کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
645643 1457145 2015 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Effect of external surface emissivity on flame-splitting limit in a micro cavity-combustor
ترجمه فارسی عنوان
اثر تابش خارجی سطح بر روی شعله در یک حفره ریز
کلمات کلیدی
احتراق میکروسکوپ، حفره، محدود شدن شعله شعله از دست دادن حرارت، تجمع گرما،
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی جریان سیال و فرایندهای انتقال
چکیده انگلیسی
Heat transfer processes are of significance for combustion in microscale channel. In the present paper, three different values (i.e., ε = 0.1, 0.5 and 0.92) are selected to numerically investigate the effect of external surface emissivity on the flame-splitting limit (the critical velocity when the combustion efficiency drops to 80%) using Fluent 6.3. The results demonstrate that the flame-splitting limit has a negatively monotonic variation trend with the external surface emissivity. This feature is interpreted from viewpoints of heat-loss from the exterior wall and heat recirculation through the upstream wall. The analyses show that the heat-loss ratio decreases with the reduction of external surface emissivity, which gives rise to a more intense reaction in the cavity and a higher wall temperature level. Therefore, more heat is recirculated to upstream wall and a better preheating of the fresh mixture can be achieved. Consequently, the chain reactions of H2/air mixture start earlier and the reaction rates are much faster for a smaller surface emissivity. The combined actions of heat loss and heat recirculation lead to a faster consumption of the hydrogen fuel at the flame tip, and a larger flame-splitting limit can be obtained for a smaller surface emissivity.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Applied Thermal Engineering - Volume 83, 25 May 2015, Pages 8-15
نویسندگان
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