煤尘二次爆炸燃烧持续时间及残留气体分析

Analysis of combustion duration and residual gas in secondary explosion of coal dust

利用20L球形爆炸装置在不同煤尘浓度、粒径及点火能量条件下进行了煤尘二次爆炸实验,分析了煤尘浓度、粒径及点火能量对燃烧持续时间及残留气体的影响。结果表明:在相同条件下,煤尘二次爆炸燃烧持续时间大于一次爆炸燃烧持续时间;点火能量对二次爆炸燃烧持续时间的影响最大,煤尘粒径的影响最小;随着煤尘浓度的增大,二次爆炸燃烧持续时间先减小后增大;随着煤尘粒径减小或点火能量的增大,二次爆炸燃烧持续时间不断减小;对于相同条件下的同种气体,煤尘二次爆炸后残留气体体积分数均小于一次爆炸后;在一定范围内,随着煤尘粒径减小,二次爆炸后残留的CO体积分数不断减小,CO,CO_2体积分数的比值减小,CH_4体积分数增大;随着点火能量的增大,二次爆炸后残留的CO和CH_4体积分数均不断增大,CO,CO_2体积分数的比值呈增大趋势。

Secondary explosion experiments of coal dust were carried out by use of 20 L spherical explosion device under the conditions of different coal dust concentration,particle size and ignition energy separately,and influence of coal dust concentration,particle size and ignition energy on combustion duration and residual gas was analyzed.The results show that under the same conditions,the secondary explosion combustion duration(T 2)of coal dust is greater than the first explosion combustion duration(T 1).Ignition energy has the greatest influence on T 2,and coal dust particle size has the least influence.With increase of coal dust concentration,T 2 first decreases and then increases.With decrease of coal dust particle size or increase of ignition energy,T 2 decreases continually.For the same kind of gas under the same conditions,volume fraction of residual gas after the secondary explosion of coal dust is smaller than that after the first explosion.In a certain range,with decreases of coal dust particle size,volume fraction of residual CO continuously decreases after the secondary explosion,ratio of volume fraction of CO to the one of CO 2 decreases,and volume fraction of CH 4 increases.With increase of ignition energy,volume fraction of residual CO or CH 4 after the secondary explosion continuously increases,and ratio of volume fraction of CO to the one of CO 2 shows an increasing trend.