بررسی عددی اثر مکان پیلوت بر بلندشدگی شعله جت آشفته با سطوح مختلف ناهمگنی در محفظه احتراق

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشجوی دکترای دانشگاه کاشان

2 عضو هیات علمی دانشکده مهندسی مکانیک - دانشگاه کاشان

چکیده

احتراق مخلوط واکنش‌دهنده‌های ناهمگن نوعی از احتراق است که در آن اختلاط سوخت و هوا به­طور کامل انجام نمی ­شود. این تحقیق به بررسی عددی اثر مکان پیلوت بر بلندشدگی شعله جت آشفته با سطوح مختلف ناهمگنی در محفظه احتراق پرداخته است. در این بررسی عددی، از مدل‌سازی معادلات ناویراستوکس به­روش میانگین‌گیری رینولدز و مدل‌سازی آشفتگی k-ε استاندارد و مدل‌سازی جریان واکنشی روش اتلاف گردابه‌ای EDC استفاده ‌شده است. مشاهدات نشان می‌دهد که ارتفاع بلندشدگی شعله با افزایش طول ناهمگنی کاهش یافته و در طول ناهمگنی مشخصی که وابسته به نسبت هم­ارزی و مکان پیلوت است، شعله به پایه می­ چسبد. در تمام حالات مورد بررسی، محدوده­ای از طول­ های ناهمگنی یافت شد که در این طول­ها شعله چسبیده بود. نتایج نشان می‌دهد که ارتفاع بلندشدگی شعله در حالت غیرپیش­مخلوط بیشتر از حالتی است که مخلوط سوخت و هوا به‌صورت تقریباً پیش­مخلوط در محفظه مشتعل می‌شوند. هرچه نسبت هم‌ارزی افزایش پیدا می‌کند، ارتفاع بلندشدگی کمتر می‌شود. براساس سه مکان مورد بررسی در دیوار جانبی برای مکان پیلوت و نتایج به­دست­آمده، پیلوتی که در محدوده وسط دیوار جانبی بود ارتفاع بلندشدگی کمتر و محدوده چسبیدن شعله بیشتری داشت. همچنین، ناحیه شعله در داخل محفظه با تغییر طول ناهمگنی تغییر می‌کند.
 

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Numerical study of The effect of Pilot place on turbulent flame lift off with different levels of inhomogeneity in combustion chamber

نویسنده [English]

  • hossein honardar 1
1 Phd candidate, Mechanical Engineering, Kashan
چکیده [English]

Combustion of a mixture of inhomogeneity reactants is a type of combustion in which the mixing of fuel and air is not complete. This study investigated the numerical effect of the pilot location on the turbulent jet flame lift off height with different levels of inhomogeneity in the combustion chamber. The effect of different equevalence ratios has also been investigated. In this numerical study, the configuration modeling of Navier Stokes equations using Reynolds averaging method, standard k-ε turbulence and reactive flow modeling of Eddy Dissipation Concept (EDC) method have been used. Observations show that the flame lift off height decreases with increasing inhomogeneity length and the flame attach during a certain inhomogeneity length, which depends on the equevalence ratio and pilot location. In all of the cases studied, a range of inhomogeneity lengths was found during which the flame was attached. The results show that the flame lift off height in nonpremixed mode is higher than in the case where the fuel-air mixture ignites almost premixed in the chamber. The higher the equevalence ratio, the lower the flame lift off height. Based on the three locations studied in the side wall for the pilot location and the results obtained, the pilot in the middle area of the side wall had a lower flame lift off height and a higher attached flame range. Also, the flame area inside the chamber changes as the inhomogeneity changes.

کلیدواژه‌ها [English]

  • pilot
  • Inhomogeneity
  • Turbulent Combustion
  • lift off height
  • Combustion chamber
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