隧道火灾中细水雾降温消烟数值模拟研究

Numerical Simulation Study of Water Mist Cooling and Smoke Elimination in Tunnel Fire

细水雾系统因其良好的控烟作用在隧道火灾中得到广泛应用。基于气溶胶动力学机理提出细水雾降温消烟数值模型,通过模拟狭长通道细水雾阻烟实验验证其有效性。为探究细水雾粒径、雾化锥角、细水雾与排烟口间距对降温消烟效果的影响规律,进一步采用该模型开展细水雾系统在大尺度隧道火灾中降温消烟效果研究。研究表明:细水雾液滴粒径越小,降温消烟效果越好,且消烟效率与粒径成反比,但当粒径小于100μm时,因液滴蒸发导致消烟效率有所降低;雾化锥角在60°时消烟效果最好,雾化锥角增大或减小都会降低细水雾系统的消烟效果;当细水雾系统与排烟系统间距较小时,由于细水雾液滴会被排烟系统抽出,导致消烟效果减弱,因此两者间距越大,消烟效果越好。

Water mist system is widely used in tunnel fire because of its good smoke control effect.A numerical model of cooling and smoke abatement of water mist was proposed based on the mechanism of aerosol dynamics,and its effectiveness was verified by simulating the smoke suppression experiment of water mist in a narrow and long channel.In order to explore the influence of particle size,spray cone angle and the distance between water mist and smoke vent on the cooling and smoke abatement effect,the model was further used to study the cooling and smoke abatement effect of water mist system in large-scale tunnel fire.The results show that the smaller the particle size of the droplets,the better the cooling and smoke abatement effect,and the smoke abatement efficiency is inversely proportional to the particle size.However,when the particle size is less than 100μm,the smoke abatement efficiency decreases due to droplet evaporation;When the spray cone angle is 60°,the smoke abatement effect is the best.The increase or decrease of the spray cone angle will reduce the smoke abatement effect of the water mist system;When the distance between the water mist system and the smoke exhaust system is small,the smoke abatement effect will be weakened because the water mist droplets will be pulled out by the smoke exhaust system.Therefore,the greater the distance between the two,the better the smoke abatement effect.