超细水雾-多孔材料协同抑制瓦斯爆炸实验研究

为探究超细水雾与多孔介质在协同作用下对多孔介质淬熄效果以及多孔介质上游爆炸超压的影响,自行设计并搭建了尺寸为80 mm×80 mm×1 000 mm透明有机玻璃瓦斯爆炸管道实验平台,研究超细水雾质量分数、多孔材料孔径及孔隙率对9. 5%甲烷压的协同抑制效果。实验结果表明,改变超细水雾质量分数、多孔材料孔径以及孔隙率,在多孔材料上游,最大火焰传播速度和最大爆炸超压有着显著变化,随着超细水雾质量分数增加,火焰锋面传播速度峰值和爆炸超压逐渐减小,爆炸超压峰值出现时间随之缩短,而随着孔径的减小,火焰锋面传播速度也逐渐减小,压力衰减率明显增加。同时,超细水雾和多孔材料的组合方式对瓦斯爆炸具有耦合抑制作用,管道内通入超细水雾可吸收反应区大量热能,降低反应速率与火焰传播速度,此外多孔材料的存在吸收了部分前驱冲击波,破坏正反馈机制,因此两者协同抑制优于单一抑制效果。放置在管道中的多孔材料使得传播火焰淬熄,且添加的超细水雾降低了多孔材料上游的超压,但是一旦多孔介质淬熄失败,火焰湍流加剧,可能会导致更为严重的事故发生。此外,与9. 5%甲空气预混气相比,孔隙率为87%,孔隙密度为20 PPI和超细水雾质量浓度为1 453. 1 g s,下降比例达到44. 23%,且多孔材料上游的最大爆炸超压为6. 13 kPa,降低了40. 62%,抑制效果最明显。

Study on synergistic inhibition of gas explosion by ultrafine water mist-porous materials

In order to explore the influence of quenching effect of porous media and the explosion overpressure upstream of porous media under the synergistic effect of ultra-fine water mist and porous media,an experimental platform of transparent plexiglass gas explosion pipeline with the size of 80 mm×80 mm×1 000 mm was designed to research the synergistic inhibition effects of ultrafine water mist concentration,pore density and porosity factor on the flame propagation and explosion overpressure of 9.5% methane/air premixed gas.The experimental results show that the maximum flame front propagation velocity and the maximum explosion overpressure have a significant diversification in the upstream of porous material by changing the concentration of ultrafine water mist,pore density and porosity factor.With the increase of ultra-fine water mist concentration,the peak flame front velocity and explosion overpressure decrease gradually,and the time of explosion overpressure peak appears shorter.As the aperture decreases,the flame front propagation velocity decreases and the pressure attenuation rate increases significantly.At the same time,the combination of ultrafine water mist and porous material has a synergistic inhibition effect on the methane/air explosion.A large amount of heat energy can be absorbed by ultra-fine water mist into the pipeline,which reduces the reaction rate and flame propagation speed.In addition,the porous material absorbs some of the precursor shock waves and destroys the positive feedback mechanism.Therefore,the synergistic inhibition effect of the two materials is better than the single inhibition effect.The porous material placed in the pipeline makes the propagation flame quenched,and ultrafine water mist added reduces the overpressure upstream of the porous material.However,once the quenching of porous media fails,the flame turbulence would intensify,which may lead to more serious accidents.In addition,compared with the 9.5% methane/air premixture,under 87% porosity factor,20 PPI pore density and 1 453.1 g/m3 ultra-fine water mist concentration,the flame front propagation speed was 12.8 m/s,the decrease rate reached 44.23% and the maximum explosion overpressure in the upstream of the porous material was 6.13 kPa,which was reduced by 40.62%,the inhibition effect was the most obvious.