Abstract Self-heating of coal is a long-standing hazard and pollution source in longwall goaf and abnormal air leakage into goaf is a key yet complex drive to the hazard. To investigate such a problem with more insights, a numerical model without considering coal moisture is established based on a Shendong longwall. Abnormal air leakage into goaf mainly sources from the edge cracks resulting in presence of high level oxygen (8 %∼13 %) in start-off area of the longwall. Two heating liable regimes were identified: one is behind longwall face and another one locates in the start-off zone. Heating in the start-off zone develops more quickly than that in heating regime one. On day 25 the maximum temperature of regime two can rise to 500 K while it can only increase to approximately 340 K in regime one. The heating spot behind longwall face tends to be self-suppressed with longwall advancing while the heating in the start-off zone can develop to a spontaneous combustion incident due to constant airflow leakage from the mining induced cracks. A wide range of inertisation plans including different locations, strategies, and flowrates of nitrogen injection were conducted. An optimum inertisation plan is to proactively inject inert gas with a low flowrate (e.g. 122 m3/h) from a seal along the start-off line. A high flowrate of nitrogen stream is preferable to suppress an on-going heating and the reactive inertisation should be maintained for a long run otherwise the heating is very likely to re-develop.

中文翻译：

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考虑采动裂缝漏风的长壁采空区煤自热数值研究

摘要 煤自热是长壁采空区长期存在的危害和污染源，异常漏风是造成该危害的关键而复杂的驱动因素。为了更深入地研究这一问题，基于神东长壁建立了不考虑煤水分的数值模型。采空区异常漏风主要来源于边缘裂缝，导致长壁起始区存在高水平氧气（8%~13%）。确定了两种受热机制：一种位于长壁工作面后面，另一种位于启动区。启动区的加热比加热区一中的加热发展得更快。在第 25 天，状态二的最高温度可以升至 500 K，而在状态一中只能升至约 340 K。随着长壁推进，长壁工作面后面的加热点趋于自我抑制，而由于开采诱发裂缝的持续气流泄漏，启动区的加热可发展为自燃事件。进行了广泛的惰化计划，包括不同的位置、策略和氮气注入流量。最佳惰性化计划是从密封件沿启动管线主动注入低流速（例如 122 m3/h）的惰性气体。高流速的氮气流对于抑制持续加热是优选的，并且反应惰性化应该长期保持，否则加热很可能重新发展。