细水雾与热烟气相互作用数值模拟研究

使用CFD软件Fluent对火灾中热烟气与细水雾的相互作用过程进行了数值模拟研究。比较了灭火过程中不同粒径细水雾在流场中的运动及其对灭火效果的影响,并研究了细水雾对着火房间火焰辐射的散射作用及细水雾的聚合破碎过程对灭火效果的影响。模拟结果表明辐射是火灾中主要的热传递过程,粒径较大的水雾比较容易离开回流区到达燃烧反应区。房间细水雾的通过吸收和散射作用减弱辐射强度,水雾在喷射初期可能使燃烧速率增大,这些结果与实验事实相符

Numerical Simulation of the Interaction BetweenSmoke and Water Mist in Fire

This paper presents a numerical simulation of the interaction between smoke and water mist in a fire using CFD software package Fluent. Motion of droplets of different size in the flow field is studied and their fire extinguishing ability is compared according to whether they can reach the combustion zone. Scattering of thermal radiation from fire by water mist and the effects of breakup and coalescence of droplets at initial stage are also studied. Modeling results demonstrate that radiation is the main heat transfer process; bigger droplets are easier than smaller one to get away from the circumfluence zone and to arrive at the combustion zone. Water mist attenuates thermal radiation by absorbing and scattering, and it may enhance combustion reaction rate at initial stage. These results agree with experimental result.