基于燃料可燃界限研究建筑火灾中的回燃现象

为了研究回燃产生的临界条件和细水雾抑制回燃产生的可行性及其抑制机理 ,建立了一套小尺寸回燃实验装置 ,并进行了一系列的实验 ;实验结果表明腔体内未燃烧燃料的质量分数是回燃产生的决定性参数 ,而细水雾确实能抑制回燃的产生 ,并且其抑制机理是降低腔体内未燃烧燃料的质量分数。最后利用燃料可燃界限图进行了实验结果的定性验证及分析。

Study on backdraft in building fires based on flammable limits of fuel

Backdraft in building fires is hazardous to the safety of people, especially to firefighters, because of its abruptness and powerful destruction. In this paper, a set of reduced scale backdraft experimental apparatus was established and a series of experiments were conducted in order to study the critical condition of occurrence of backdraft and the feasibility and mitigation mechanism of water mist mitigating backdraft. The experimental results show that the mass fraction of unburned fuel in the compartment is the key parameter determining the occurrence of backdraft, and water mist assuredly mitigates backdraft and the mitigation mechanism is by means of diluting gases in the compartment and reducing the mass fraction of fuel. At last the experimental results are qualitatively validated and analyzed based on flammability diagram of fuel.