ÇOK PÜSKÜRTMELİ DİREKT ENJEKSİYONLU DİZEL BİR MOTORDA ENJEKSİYON STRATEJİLERİNİN YANMA KARAKTERİSTİKLERİ VE KİRLETİCİ EMİSYONLAR ÜZERİNDEKİ ETKİLERİNİN ANALİZİ

Direk enjeksiyonlu dizel bir motorda çok püskürtmeli yakıt enjeksiyonu ve farklı püskürtme açılarının yanma karakteristikleri ve emisyon oluşumuna etkilerini açıklamak amacıyla gelişmiş HAD simülasyonu gerçekleştirilmiştir. AVL-FIRE yazılımı kullanılarak silindir içi basınç, sıcaklık, ısı salınım oranı, yanma süreci ve emisyon oluşumları farklı püskürtme açıklarında gösterilmiştir. Yanma modeli olarak gelişmiş ECFM-3Z model kullanılmış olup, NO ve İs oluşumları için sırasıyla gelişmiş Zeldovich ve Kinetik modeller kullanılmıştır. Sayısal simülasyonlar, silindir içi basınç ve ısı salınım oranına bağlı deneysel verilerle doğrulandıktan sonra, püskürtme açısının etkisinin incelenmesi için geliştirilmiştir. Sayısal çalışmalarla silindir içi basınç ve ısı salınım oranının 120º ve 160º püskürtme açılarında kısmen artığı gözlenmiştir. Kütlesel NO oranı 150º püskürtme açısında en düşük olarak elde edilirken, kütlesel İs oranı 120º ve 160º püskürtme açılarında en düşük sonucu vermiştir. Tüm simülasyon konfigürasyonları yanma stroku boyunca silindir içi etkileri anlamak için gerçekleştirilmiştir. Elde edilen sonuçlar yanma sürecini etkileyecek ve yeni nesil emisyonları tamamen değiştirecek kadar önemlidir.

Anahtar Kelimeler:

Çoklu püskürtme, Dizel yanması, Kirletici Emisyonlar, HAD simülasyonu

ANALYSIS THE EFFECTS OF INJECTION STRATEGIES ON COMBUSTION CHARACTERISTICS AND POLLUTANT EMISSIONS IN A MULTIPLE DIRECT INJECTION DIESEL ENGINE

An advanced CFD simulation has been performed to explore different spray cone angles and multiple-fuel injection on combustion characteristics and emission formations in a DI-diesel engine. The in-cylinder pressure, temperature, heat release rate, combustion progresses and formation of emissions are simulated at different spray cone angles with AVL-FIRE code. An improved version of the ECFM-3Z combustion model has been applied and coupled with advanced Zeldovich and Kinetic models for NO and soot formation, respectively. After the validation of cylinder pressure and heat release rate experimental engine tests, further numerical simulations were performed to investigate the effects of spray cone angles. It has been determined that the cylinder peak pressure and heat release rate were slightly increased by 120° and 160° spray cone angles. The NO mass fraction is the lowest at a spray angle of 150°, while the soot mass fraction is the lowest at spray cone angles of 120° and 160°. Simulations of all configurations were subsequently performed to understand the effects of in-cylinder parameters during the combustion stroke. These results are significant enough to affect the combustion process and completely change the next generation of emissions.

Keywords:

Multiple injections, Diesel combustion, Pollutant emissions, CFD simulation,

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