کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
168437 457925 2016 11 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Onset mechanism of primary acoustic instability in downward-propagating flames
ترجمه فارسی عنوان
مکانیزم شروع بی ثباتی صوتی اولیه در شعله های شعله ور انتشار یافته
کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی مهندسی شیمی (عمومی)
چکیده انگلیسی

This paper deals with the onset mechanism of primary acoustic instability of downward-propagating flames in a combustion tube. We focus on the effects of a coupling constant, βM, where β and M represent the Zel'dovich and Mach numbers, respectively, and the variation in the flame surface area. To change the coupling constant, various gas compositions for lean ethylene flames diluted with carbon dioxide or nitrogen are used. We obtain a linear relationship between the coupling constant and the average acoustic intensity, and the critical values of the coupling constants are acquired through linear approximation regarding the onset of the primary acoustic instability. Furthermore, we adopt the CO2 laser irradiation method to alter the shape of the flame front, and experimental results show that the variation in the flame surface area does not always cause spontaneous generation of the primary acoustic instability in initially non-vibrating flames. Furthermore, even in initially vibrating flat flames, the growth rate of the primary acoustic instability is not associated with the increase or decrease in the flame surface area in the present experiments. Finally, we also estimate the effects of acoustic losses on acoustic instability, and experimental results show that larger total acoustic losses tend to suppress acoustic vibration even at the same coupling constant.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Combustion and Flame - Volume 170, August 2016, Pages 1–11
نویسندگان
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