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固体燃面上方流动和扩散的气体?炭黑(soot)混合介质对火焰热量反馈(包括外界热源辐射传热)的阻碍作用称为火焰传热阻碍,它影响着燃烧速率和释热速率.这一影响应当在火灾蔓延理论模型中定量体现.小尺寸燃烧的机理研究对于全面描述全尺寸火行为至关重要.在火蔓延实验装置上,以非直接测量方式定量研究了不同环境氧浓度时的火焰传热阻碍,并提出了传热阻碍现象的实验证据和测量途径.同时建立了独立于实验的、着重描述火焰介质吸收与发射的一维稳态扩散火焰模型,进一步从物理本质上揭示了现象的机理和规律.研究发现火焰的传热阻碍系数可高达0.3至0.4,且基本不随外加辐射强度变化而变化,但随环境氧浓度升高而增大.实验数据与模型计算结果符合程度较好.
The blocking effect of the soot mixing medium on the flame heat feedback (including heat transfer from external heat sources) is called the heat transfer obstruction, which affects the combustion rate and the rate of heat release. One effect should be quantitatively reflected in the theoretical model of fire spread.The study on the mechanism of small-size combustion is very important for the full description of full-scale fire behavior.In the fire spread experiment device, the indirect measurement of the oxygen concentration in different environments The heat transfer of the flame is obstructed, and the experimental evidence and measuring ways of heat transfer obstruction are also presented.At the same time, a one-dimensional steady-state diffusion flame model emphatically describing the absorption and emission of the flame medium is established independently from the experiment, The mechanism and rule of the phenomenon.The research found that the heat transfer obstruction coefficient of the flame can reach as high as 0.3 to 0.4 and basically does not change with the change of the applied radiation intensity but increases with the increase of the oxygen concentration in the environment.The experimental data and the calculated results are in good agreement it is good.