بررسی عددی هندسه محفظه احتراق و بکارگیری گاز سنتز در یک موتور اشتعال تراکمی واکنش کنترل شده سنگین کار غیر جاده ای

نوع مقاله : مقاله پژوهشی

نویسندگان

1 استادیار دانشکده مهندسی فناوریهای نوین- دانشگاه تخصصی فناوریهای نوین آمل

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

3 استادیار، دانشکده مهندسی مکانیک، دانشگاه صنعتی امیرکبیر، تهران

چکیده

این مطالعه عددی با استفاده از کد دینامیک سیالات محاسباتی CONVERGE انجام شده است و به ارزیابی اثرهای هم­ زمان و جداگانه زمان­بندی پاشش مستقیم دیزل (16 تا 6 درجه میل­لنگ قبل از نقطه مرگ بالا با گام   2 درجه)، هندسه محفظه احتراق (مقعری (حالت پایه)، استوانه­ ای و کم­ عمق عریض)، و به­ کارگیری گاز سنتز (20 و 40 درصد کل انرژی سوخت در هر چرخه) در یک موتور غیرجاده­ای کار سنگین اشتعال تراکمی واکنش کنترل­ شده پرداخته است. برای شبیه­ سازی فرایند احتراق، از الگوی SAGE در کنار یک سازوکار سنتیک شیمیایی دقیق متشکل­ از 72 گونه و 360 واکنش استفاده شده است. نتایج نشان داده است در شرایط پایه کارکردی (زمان­ بندی پاشش 10 درجه میل­لنگ قبل از نقطه مرگ بالا و استفاده از کاسه پیستون مقعری) افزایش نسبت انرژی گاز سنتز به دیزل تا 40% باعث افزایش اتلاف حرارتی تا 4/3 درصد و کاهش هم­ زمان آلاینده ­های اکسیدهای ازت تا 12%، ذرات دوده حدود 88%، و هیدروکربن­ های نسوخته به مقدار تقریبا 82% در مقایسه با حالت پایه احتراق دیزل خالص شده است. علاوه ­بر این، به­ کارگیری هندسه کم عمق عریض به همراه پاشش سوخت دیزل در 16 درجه میل­لنگ قبل از نقطه مرگ ­بالا در شرایط کارکردی احتراق دیزل-گاز سنتز 40% باعث افزایش انتقال حرارت اتلافی (%7)، احتراق ناقص (%2/5) و همچنین کاهش هم­زمان اکسیدهای ازت (%3)، ذرات دوده (%37)، هیدروکربن­های نسوخته (%62)، و بازده ناخالصی اندیکاتوری (%4/7) در مقایسه با حالت پایه کارکردی احتراق دیزل خالص می ­شود.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Computational evaluation of the combustion chamber geometry and applying syngas in a heavy-duty off-road Reactivity Controlled Compression Ignition (RCCI) engine

نویسندگان [English]

  • bahram jafari 1
  • Mahdi Seddiq 2
  • Seyyed Mostafa Mirsalim 3
1 Faculty of Engineering Modern Technologies, Amol University of Special Modern Technologies (AUSMT
2 Department of Mechanical Engineering, Faculty of Engineering, Ayatollah Boroujerdi University, Borujerd, Iran
3 Department of Mechanical Engineering, Amirkabir University, Tehran, Iran
چکیده [English]

This numerical research conducted using CONVERGE Computational Fluid Dynamic (CFD) code and devoted to assessing the simultaneous and separate impacts of Diesel Direct Injection Timing (DDIT) (16 to 6 Crank Angle (CA) Before Top Dead Center (BTDC) with 2 CA steps), combustion chamber geometry (re-entrant (baseline), cylindrical, and wide-shallow chamber), and applying syngas (20 and 40% of total energy per cycle) in a heavy-duty off-road RCCI engine. In the case of combustion simulation, the SAGE combustion model was used coupled with a detailed chemical kinetic mechanism consist of 72 species and 360 reactions. Results showed that under baseline operating conditions (DDIT of 10 CA BTDC and using re-entrant piston bowl) increasing the syngas to diesel ratio up to 40% caused a 3.4% rise in heat transfer loss and simultaneous reduction in Nitrogen Oxides (NOx) about 12%, Particulate Matter (PM) up to 88%, and Hydro-Carbons (HCs) nearly 82% compared to Pure Diesel Combustion (PDC) conditions. Besides, utilizing the wide-shallow combustion chamber along with diesel injection at 16 CA BTDC at diesel- 40% syngas combustion operating conditions led to the increment of heat transfer loss (7%), combustion loss (2.5%), and also, simultaneous reduction of NOx (3%), PM (37%), HC (62%), and gross indicated efficiency (4.7%) compared to baseline PDC case.

کلیدواژه‌ها [English]

  • RCCI combustion
  • Syngas
  • Combustion chamber
  • Diesel injection timing
  • Emission
  • Gross indicated efficiency

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سوخت و احتراق
دوره 14، شماره 1 - شماره پیاپی 34
فروردین 1400
صفحه 117-143

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سابقه مقاله

  • تاریخ دریافت: 12 اسفند 1399
  • تاریخ بازنگری: 07 اردیبهشت 1400
  • تاریخ پذیرش: 11 اردیبهشت 1400

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