Yanma Verimi Yaklaşımıyla İkili Çevrim Analizi
Yanma Verimi Yaklaşımıyla İkili Çevrim Analizi
Dosyalar
Tarih
2009-06-17
Yazarlar
Karaman, Emre
Süreli Yayın başlığı
Süreli Yayın ISSN
Cilt Başlığı
Yayınevi
Fen Bilimleri Enstitüsü
Institute of Science and Technology
Institute of Science and Technology
Özet
Buharlı makinelerin yerini alan içten yanmalı motorlar, icat edilmelerinden günümüze kadar gelişmeler göstermiş, üzerlerinde sayısız bilimsel araştırmalar yapılmıştır. Önceleri bu araştırmalar sadece güç yoğunluğunu arttırma ve bakım giderlerini azaltma amaçlı olsa da, artan çevre kirliliği ve küresel ısınma gibi olgular yüzünden atık ısının ve egzoz gazlarının kontrolü gibi konuları da içermeye başlamıştır. İdeal hava çevrimleri olgusu ışığında pek çok verim analizleri yapılmış, olabildiğince gerçek duruma yakın modellemelerle mühendislik problemlerine çözümler aranmıştır. Bu düşünceden hareketle bu çalışmada model olarak kullanılan ikili ideal çevrim (dual cycle) teorisi anlatılmıştır. Sisteme enerji girişinin biri sabit hacimde, diğeri de sabit basınçta olmak üzere iki aşamalı olduğu kabul edilmiştir. Kullanılan teoriye göre, çevrimde kullanılabilen enerjinin, sisteme giren toplam enerjiye oranı yanma verimi olarak ifade edilmiştir. Bu yaklaşıma göre sisteme giren yakıtın tamamı yakılamamakta, bir kısmı kayıp olarak sistemden dışarı atılmaktadır. Çalışmanın beşinci bölümünde, ikili ideal çevrim simülatörü olarak kullanılan MATLAB yazılımı, çalışma prensibi ve yapılan kabullerden bahsedilmiştir. Altıncı bölümde yapılan analizlerde ise sıkıştırma oranı, yanma verimi, tersinmez iş, ısıl verim, basınç oranı ve kesme oranı gibi tanımların birbirleri üzerindeki etkileri incelenmiş ve sonuçlar grafikler halinde sunulmuştur.
Internal combustion engines which have superseded steam engines are being developed since they were invented and countless researches have been made about them. Previously, these researches only focused on increasing power/weight ratio and reducing maintenance costs. But after the importance of some facts like global warming and environmental pollution is realized, researchers became more interested in subjects like waste heat and exhaust gases control. Very large number of analysis have been made with an air standard cycle approach, and searched for solutions of engineering problems with using realistic models closest to the real operations. As a consequence of this, in this work, information and calculations are given about air standard dual cycle theory which is used as a model in this thesis. It is assumed that fuel energy is supplied into two separate sessions as one with constant volume and the other is with constant pressure. According to the theory, a parameter called combustion efficiency is defined as a ratio between usable fuel energy and total fuel energy. With this point of view, energy that supplied to the system can not be used totally but some part of it becomes a waste. In the fifth chapter of this work, information is given about the working principles of the MATLAB code that is used as a dual cycle simulator and also given the assumptions that are made. In analysis in sixth chapter, the relations of compression ratio, combustion efficiency, irreversible work, thermal efficiency, pressure ratio and cut-off ratio between each other has been examined and results are given by graphs.
Internal combustion engines which have superseded steam engines are being developed since they were invented and countless researches have been made about them. Previously, these researches only focused on increasing power/weight ratio and reducing maintenance costs. But after the importance of some facts like global warming and environmental pollution is realized, researchers became more interested in subjects like waste heat and exhaust gases control. Very large number of analysis have been made with an air standard cycle approach, and searched for solutions of engineering problems with using realistic models closest to the real operations. As a consequence of this, in this work, information and calculations are given about air standard dual cycle theory which is used as a model in this thesis. It is assumed that fuel energy is supplied into two separate sessions as one with constant volume and the other is with constant pressure. According to the theory, a parameter called combustion efficiency is defined as a ratio between usable fuel energy and total fuel energy. With this point of view, energy that supplied to the system can not be used totally but some part of it becomes a waste. In the fifth chapter of this work, information is given about the working principles of the MATLAB code that is used as a dual cycle simulator and also given the assumptions that are made. In analysis in sixth chapter, the relations of compression ratio, combustion efficiency, irreversible work, thermal efficiency, pressure ratio and cut-off ratio between each other has been examined and results are given by graphs.
Açıklama
Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2009
Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2009
Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2009
Anahtar kelimeler
ideal hava çevrimleri,
ikili ideal çevrim,
yanma verimi,
air standard cycles,
dual cycle,
combustion efficiency