Numerical study on ultra-lean rotating counterflow twin premixed flame of hydrogen-air
Numerical study on ultra-lean rotating counterflow twin premixed flame of hydrogen-air
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氢-空气超稀旋转逆流双预混火焰数值研究
DOI：
10.1016/j.proci.2012.07.036
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
Makihito Nishioka
中科院分区：
文献类型：
--
作者：
Akane Uemichi;Makihito Nishioka
为了探索超贫燃烧的可能性，采用详细化学方法对氢气-空气旋转逆流双预混火焰进行了数值模拟。结果，发现实现了当量比Φ=0.052的超贫RCTF，其远比通常公认的可燃性极限Φ=0.10贫。还发现，在超贫条件下，RCTF的火焰温度大大超过绝热火焰温度;例如，当Φ=0.06时，前者为1171 K，后者为503 K。燃烧气体温度的这种增加归因于可燃极限内的所谓低刘易斯数效应，但在超贫条件下，一些其它的增加温度的机制是占主导地位的。RCTF的燃烧气体的“伪局部当量比”与未燃烧气体的“伪局部当量比”有很大不同，这是由于H2O的浓度非常高。这表明反应区的局部条件比未燃烧的气体富得多，这导致了大的温度升高。
Rotating counterflow twin premixed flame (RCTF) of hydrogen air was numerically simulated with detailed chemistry to explore the possibility of ultra-lean combustion. As a result, it was found that ultra-lean RCTF of equivalence ratio Φ=0.052, which is far leaner than the generally-recognized flammability limit Φ=0.10, is realized. It was also found that under ultra-lean conditions the flame temperature of RCTF largely exceeds the adiabatic flame temperature; e.g., at Φ=0.06 the former is 1171K, while the latter is 503K. This increase of burned gas temperature is attributed to the so-called low Lewis number effect within the flammability limit, but under an ultra-lean condition some other mechanism to increase temperature is dominant. The “pseudo local equivalence ratio” of burned gas of RCTF differs largely from that of the unburned gas due to the extraordinarily high concentration of H2O. This suggests the possibility that the local condition at the reaction zone is much richer than the unburned gas, which brings about the large temperature increase.