Abstract Compressed air foam (CAF) is an environment friendly fire extinguishing technique being used around the world since the ban of halogen-based agents. In this work, its extinguishing behavior on a radiation-controlled storage tank fire was firstly investigated based on the controlling mechanism of burning rate. A formula of burning rate after foam discharge is deduced. It was found that the oleophobic effect of fluorocarbon surfactants, the increased foam layer thickness and lower diffusion coefficient had coupled chemical and physical effects on extinguishing, which outweighed the cooling effect of foam evaporation. Due to the properties of CAF, a special phenomenon of the sudden increase in the flame temperature and radiation after foam discharge was analyzed. The increase in foam spreading length with time was found to still abide by a power law under fire conditions. A concept of effective and total extinguishing time was suggested, both of which reduce with a rising foam flow rate, but the reduction rate decreases at higher flow rate. In addition, the foam dosage with flow rate had a U-shaped curve at total extinction. For the case of lower fuel thickness, its burning rate was lower and the extinguishing time was longer.

中文翻译：

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变燃料厚度正庚烷储罐火灾中压缩空气泡沫灭火理论与实验研究

摘要 压缩空气泡沫 (CAF) 是一种环保灭火技术，自从卤素类灭火剂被禁用以来，全世界都在使用它。在这项工作中，首先基于燃烧速率的控制机制研究了其对辐射控制的储罐火灾的灭火行为。推导出泡沫排出后的燃烧速度公式。发现氟碳表面活性剂的疏油作用、增加的泡沫层厚度和降低的扩散系数对灭火的化学和物理作用耦合，超过了泡沫蒸发的冷却作用。由于CAF的特性，分析了泡沫排出后火焰温度和辐射突然升高的特殊现象。发现泡沫蔓延长度随时间的增加在火灾条件下仍然遵守幂律。提出了有效灭火时间和总灭火时间的概念，两者都随着泡沫流速的增加而减少，但减少率随着泡沫流速的增加而降低。此外，泡沫剂量随流速的变化在完全消光时呈U形曲线。燃料厚度越小，其燃烧速度越低，灭火时间越长。