露天煤堆群自燃特性的数值模拟

Numerical simulation of spontaneous combustion characteristics of open-pit coal piles

为了研究露天煤堆群中各煤堆之间自燃趋势的差异,采用数值模拟方法分析了先低后高、等高、先高后低3种排列方式下煤堆群整体的温度及CO分布情况,结果表明:迎风向首座煤堆的形状规模会影响后方煤堆的漏风强度,首座煤堆越高,掠过的风流越不易直接进入第二座煤堆;在堆放18 d时先高后低排列方式的煤堆群高温区面积较其他2种排列方式的显著缩小;CO最易集聚的地点在2座煤堆之间区域,煤堆高度不均易使风流绕过煤堆后形成大面积低速涡流,产生CO富集区;煤堆间距从2 m增大至8 m后,煤堆间CO质量分数从2.3×10^-5降低至1.2×10^-5以下。煤堆群中每座煤堆体现出不同的自燃危险性,日常安全管理应考虑煤场中每座煤堆的自燃特性,合理制订防火技术方案,及时采取防火措施。

In order to study the difference of spontaneous combustion tendency among different coal piles in open-pit coal piles,numerical simulation method was used to analyze the overall temperature and CO distribution of coal piles under three arrangement modes:low first and then high,equal height,high first and then low.The results show that the shape and scale of the first coal pile facing the wind will affect the air leakage intensity of the rear coal pile,the higher the first coal pile,the less easy it is for the wind to pass directly into the second one;when stacking for 18 days,the area of high temperature zone in the coal piles with the arrangement of high first and then low is significantly reduced compared with the other two arrangement modes;CO is most likely to gather in the area between two coal piles,and the uneven height of the coal piles is easy to cause the wind to bypass the coal piles and form a large area of low-speed eddy,generating the CO rich area;when the coal pile spacing increases from 2 m to 8 m,the CO mass fraction between the coal piles decreases from 2.3×10^-5 to less than 1.2×10^-5,each coal pile in the coal piles presents a different risk of spontaneous combustion.In daily safety management,the spontaneous combustion characteristic of each coal pile should be considered,the fire prevention technical plan should be made reasonably,and the fire prevention measures should be taken in time.