煤巷高冒区松散煤体自然发火的数值模拟研究

巷道高冒区自燃火灾，不仅严重影响到采掘工作面的安全生产，而且威胁到矿工们的生命安全．通过对煤巷高冒区特点和影响煤炭自燃因素的分析，根据多孔介质流体动力学、传热和传质理论，建立了高冒区松散煤体自然发火过程三维数学模型．以旗山煤矿高冒区为例，用有限元法进行了数值求解，得到高冒区渗流速度场、温度场和氧浓度场的分布，在此基础上划分出最易自然发火的区域，分析了高冒区自然发火的机理．结果表明：高冒区松散煤体漏风强度随孔隙率的增大而增加；高冒区松散煤体的中部区域存在最易自然发火区，是现场防治高冒区自然发火的重点区域．现场试验数据验证了数值模拟结果的合理性．

Numerical Simulation on the Spontaneous Combustion of Loose Coal in the Top-Coal Caving Region of Coal Drift

The spontaneous combustion hazard of loose coal in the top-coal region not only affect the normal production of working face, but also threat the safety of the coal miners. Based on the analysis of characteristics of the top-coal caving region of the roadway and factors of coal spontaneous combustion, the 3-D mathematical model of spontaneous combustion of loose coal in the top coal region was proposed using the theories of fluid dynamics in porous medium, heat transfer and mass transfer. By using the finite element method, the velocity field of air leakage, the temperature field and the oxygen concentration field were obtained during the combustion process of loose coal in the top-coal caving region in Qishan Coal Mine. The most possible area where spontaneous combustion might take place was specified and the mechanism of coal spontaneous combustion in the top-coal region was analyzed. The results show that the air leakage rates increase with the increasing of the porosity of loose coal and there exits the most possible combust area which is the key place to prevent the fire in the fields. The validity of the numerical simulation results is verified by the measured data.