کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
7717681 1497474 2014 17 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Direct numerical simulation of lean premixed CH4/air and H2/air flames at high Karlovitz numbers
موضوعات مرتبط
مهندسی و علوم پایه شیمی الکتروشیمی
پیش نمایش صفحه اول مقاله
Direct numerical simulation of lean premixed CH4/air and H2/air flames at high Karlovitz numbers
چکیده انگلیسی
Three-dimensional direct numerical simulation with detailed chemical kinetics of lean premixed CH4/air and H2/air flames at high Karlovitz numbers (Ka ∼ 1800) is carried out. It is found that the high intensity turbulence along with differential diffusion result in a much more rapid transport of H radicals from the reaction zone to the low temperature unburned mixtures (∼500 K) than that in laminar flamelets. The enhanced concentration of H radicals in the low temperature zone drastically increases the reaction rates of exothermic chain terminating reactions (e.g., H + O2+M = HO2 + M in lean H2/air flames), which results in a significantly enhanced heat release rate at low temperatures. This effect is observed in both CH4/air and H2/air flames and locally, the heat release rate in the low temperature zone can exceed the peak heat release rate of a laminar flamelet. The effects of chemical kinetics and transport properties on the H2/air flame are investigated, from which it is concluded that the enhanced heat release rate in the low temperature zone is a convection-diffusion-reaction phenomenon, and to obtain it, detailed chemistry is essential and detailed transport is important.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: International Journal of Hydrogen Energy - Volume 39, Issue 35, 3 December 2014, Pages 20216-20232
نویسندگان
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