سوخت و احتراق

سوخت و احتراق

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
بهرام جعفری 1
مهدی صدیق 2
سید مصطفی میرسلیم 3
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
10.22034/jfnc.2021.275881.1270
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
احتراق اشتعال تراکمی واکنش کنترل‌شده
گاز سنتز
محفظه احتراق
زمان‌بندی پاشش مستقیم دیزل
آلایندگی
بازده ناخالصی اندیکاتوری

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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