Abstract In addition to classical compartment fire development stages, smoke explosions can occur for underventilated conditions while the ventilation openings remain the same. Smoke explosions are different from backdrafts, involving changes in ventilation by additional openings. In this study, the burning history of medium-density fibre (MDF) cribs located at three different elevations has been investigated for the first time in an underventilated enclosure having two vertical openings at the front wall. The effects are examined of different fuel locations, the crib geometry and the ventilation on the mass loss and heat release rates. The fuel mass loss and heat release rates being nearly independent of the crib location and type depend on a new ventilation parameter determined from the distance between the two openings in a simplified way including effects of mass pyrolysis rate and gas temperatures. The mass air inflow is also proportional to this ventilation parameter and independent of the gas temperatures. In some experiments, however, the fires produced single or multiple smoke explosions after a dip in the heat release rate ejecting flames outside. The occurrence of a smoke explosion in relation to the porosity of crib, appearance of smouldering and the vitiated environment is also discussed.

中文翻译：

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两个前垂直开口围墙通风不足火灾及烟雾爆炸发生的实验研究

摘要 除了经典的隔间火灾发展阶段外，在通风口保持不变的情况下，在通风不足的情况下也会发生烟雾爆炸。烟雾爆炸与倒吸不同，涉及通过额外的开口改变通风。在这项研究中，首次在前壁有两个垂直开口的通风不足的围栏中调查了位于三个不同高度的中密度纤维 (MDF) 婴儿床的燃烧历史。检查了不同燃料位置、婴儿床几何形状和通风对质量损失和热释放率的影响。燃料质量损失和热释放率几乎与婴儿床位置和类型无关，这取决于以简化方式从两个开口之间的距离确定的新通风参数，包括质量热解率和气体温度的影响。流入的空气质量也与该通风参数成正比，并且与气体温度无关。然而，在一些实验中，在热释放率下降后，火灾会产生单次或多次烟雾爆炸，将火焰喷射到外面。还讨论了与婴儿床的孔隙率、阴燃的出现和污染环境有关的烟雾爆炸的发生。然而，在一些实验中，在热释放率下降后，火灾会产生单次或多次烟雾爆炸，将火焰喷射到外面。还讨论了与婴儿床的孔隙率、阴燃的出现和污染环境有关的烟雾爆炸的发生。然而，在一些实验中，在热释放率下降后，火灾会产生单次或多次烟雾爆炸，将火焰喷射到外面。还讨论了与婴儿床的孔隙率、阴燃的出现和污染环境有关的烟雾爆炸的发生。