagation is affected by the wall. Aftervented explosion, gas in the open position move to the closed end under the action of negativepressure backflow, which leads to the temperature in the closed end rises. 9/%volume fraction of CH4will still explode in the6~18/%volume fraction CO2.Withthe increase of CO2, the explosion pressure decreases, the intens

关 键 词： 甲烷爆炸 火焰传播特性 数值模拟 流场特征

领　　域： [矿业工程]