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为分析煤粉粉尘的爆炸特性,利用20 L爆炸球测试装置与Fluent软件,试验研究煤粉粒径、质量浓度对煤粉云最大爆炸压力、爆炸指数的影响。结果表明,当试验环境温度为293~303 K时,点火能量为10 k J,粒径为26,73和115μm等3种粉尘云的最大爆炸压力均随着粉尘质量浓度的增加先升后降,在350 g/m3处达到最大值。同一粉尘质量浓度下,最大爆炸压力、爆炸指数均随着粒径的减小而增大。在60~120 ms时间内,粒径为26μm、质量浓度为350 g/m3的粉尘颗粒在球体内能保持一定的稳定状态,60 ms左右扩散达到相对均匀状态。爆炸后,燃烧最高温度为2 060 K,未燃区温度由300 K上升至375 K。粒径为26μm的煤粉尘云爆炸危险性等级为Ⅱ级,粒径为73和115μm的煤粉尘云爆炸危险性等级为Ⅰ级。
In order to analyze the explosion characteristics of pulverized coal dust, the influence of pulverized coal particle size and mass concentration on the maximum explosion pressure and explosion index of pulverized coal dust was studied by using 20 L explosion ball test equipment and Fluent software. The results show that the maximum explosion pressure of three kinds of dust clouds with the ignition energy of 10 kJ and particle sizes of 26, 73 and 115 μm increases at first and then decreases with the increase of dust mass concentration when the ambient temperature is 293 ~ 303 K , Reaching a maximum at 350 g / m3. Under the same dust concentration, the maximum explosion pressure and explosion index increase with the decrease of particle size. In the time of 60-120 ms, the dust particles with particle size of 26 μm and mass concentration of 350 g / m3 can maintain a certain steady state in the sphere and spread to a relatively uniform state in about 60 ms. After explosion, the maximum combustion temperature is 2 060 K and the unburned zone temperature rises from 300 K to 375 K. Coal dust with a particle size of 26μm is classified as Grade Ⅱ, and dust explosions with grade 73 and 115μm are Class Ⅰ.