极限平衡区顶煤自燃三维非均质动态数值模拟

为探究极限平衡区内顶煤自燃规律,利用Fluent软件对顶煤自燃进行数值模拟研究。通过对顶煤移动变形及自燃特点的分析,确定顶煤自燃过程的模拟为三维非均质动态模拟,并建立数学模型,给出相关参数及边界条件的确定方法。以恒大矿某工作面为例,对其顶煤的自燃过程进行数值模拟,并分析工作面风量及煤体耗氧速度与自然发火期之间的关系。结果表明:对计算区域进行模拟所得到的速度场、氧浓度场及温度场与现场观测结果及理论结果比较吻合;工作面风量对煤体自然发火期影响较小,而对高温区域中心点位置影响较大;煤体耗氧速率与自然发火期近似成负指数函数关系。

Three-dimension Heterogeneity Dynamic Numerical Simulation of Top Coal Spontaneous Combustion in Limit Equilibrium Zone

To find the law of top coal spontaneous combustion in limit equilibrium zone,a numerical simulation of the top coal spontaneous combustion was carried out using the Fluent software.The analysis of top coal deformation and top coal spontaneous combustion characteristics led to the conclusion that the numerical simulation of top coal spontaneous combustion was a three-dimension heterogeneity dynamic numerical simulation.A mathematical model was built.Methods for determining parameters and boundary conditions were established.Top coal spontaneous combustion was studied through the method of numerical simulation—taking a working face of Hengda mine for an example.The relations of spontaneous combustion period with air-volume of working face and the oxygen consumption rate of top coal were analyzed.The results show that the velocity field,oxygen concentration field and temperature field obtained through numerical simulation are coincident with the results of actual measurement and theoretical analysis,that the effect of air-volume of working face on spontaneous combustion period is little,that the effect on the centre position of high temperature zone is great,and that the relationship between spontaneous combustion period and the oxygen consumption rate is a negative exponent function.