腔体影响全巷道甲烷爆炸冲击波传播的特性

Cavity effect on the characteristics of methane blast wave propagation in the whole roadway

近年来,国内外学者对甲烷爆炸抑爆技术主要分为主动式和被动式两大类,对煤矿甲烷抑爆的发展产生了积极的影响,而现有被动式抑爆技术通常是一次性,对于全巷道瓦斯次生爆炸失效,主动式响应时间长,维修成本昂贵。为探索巷道结构对甲烷爆炸传播性能影响,以数值模拟方法对800 mm×500 mm×200 mm和500 mm×500 mm×200 mm(长×宽×高)双腔体进行分析,发现该腔体具有良好的消波效果。选用与数值模拟一样尺寸腔体结构,使用钢质材料加工成串联的双腔体作为试验腔体,ABC干粉作为抑爆剂,并与部分充填甲烷腔体进行对比分析,从火焰速度、火焰持续光照强度和爆炸波峰值超压的影响情况来判定抑爆效果。结果表明:数值模拟发现,甲烷爆炸在双腔内的传播过程,火焰传播过程经历熄灭与再次点燃阶段,腔体中的爆炸波被分批次传送出;2号腔体进一步提高了熄火、消波性能;腔体通过爆炸波的折射、反射和叠加等综合作用有效抑爆,在两腔体内来回震荡,在此过程中,预混气体耗尽火焰消失,爆炸波被分批传出。试验发现,双腔体对甲烷爆炸波传播有抑制作用,全充填甲烷的火焰大小和爆炸波峰值超压比部分充填甲烷腔体时衰减率均降低,耦合干粉提高了双腔体对火焰和爆炸波的抑制率,其中干粉量是800 g,火焰速度衰减率和峰值超压衰减率较全充填甲烷腔体分别提升了58.11%和25.80%,火焰大小衰减率达到98.13%。

In recent years,scholars at home and abroad mainly divide gas explosion suppression technology into active and passive types,which have a positive impact on the development of coal mine gas explosion suppression.However,the existing passive explosion suppression technology is usually one-off,for the failure of gas secondary explosion in the whole roadway,the active response time is long and the maintenance cost is expensive.To explore the influence of roadway structure on methane explosion propagation performance,the double cavities of 800 mm×500 mm×200 mm and 500 mm×500 mm×200 mm(length×width×height)were analyzed by numerical simulation method,and it was found that the cavities had good wave elimination effect.The cavity structure of the same size as that in the numerical simulation was selected.The double-cavity made of steel material in series was used as the test chamber,and the ABC powder was used as the explosion suppressor.The comparative test of partially filled methane chamber was conducted.The numerical simulation shows that in the propagation process of methane explosion in the double chamber,the flame propagation process goes through the extinguishing and reigniting stages,and the explosion waves in the chamber are transmitted in batches.The quenching and wave extinction performance of cavity 2 is further improved.The cavity is effectively suppressed by refraction,reflection and superposition of the explosion wave,and oscillates back and forth in the two cavities.In this process,the premixed gas is exhausted and the flame disappears,and the explosion wave is sent out in batches.It was found that the dual-chamber had an inhibitory effect on the propagation of methane explosion wave,and the coupling dry powder increased the inhibition rate of the dual-chamber to the flame and the explosion wave,in which the amount of dry powder was 800 g,the attenuation rate of flame velocity and peak overpressure increased by 58.11%and 25.80%respectively,and the attenuation rate of flame size reached 98.13%.