Abstract: In order to prevent fire accident caused by leakage of liquid fuels in the process of storing,using and transporting,a schlieren system,CCD cameras and K-thermocouples were used to study the characteristics of flame spreading over sand bed wetted with 1-butanol.The effect of surface inclination angle of sand bed on the mechanism of flame spread was analyzed.The results indicate that the flame spreads on the sand bed at constant speed.When the flame spreads upward,its height,yellow luminous zone and spread rate increase with surface angle; when the flame spreads downward,they all decrease as the surface angle increases.As the surface inclination angle increases,the preheating zone magnifies,which is in front of the flame,and the thickness of thermal boundary layer decreases,which is in the sand layer.The investigation on flame spread characteristics and burning mechanism provide some guideline for fire suppression and environmental protection.

Key words: flame spread, porous media, fuel, surface inclination angle, heat transfer, temperature distribution

摘要： 利用纹影系统、CCD相机以及K型热电偶对正丁醇润湿条件下不同角度的砂床表面火蔓延特性进行了研究,分析了不同砂床表面倾角对火蔓延的影响机理。研究结果表明:正丁醇润湿条件下变角度砂床表面火焰是稳定匀速蔓延的,向上蔓延时,火焰的高度、黄色发光区以及蔓延速度随着倾角的增加而增大;向下蔓延时,火焰的高度、黄色发光区以及蔓延速度随着倾角的增加而减小;蔓延火焰前方存在预热区,且预热区随表面倾角的增大而增大:砂层内部存在热边界层,且砂床热边界层厚度随表面倾角的增加而减小。得到的火蔓延特性及燃烧机理为此类液体燃料的储存、使用以及环境保护提供了一定的科学依据。

关键词: 火蔓延, 多孔介质, 燃料, 表面倾角, 传热, 温度分布