煤堆非均质分布及其自热研究

Research on Heterogeneous Distribution of Coal Pile and Its Self Heating

为了掌握煤堆内的非均质分布状态以及非均质煤堆的自热过程,利用颗粒动力学原理提出了基于颗粒下落堆积演化规律的堆体数值重构方法,研究了不同倾倒高度和颗粒粒径下所形成堆体的内部空隙分布情况,将所得空隙分布变化规律及与空隙关联的变量编成自定义函数、进行非均质煤自热模拟,分析非均质煤堆内部温度场、压力场、组分浓度场的变化。结果表明,空隙率随堆体内部垂直方向距离的增加而先减小后增大,而在内部相同高度的水平方向上空隙分布近乎均匀;0.55~0.95 m的倾倒高度大小变化以及1.1~1.9 cm的粒径粗细变化对堆体内部空隙率影响较小;非均质煤自燃中,高温区域逐渐缩小成靠近迎风侧、背风侧与底部接触的两个温度极高、对煤堆安全威胁最大的点。

In order to grasp the heterogeneous distribution state inside the coal pile and the self heating process of the heterogeneous coal pile,a numerical reconstruction method based on the evolution law of particle falling and stacking is proposed using the principle of particle dynamics.The internal void distribution situation of the pile formed under different dumping heights and particle sizes is studied.The obtained void distribution variation law and variables associated with voids are compiled into a custom function to simulate the self heating of heterogeneous coal,analyze the changes in temperature field,pressure field,and component concentration field inside heterogeneous coal piles.The results show that the void fraction decreases first and then increases with the increase of vertical distance inside the pile body,and the distribution of voids is almost uniform in the horizontal direction at the same height inside the pile body;The size variation of dumping height from 0.55 to 0.95 meters and the thickness variation of particle size from 1.1 to 1.9 centimetres have a relatively small impact on the internal void fraction of the pile;In the spontaneous combustion of heterogeneous coal,the high temperature area gradually shrinks to two extremely high temperature points near the windward side and the leeward side in contact with the bottom,which pose the greatest threat to the safety of the coal pile.