地下矿山腔室溢流火羽流特性及其与水平巷道风流作用机理

In this research project, we focus on the dynamics of fire plume ejected from openings of cavity-type confined space in underground mine. Methods including model scale fire experiments, theoretical analysis and numerical simulations are used to reveal the development of cavity fire and flashover, the behavior of ejected plum and its interaction with the horizontal roadway airflow. Under the condition of roadway airflow, the combined effect of wind pressure and thermal pressure that respectively caused by air flow through multi-openings and fire heating is studied. The mass flow model that estimate mass of air entering the cavity is established, which take the dimensions of openings into account. The indoor combustion state is further characterized and the heat release rate of ejected flame is calculated. The influences of opening geometry on temperature distribution of ejected fire plume and on the characteristics of hot smoke entrainment are studied. The change of mechanisms of ejected plumes with heat release rates are analyzed. Based on the classical plume model, ceiling ejected-plume model and wall bounded ejected-plume model are respectively established to predict smoke layer temperature and velocity. The interaction of smoke spreading and roadway airflow is studied. The critical velocity model and the backlayering length model of ejected fire plume are established. Computational fluid dynamics (CFD) model with mixture fraction combustion method is developed to simulate the behaviors of ejected fire plume in ventilated roadways. The predicted results are compared with the experimental results in order to examine the reliability of the CFD model. The research results of this project can provide technical and theoretical supports for cavity-type fire prevention and control in underground mine.

本项目以地下矿山腔室类密闭空间溢流火羽流为研究对象，采用小尺寸实验、理论分析及数值模拟方法，着重研究腔室火灾发展规律、轰燃演化机理、溢流羽流特性及其与水平巷道风流的作用机理。研究巷道风流影响下腔室内外风压和热压对腔室通风的综合作用，考虑开口尺寸因素，建立进入腔室的空气质量流率模型，表征腔室内燃烧状态，进一步求解溢流火焰热释放速率；研究腔室开口形状对溢流羽流温度和烟气卷吸特性的影响，分析溢流羽流随热释放速率变化的机理，从经典羽流模型出发，分别建立溢流顶棚射流羽流模型和溢流壁面贴附羽流模型，预测巷道烟气层温度和速度分布规律；研究烟气蔓延与巷道风流作用机理，建立腔室溢流火羽流条件下临界风速模型和烟气逆退距离模型；建立数值模型，通过数值模拟结果与实验结果的对比分析，探讨混合分数燃烧模型在模拟通风巷道中腔室溢流羽流动力学特性的可靠性。本项目研究成果可为地下矿山腔室类构筑物火灾防治提供方法与理论支持。

本项目以地下矿山腔室类密闭空间溢流火羽流为研究对象，采用小尺寸实验、理论分析及数值模拟方法，着重研究腔室火灾发展规律、轰燃演化机理、溢流羽流特性及其与水平巷道风流的作用机理。研究了巷道风流影响下腔室内外风压和热压对腔室通风的综合作用，考虑开口尺寸因素，表征了腔室内燃烧状态，进一步获取了溢流火焰热释放速率；研究腔室开口形状对溢流羽流温度和烟气卷吸特性的影响，分析了溢流羽流随热释放速率变化的机理，从经典羽流模型出发，预测了巷道烟气层温度分布规律；研究了烟气蔓延与巷道风流作用机理，建立腔室溢流火羽流条件下临界风速模型；建立了数值模型，通过数值模拟结果与实验结果的对比分析，探讨了数值燃烧模型在模拟通风巷道中腔室溢流火羽流动力学特性的可靠性。本项目研究成果可为地下矿山腔室类构筑物火灾防治提供方法与理论支持。