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运用Fluent动网格模型实现采空区的四维动态变化,并用用户自定义函数将煤低温氧化动力学机理及非均质孔隙率函数编入Fluent中,结合时间和空间,对U+L型通风系统采空区升温规律进行四维动态模拟研究.研究表明:非均质孔隙率四维动态模型能更真实地反应孔隙率的空间与时间变化,空间某一位置的孔隙率随时间呈负指数递减;工作面推进速度越大,采空区升温速率越小,推进速度为3.6 m·d-1时平均升温速率仅为推进速度为1.2 m·d-1时的1/5;然而,推进速度越大,高温点的深度越大,不利于自燃的预防;尾巷的存在使得温度场范围扩大,温度升高,CO主要从尾巷流出,尾巷释放的CO量是回风巷CO释放量的10倍.最后利用现场实测的数据对结果进行验证,表明模拟结果是正确可信的.
Fluent dynamic grid model was used to realize the four-dimensional dynamic change of goaf. The kinetic mechanism of low temperature oxidation kinetics and heterogeneous porosity function of coal were programmed into Fluent with a user-defined function. Combined with time and space, U + L ventilation Dimensional dynamic simulation study on the law of temperature rise in the goaf.The results show that the four-dimensional dynamic model of the heterogeneous porosity can more truly reflect the spatial and temporal changes of the porosity, and the porosity of a certain position in space decreases negatively exponentially with time. The higher the working face propulsion speed, the smaller the heating rate of goaf. When the propulsion speed is 3.6 m · d-1, the average heating rate is only 1/5 when the propulsion speed is 1.2 m · d-1; however, The greater the depth of large and hot spots, is not conducive to the prevention of spontaneous combustion; the presence of tail lane makes the temperature range expanded, the temperature rises, CO mainly from the tail lane outflow, 10 times.Finally, the field test data were used to verify the results, indicating that the simulation results are correct and credible.