Abstract:

In order to study the inhibiting effect of C₆F₁₂O on the combustion of aviation kerosene, the combustion mode of cup burner is changed from liquid level combustion to wick combustion, which overcomes the difficulty of ignition in the fire extinguishing performance test of gas extinguishing agent due to the high flash point of aviation kerosene. It can be seen from the experiment that with the increase of the concentration of C₆F₁₂O in the air, the height of aviation kerosene flame experienced a process of slow increase and then rapid decrease. That means the effect of C₆F₁₂O on combustion changes from promotion to inhibition at different concentrations. In order to further explore the reason of that transformation, the mechanism of inhibiting RP-3 aviation kerosene combustion by C₆F₁₂O with 1403 species and 7496 reactions was constructed. According to the chemical kinetics analysis, the inhibition effect of C₆F₁₂O on combustion at low temperature is better than that at high temperature. The inhibition effect of C₆F₁₂O at low concentration increases mainly because the reaction rates of promoting combustions are much faster than other reactions after the temperature rising. One of the ways to reduce the combustion temperature of RP-3 aviation kerosene is through endothermic reactions such as thermal decomposition. And with the increase of the concentration of C₆F₁₂O, the reaction path changes, resulting in a decrease in the production of H, O and OH free radicals and a large increase in consumption, which macroscopically weakens the promotion effect of C₆F₁₂O on combustion as a fuel, and enhance the inhibition effect as an extinguishing agent. The results can provide theoretical guidance for the prevention and control of aviation kerosene fire by using C₆F₁₂O, and provide reference for the development of new extinguishing agent.

Key words: C₆F₁₂O, aviation kerosene, cup burner, chemical reaction, kinetics, radical

摘要：

为了研究全氟己酮对航空煤油燃烧的抑制作用，将杯式燃烧器的燃烧方式由液面燃烧改为灯芯燃烧，解决了气体灭火剂灭火性能测试中较高闪点燃料难以点燃的问题。通过实验可知，随着空气中全氟己酮浓度的增加，航空煤油的燃烧经历了火焰先缓慢增高再迅速降低的过程，可见全氟己酮在不同浓度下对燃烧的作用存在由促进到抑制的转变。为深入探索这一转变的原因，基于化学动力学构建了1403个组分、7496个反应组成的全氟己酮抑制RP-3航空煤油燃烧机理并进行了验证。通过化学动力学分析可知全氟己酮在低温下对燃烧的抑制比在高温下的效果更好，全氟己酮在低浓度时温度升高导致抑制作用减弱主要是源于温度升高后，促进燃烧的反应提速幅度远大于其他反应；全氟己酮降低RP-3航煤燃烧温度的途径之一是通过热分解等吸热反应来实现的；随着全氟己酮浓度的增大，反应路径发生变化，使得H、O和OH自由基的生成量减少、消耗量大量增多，宏观上体现出全氟己酮作为燃料的促进燃烧的作用减弱、作为灭火剂抑制燃烧的作用增强。研究结果可为利用全氟己酮防控航空煤油火灾提供理论指导，为研制新型灭火剂提供参考。

关键词: 全氟己酮, 航空煤油, 杯式燃烧器, 化学反应, 动力学, 自由基