بررسی عددی تاثیر افزودن دی‌متیل‌اتر به متان بر عملکرد و آلایندگی موتور اشتعال تراکمی شارژ همگن

نوع مقاله: مقاله پژوهشی

نویسندگان

دانشگاه صنعتی نوشیروانی بابل

چکیده

احتراق اشتعال تراکمی شارژ همگن،  به­دلیل بازده حرارتی بالا و آلایندگی کم، به­عنوان نسل جدید موتورهای احتراق داخلی مورد توجه قرار گرفته است. کنترل این نوع احتراق دشوار است، زیرا این امر توسط سینتیک شیمیایی مخلوط هوا و سوخت صورت می­گیرد. در این مطالعه، یک مخلوط همگن از گاز طبیعی و هوا در یک موتور اشتعال تراکمی برای کاهش انتشار اکسیدهای نیتروژن و بهبود بهره­وری حرارتی استفاده و  برای کنترل زمان اشتعال و احتراق، مقدار کمی دی متیل اتر با گاز طبیعی مخلوط شد. یک مدل دینامیک سیالات محاسباتی سه بعدی همراه با سینتیک شیمیایی برای بررسی اثر دما، فشار، نسبت هم­ارزی بر احتراق و آلایندگی موتور اشتعال تراکمی سوخت همگن استفاده شد. نتایج شبیه­سازی نشان دادند با استفاده از این مخلوط می­توان موتور را در یک محدوده بار گسترده راه­اندازی کرد و با افزودن مقدار محدودی دی متیل اتر بازده حرارتی را افزایش داد. از نتایج مهم دیگر این مطالعه می­توان به بهبود زمان شروع احتراق، افزایش بیشینه فشار و کاهش چشمگیر انتشار اکسیدهای نیتروژن در اثر افزودن دی متیل اتر اشاره کرد.
 

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

The effect of adding DME to methane on HCCI combustion performance and emissions

نویسندگان [English]

  • hosein ezoji
  • Rouzbeh Shafaghat
  • Omid Jahanian
Department of Energy Conversion, Faculty of Mechanical Engineering, Babol Noshirvani University of Technology, Babol, IRAN
چکیده [English]

Homogeneous charge compression ignition (HCCI) is regarded as the next generation combustion trend in terms of high thermal efficiency and low emissions. It is difficult to control autoignition and combustion because they are controlled primarily by the chemical kinetics of air/fuel mixture. In this study, a homogeneous mixture of natural-gas and air was used in a compression ignition engine to reduce NOx emissions and improve thermal efficiency. In order to control ignition timing and combustion, a small amount of Dimethyl Ether (DME) was mixed with the natural-gas. In this paper, a multi-dimensional computational fluid dynamics (CFD) model coupled with chemical kinetics mechanisms was applied to investigate the effects of various temperatures, pressures, equivalence ratios and fuel compositions on the combustion performance and emission characteristics of an HCCI engine. The mixture could run the engine quietly and smoothly over a wide range of loads. Under the present test conditions, finite amount of DME was necessary in order to achieve ignition of the mixture. In addition, thermal efficiency was higher than that of methane fueled engine, when the DME proportion was optimized. NOx emissions were extremely low, however, the emissions of total unburned hydrocarbon were high.
 

کلیدواژه‌ها [English]

  • "HCCI"
  • "DME"
  • "fuel component"
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