کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
168861 457957 2015 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Development and application of CN PLIF for single-shot imaging in turbulent flames
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی مهندسی شیمی (عمومی)
پیش نمایش صفحه اول مقاله
Development and application of CN PLIF for single-shot imaging in turbulent flames
چکیده انگلیسی

A laser-induced fluorescence concept for improved interference-free imaging detection of the cyano radical (CN), an intermediate species in nitrogen combustion chemistry, has been investigated. Both a standard Nd:YAG-pumped dye laser and a solid-state alexandrite laser were employed for excitation of CN B–X (1–0) lines near 359 nm in combination with detection of the (1–1) band near 387 nm, providing a direct comparison of interferences and achievable detection sensitivity. Measurements in ammonia-doped premixed methane–air flames showed that the alexandrite laser, with longer pulse duration (∼30 ns) and broader line width (2.5 cm−1), can provide around 4 times stronger CN signal than that achievable with conventional Nd:YAG pumped dye laser system. Enhanced CN detection using alexandrite laser excitation is demonstrated that signal-to-noise ratio ∼5 is achieved for single-shot fluorescence imaging at conditions with CN concentration levels experimentally estimated to be a few hundred ppbs. This improved detection sensitivity, however, might still not be sufficient for pure methane/air flames due to low CN concentration. Observations of local extinction, represented by CN layer dis-continuation, in turbulent flames suggest that the improved CN detection will be useful for deepened understanding of interactions between fuel-nitrogen chemistry and local turbulent transport in combustion.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Combustion and Flame - Volume 162, Issue 2, February 2015, Pages 368–374
نویسندگان
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