摘要
选用厚度为2mm与3mm的木材,研究了可碳化固体可燃物在静止氛围中不同角度下的火蔓延特性。研究表明,在不同角度范围内火蔓延经历着熄灭、稳定燃烧、加速燃烧以及快速燃烧等变化过程。对两种厚度的木材火蔓延行为对比分析发现,在自然对流条件下,两种厚度木材的火蔓延极限角度分别为-5°,5°。另外,研究了试样上下表面火焰参数与火蔓延速度之间的关系。在10°<α<60°范围内,火蔓延速度计算值与实验值能较好拟合。
The present paper is aimed at introducing its experimental research of the flame spreading mechanism over charring materials facing the orientation under the natural convection in the direction of gravity assistance. In this research we have chosen wood sheets as typical charring materials while the burning process was observed at an angle of orientation a from 20° to 90° （, i.e. a vertically upward burning）. Data the paper has adopted are taken to show the flame spreading characteristics of thermodynamically thick-enough Charring materials. Thus we have found that the flame behavior over the solid surface may go through such states as extinguishment after removing the igniter, steady burning, accelerated burning and full burning similar to the flash with the constantly increasing burning angle. But the local flame spreading rate actually fluctuates increasingly with the angle. And when the flame spreading behaviors for the sample thickness d = 2mm is compared to that for the sample thickness d d= 3mm, it can be found that the thinner the sample is the more sensitive to the angle change. The flame parameters such as the flame angle θ, flame length L can be measured for the sample thickness d = 3mm. The above parameters also contribute to the deduction of the calculated flame spreading rates, which can be compared with the experimental results. In the range of 0° 〈 α 〈 60°, the predicted flame spreading rates prove to be in well conformity with the experimental flame spreading rates, but in the range of α ≥ 60°, the discrepancy is also to be noted. Measurements of the temperature distribution on the upper and rear surfaces of the samples have also been carried out by using the fine thermocouples. Based on the temperature data, the contributory factors of the flames over both up and rear surface to the flame spreading behavior are also discussed here in the paper. For α 〈 30°, the flame over the ear-surface is predominant for the whole burning process and the flame over up-surface is predominant just for α ≥ 30°.
出处
《安全与环境学报》
CAS
CSCD
2006年第3期27-31,共5页
Journal of Safety and Environment
基金
国家自然科学基金重点项目(50536030)
国家重点基础研究发展规划"973"资助项目(2001CB409606)
关键词
安全工程
木材
火蔓延速度
火焰特性
试样角度
safety engineering
wood sheets
flame spread rates
flame characteristics
samole orientation
