The tendency of self-ignition of coal is the root cause of underground coal fires (UCFs). A parametric study is carried out on a lab-scale experimental setup developed based on the essential heat and mass transfer characteristics of actual UCFs to understand the factors influencing the inception and evolution of coal fires. Effects of heat accumulation, moisture content and coal layer height are systematically examined by varying the relevant parameters on the experimental setup. Temporal evolution of coal temperature and volumetric fractions of CO and CO 2 are measured and analyzed. The results indicate that heat accumulation, moisture content and coal layer height mainly influence the time needed to reach the ignition state. Without sufficient heat accumulation, coal–oxygen reactions are not self-sustainable even after they enter the rapid reaction stage. The reaction regimes inside the coal tank are mainly determined by the local oxygen concentration, while the temperature changing rate depends on the relative magnitudes of heat generation and heat transfer (gain/loss). The ratio of CO 2 /CO is more informative in the detection of high-temperature stage of UCFs.

中文翻译：

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基于实验室规模实验装置的地下煤火发生和演变的参数研究

煤的自燃倾向是地下煤火（UCFs）的根本原因。对基于实际 UCF 的基本传热和传质特性开发的实验室规模实验装置进行了参数研究，以了解影响煤火发生和演变的因素。通过改变实验装置上的相关参数，系统地检查了热量积累、水分含量和煤层高度的影响。测量和分析了煤温度和 CO 和 CO 2 体积分数的时间演变。结果表明，蓄热、含水率和煤层高度主要影响达到点火状态所需的时间。没有足够的热量积聚，煤-氧反应即使进入快速反应阶段也不能自我维持。煤罐内的反应方式主要由局部氧浓度决定，而温度变化率取决于发热和传热（增益/损失）的相对大小。CO 2 /CO 的比值在检测 UCF 的高温阶段时提供更多信息。