Research on the inhibition characteristics of ultrafine water mist on gas/dust two-phase mixture explosions

Abstract

Inhibition of water mist on the gas/dust two-phase explosions and its influence factor were studied inside the vessel. The effects of mist and methane concentrations on the pressure and its rise rate, flame propagation characteristics and its temperature were explored. Especially the explosion products were analyzed by the infrared spectroscopy. The weakening effect was revealed based on the corresponding relationship and changing rule of explosion parameters. As the flame developed and changed, the pressure rise showed the same correspondence. However, the corresponding moment was evidently prolonged compared with the case no mist. The mist could effectively inhibit the intensity of mixture explosions, causing a dark-irregular structure in the early stage and accelerating its extinction in the later stage. After the mist concentration increased, the explosion parameter was evidently reduced. As the methane concentration increased (4% ≤ c ≤ 10%), the explosion parameters appeared a trend of firstly rising and then reducing. As c = 6%, the explosion intensity was the greatest. After adding mist, the explosion parameter exhibited the same change regular. And the weakening effect of mist on the weaker flame was more outstanding and was constantly enhanced as the rise of mist concentration. Besides, the mist could effectively inhibit the pyrolysis and combustion reactions of macromolecular functional groups, further leading to evident increase in the functional group content inside the coal dust as the mist concentration increased.