Ignition And Development Law Of Deposited Dust In Connecting Pipe Induced Explosion In Connecting Pipe Induced By Initial Explosion In Container

In many dust explosion accidents,it is found that combustible dust reaches a certain concentration,and it is easy to explode when encountering ignition source.Enterprise dust collector is a high risk area for dust explosion.Once dust explosion occurs,it is easy to spread into the air inlet pipe.It is easy to form deposited dust at the joint,turning and uneven surface of the air inlet pipe.The dust explosion in the dust collector further induces the deposition dust to participate in the combustion,and the explosion flame wave spreads along the air inlet pipe and leads to the occurrence of hazardous accidents of different degrees under the influence of the deposition dust.But at present,the influence of dust deposition quality,location,length and other characteristics on dust explosion has not provided accurate and effective theoretical support.In order to study the influence of deposited dust on dust explosion in dust collector,a 12 L cylindrical explosive container connecting to a 2m long transparent glass pipe was used.The explosion propagation process of dust explosion in the container raising deposited dust in the pipe and making it participate in combustion was studied,and the influence of deposited dust in the air inlet pipe on the dust explosion propagation was analyzed.The findings are as follows:(1)The study on the influence of whether is deposited dust in the connecting pipeline on the dust explosion propagation shows that when there is no deposited dust involved in combustion and explosion,the pressure measured at each pressure measuring point of the experimental equipment is small,the pressure curve has a bimodal structure,and the flame propagation velocity is proportional to the dust explosion concentration in the container.It is found that the combustion of deposited dust leads to a significant increase in the maximum explosion pressure of dust explosion in the experimental equipment,and the increase rate of explosion pressure is obviously accelerated.The pressure double-peak curve in the pipe disappears due to the participation of enough deposited dust in the combustion.The flame propagation speed is inversely proportional to the increase of dust explosion concentration.The participation of deposited dust in combustion intensifies the brightness of flame propagation in the pipeline,making the flame brightness change more gentle and stable.(2)The study on the influence of the change of dust deposition mass in the connecting pipeline on the dust explosion propagation in the container shows that with the increase of dust deposition mass,the maximum explosion pressure in the container increases first and then decreases,the flame propagation speed decreases gradually,and the combustion of dust deposition in the pipeline consumes the energy of flame wave and the oxygen content in the pipeline.Flame propagation length,flame brightness reduced.(3)The study on the influence of the change of dust deposition position in the connecting pipeline on the dust explosion propagation in the container shows that with the increase of the distance between the dust deposition position and the connection port of the pipeline,the maximum explosion pressure in the container increases first and then decreases.The propagation speed of flame wave in the pipeline gradually increases and gradually becomes stable,and the flame becomes brighter in the process of flame propagation.(4)The study on the influence of the change of dust deposition length in the connecting pipeline on the dust explosion propagation in the container shows that with the increase of dust deposition length,the maximum dust explosion pressure in the container presents a change trend of first decreasing and then increasing,the flame propagation speed in the pipeline accelerates and gradually becomes stable,and the flame brightness in the pipeline presents a trend of first increasing and then decreasing.