مطالعه تأثیر دمای دیواره و ساختار اکسنده بر توزیع دما و ناکس کوره احتراق غیرپیش‌آمیخته

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشجوی دکتری دانشگاه کاشان، کاشان، ایران

2 کاشان-کیلومتر 6 بلوار قطب راوندی-دانشگاه کاشان-دانشکده مهندسی- گروه مهندسی مکانیک

3 دانشگاه تربیت مدرس، دانشکده مهندسی مکانیک

چکیده

هدف از مطالعه حاضر بررسی تأثیر شرایط حرارتی حاکم بر دیواره کوره و ساختار اکسنده بر انتشار آلاینده ناکس و شرایط دمایی داخل کوره احتراق غیرپیش‌آمیخته است. بدین منظور شبیه‌سازی کوره احتراق غیرپیش‌آمیخته با استفاده از نرم افزار اپن‌فوم انجام شده است. در شبیه‌سازی‌های عددی از مدل آشفتگی کی- اپسیلون استاندارد، مدل احتراقی مفهوم اتلاف گردابه اصلاح شده و مدل تشعشعی فاز گسسته استفاده شده است. همچنین به‌منظور تحلیل نتایج حاصل از شبیه‌سازی‌های عددی، محاسبات شیمیایی با استفاده از واکنشگاه کاملاً مخلوط مورد توجه قرار گرفته است. مطابق با نتایج، افزایش دمای دیواره کوره تا رسیدن به شرایط عایق حرارتی منجر به افزایش قابل توجه دمای متوسط و بیشینه درون محفظه احتراق گردیده و رژیم احتراقی را از بدون شعله به دما بالا منتقل می‌کند. علاوه‌بر این جایگزینی دی‌اکسید کربن با نیتروژن همراه با کاهش دمای محفظه احتراق به علت تفاوت‌های فیزیکی و شیمیایی این دو گونه خواهد بود. براساس نتایج، افزایش دمای دیواره با وجود کاهش اتلاف حرارتی منجر به افزایش ناکس در رژیم احتراقی دما بالا می‌گردد. استفاده از دی‌اکسید کربن به جای نیتروژن در ساختار اکسنده می‌تواند روشی راهگشا در کاهش اتلاف حرارتی همزمان با کاهش ناکس منتشر شده از کوره احتراق غیرپیش‌آمیخته مورد توجه قرار گیرد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Study of The Effect of Wall Temperature and Oxidant Structure on Temperature Distribution and NO Emission in Non-Premixed Combustion Furnace

نویسندگان [English]

  • Amin Tajdani 1
  • seyed abdolmehdi hashemi 2
  • Esmaeil Ebrahimi Fordoei 3
1 PhD Student of Kashan University, Kashan, Iran
3 Faculty of Mechanical Engineering , Tarbiat Modares University
چکیده [English]

The aim of this study was to investigate the effect of the thermal condition of furnace wall and oxidant structure on NOx emission and thermal conditions inside the non-premixed combustion furnace. For this purpose, non-premixed combustion furnace simulations have been performed using OpenFOAM software. Standard k-ε turbulence model, modified eddy dissipation concept combustion model, and discrete ordinates radiation model are used in numerical simulations. In order to analyze the results of numerical simulations, chemical calculations using a well stirred reactor have also been considered. According to the results, increasing the furnace wall temperature to reach thermal insulation conditions leads to a significant increase in the average and maximum temperature inside the combustion chamber and transfers the combustion regime from flameless to high temperature. In addition, the replacement of carbon dioxide with nitrogen will be accompanied by a decrease in the combustion temperature due to physical and chemical differences between the two species. According to the results, increasing the wall temperature, despite reducing the heat loss, leads to an increase in NOx in the high temperature combustion regime. The use of carbon dioxide instead of nitrogen in an oxidizer can be considered as a way to reduce heat loss while reducing NOx emission from the non-premixed combustion furnace.

کلیدواژه‌ها [English]

  • NOx
  • Wall temperature
  • Oxidant structure
  • Combustion regime
  • Non-premixed combustion
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