采用实验模拟研究了自制复合型添加剂对细水雾灭火性能的影响.重点考察了细水雾灭火有效性随添加剂浓度的变化规律.结果表明:复合型添加剂显著增强了细水雾的灭火性能,最大可缩短灭火时间5~8倍。并且随着细水雾中添加剂含量的不断增加,油池火的灭火时间呈现出先快速下降,尔后略微增长的趋势;而木垛火的灭火时间则表现为平缓下降,并趋于饱和.对应最短灭火时间,油池火的最佳添加剂灭火浓度约为临界胶束浓度(CMC)的2~3倍,木垛火的最佳添加剂灭火浓度为临界胶束浓度的(CMC)8~10倍.含添加剂细水雾扑灭火焰是物理化学复合作用机制,但主导灭火机理是燃料表面的冷却与隔离作用.并且对于油池火,添加剂灭火关键是表面活性剂在油面快速成膜.而对于木垛火,添加剂灭火关键是在表面覆盖较厚泡沫层.
The effectiveness of using composite additives in water mist was investigated. The additives used in the study were two new-developed additives named F1 and F2 by our research group. Tests were conducted using crib fires, ethanol and diesel pool fires with varied additive concentration. Results show that the suppression performance varies greatly depending on the quantity of the additives in the water mist. For the hydrocarbon fuel, the optimum concentration is almost twice of CMC, when a thin layer of film formed by fluorinated surfactant on the pool surface reduces the amount of the radiant energy that is absorbed by the fuel. While for the wood cribs, the optimum concentration is almost 8-10 times the CMC at normal temperature for both agents, when a thick foam blanket on the crib surface is formed to stop the burning. The fire suppression mechanism of water mist with additives is combined with physical and chemical effect. However, the surface cooling and fuel isolation are considered to be the crucial suppression mechanism.