基于cup burner的含铁基添加剂超细水雾灭火有效性分析

针对典型的液体燃料（乙醇和正庚烷）油池火焰,在自行搭建的实验台上对含铁基添加剂的超细水雾的临界灭火浓度进行测量,定量评价其灭火性能。为深入分析铁基添加剂的灭火机理,基于密度泛函理论,对铁氧化物与H自由基反应产物的结构进行优化计算。研究表明：二茂铁与硫酸亚铁添加剂均能使超细水雾的临界灭火浓度呈现不同程度的降低,并且存在最佳浓度。二茂铁与硫酸亚铁的质量分数分别为0.01%和1%时,灭火效果最好;含铁基添加剂细水雾灭乙醇火的效果好于正庚烷火。铁氧化物与H自由基反应生成的Fe(OH)₂是一种活性催化物质,能够通过链式反应消去H自由基。

Analysis of fire suppression effectiveness of ultra-fine water mist containing iron compounds additives in cup burner

To evaluate the fire suppression effectiveness of ultra-fine water mist containing iron compounds additives qualitatively and quantitively, a small-scale experiment platform was set up to explore the minimum extinguishing concentration of the water mist under different fuels. Ethanol and n-heptane were separately used as fuels. Air flow was kept as 60 L/min during experiments. The water mist content in the air was gradually increased by adjusting the power of atomizer. The critical fire suppression concentration was obtained until fire was extinguished. Furthermore, to understand the fire suppression mechanisms deeply, structures formed by iron oxides and H radicals were relaxed based on the density functional theory. The results show that ferrocene and ferrous sulfate can obviously reduce the minimum extinguishing concentration of ultra-fine water mist. The decreasing degree of minimum extinguishing concentration is not linear with the content of additives. There are optimal concentrations of iron compounds additives match to fire suppression effectiveness of the water mist. The optimal concentrations of ferrocene and ferrous sulfate are 0.01% and 1% respectively. The fire suppression effectiveness is affected by the type of fuels. Its order is as following in this experiment: ethanol > n-heptane. Fe(OH)₂ formed by the reaction of iron oxide with H radical is an active catalytic substance capable of eliminating H radicals by chain reaction.