مطالعه‌ی عددی تاثیرات زمان‌بندی و به‌کارگیری راهبرد سوراخ گروهی جهت پاشش سوخت در یک موتور اشتعال تراکمی

نوع مقاله: مقاله پژوهشی

نویسندگان

1 گروه مهندسی مکانیک، دانشکده فنی و مهندسی، دانشگاه آیت الله بروجردی، بروجرد، ایران

2 دانشکده فنی و مهندسی، دانشگاه آیت الله بروجردی، بروجرد، ایران

3 دانشکده مهندسی مکانیک، دانشگاه تبریز، تبریز، ایران

چکیده

در این مطالعه عددی، تأثیرات زمان ­بندی پاشش مستقیم سوخت دیزل و به­ کارگیری راهبرد سوراخ گروهی با زاویه واگرایی 10 درجه بر مشخصه ­های احتراق و قطره­ سازی ذرات سوخت، میزان آلاینده­ های منتشرشده و سطح عملکرد در یک موتور اشتعال تراکمی سنگین بررسی شده است. برای شبیه­ سازی احتراق، از مکانیزم سنتیک شیمیایی کاهش‌یافته با 61 گونه و 296 واکنش استفاده شده است. طبق نتایج، با کاهش طول دوره تأخیر در اشتعال بیشتر جرم سوخت در حالت نفوذی سوخته، فرایند احتراق تضعیف‌ شده و در نتیجه میزان آلاینده ذرات دوده افزایش و سطح عملکرد موتور کاهش‌‌یافته است. همچنین، با تعویق زمان بندی پاشش سوخت دیزل همزمان با افزایش فشار و دمای محفظه احتراق، لزجت جریان درون سیلندر افزایش و ضریب نسبی پخش کاهش یافته است. با کاهش عرض افشانه، ذرات سوخت دیزل در ناحیه باریک ‏تری افشانده شده و به­ دلیل تراکم ناحیه­ ای افشانه، ذرات سوخت بیشتری باهم برخورد کرده‌اند. در ادامه، به‏ دلیل افزایش حجم لختگی، ذرات دوده افزایش یافته است. علاوه ­بر این، به­ کارگیری راهبرد سوراخ گروهی می­تواند باعث بهبود فرایند اکسایش ذرات سوخت و همچنین بهبود عملکرد موتور شده، ولی بااین‌حال، افزایش آلاینده­ هیدروکربن­ های نسوخته در مقایسه با حالت تک سوراخه از معایب به‌کارگیری این راهبرد پاشش سوخت است.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Numerical Study of the Effects of Injection Timing and Using Group-Hole Nozzle for Fuel Injection in a Compression Ignition Engine

نویسندگان [English]

  • Mohammad Javad Noroozi 1
  • Mahdi Seddiq 2
  • Hesamedin Habibi 3
1 Department of Mechanical Engineering, Faculty of Engineering, Ayatollah Ozma Borujerdi University, Boroujerd, Iran
2 Department of Mechanical Engineering, Ayatollah ozma Borujerdi University, Borujerd, Iran
3 Department of Mechanical Engineering, Tabriz University, Tabriz, Iran
چکیده [English]

In 
degrees as divergence angle on combustion and fuel atomization characteristics, pollutant emissions, and performance in a heavy duty diesel engine have been investigated. Regarding compression ignition combustion simulation, a chemical kinetic mechanism consists of 61 species, and 296 reactions have been used. Results showed that with a decrease in ignition delay duration, most of the fuel burnt in diffusive mode, combustion process weakened, PM increased, and engine performance deteriorated. Also, by retarding the diesel injection timing simultaneous with an increase in in-cylinder pressure and temperature, relative span factor has been decreased. With the reduction of fuel spray width, diesel fuel droplets sprayed in a narrower region, and due to the high density of the spray region, more fuel droplets collide. In the following because of the increase in coagulation volume, PM increased. Furthermore, using group-hole nozzle strategy can improve fuel oxidation process but results in more UHC emission compared with the baseline case which must be considered as a disadvantage of using group hole nozzle concept.

کلیدواژه‌ها [English]

  • Combustion simulation
  • Injection Timing
  • Group-hole nozzle
  • Engine Performance
  • Pollutants
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