注氮对相邻采空区自燃“三带”影响模拟研究

相邻工作面开采会导致复杂的漏风情况，浮煤易自燃，增大防火工作的难度。为明确相邻采空区自燃“三带”分布特征及确定最佳注氮防灭火参数，以贵州某矿4244工作面为背景，结合现场实测，应用Fluent流场分析软件，模拟研究不同注氮方案下采空区氧气浓度场分布规律。结果表明，实测结果与模拟相吻合，验证了模拟的可靠性；当注氮位置为X=50 m，注氮流量为100 m3/h时，采空区进、回风巷侧氧化带宽度分别为7 m和38 m，能明显减少本采空区氧化带面积，且能防止氧化带距工作面太近；此工作面进风侧注氮对相邻采空区氧化带影响范围较小，这要求在回采过程中需要对煤柱进行加固，降低孔隙率，控制漏风，减少氧气进入相邻采空区，降低煤自燃风险。模拟结果为相邻采空区灾害防治工作提供了的理论指导。

Simulation study on effect of nitrogen injection on "Three Zones" of coal spontaneous combustion in adjacent goaf

The mining of adjacent working face will lead to complex air leakage,and the floating coal is easy to self-ignite,which increases the difficulty of fire prevention.In order to clarify the distribution characteristics of "three zones" of spontaneous combustion in adjacent goaf and determine the best parameters of nitrogen injection for fire fighting,taking No.4244 working face of a coal mine in Guizhou as the background,combined with field measurement,the distribution law of oxygen concentration field in goaf under different nitrogen injection schemes was simulated and studied by using Fluent flow field analysis software.The results show that the measured results are consistent with the simulation,and the reliability of the simulation is verified.When the nitrogen injection position is X=50m and the nitrogen injection flow rate is 100 m3/h,the width of the oxidation zone on the side of the entry and return air roadway in the goaf is 7 m and 38 m respectively,which can obviously reduce the oxidation zone area of the goaf and prevent the oxidation zone from being too close to the working face.Nitrogen injection on the air intake side of this working face has little influence on the oxidation zone of the adjacent goaf,which requires strengthening the coal pillar,reducing porosity,controlling air leakage,reducing oxygen into the adjacent goaf and reducing the risk of coal spontaneous combustion.The simulation results provide theoretical guidance for disaster prevention and control of adjacent goaf.