热壁条件下油气的热着火现象

Thermal ignition phenomena of gasoline-air mixture induced by hot wall

设计了高温热壁油气热着火实验系统，对受限空间油气混合气体在热壁条件下的热着火现象进行了实验研究。根据实验结果，详细讨论了油气混合物的着火方式、临界着火温度、着火压力范围以及体积分数、温度的变化规律。实验发现：热壁条件下油气混合物引燃分为油蒸气的热裂解-油气快速氧化反应-油气急速氧化反应3个阶段；油气混合物着火模式为燃烧、热爆燃和热爆炸；油气在汽油自燃点附近开始快速化学反应，热着火临界温度高于汽油自燃点近80K；温度特征曲线在着火时具有突变性质；热壁温度达到783～873K时，存在压力范围为2．2～17．6kPa的三角形油气热着火压力半岛。

A special experiment system was designed to carry out an experimental investigation about gasoline-air mixture ignition phenomena induced by the hot wall in a confined space. According to experimental results, the ignition manner of gasoline-air mixture, the critical ignition temperature and the ignition pressure region and the change laws of concentration, temperature in the course of fire were discussed in detail. It is found that the ignition course of gasoline-air mixture in the confined space is divided into three phases, namely, gasoline steam pyrolysis, oxidation reaction, accelerated oxidation. There are three ignition manners of gasoline-air mixture caused by the hot wall, namely combustion, deflagration, and explosion. Gasoline-air mixture in the confined space starts its rapid chemical reaction at the spontaneous combustion temperature of gasoline. And its ignition temperature is about 80 K higher than spontaneous combustion point of gasoline. Regardless of region of the fire, or other region in the confined space, there is a sudden rise of temperature at the time of ignition. When the temperature of the hot wall reach 773-873 K, there is a triangle pressure peninsula of thermal ignition of gasoline-air mixture, where the ignition pressure region is of 2.2-17.6 kPa