Effect of the Wire Mesh Structure on the Flame Characteristics of Methane/Air Deflagration
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摘要: 在自主设计的方形管道中开展了金属丝网对甲烷/空气预混气体爆燃火焰传播特性影响的实验,通过改变金属丝网的目数和层数,探讨其对爆燃火焰超压和温度的影响。结果表明:金属丝网能有效抑制爆燃火焰的超压与温度,安装金属丝网后,管道内测得的超压峰值与温度峰值相较于无金属丝网均出现降低,温度峰值衰减率最高达到52.37%,超压峰值衰减率最高达到66.84%;金属丝网的目数和层数是影响金属丝网对超压抑制效果的重要因素,层数与目数较小时,达到超压峰值的时间相较于无金属丝网时提前,层数与目数适中时,超压曲线出现二次峰值现象,层数与目数较大时,超压能得到有效抑制;随着目数与层数的增加,火焰热量向前扩散速度变慢,温度曲线起始时间相较于无金属丝网时延后。Abstract: A deflagration experiment of methane/air premixed gas with or without wire mesh was carried out in the self-design square pipe. The effects of the mesh number and layer number of the wire mesh on the deflagration overpressure and temperature were discussed. The results show that the wire mesh can effectively suppress the temperature and overpressure of the deflagration flame. After the wire mesh is installed, the temperature peak and the overpressure peak measured in the pipeline are reduced compared to the case without wire mesh, and the temperature peak attenuation rate reaches 52.37%, the peak attenuation rate of overpressure reaches 66.84%; the mesh number and layer number of the wire mesh are important factors that affect the suppression effect of the wire mesh on overpressure. When the number of layers and meshes are small, the time to reach the peak of the overpressure is earlier than the condition with no wire mesh; when the number of layers and meshes are moderate, the secondary peak appears in the overpressure curve; when the number of layers and meshes are large, the overpressure is effectively suppressed. With the increase of the number of meshes and layers, the flame heat diffusion rate forward becomes slower, and the start time of the temperature curve is delayed compared to the time delay without the wire mesh.
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表 1 金属丝网结构参数
Table 1. Mesh structure parameters
Wire mesh Holes per cm Aperture/cm Wire diameter/mm Metal area fraction/% Metal volume fraction/% 10 3.937 2.110 0.450 0.723 2 0.272 5 20 7.874 0.950 0.315 0.565 6 0.389 6 30 11.811 0.610 0.234 0.524 0 0.434 1 -
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