Abstract Smoldering firebrands can be lofted over long distances, easily igniting spot fires. This poses a threat to structures in the wildland-urban interface (WUI), where wildland fires spread into and within communities. This study investigates the influence of firebrand size and makeup on heating from a pile to a recipient surface in a small-scale wind tunnel. Two sizes of fluted birch wooden pins and wooden discs, one size of cylindrical birch dowels, two lengths of eucalyptus sticks, and pine bark flakes were used to simulate firebrands; all with 4 g of smoldering brands deposited. The porosity of the different firebrand piles, the heat flux to an inert test surface, spatial measurements of surface temperature, and videos of the experiments were recorded and analyzed. It was found that the realistic fuels, i.e. pine bark and eucalyptus sticks, could achieve higher peak heat fluxes than artificial birch fuels at higher wind speeds, which exhibited little change with geometry. This change was not due to material makeup alone, but also the way in which the bulk density and height of the pile changed for different smoldering fuels.

中文翻译：

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火焰尺寸和几何形状对风下阴燃堆加热的影响

摘要 阴燃的火把可以长距离放出，很容易点燃现场火灾。这对荒地 - 城市界面 (WUI) 中的结构构成威胁，在那里，野火蔓延到社区内和社区内。本研究调查了火炬大小和组成对小规模风洞中从桩到接收表面的加热的影响。两种尺寸的带凹槽的桦木销和木盘，一种尺寸的圆柱形桦木销钉，两种长度的桉树枝和松树皮片用于模拟火把；全部用4克阴燃牌沉积。记录和分析了不同火种桩的孔隙率、惰性测试表面的热通量、表面温度的空间测量以及实验视频。发现现实的燃料，即 松树皮和桉树枝在更高的风速下可以达到比人造桦木燃料更高的峰值热通量，这几乎没有几何变化。这种变化不仅是由于材料组成，而且还与不同阴燃燃料的堆积密度和高度发生变化的方式有关。