Abstract Aqueous film-forming foam (AFFF) is a very important extinguishing agent for hydrocarbon fuel fires. The spreading performance of AFFF is one of the key factors to decide its extinguishing efficiency. There are many parameters that affect the spreading performance of AFFF, but few studies have been done on its spreading mechanism. A method for studying the spreading performance of surfactant solution on different oil surfaces was provided in this work. Additionally, the kinetics of C4-Br/CH3(CH2)5NaO3S, C6-Br/CH3(CH2)5NaO3S and C8-Br/CH3(CH2)5NaO3S equimolar system spread on the surfaces of cyclohexane, n-heptane, aviation kerosene, solvent naphtha and diesel oil 0# were investigated. Meanwhile, the relationship between spreading length and time at 25℃ were obtained and the experimental data were evaluated using the model for surface-tension-viscous regime. The root-mean-square deviation (RMSD) values obtained from the correlation using surface-tension-viscous regime model for all of the systems we studied below 3.41, indicating a good agreement between the experimental and theoretical values. It meant that the surface-tension-viscous regime model could be used to predict the process of the aqueous film formed by surfactant solution spread on the hydrocarbon oils. Furthermore, the theoretical spreading rate (R) and average spreading rate ( R ¯ ) from 0 to 50 s of C4-Br/oil, C6-Br/oil and C8-Br/oil systems were also investigated. The results showed that the R decreased with increasing time and the rate of decline slowed down gradually. The R ¯ increased with the increase of fluorocarbon chains. In particular, the effect of fuel kinematic viscosity on spreading rate was also very obvious. The greater the kinematic viscosity of fuel, the smaller influence of the surfactant tail length on spreading rate.

中文翻译：

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氟碳表面活性剂在几种液体燃料表面的扩散动力学

摘要 水成膜泡沫（AFFF）是一种非常重要的烃类燃料火灾灭火剂。AFFF的扩散性能是决定其灭火效率的关键因素之一。影响AFFF扩散性能的参数很多，但对其扩散机制的研究较少。本文提供了一种研究表面活性剂溶液在不同油表面的铺展性能的方法。此外，C4-Br/CH3(CH2)5NaO3S、C6-Br/CH3(CH2)5NaO3S和C8-Br/CH3(CH2)5NaO3S等摩尔体系的动力学分布在环己烷、正庚烷、航空煤油、对溶剂石脑油和柴油0#进行了研究。同时，获得了25℃下铺展长度与时间的关系，并利用表面张力-粘性状态模型对实验数据进行了评估。对于我们在 3.41 以下研究的所有系统，使用表面张力粘性机制模型从相关性中获得的均方根偏差 (RMSD) 值表明实验值和理论值之间具有良好的一致性。这意味着表面张力-粘性状态模型可用于预测表面活性剂溶液在烃油上形成水膜的过程。此外，还研究了C4-Br/油、C6-Br/油和C8-Br/油体系0至50 s的理论铺展率(R)和平均铺展率(R¯)。结果表明，R随着时间的增加而减小，并且下降的速度逐渐减慢。R¯随着氟碳链的增加而增加。尤其是燃料运动粘度对铺展率的影响也非常明显。燃料的运动粘度越大，表面活性剂尾长对铺展速度的影响越小。