【作者】 刘晅亚；

【导师】 陆守香；

【作者基本信息】 中国科学技术大学 ， 安全技术及工程， 2006， 博士

【摘要】 细水雾具有良好的液滴分散性、高热容、易蒸发等特性，因此作为卤代烷烃灭火剂的替代物，细水雾灭火技术己得到了广泛的研究与应用。在可燃气云惰化以及爆炸火焰抑制等方面，细水雾技术也得到人们的普遍关注，利用细水雾进行可燃气云惰化、抑爆的相关研究也已大量开展。可燃气云爆炸是处于爆炸极限范围内的预混气、燃料液滴群急剧燃烧，火焰加速传播的过程。细水雾对可燃气云惰化、抑爆技术的核心和技术基础就是细水雾与预混火焰的相互作用。本文通过对水雾作用下甲烷／空气预混火焰燃烧特性的实验研究，揭示水雾对预混火焰稳定燃烧的影响以及水雾的惰化、抑制机理和条件。本文的主要工作与研究成果包括： 1．设计、建造了新颖的大口径(15mm)水雾协流管式燃烧器实验台。 利用该实验台可在开放空间内，对具有较大粒径分布的细水雾(雾滴直径范围30μm～150μm)与甲烷／空气预混火焰之间的相互作用过程进行实验研究。与目前传统的管式燃烧器以及Fuss等人研制的出口直径5.4mm，雾滴直径小于10μm的管式燃烧器相比，本实验台研究适用范围更宽广。 在对燃烧器设计思路理论分析的基础上，对实验系统进行了校准与误差分析；利用LDV／APV系统对管式燃烧器出口气体协流水雾特性进行测量，分析混合气体流量对管式燃烧器烧嘴出口处水雾特性的影响，并运用两相流理论分析了燃烧管烧嘴出口处水雾与协流气体之间的相互作用； 2．利用高速纹影实验系统对水雾协流作用下的甲烷／空气层流预混火焰燃烧特性进行研究，揭示了水雾协流作用过程中甲烷预混火焰的熄火模式与规律。通过分析水雾对层流火焰稳定性、火焰拉伸、燃烧速度以及火焰化学发光特性的影响，研究水雾作用过程中的火焰熄火、抑制模式的产生过程与机理；利用水雾协流管式燃烧器，通过实验的方法得到了惰化与抑制甲烷／空气层流预混火焰所需的水雾条件。 3．在不同的水雾协流条件下，对甲烷／空气层流预混火焰拉伸现象及火焰拉伸率的变化规律进行研究，分析水雾液滴蒸发与扰动对锥形预混火焰面拉更多还原

【Abstract】 Due to the fine dispersity, high heat capacity, and ease of evaporation, water mists have got widely used and concerned about as the substitute of the haloalkane extinguishing agent. Flammable gas flame acceleration is the universal phenomena in fires and explosion industrial hazards, such as coal mine gas explosion, oil vapor explosion in the ship machine space, flashover and backdraft in building and so on. It indicated that certain condition water mist could be available to inert the flammable gases and inhibit the gas explosion in the gas or vapor congregated location. The corresponding researches are mainly about the mechanism of the methane/air premixed gas inerting and the mitigation of premixed gas laminar flame propagation by water mist. The kernel and fundamentals of flammable gas inerting and inhibition by water mist are interactions of water mist and premixed flame. This paper would try to explore the influence and mechanism of inerting and inhibition of premixed flame by water mist, by the experiments of the combustion characteristic on the influence of water mist. The main works and achievements in the paper contain the following sections.1. The original experimental equipments of the bigger aperture tube burner with coflow water mist were designed and setup.With this experimental equipment the interaction of large size distribution water mist (water mist diameter distributed within 30μm～150μm) and methane/air premixed flame were studied. Compared with the present classical tube burner and the Fuss burner whose burner nozzle diameter was 5.4mm and the water mist size was 10μm, this burner equipment can be applied more widely.According to the design theory of the tube burner, the calibration and error analysis were carried out. And the LDV/APV system was employed to study the water mist characteristic along the axis outside the burner nozzle of the tube burner. The effects of coflow inlet gases flux on the droplets movement were analyzed. In addition, the water mist characters and the tow-phrase flow of the tube burner with different coflow conditions were also studied in theory.更多还原