Effective Lewis number of smoldering spread over a thin solid in a narrow channel
Effective Lewis number of smoldering spread over a thin solid in a narrow channel
复制标题
DOI：
10.1016/j.proci.2016.06.159
复制
发表时间：
2017
期刊：
影响因子：
--
通讯作者：
K. Kuwana;Kenta Suzuki;Y. Tada;G. Kushida
中科院分区：
文献类型：
--
作者：
K. Kuwana;Kenta Suzuki;Y. Tada;G. Kushida
当固体在两块平行板之间的狭窄通道中燃烧时，发生阴燃燃烧。由于阴燃锋的不稳定性，形成了指状结构。本文的目的是修改Kagan和Sivashinsky提出的理论，并通过将其预测与实验数据进行比较来评估其有效性。在Kagan-Sivashinsky理论中增加了一个与通道高度有关的热损失项，因为通道高度对指进不稳定性有影响。然后进行线性稳定性分析，导致有效的刘易斯数的定义，这是建议的管理参数。进行了一系列的实验，其中通道高度，氧化剂的速度，和氧气浓度的变化。获得的指法模式进行量化的图像分析，平均手指宽度，烧伤的分数，和指尖分裂的数量计算在每个实验条件下。证实了所有的实验数据都可以用单一的参数来表示，即，有效刘易斯数。此外，理论预测的指宽与实验数据相当吻合。
Smoldering combustion occurs when a solid is burned in a narrow channel between two parallel plates. A fingering pattern is then formed owing to the instability of smoldering front. The objective of this paper is to modify the theory proposed by Kagan and Sivashinsky and assess its validity by comparing its predictions with experimental data. A heat loss term that depends on channel height is newly added to the Kagan-Sivashinsky theory because the channel height is known to influence fingering instability. A linear stability analysis is then conducted, leading to the definition of an effective Lewis number, which is proposed to be the governing parameter. A series of experiments are conducted in which channel height, oxidizer velocity, and oxygen concentration are varied. Obtained fingering patterns are quantified by image analysis; the average finger width, the fraction burned, and the number of fingertip splits are calculated under each experimental condition. It is confirmed that all the experimental data can be expressed by the single parameter, i.e., the effective Lewis number. Further, theoretically predicted finger width agrees reasonably well with experimental data.