Numerical analysis of laminar diffusion flames—Effects of preferential diffusion of heat and species
Numerical analysis of laminar diffusion flames—Effects of preferential diffusion of heat and species
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DOI：
10.1016/0010-2180(94)90157-0
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发表时间：
1994
影响因子：
4.4
通讯作者：
T. Takagi;Zhenliang Xu
中科院分区：
文献类型：
--
作者：
T. Takagi;Zhenliang Xu
对轴对称层流射流扩散火焰进行了数值计算，考虑了详细的化学动力学和多组分扩散。计算结果与Ishizuka和Sakai获得的氢气/甲烷/氮气同向流动火焰中的温度和组分浓度的实验结果吻合较好。结果表明，热和组分的优先扩散导致了火焰中大量的过量和亏损的热焓，以及H_2摩尔分数的增加和减少。这些影响导致上游区域的火焰温度高于原始燃料的最高绝热温度，而火焰尖端附近的温度显著降低。H_2摩尔分数的降低和优先扩散导致的火焰尖端过剩热焓的降低可能是火焰尖端熄灭(火焰尖端张开)的合理原因。
Numerical computations were made of axisymmetric laminar jet diffusion flames, taking into account detailed chemical kinetics and multicomponent diffusion. The computations are in good agreement with the experimental results of temperature and species concentration in hydrogen/methane/nitrogen fuel flames with coflowing air obtained by Ishizuka and Sakai. It was shown that preferential diffusion of heat and species causes significant amount of excess and deficit of enthalpy, and also an increase and decrease of H2mole fraction in the flame. These effects result in higher flame temperature than the maximum adiabatic temperature for the original fuel in the upstream region, and significantly lower temperature near the flame tip. The temperature decrease induced by the decrease of H2mole fraction and decrease of excess enthalpy near the flame tip resulting from preferential diffusion is presumed to be the rational explanation for the flame tip extinction (flame tip-opening).