压缩空气泡沫析液过程分析

Study on liquid drainage process of compressed air foam

利用压缩空气泡沫灭火系统和析液装置，对典型的蛋白型A类泡沫灭火剂在压缩空气泡沫产生方式下的泡沫析液（泡沫溶液的质量分数取0．3％～2．4％）过程进行了实验研究，同时通过建立分析模型来反映析液过程．研究发现泡沫在析液之前存在延迟现象，析液速率并非从一开始就递减，而是先有一个峰值，峰值过后其值逐步降低并趋近于0，此时析液质量趋于平稳．实验表明：最大析液速率、析液速率常数、50％析液时间都与溶液质量分数相关，增大溶液质量分数则最大析液速率、析液速率常数都会呈指数衰减而50％析液时间则呈指数上升．模型和实验结果的对比很吻合，能恰当地反映压缩空气泡沫的析液过程．

Using compressed air foam system and drainage apparatus, the drainage process of compressed air foam with typical protein based class A agent was studied under the concentration range of 0. 3 % 2.4%, and an analysis model was proposed for the drainage process. It was found that a delay period exists before foam drains, and the drainage rate firstly rises to a peak and then drops slowly to zero, which is different to the empirical thought that drainage decreases from the moment that drainage begins. Some important drainage parameters as maximum drainage rate, specific constant of drainage and drainage halflife are all related closely to the foam concentration. Increasing the concentration will lead the maximum drainage rate and the specific constant of drainage rate to decay exponentially while the half-life of drainage shows an exponential increase. The model was found to be in good agreement with the experimental result and reflect the drainage process of compressed air foam well.