细水雾抑制熄灭火焰过程中一氧化碳的浓度是评价细水雾灭火系统安全可靠性的一个重要参数.本文通过受限空间内细水雾抑制熄灭障碍火的模拟实验研究,发现细水雾抑制熄灭火焰过程中一氧化碳生成率存在两种控制模式,即燃料控制模式和细水雾流量控制模式.实验结果表明,在燃料控制模式下,一氧化碳生成率随着燃料流量的增大而增大;在细水雾控制模式下,一氧化碳生成率随着细水雾流量的增大而增大.为了获得两种控制模式的临界转变条件,对燃料控制模式和细水雾控制模式的临界工况进行水蒸气含量分析.通过理论分析,得到一氧化碳生成率控制模式转变的水蒸气含量临界范围与Suh and Atryeya理论基本一致,即空气中水蒸气质量分数达到25%～65.5%时,水蒸气对火焰的作用从化学作用转为物理作用,一氧化碳生成率控制模式开始转变.
在新制备了一种多组分泡沫灭火剂的基础上,发展了多组分压缩空气泡沫灭火系统(multi-component compressed air foam system,MCAFS),并开展了在不同泡沫浓度、不同结构类型混合腔和不同工作压力等工况条件下,其对油池火和木垛火的灭火有效性实验研究.实验结果表明,泡沫浓度对灭火效果有显著影响,且对不同可燃物存在一个不同的最佳灭火浓度,例如,对于煤油池火,该最佳泡沫溶液浓度约为2.2%,而对于木垛火则为4.0%.此外,采用同轴型混合腔比采用T型混合腔,系统具有更好的灭火效果.系统工作压力对灭火效果的影响也很明显,即系统工作压力越高,灭火越迅速.
A multi-component compressed air foam system (MCAFS) was developed with newly prepared multi-component foaming agents. Extinguishing of wood crib and oil pool fires was performed under different conditions, such as foam concentration, mixing chamber forepart structure and working pressure. It was found that the foam concentration had sufficient effects on fire extinguishing efficiency, and an optimized concentration value exists. For instance, for diesel oil pool fires, this value is about 2.2% while it is about 4.0% for wood crib fires. The results also show that the system with a coaxial mixing chamber has greater efficiency than a T-shape. The effects of working pressure on fire extin- guishing are evident in experiments, i.e., the higher the working pressure is, the more readily the fire is extinguished.
