Multiple fire interactions: A further investigation by burning rate data of square fire arrays
Multiple fire interactions: A further investigation by burning rate data of square fire arrays
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DOI：
10.1016/j.proci.2012.06.098
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
Naian Liu;Qiong Liu;J. Lozano;Linhe Zhang;Zhihua Deng;B. Yao;Jiping Zhu;K. Satoh
中科院分区：
文献类型：
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作者：
Naian Liu;Qiong Liu;J. Lozano;Linhe Zhang;Zhihua Deng;B. Yao;Jiping Zhu;K. Satoh
本文首次通过分析从3×3到15×15范围内的实验方形火灾阵列的燃尽时间数据，探讨了由大量火点组成的群火中燃烧速率的空间分布。引入并定义了一个新的概念，即火灾层，以表征火点的空间位置，通过该概念，可以分析和物理解释不同条件下燃烧速率的复杂空间变化。分析表明，火层燃烧速率由外向内呈一定的非线性模式变化。这表明，热反馈增强和空气供应限制这两种火灾相互作用效应在火灾阵列中存在明显的空间波动。两种相互作用效应的空间波动受到火力间距和火力阵大小这两个主要参数的显著影响。明确了两种相互作用效应的空间波动和高度竞争的空间区域和参数范围。结果表明，各火层的平均燃烧速率随火灾间距或火灾阵列大小的变化而变化，特别是与整个火灾阵列具有很高的可比性。研究发现，随着火灾间距的变化，各火灾层的平均燃烧速率随火灾面积比呈线性变化，且与整个火灾阵列在相同的范围内，而火灾层燃烧速率随火灾阵列尺寸的波动模式不同。此外，分析表明，火灾发生时，火灾各层的燃烧速度都会受到火灾合并的显著影响。最后，提出了一种模拟离散燃料源间火焰传播的新方法，明确指出了周围新火点对原火点燃烧速度的积极影响。
This paper presents the first effort to explore the spatial distributions of the burning rates in group fires consisting of a large number of fire points, by analyzing burn-out time data from experimental square fire arrays ranging from 3×3 to 15×15. A new concept termed fire layer is introduced and defined to characterize the spatial locations of fire points by which the complex spatial variations of burning rates, under different conditions, are analyzed and physically interpreted. Analysis shows that the fire layer burning rates vary from outer to inner in definite nonlinear modes. This indicates that the two fire interaction effects, heat feedback enhancement and air supply restriction, involve distinct spatial fluctuations in fire arrays. The spatial fluctuations of the two interaction effects are significantly affected by the two major parameters, fire spacing and fire array size. Definite spatial regions and parameter ranges for the spatial fluctuations and high competitions of the two interaction effects are clearly distinguished. It is demonstrated that the average burning rates of all fire layers involve consistent variations versus fire spacing or fire array size, especially with high comparability to the entire fire array. It is found that by varying fire spacing, the average burning rates for all fire layers vary linearly versus the fire area ratio, within the same ranges as the entire fire array, while there exist different fluctuation modes of fire layer burning rates with respect to fire array size. Furthermore, analysis shows that the burning rates of all fire layers will be significantly affected by fire merging when it occurs. Finally, a new approach is presented to simulate fire propagation among discrete fuel sources, by which the positive effect of the surrounding new fire points on the burning rates of the original ones is definitely indicated.