低压环境下氮气-水低压双流体细水雾抑灭油池火

Effect of Low Pressure Environment on Fire Suppression of Low-pressure N_2-water Twin-fluid Water Mist

基于民用飞机货舱低压变动环境下火灾特点,进一步探寻低压双流体细水雾灭火技术在低压环境的应用。采用马尔文粒径仪和低压燃烧测试舱等设备,对自行研发N2-水低压双流体细水雾系统进行测试;研究该系统的雾场特性和低压环境下的灭火特性机理。发现N2压力低于0.4 MPa便可得到雾场均匀、粒径较小;且方便可调双流体细水雾。低压舱内灭火实验结果表明,在低压下可有效地扑灭油池火,灭火时间呈现随环境压力降低而减小趋势。揭示火焰周围逆流扩散流动场和水雾对火焰与油面的冷却隔离作用,在抑灭油火中的重要作用。

Based on the fire characteristics in changing pressures environment of civil aircraft cargo compartment,the application of twin-fluid water mist in low pressure environment needs more researches and exploration.A self-developed low-pressure nitrogen-water twin-fluid water mist fire suppression system is introduced.More information about the characteristics of the water mist and the effect of fire suppression in low-pressure environment are obtained through the Malvern particle size analyzer.The results show that atomization with uniform distributed and adjustable twin-fluid water mist can be achieved with a low nitrogen pressure of0.4MPa in a low-pressure combustion chamber.N-heptane pool fire can be well suppressed with this system in a low-pressure environment,and the suppression time decreases with the decrease of environmental pressure.Under the effect of flow field around the flame,the twin-fluid water mist with fine diffusion characteristic could continuously cut in the fire flame from the bottom and interact with fire,which is crucial for the fire suppression.After the process of cooling,diluting,reducing heat radiation,the evaporation rate of fuel is descending gradually,and the fire flame is isolated and burning-out finally.