初始封堵时刻对独头巷道火灾火行为的试验研究

Experimental study on fire behavior in blind roadway fires at initial sealing time

  • 摘要: 独头巷道一端为完全封闭的掘进头,另一端与主巷相连。独头巷道特殊的结构特征决定其火灾的火行为和烟气输运特征与其他场景下存在一定差异。通过建立小尺寸的独头巷道模型研究不同初始封堵时刻的烟气运输特征。结果表明:初始封堵时刻越晚,烟气在独头巷道内的积聚量越大,巷道内温度越高。但距火源0 m时,温度受火焰倾角影响,并不存在相同规律;实施封堵后,氧气体积分数显著下降,下降至一定数值时火源会发生自熄或即将自熄,主巷中的新鲜空气通过缝隙进入独头巷道,氧气体积分数出现上升趋势;初始封堵时刻较早的工况因燃料在短时间内变为不充分燃烧,一氧化碳体积分数普遍高于初始封堵时刻较晚的工况,但这种现象在较大油盘尺寸的工况中并不明显。

     

    Abstract: The distinct structural characteristics of a blind roadway lead to differences in the fire behavior and smoke transport characteristics of oil pool fires in blind roadway and in other scenarios since one end of a blind roadway is a completely sealed heading face while the other end is connected to the main roadway.This study conducted small-scale experiments to investigate the smoke transport characteristics at different initial sealing times in blind roadways.Results show that delayed initial sealing time could cause increasing accumulation of smoke and higher temperature in the blind roadway.However, such pattern was not valid at a distance of 0 m from the fire source since temperature was affected by the flame inclination angle.After sealing, the oxygen volume fraction significantly decreased.As it dropped to a certain value, the fire source would self-extinguish or be in a state of imminent self-extinguishment.Combustion demanded less oxygen, and fresh air in the main roadway would enter the blind roadway through gaps, with the oxygen volume fraction showing an upward trend.Carbon monoxide concentration was generally higher in working conditions with an earlier initial sealing time than that with a delayed initial sealing time as fuel combustion became insufficient within a short time span.This is not explicit in working conditions with a larger oil pan size.

     

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