风-热耦合对建筑外立面火源融合燃烧的影响

Fusion combustion behaviour of multiple ignition sources on building facade under wind-heat coupling

针对建筑外立面火源融合燃烧现象,展开了影响受体引燃过程的因素分析和环境风作用下多火源融合时热参数的演化研究,分析了燃烧过程中系统产热能力、温升和引燃时间变化,探明了风-热耦合作用下建筑外立面多火源融合燃烧行为机制。结果表明,风速增大会限制火源融合后外立面火焰燃烧行为,表现在受体引燃时间变长、温度和单位温升值变小,但风速介于1~1.5 m/s时会增强EPS燃烧产热能力,风速为2 m/s左右时有利于受体内部引燃过程;相同风速环境时,对系统EPS燃烧产热能力和受体引燃时间影响为竖向三火源>竖向四火源>竖向双火源,而对单位温升影响最大的则是竖向双/三火源融合,其温度最大影响区间为融合层向上1—2层高度。

Aiming at the phenomenon of fire source fusion combustion on the facade of the building,the factors affecting the ignition process of the receptor and the evolution of thermal parameters during the fusion of multiple fire sources under the action of environmental wind were carried out,the changes of heat production capacity,temperature rise and ignition time during the combustion process were analyzed,and the combustion behaviour mechanism of multi-ignition source fusion on the building facade under the coupling action of wind and heat was explored.The results show that the increase of wind speed will limit the flame combustion behaviour of the facade after the fusion of the ignition source,which is manifested in the longer ignition time of the acceptor and the decrease of temperature and unit temperature rise,but when the wind speed is between 1-1.5 m/s,it will promote the enhancement of EPS combustion heat production capacity,and when the wind speed is about 2 m/s,it is conducive to the internal ignition process of the acceptor.Under the same wind speed environment,the ignition source with the greatest influence on the combustion heat generation capacity and receptor ignition time of the system is fused as vertical three ignition sources>vertical four ignition sources>vertical double ignition sources,while the largest influence on unit temperature rise is vertical double/triple ignition source fusion,and the maximum temperature influence range is the height range of 1-2 layers up the fusion layer.