Appearance of target pattern and spiral flames in radial microchannels with CH4-air mixtures
Appearance of target pattern and spiral flames in radial microchannels with CH4-air mixtures
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DOI：
10.1063/1.2836670
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发表时间：
2008-02
影响因子：
4.6
通讯作者：
Sudarshan Kumar;K. Maruta;S. Minaev;R. Fursenko
中科院分区：
文献类型：
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作者：
Sudarshan Kumar;K. Maruta;S. Minaev;R. Fursenko
本文提出了在相距毫米级距离（≤5mm）的两个平行圆形石英板中心引入预混合甲烷-空气混合物形成旋转螺旋火焰的实验证据。两个板都经过外部加热，以在流动方向上产生正的壁温度梯度，类似于通过固体壁的热再循环，这是在微型燃烧器中获得稳定燃烧的必要条件。与径向位置处稳定的预混合火焰锋的一般看法相反，观察到多种非稳态火焰传播模式。对于较低的混合物流速和一定范围的混合物当量比，观察到径向火焰传播模式，同时在不同的径向位置处存在两个圆形火焰。对于较高的流速，观察到旋转螺旋火焰传播模式。除了径向和螺旋火焰传播模式外，还观察到随机和不对称的火焰振荡...
This paper presents the experimental evidence of the formation of rotating spiral flames with premixed methane-air mixtures introduced at the center of the two parallel circular quartz plates which are separated by a millimeter scale distance (≤5mm). Both plates are externally heated to create a positive wall temperature gradient in the flow direction to resemble heat recirculation through solid walls, which is a requisite to obtain stabilized combustion in microburners. Contrary to the general perception of a stable premixed flame front at a radial location, a variety of nonstationary flame propagation modes are observed. For lower mixture flow rates and a range of mixture equivalence ratios, a radial flame propagation mode is observed with simultaneous presence of two circular flames at different radial locations. For higher flow rates, a rotating spiral flame propagation mode is observed. In addition to radial and spiral flame propagation modes, random and unsymmetrical flame oscillations are also obse...