半封闭管道内瓦斯煤尘爆炸火焰传播规律研究

为了探究瓦斯煤尘爆炸火焰的传播规律,采用自行搭建的半封闭垂直管道爆炸试验系统,研究瓦斯体积分数和煤尘质量浓度的改变对火焰传播规律的影响。结果表明:1)加入煤尘后的瓦斯爆炸火焰传播速度显著增大;2)在爆炸腔体内,瓦斯体积分数越接近化学当量比,煤尘质量浓度越接近50 g/m3,爆炸火焰传播速度越快;3)在传播管道内,大量的氧气从开口端进入参与反应,瓦斯体积分数和煤尘质量浓度较大的试验组,火焰传播速度会迅速上升;4)煤尘质量浓度和瓦斯体积分数存在最佳配比,煤尘质量浓度和瓦斯体积分数偏离最佳浓度配比程度较大时,火焰传播加速度下降,传播距离变短。

On the flame propagation regularity of the gas and coal explosive dust in the semi-closed pipeline

The present paper intends to conduct an explosion experiment by changing the gas and coal dust concentration rates in the self-prepared semi-closed vertical pipeline through the experimental explosion system to further explore the propagation regularity of the gas and coal dust explosion flames.To achieve the purpose,we have done observations over the strength of the coupled explosion reaction of the gas and coal dust under different concentration ratio conditions,whereas keeping on tracing the impact of the concentration change on the flame propagation regularity.The results of our observation and examination show that:(1)In the explosion chamber,little effect has been made on the development of the flame situation by adding the coal dust.As the reaction is going on,it has been found that the coal dust adding to the propagation pipeline can significantly enhance the intensity of the explosive gas.As compared with the explosive gas,the gas-dust coupled explosion reaction rate can be greatly enhanced.However,the time for the flame to reach the specified point can be shortened,and in turn the propagation speed can significantly be increased,too.(2)In the explosion chamber,the optimal concentration ratio between the coal dust concentration and the gas concentration can be obtained properly.That is to say,the closer the gas concentration is to the stoichiometric ratio,the closer the coal dust concentration can likely be to 50 g/m3.And,in the similar way,the more intensive the coupled explosion reaction,the greater the flame propagation speed can likely be produced.And(3),in such a situation,in the propagation pipeline,large amounts of oxygen would enter into the open end of the pipeline to join in the reaction.In so doing,the flame of the experimental group with the gas concentration and that of the coal dust will turn slightly to be higher than the optimal concentration ratio in the later stage.(4)The explosion reaction rate and the flame propagation distance may not become proportional to the gas and coal dust concentration,when the coal dust and gas concentration rates deviate from the optimal concentration ratio,the gas-dust coupled explosion reaction rate would become smaller,so as for the flame propagation acceleration speed to come down,and in turn to make the broadcast distance shorter.