Lower limit of weak flame in a heated channel
Lower limit of weak flame in a heated channel
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DOI：
10.1016/j.proci.2008.06.151
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
Y. Tsuboi;T. Yokomori;K. Maruta
中科院分区：
文献类型：
--
作者：
Y. Tsuboi;T. Yokomori;K. Maruta
对加热中尺度通道内的稳态和非稳态火焰响应进行了实验和计算研究。特别注意火焰稳定性，特别是弱火焰区下限的存在。先前的微燃烧方法与外部热源，以形成固定的温度梯度在通道壁。实验证实了高、低速区的正常稳定火焰和中速区的非稳态动态火焰（FREI）。除此之外，还首次从实验上确定了弱火焰区的下限。在这样弱的火焰中测得的温度增加被发现接近于零度。有人发现，在弱火焰制度的下限的火焰温度对应于所采用的混合物的点火温度。详细的化学和输运性质的一维计算显示出ε形曲线，该曲线与先前的S形曲线相比具有额外的最低速度区。计算结果全面地支持和解释了目前的实验结果表明，弱火焰区的下限是由弱反应引起的，由于不频繁的分子碰撞扩散质量耗散在极低的速度区。
Stationary and non-stationary flame responses in a heated meso-scale channel were investigated both experimentally and computationally. Special attention was paid to flame stabilities, particularly the existence of lower limit of weak flame regime. Previous microcombustion methodology with an external heat source to form stationary temperature gradient in the channel wall was employed. Normal stable flames at high and low velocity regimes, and non-stationary dynamic flames (FREI) at moderate velocity regime were confirmed experimentally. In addition to them, the lower limit of weak flame regime was experimentally identified for the first time. Measured temperature increase in such weak flame was found to be approaching to nearly zero degree. It was found that the flame temperature at the lower limit of the weak flame regime corresponds to ignition temperature of the employed mixture. One-dimensional computations with detailed chemistry and transport properties exhibited ε-shaped curve which has additional lowest velocity regime with previous S-shaped curve. Computational results comprehensively support and interpret the present experimental results indicating that the lower limit of weak flame regime is induced by the weakened reaction due to less frequent molecular collisions by diffusive mass dissipation at extremely low velocity regime.