大型储煤筒仓进料过程煤尘浓度分布及煤尘爆炸数值模拟

Numerical simulation of concentration distribution of coal dust during feeding process and coal dust explosion in large coal silo

采用Fluent模拟进料过程中仓内煤尘浓度场分布,在此基础上基于OpenFOAM平台开展煤尘爆炸过程数值模拟,以指导大型储煤筒仓安全设施的布置。结果表明:仓内竖向空间越小,煤尘竖向浓度梯度越明显,空间内平均浓度越高,空仓、半仓条件下筒仓竖向几何中心线上煤尘质量分数分别达到30%、40%以上;仓内竖向空间越小,筒仓内最大爆炸温度越高,但最大爆炸超压越小,空仓、半仓条件下最大爆炸温度分别可达2 000、3 000 K,最大爆炸超压分别为1、0.82 MPa;建议在筒仓顶部及侧壁靠上部位设置煤尘浓度监测及预警装置,并在筒仓顶部设置有效的泄爆装置,以有效防范筒仓爆炸风险、降低筒仓爆炸损失。

A numerical simulation of the concentration distribution of coal dust in the silo during the feeding process was carried out in this paper by using Fluent software,and then on this basis,a numerical simulation of the process of coal dust explosion was carried out based on the Open FOAM platform,to guide the layout of related safety facilities in the large coal silo.The results show that the smaller the vertical space in the silo is,the more obvious the vertical concentration gradient of coal dust is,and the greater the average concentration in the space is.The mass fraction of coal dust on the vertical geometric centerline of the silo under the empty and half-full silo conditions reaches above 30% and 40% respectively.The smaller the vertical space in the silo is,the greater the maximum explosion temperature in the silo is,but the smaller the maximum explosion overpressure is.Under the empty and half-full silo conditions,the maximum explosion temperature reaches 2 000 K and 3 000 K respectively,and the maximum explosion overpressure is 1 MPa and 0.82 MPa respectively.It is recommended to install the coal dust concentration monitoring and early warning devices on the top of the silo and the upper part of the side wall,and install effective explosion venting devices on the top of the silo,in order to effectively prevent the risk and reduce the loss of silo explosion.