非连续介质热解挥发分对其着火的影响

Influence of pyrolytic volatiles on ignition of discrete objects

建立非连续介质热解挥发分的运动填充模型,推导出热解挥发份的空间浓度分布函数表达式,得出非连续介质热解质量通量对其着火影响的函数关系,并用小规模燃烧实验进行验证。结果表明,室内火灾时非连续介质表面上方一定高度的某点处热解挥发分的浓度与其在该点的质量通量成正比,与其在该点的流动速度成反比;室内火灾时非连续介质要着火燃烧,其热解质量通量必须达到临界值,该临界值大小与烟气层达到稳定时的高度有关。

By building the filling model of pyrolytic volatiles of discrete objects,the functional expression of space concentration distribution of pyrolytic volatiles was deduced,and then the mathematical relationship between the pyrolytic mass flux of discrete objects and their ignition was gained,and small scale fire experiments were done to verify them.The results showed that,in enclosure fires,the pyrolytic volatiles concentration at some height above the discrete object is proportional to the mass flux,and inversely proportional to the flow rate;in enclosure fires if the discrete objects catch fire then their pyrolytic mass flux must reach a certain threshold which is related to the stable height of smoke layer.