پخش سوخت مایع در محفظه احتراق از طریق برخورد جت با موانع استوانه ای کوچک

نوع مقاله: مقاله پژوهشی

نویسندگان

1 حرارت و سیالات، مکانیک، تربیت دبیر شهید رجایی،تهران، ایران

2 حرارت و سیالات، مکانیک، تربیت دبیر شهید رجایی، تهران، ایران

چکیده

همگن­ سازی یک مخلوط رقیق از سوخت و هوا باعث می ­شود دمای جبهه شعله کاهش پیدا کرده و به‌طورهم­زمان باعث کاهش تولید اکسیدهای نیتروژن و ذرات معلق می­ شود. کارهای تجربی نشان داده است که سطح بالایی از پراکندگی برای رسیدن به مخلوط همگن را می ­توان با برخورد جت دیزل بر روی یک سری از موانع استوانه­ ای، به­ عنوان ساختار نزدیک به محیط متخلخل، به ­دست آورد. سوخت تزریق­ شده با اولین مانع استوانه ای برخورد می ­کند و به دو جت کوچک­تر تقسیم می­شود. سپس، با برخورد با موانع بعدی جت چندتایی به ­وجود آمده که باعث پخش سوخت می ­شود. کارهای تجربی قبلی نشان داده­ اند که ساختار هندسی و قطر موانع از عوامل اصلی در شکل­ گیری چند جت و توزیع فضایی سوخته­ اند. در این مقاله، مدل‌های دینامیک سیالات محاسباتی، که با دقت رفتار شکل­ گیری چند جت گذرا را پیش ­بینی می­ کنند، توسعه می­ یابد و پس از اعتبارسنجی ساختارهای جدیدی از موانع با افزایش فاصله بین آن‌ها و یک ساختار بهبودیافته ارائه‌ شده است. مدل­ سازی جدید نشان می‌دهد که این ساختارها، نسبت ­به ساختارهایی که قبلاً مورد بررسی قرار گرفته‌اند، دارای ویژگی­های همگن‌سازی بهتر بوده و توزیع فضای در آن‌ها کارآمدتر است.  

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

liquid fuel distribution in the combustion chamber by jet impingement with small cylindrical obstacles

نویسندگان [English]

  • Saeed Kazemi Seresht 1
  • arash mohammdi 2
2 Heat and Fluids, Mechanics, Shahid Rajaee Teacher Training , Tehran, Iran
چکیده [English]

Homogenization of lean air-fuel mixture decrease flame front temperature and simultaneously reduces NOx and particulate matter. Experimental work has been shown high level of dispersion can be obtained by impingement of diesel jet onto a matrix of cylindrical obstacles in accordance structure close to Porous media. The injected fuel impinges with the first cylindrical obstacle and splits to two smaller jets and with impingement with other obstacles causes to multi-jets formation causes to fuel dispersion. Previous experimental works have been shown geometrical structure and obstacle diameter are of key factors in multi‐jet formation and spatial distribution of the charge. In this paper, computational fluid dynamics models that accurately predict the formation behavior of several transient multi-jet are developed, and after validation, new structures of obstacles with increasing distances between them and an improved structure are proposed as novel innovations. New modeling shows that these structures have better homogenization properties and space distribution is more efficient than the structures previously studied. Also, with increasing the distance between the cylindrical obstacles, the diffusion and penetration of some fuel jets has increased and for all geometrical structures, it has increased the fuel distribution angle. The geometrical structure of the obstacles is very important to achieve the proper fuel distribution pattern and is not dependent on the number of obstacles.

کلیدواژه‌ها [English]

  • Diesel spray
  • Mixture formation
  • small cylindricals
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