单室火灾的燃烧特性

Combustion characteristics for single room fire

通过实验研究火源功率及单室的通风状况对单室室内火灾燃烧时的温度变化及分布、烟气流动特性及气体成分的变化影响。结果表明:在全封闭情况下,热烟气以垂直流动为主,且随着热烟气的流动,室内温度逐渐升高,O2浓度逐渐降低。边界层不稳定导致的火焰振荡使热烟气层的最高温度出现在距离单室顶部70～80 cm处。火源功率越大,室内温度升高越快,升温幅度越高,火焰脉动进一步加剧,火焰偏移越大。在单室通风口打开的情况下,热烟气以水平流动为主,室内O2浓度和CO浓度变化不大,而以通风口上沿为界,温度分布呈现明显的上下2层。

Temperature distribution,smoke flow characteristics and gas component in different parts of fire and the open condition were investigated.Hot smoke flowed vertically in close condition which led to temperature increasing and O2 concentration decreasing.Flame oscillation caused by boundary layer instability made the maximum temperature of hot smoke layer appear in the region about 70-80 cm apart from top.As fire power increased,indoor temperature elevation speed,temperature elevation scope,flame oscillation intensity,and flame deflection increased.Hot smoke flowed horizontally in the open condition,and O2 and CO concentrations almost unchanged.The temperature distribution was on two layers obviously nearby the top horizon of the open door.