顶部排烟耦合细水雾作用下的火灾烟气特性

Coupling Effect of Top Smoke Discharging and Water Mist on Characteristics of Fire Smoke

利用长宽高为6 m×1.5 m×2 m的隧道模型,进行了顶部排烟和细水雾灭火实验.通过对各测点烟气温度、火焰温度、CO含量及能见度的测试,分析了不同的顶部排烟以及细水雾耦合作用模式对火灾烟气的控制效果.结果表明:顶部排烟加快了柴油燃烧速率,顶部排烟耦合细水雾的冷却作用明显.在火灾增长阶段(50 s),细水雾耦合顶部排烟对于烟气控制效果最优;在火灾充分发展阶段(90 s),细水雾耦合顶部排烟作用易引起沸溢及轰燃,且细水雾喷洒瞬间,火焰强化现象最明显,CO含量迅速上升.顶部排烟对于能见度的提高效果明显;单独施加细水雾虽然能起到控制烟气的作用,但会使能见度进一步降低;在顶部排烟的耦合作用下,烟气经细水雾吸附沉降后能见度的提高速率增大.

A tunnel model （6 m ×1.5m× 2 m） was designed to do the fire-suppression experiment under the joint action of top smoke discharging and water mist. The temperature of the smoke and flame, the concentration of CO, as well as the visibility of smoke were measured to analyze the suppression and cooling effect on fire and smoke under different coupling modes of water mist and top smoke discharging. The results show that top smoke discharging accelerates the burning rate of diesel oil, and cooling effect is obvious under the coupling mode. In the fire growth stage （50 s）, water mist coupled with top smoke discharging has the optimal control effect on smoke. Whereas it is easy to lead boil over and flashover in the fire fully-developed stage （90 s）. Meanwhile, the flame enhancement is most obvious and the concentration of CO increases sharply. Top smoke discharging can greatly improve the visibility, and water mist alone can control the smoke effectively but decrease the visibility. The increasing rate of visibility can be accelerated because of the sedimentation of smoke absorbed by water mist combined with top smoke discharging.