超细水雾熄灭甲烷火焰的临界灭火质量浓度

Minimum Extinguishing Concentration of Ultra-Fine Water Mist in Extinguishing Methane Diffusion Flame

利用发展的临界灭火质量浓度预测模型,分别在1600K和1700K两种燃烧极限温度下对超细水雾和水蒸气的临界灭火质量浓度进行计算,并采用FLUENT软件开展具有详细化学反应的数值模拟.模型采用1600K得出的理论结果与模拟结果、前人实验结果均较为接近;通过对比理论结果与模拟结果,发现超细水雾冷却在灭火作用中的效果稍高于水蒸气,但却远低于水;模拟发现在火焰温度降低到1600K以下时,才可实现稳定灭火,这对于消防工程中火焰熄灭温度的选取具有一定理论指导作用.

The study on fire extinguishing performance has gradually become an international fire research focus. A prediction model of minimum extinguishing concentration is developed in this paper. The minimum extinguishing concentration of UFM and water vapor are calculated based on the combustion limit temperature of 1 600 K and 1 700 K, respectively. Numerical simulation with a detailed chemical reaction is conducted by FLUENT software. The calculated result （using model by 1 600 K） agrees with the simulation result and previous experimental result. By comparing the theoretical result with the simulation result and previous experimental result, it is found that the cool- ing effect of UFM in fire extinguishing is better than that of water vapor, but lower than that of water. A concentration range of UFM is found in the simulation, which is consistent with the previous experiment. Only when the flame temperature is reduced below 1 600 K can stable extinguishing be achieved, which can serve as a guide for the selec- tion of combustion limit temperature in the fire engineering.