水成膜泡沫(AFFF)灭火剂是扑灭大型舰船甲板油面火灾最有效的灭火剂.阻热作用是水成膜泡沫灭火剂的主要灭火机制之一,当AFFF在火灾表面形成薄膜层后,一方面由于铺展作用,外部不断地补充AFFF;另一方面,由于火灾的热辐射作用,AFFF内部不断发生消融.消融的存在使AFFF厚度变薄,其阻热能力也不断降低,当AFFF下方的燃油达到闪点时,由于AFFF内部存在空气,下方的燃油可能发生复燃.定量分析AFFF的阻热性能,研究热态环境下AFFF内部温度场的分布情况是研究AFFF灭火效能的重要组成部分,对于防止火灾复燃和消防决策有重要意义.本文在建立固态消融模型的基础上,结合AFFF的消融特点和假设条件,建立AFFF消融的稳态模型,并补充AFFF密度、消融速率和组分速率计算模型,通过仿真求解AFFF内部温度场的分布,并和实验进行对比,得到实验值高于仿真值,误差在10%以内.通过该模型的研究可以定量指导和计算单位面积油火需要的AFFF流量.

Aqueous Film Forming Foam (AFFF) fire extinguisher is the most effective firefighting system for large scale oil fire on big warship deck. The heat resistance effect is one of the primary extinguishing mechanism of AFFF as the extinguishing agent. When the AFFF film layer is formed on the surface of fire, its spreading effect will continually feed AFFF from outside; and due to the heat radiation of the fire, AFFF continues to ablate inside. The presence of the ablation process makes AFFF thinner, the thermal resistance capacity will decrease. When the fuel under the AFFF reaches a flash point, the fuel may be re-ignited, due to the air inside of the AFFF. To improve the AFFF extinguishing efficacy, a quantitative analysis of the flame retardant properties of AFFF and the distribution of the temperature field in the AFFF thermal invironment is of great significance. In this paper, a solid-state ablation model is proposed, and, based on this model, a steady-state ablation model of AFFF is established, combinating the ablation characteristics of AFFF and some assumptions, concerning AFFF density, ablation rate and the components rate of model. The temperature distribution within AFFF can be obtained through simulations. The result of simulation is lower than the experimental result, with an error of within 10%. The model can be used to calculate the AFFF flux for oil fire per area on the warship deck.