摘要
应用三维LDV/APV系统和热成像方法,测量了细水雾和气体扩散火焰作用过程中的细水雾雾场、火焰温度场并研究了细水雾和气体扩散火焰的作用过程.探索了细水雾抑制火焰的机理和规律,比较了细水雾抑制气体扩散火焰时3种主要灭火机理.用数据定量表征了细水雾灭火时,水雾的蒸发潜热吸热作用、热容吸热作用以及稀释氧气作用对抑制气体扩散火焰所做的贡献.细水雾直接喷射或被卷吸进入火焰内部时,由于表面积大,吸收热量快,迅速汽化,体积扩大.大量的汽化潜热会降低火焰区及气相燃料的温度,细水雾及其蒸汽吸收部分热辐射,降低对燃料的热回馈,减少其汽化蒸发,从而降低反应区的可燃气体积分量.这些因素都会大大降低化学反应速度,抑制火灾的发展,直至扑灭火灾.
The laser doppler velocimeter and adaptiue phase/doppler velocimeter (LDV/APV) system and thermal video system were used to measure water flux, parameters of the field of water mist and temperature. The process of water mist on gaseous diffusion flame was studied. The mechanisms and rule of water mist suppression was explored. The article compared the three fire extinguishing mechanisms of the water mist in preventing the spread of fire by gas and analysed the experiment result. By using the experimental data, this article quantitatively described the following actions in the fire extinguishing process by water mist: the heat absorption due to the latent heat of vaporization of water mist, the heat absorption of heat due to the heat capacity of water mist and the effect of dilution of oxygen by the water mist in suppressing the spread of fire. When the water mist is sprayed directly or when it is sucked into the fire, due to its large surface area, it absorbs heat at a fast rate, vaporizes quickly, and its volume expands greatly. The huge amount of latent heal of vaporization will lower the temperature in the fire region and the temperature of the gaseous fuel. Water mist and its vapour absorb part of the heat radiation , reduce the amount of heat fed back to the fuel, decrease the extent of vaporization, and hence lower the fraction by volume of the flammable gases in the reaction region. These factors greatly lower the rate of chemical reaction and suppress the further development of fire until the fire is extinguished.
出处
《燃烧科学与技术》
EI
CAS
CSCD
2003年第5期391-396,共6页
Journal of Combustion Science and Technology
基金
国家重点基础专项经费资助项目(2001CB409600)
中国科学院知识创新资助项目(KGCX2 308 2)
安徽省自然科学基金资助项目(03045404)
教育部留学回归人员科研启动基金资助项目.
关键词
细水雾
抑制
气体扩散火焰
模拟实验
Diffusion
Fire protection
Flame research
Flame retardants
Gas fuels
Laser Doppler velocimeters
Vaporization
Water
