多场耦合下煤堆自燃过程及影响因素分析

Analysis on Coal Pile Spontaneous Combustion Process and Influence Factors Under Multi Field Coupling

为研究煤堆自燃特征及发火规律,建立了风力和浮力驱动下煤堆的多场(速度场、温度场和氧气浓度场)耦合自然发火模型,并运用COMSOL Multiphysics软件对煤自燃的过程及其影响因素进行了数值模拟分析。研究结果表明:在风速3.6 m/h条件下,煤堆自燃最高温度点位于进风侧的煤堆中下部,最终于第65 d在此位置开始自燃;随着风速的增大,煤堆自然发火点往风流的下方向迁移,自然发火周期缩短;煤堆孔隙率、高度和角度的减小能延长煤堆的自然发火周期。

In order to study spontaneous combustion features and ignition law of the coal pile, a multi fields （ velocity field, temperature field and oxygen concentration field） coupling spontaneous combustion model under the wind power and buoyant power driving was estab- lished. The COMSOL Muhiphysics software was applied to the numerical simulation analysis on the coal spontaneous combustion process and the influence factors. The study results showed that under the wind velocity of 3.6 m/h, the max temperature point of the spontaneous combustion in the coal pile would be at the middle and low sections of the coal pile. After 65 days, the spontaneous combustion at the lo- cation would start finally. With the wind velocity increased, the spontaneous combustion point of the coal pile would downwardly migrated with the wind flow in the spontaneous combustion of the coal pile. The natural ignition period would be reduced. The reduction of porosity rate, height and angle could expand the natural ignition period of the coal pile.