火灾科学
火災科學
화재과학
FIRE SAFETY SCIENCE
2011年
2期
75-80
,共6页
飞火%蔓延距离%城市火灾
飛火%蔓延距離%城市火災
비화%만연거리%성시화재
Firebrands%Propagation distance%Urban fires
飞火是城市火灾特别是城市震后火灾的重要蔓延方式之一，它可以使火灾在相距较远的离散可燃物之间进行跳跃式蔓延，从而增加了扑救难度，威胁扑救人员的安全。因此，对飞火蔓延现象的认识和飞火蔓延距离的计算是降低飞火危险性的前提。基于Baum-McCaffrey火焰羽流模型，重点研究在城市火灾羽流中球形飞火颗粒的上升行为和环境风影响下颗粒的蔓延过程，给出了计算飞火蔓延距离的方法和飞火颗粒在火焰羽流中能够上升的直径区间，并探讨了火灾热释放速率、环境风速和颗粒燃烧特性等因素对飞火蔓延距离的影响。
飛火是城市火災特彆是城市震後火災的重要蔓延方式之一，它可以使火災在相距較遠的離散可燃物之間進行跳躍式蔓延，從而增加瞭撲救難度，威脅撲救人員的安全。因此，對飛火蔓延現象的認識和飛火蔓延距離的計算是降低飛火危險性的前提。基于Baum-McCaffrey火燄羽流模型，重點研究在城市火災羽流中毬形飛火顆粒的上升行為和環境風影響下顆粒的蔓延過程，給齣瞭計算飛火蔓延距離的方法和飛火顆粒在火燄羽流中能夠上升的直徑區間，併探討瞭火災熱釋放速率、環境風速和顆粒燃燒特性等因素對飛火蔓延距離的影響。
비화시성시화재특별시성시진후화재적중요만연방식지일，타가이사화재재상거교원적리산가연물지간진행도약식만연，종이증가료복구난도，위협복구인원적안전。인차，대비화만연현상적인식화비화만연거리적계산시강저비화위험성적전제。기우Baum-McCaffrey화염우류모형，중점연구재성시화재우류중구형비화과립적상승행위화배경풍영향하과립적만연과정，급출료계산비화만연거리적방법화비화과립재화염우류중능구상승적직경구간，병탐토료화재열석방속솔、배경풍속화과립연소특성등인소대비화만연거리적영향。
Spotting is one of important propagation mechanisms for large〉scale urban fires, especially for post-earthquake urban fires. Firebrands can start new ignitions beyond the continuous fire zone and lead to fire spreading in a non-continuous way, so it can impend fire controlling and threaten to firefighters＇ safety. Understanding the propagation distance of firebrands is the premise for reducing the risk of spotting fire. Based on research results of Baum McCaffrey fire plume structure, this work is an effort to study firebrands lofting in large-scale fires and transporting in ambient wind. In this work, one model for predicting the maximum propagation distance of firebrands is proposed and the factors affecting this distance, including heat release rate of fire, wind speed and firebrand combustion characteristics, are analyzed.
