CO_2-超细水雾对CH_4/Air初期爆炸特性的影响

Effect of CO_2-ultrafine water mist on initial explosion characteristics of CH_4/Air

为了研究CO_2和超细水雾对9.5%甲烷/空气初期爆炸特性的影响,采用高速纹影系统和定容燃烧弹对9.5%甲烷/空气初期爆炸特性进行了研究。分别改变CO_2稀释体积分数和超细水雾质量浓度,分析在二者单独和共同作用下球形火焰传播过程、火焰传播速度和爆炸超压的变化规律。结果表明:58.3g/m^3超细水雾增强了火焰不稳定性,促进了火焰加速和爆炸超压增加,表明超细水雾不足能产生促爆作用,只有当超细水雾充足时才会抑制甲烷爆炸;CO_2和超细水雾共同作用时能避免因超细水雾带来的促爆现象,可以明显减弱火焰不稳定性,减小火焰传播速度,降低爆炸超压和平均压升速率,以及明显推迟超压峰值来临时间。

In order to study the effect of CO2 and ultrafine water mist on the initial 9.5% methane/air explosion characteristics, a high speed schlieren system and a constant volume combustion bomb were used to study the 9.5% methane/air explosion characteristics. By changing the dilution volume fraction of CO2 and mass concentration of ultrafine water mist respectively, the change rules of flame propagation speed and explosion overpressure were analyzed under two separate and combined actions. The results show that the ultrafine water mist with a mass concentration of 58.3 g/m^3 enhanced the instability of the flame and accelerated flame acceleration and explosion overpressure. This indicates that the insufficiency of the ultrafine water mist can produce detonation promotion, and the methane explosion will be suppressed only when the ultrafine water mist is sufficient. When CO2 and ultrafine water mist act together, it can avoid the explosion phenomenon caused by ultrafine water mist, weaken the instability of spherical flame significantly, reduce the propagation velocity of the spherical flame, decrease the explosion overpressure and the mean rate of pressure rise, and delay the arrival time of the overpressure peak. This study can provide a guidance for the prevention of methane explosion.