变重力环境下火焰行为与烟气运动特征的演化机理研究

Most of the aircraft fire will happen during a few minutes after take-off or before landing of the air plane, when the gravity is larger or smaller than 1 G0. The characteristics of fire behavior and smoke movement under a variable gravity condition will be very different with the ones under normal gravity, which should be described by new mathematical models. The characteristics of fire behavior and smoke movement under a variable gravity condition in the long and narrow space will be investigated in this project. The characteristics of fire behavior under a variable gravity condition will be studied, the influence mechanism of Rayleigh-Taylor instability on fire behavior characteristics will be analyzed, the prediction models of flame length, and temperature distribution in the long and narrow space will be developed. The evolution rules of fire behavior will be analyzed under the coupling effect of variable gravity and different inclined angles of the long and narrow space. The influence mechanism of thermal convection on smoke flow speed and thickness will be studied, and the criterion of smoke layer instability will be obtained. The models of fire dynamic characteristics for variable gravity condition in the long and narrow space could also be suitable for the normal gravity, which is an effective extension. It takes on a certain theoretic meaning and engineering application value

多数飞机火灾是发生在飞机起飞后或降落前的几分钟，这一时段飞机机舱处于失重或者超重的变重力环境下。火灾发生后，火焰行为特性和烟气运动特征具有不同于常重力环境的特殊演化规律，需要建立新的数学模型来描述。本项目拟揭示机舱类狭长空间内变重力环境下火焰行为和烟气运动特征的演化规律：研究变重力环境下火焰行为特征规律，阐析变重力环境下瑞利泰勒不稳定性对火焰行为特征的影响，建立火焰行为特征参数与重力耦合的数学预测模型；研究水平及倾斜狭长空间内变重力环境下火焰拓展长度、温度等特征参量的演化特性，揭示此特殊条件下烟气运动速度、烟气层厚度等受热对流影响的物理机制，建立烟气层失稳的临界判据。本项目针对狭长空间内变重力环境下火焰行为和烟气运动特征开展相关研究，可对现有的火羽流动力学理论进行有效的补充，具有较好的理论意义。也可以此为基础，为进一步研究飞机机舱的防灭火措施提供基础数据，具有较强的工程应用价值。

在变重力环境下，火焰行为和烟气运动呈现不同于常重力环境的特殊演化规律，现有的火羽流理论无法对其进行数学描述。本项目通过理论分析和数值模拟研究，揭示了该变重力环境下火焰行为特征与烟气输运特性的演化规律。1) 分析了重力环境与火焰行为特征（火焰高度、温度分布、空气卷吸强度等）之间的耦合关系；2）研究了重力环境变化对热对流强度、瑞利泰勒不稳定的影响，并分析了其影响火焰行为特征的内在物理机制；3）研究了重力环境变化所引起的火焰卷吸特征差异，明析了火焰卷吸与火焰行为特征的关系，建立相应的理论预测模型。4）改变了重力环境，研究了不同倾斜角度顶棚条件下火羽流区域温度分布情况，分析了其基本演化规律和作用机制。项目完成了预定的研究目标和成果指标：已在国际著名学术期刊发表SCI论文20篇，包括Fuel，Energy，Tunnelling and Underground Space Technology等国际权威学术期刊；申请发明专利4项，授权2项。项目培养硕士研究生4名；搭建了变重力火灾实验平台；项目注重学术交流合作，累计参加学术会议多次，做会议报告2次。