喷射超细ABC粉体对瓦斯爆炸的抑制与增强作用

Suppression and enhancement of methane/air explosion by discharge of ultrafine ABC powders

通过触发抑爆装置气体发生器产生高压运载气体(氮气),驱动超细ABC粉体快速喷射的方式,在100 L爆炸容器内开展了甲烷/空气混合物爆炸抑制研究,旨在揭示抑爆介质喷射量、抑爆装置触发时间等关键参数对瓦斯爆炸抑制效果的影响。结果表明:在抑爆介质喷射总量40 g条件下,甲烷/空气混合物点燃后50 ms时间段内触发抑爆装置,超细ABC云幕均能将爆炸火焰轮廓完全覆盖,甲烷/空气混合物爆炸火焰传播得以完全抑制,当抑爆装置触发时刻超过55 ms时,仅使爆炸发展过程推迟,并不能降低爆炸强度。抑爆装置触发时间维持55 ms不变,只有将抑爆介质喷射量增加到60 g时,才能将爆炸火焰传播熄灭。研究还发现,在抑爆装置触发时间一定时,抑制爆炸所需的超细ABC粉体存在较为确定的临界量,当抑爆介质喷射量低于临界值时,在抑爆介质喷射的初始阶段,爆炸火焰传播有所衰减,但随后火焰传播更加迅速,整体上对爆炸火焰传播起到促进和强化作用;而当抑爆介质喷射量高于临界值时,过量喷射抑爆介质对爆炸抑制效果也起不到进一步改善作用。作为驱动超细ABC粉体的必要动力源,氮气喷射过程对爆炸的强化作用十分显著,通过合适的超细ABC粉体冗余量充装可有效克服上述不足。

Active explosion suppression test of methane/air mixtures was carried out in a 100 L closed chamber through an ultrafast trigging of the trial-manufactured suppressor,in which the superfine ABC powder was pre-filled and temporary pressurized by the activation of solid nitrogen generator at proper time after ignition,intended to investigate the influence of key parameters on the efficiency of explosion suppression.Results show that the flame propagation could be quenched completely if the gas generator was triggered within critical time,in which case all of the flame profile were covered by 40 g discharged superfine ABC cloud,whereas the explosion intensity could not be suppressed when the trigger time exceeds 55 ms after ignition.Under the trigger time of 55 ms,the explosion flame propagation can be extinguished only when the discharging amount of explosion suppression medium is increased to 60 g.It was verified that no inhibition effect on explosion was presented when the discharge of superfine ABC powder was below the critical mass,whereas further improvement of explosion suppression effect was not significant in case of the injection of explosion suppression medium was above this threshold level.In addition,as a necessary carrier for ultrafine ABC powder discharge,the injection of nitrogen into the chamber of 100 L volume significantly strengthened flame propagation,this deficiency can be overcome expectedly by appropriate redundancy discharge of the ultrafine ABC powder.