大倾角工作面采空区均压-注氮联合防火数值模拟研究

Numerical Simulation Study on Combined Fire Prevention of Pressure Equalization and Nitrogen Injection in Goaf of Large Dip Angle Working Face

以峻德煤矿93172大倾角外部漏风工作面为例,研究大倾角外部漏风采空区均压参数合理性以及对注氮防火的影响。采用Fluent数值模拟方法对采空区进行流场分析,充分考虑位压的影响,合理设置工作面和采空区进回风口及漏风口压力边界参数;建立了“L”形大倾角采空区冒落分布模型,进行采空区“恰当均压”,“欠均压”,“过均压”数值模拟,探究不同均压工况的采空区自燃三带分布,同时探讨了采空区均压注氮的合理参数选择。结果表明:“恰当均压”的采空区自然氧化带宽度最短;注氮防火应在“恰当均压”条件下进行,否则将会极大降低采空区惰化效果,徒增注氮量。研究结果对现场科学制定均压-注氮联合防火措施提供理论指导,同时压力边界参数设置方法为大倾角工作面采空区均压-注氮联合防火相关数值模拟研究提供科学参考。

Taking 93172 large dip angle external air leakage working face of Junde coal mine as an example,the rationality of pressure equalization parameters in large dip angle external air leakage goaf and its influence on nitrogen injection fire prevention are studied.The Fluent numerical simulation method is used to analyze the flow field in the goaf,and the influence of the potential pressure is fully considered.The pressure boundary parameters of the working face and the inlet and outlet of the goaf and the air leakage are set reasonably.The caving distribution model of"L"shape goaf with large dip angle is established,and the numerical simulation of"appropriate pressure equalization","under pressure equalization"and"over pressure equalization"in goaf is carried out to explore the distribution of spontaneous combustion three zones in goaf under different pressure equalization conditions.At the same time,the reasonable parameter selection of nitrogen injection in goaf is discussed.The results show that the width of the natural oxidation zone in the goaf of"appropriate pressure equalization"is the shortest;nitrogen injection fire prevention should be carried out under the condition of"proper pressure equalization",otherwise it will greatly reduce the inerting effect of goaf and increase the amount of nitrogen injection.The research results provide theoretical guidance for the scientific formulation of pressure-nitrogen injection combined fire prevention measures on site.At the same time,the pressure boundary parameter setting method provides a scientific reference for the numerical simulation of pressure-nitrogen injection combined fire prevention in goaf of large dip angle working face.