细水雾耦合机械排烟在公路隧道的数值模拟研究

Numerical simulation of fire suppression by coupling mechanical exhaust and water mist in highway tunnel

以某公路隧道为研究对象,采用流体动力学软件Fluent,设置火源在细水雾正下方,分析雾化锥角为60°,粒径为100μm时,不同工况下施加细水雾对隧道内温度、氧气浓度、二氧化碳浓度的影响。结果表明:细水雾对火势的抑制效果明显,在没有排烟的情况下,质量流量较小的细水雾(0.1kg/s)可以起到很好的灭火效果,而加大细水雾质量流量(0.2kg/s)对火势的抑制起到很好的促进作用,灭火效果更为明显;在细水雾和排烟同时开启情况下,质量流量较小的细水雾(0.1kg/s)动量不足以克服排烟造成的对细水雾的夹带和飘移作用,灭火效果不佳,温度明显高于同质量流量细水雾的无排烟情况,当质量流量(0.2kg/s)较大时,细水雾与排烟可以优化耦合,在排除高温烟气的同时发挥细水雾的最佳灭火效果。

Take a highway tunnel as the research object and based on Fluent simulation,this paper analyses the effect on the temperature,the oxygen concentration and the carbon dioxide concentration in the different water mist working condition,which fire in the water directly,spray cone angle of 60 degree and 100μm diameter.The results show that water mist has a better effect on fire suppression.When there is no mechanical exhaust,small mass flow of water mist(0.1kg/s) can have a good effect on fire suppression,increase the quality(0.2kg/s)will further accelerate this effect.When mechanical exhaust and water mist start at the same time,because the momentum of small mass flow rate of water mist(0.1kg/s) is not able to overcome interference and drift caused by smoke exhaust,the function does not work well,and the temperature is obviously higher than the same mass flow rate of water mist without smoke exhaust.Water mist and smoke exhaust can be optimal coupling when adding mass flow rate of water mist(0.2kg/s),which develops best fire extinguish,at the same time,high temperature flue gas excludes.