动态低压环境下火灾燃烧动力学机理及火行为特性研究

Fire is a major risk factor for aircraft flight safety. The initiative pressure relief process and cruising altitude change during the fire occurrence and spread in the cabin can make the pressure inside the cabin constantly change, and the concentration of oxygen is relatively low. The study of fire burning dynamics mechanism and fire behavior under such a kind of dynamic pressure is the premise for the prevention and control of fire safety and the fire protection design in aviation transportation, is the extending, complementing and development of fire behavior study under static pressures of high altitude, and is also a new question being faced by the interdisciplinary science of safety science and fire science. The main subjects of this project is to (1) examine the fire behaviors and the plume characteristics under the continuously changing pressure based on experimental approach in a large-scale altitude chamber, (2) explore the influence law of dynamic pressure on the plume characteristics and heat feedback mechanism, (3) study the scale effect of the combustion rate’s dependency relationship on pressure, (4) obtain the law of combustion rate, flame temperature, heat radiative flux, soot concentration and flame shape varying with pressure, (5) set up the basic theory model of pool fire combustion under dynamic pressure.

火灾是威胁飞机飞行安全的主要危险因素，飞机机舱火灾的发生发展过程中主动泄压及巡航高度的改变都可引起机舱内的压力持续变化，并且氧浓度较为稀薄。这类动态压力条件下的火灾燃烧动力学机理和火行为特性研究是航空运输中火灾安全防治及消防设计的前提，是高海拔实地静态低压火行为研究的深入延续、补充和重要拓展，也是安全学与火灾学交叉学科面临的新课题。本课题通过设备和技术创新首次在低压实验舱内开展动压池火实验，采用抽气兼通风系统真实模拟飞行过程压力环境和氧气浓度变化，对连续变化的动压环境下的火行为及羽流特性进行研究，探讨动态低压环境对火羽流特性和热反馈机制的影响规律，研究池火燃烧速率与环境压力的依赖关系的尺度效应。研究得到燃烧速率、火焰多点温度、热辐射、碳烟浓度以及火焰形态等参数随压力及池火尺寸变化的规律，揭示动态压力条件下的火灾燃烧动力学机理及火行为特性，结合实验数据及理论分析建立动压池火燃烧基本理论模型。

飞机货舱火灾是威胁飞机安全的主要危险因素，此类火灾事故所处的环境具有气压低、氧浓度稀薄等特点，并且火灾发展过程和机舱主动泄压都会引起压力的瞬态变化。动态压力条件下的火行为特性及火灾演化机制研究是高海拔航空运输中火灾安全防治及消防设计的前提。本课题通过设备和技术创新首次在低压实验舱内开展动压池火实验，采用抽气兼通风系统真实模拟飞行过程压力环境和氧气浓度变化，对连续变化的动压环境下的火行为及羽流特性进行研究，探讨动态低压环境对火羽流特性和热反馈机制的影响规律，研究池火燃烧速率与环境压力的依赖关系的尺度效应。研究得到燃烧速率、火焰多点温度、热辐射、碳烟浓度以及火焰形态等参数随压力及池火尺寸变化的规律，揭示动态压力条件下的火灾燃烧动力学机理及火行为特性。研究发现环境压力的变化对火行为有较大影响，火焰高度随海拔高度的增加而升高，质量燃烧速率随着压力的上升呈现指数上升。