期刊
INTERNATIONAL JOURNAL OF WILDLAND FIRE
卷 26, 期 1, 页码 71-81出版社
CSIRO PUBLISHING
DOI: 10.1071/WF16096
关键词
ignition delay; ignition limit; pine needles; smouldering-to-flaming transition; spotting
类别
资金
- National Natural Science Foundation of China [51576184]
- National Key Research and Development Program [2016YFC0800104]
- Fundamental Research Funds for the Central University [WK2320000036]
Ignition of natural fuels by hot metal particles from powerlines, welding and mechanical processes may initiate wildfires. In this work, a hot steel spherical particle (6-14 mm and 600-1100 degrees C) was dropped onto pine needles with a fuel moisture content (FMC) of 6-32% and wind speed of 0-4 m s(-1). Several ignition phenomena including direct flaming, smouldering and smouldering-to-flaming transition were observed. The critical particle temperature for sustained ignition was found to decrease with the particle size (d) and increase with FMC as T-p,T-crt = 1800(1 + 4FMC)/d + 500(degrees C), and the maximum heating efficiency of particle was found to be eta(sp) = 10%. As the particle size increases, the influence of FMC becomes weaker. The flaming ignition delay times for both direct flaming and smouldering-to-flaming transition were measured, and decreased with particle temperature and wind speed, but increased with FMC. The proposed heat-transfer analysis explains the ignition limit and delay time, and suggests that the hot particle acts as both heating and pilot sources like a small flame for direct flaming ignition, but only acts as a heating source for smouldering. This study deepens the fundamental understanding of hot-particle ignition, and may help provide a first step to understanding the mechanism behind firebrand ignition.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据