飞火是高能量火中最复杂、最危险的现象,是在燃烧过程中由火焰热对流带出的未燃尽的木屑、炭块等可燃物,散布在火区外形成新的火点现象.飞火被看成除了传导、对流和辐射之外的第四种热量传递的方式.飞火的出现增加了新的火源,使火场的扩散由连续变成跳跃,大大加快了火灾的蔓延,有时还改变蔓延的方向.以"3·29"昆明安宁市森林火灾为研究对象,调查火烧迹地并取样,分析可燃物特征,并对飞火发生的距离进行模拟计算.结果表明,由于云南松林立地干燥,林内可燃物多,连续性好,地形复杂,小气候明显,易发生飞火;引发飞火的可燃物主要是云南松的球果;经验公式和模型计算的飞火距离与实际距离比较接近.%Spotting fire is the most complex and dangerous phenomena of large fires during forest combustion. It is from such fuels as wood dust and charcoal during forest burning when wind and thermals carry them to unburned area. Spotting fire has been looked as the fourth energy transfer way besides radiation, convection and conduction,and it can increase new fires, widen burning area, make fire spread faster and change spread direction. Based on fire sites of Anning, Kunming, burned out 29 March, 2006, about 30 plots were surveyed and samples were collected in order to analyze fuel characteristics including length, diameter, moisture content, et al, and modify spotting distance by models. The results showed that spotting fires occurred due to fuel heavy loads and well continuity,dry site of pine forest, complex topography and microclimate. Fuels bring out spotting fires were cones of Pinus yunnanensis, the distance computed by experiential equations and models were near the factual distance.
展开▼
