Abstract The limited stability and heat insulation performance of the traditional aqueous film forming foam (AFFF) affects its efficiency in fire extinguishing. Recently, functional nanoparticles have been used as stabilizers. The formed three-phase foam exhibits better performance. However, the mechanisms and heat transfer behaviors of the three-phase foam are still unclear and require further clarification. Therefore, in this study, the thermal stability, the volume expansion, and the temperature profiles inside the foam layer exposed to the high-temperature environment are studied. The results indicate that the high ambient temperature benefits the foaming but reduces the foam stability. The foam layer exposed to continuous radiant heating presents three successive stages, i.e. the initial stage, the balanced stage, and the collapse stage due to distinct heat transfer characteristics in the depth direction. Moreover, the effects of foam composition and operation conditions on foam insulation are further evaluated. It is found that the insulation performance of foam can be enhanced with higher particle concentration, especially hydrophobic particles. High foam expansion ratio leads to better foam stability but worse thermal insulation. The life of foam decreases with the radiation heat flux. The results provide useful guidance for achieving high fire-extinguishing efficiency of foam.

中文翻译：

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三相的热稳定性和绝缘特性

摘要 传统水性成膜泡沫（AFFF）的稳定性和隔热性能有限，影响了其灭火效率。最近，功能性纳米颗粒已被用作稳定剂。形成的三相泡沫表现出更好的性能。然而，三相泡沫的机理和传热行为仍不清楚，需要进一步澄清。因此，在本研究中，研究了暴露在高温环境下的泡沫层内部的热稳定性、体积膨胀和温度分布。结果表明，高环境温度有利于发泡，但会降低泡沫稳定性。暴露于连续辐射加热的泡沫层呈现三个连续阶段，即初始阶段、平衡阶段、由于在深度方向上具有明显的传热特性，因此进入坍塌阶段。此外，进一步评估了泡沫组成和操作条件对泡沫绝缘的影响。研究发现，较高的颗粒浓度，尤其是疏水性颗粒，可以提高泡沫的保温性能。高泡沫膨胀比导致更好的泡沫稳定性但更差的隔热性。泡沫的寿命随着辐射热通量的增加而降低。结果为实现泡沫的高灭火效率提供了有用的指导。尤其是疏水颗粒。高泡沫膨胀比导致更好的泡沫稳定性但更差的隔热性。泡沫的寿命随着辐射热通量的增加而降低。结果为实现泡沫的高灭火效率提供了有用的指导。尤其是疏水颗粒。高泡沫膨胀比导致更好的泡沫稳定性但更差的隔热性。泡沫的寿命随着辐射热通量的增加而降低。结果为实现泡沫的高灭火效率提供了有用的指导。