Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

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COAR Access Rights: search.filters.coarAccessRights.open accessSubject: search.filters.subject.Internal combustion engines

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  • Master Thesis
    Numerical Investigations of Flash-Boiling Gasoline Direct Injection Sprays
    (Izmir Institute of Technology, 2019) Oral, Orhan; Barışık, Murat; Barışık, Murat; Çelik, Hasan
    Gasoline Direct Injection (GDI) system is a new technology that is the combination of injection in diesel engines and ignition in gasoline engines. Comparing with the conventional methods of injection, it has many advantages including, fuel economy, higher engine power, lower engine knock tendency, NOx and cold-start HC emission rates. The operation of the GDI engine is affected by the processes of fuel injection, spray atomization and vaporization, charge cooling, air/fuel mixture preparation, and incylinder charge motion. Therefore, numerical modeling has an important role to improve all these factors affecting the engine. This thesis focuses on numerical analyses of the fuel sprays injected into a constant volume chamber by a single hole GDI injector under flash-boiling and non-flashboiling conditions. The aim of this thesis is to develop a numerical model that can be used in flash-boiling spray simulations and to validate the results of the numerical model against experimental data in terms of spray angle and spray penetration. Initially the GDI sprays were simulated by the standard spray simulation model of OpenFOAM solver package that was tuned for gasoline injections. Then the model was modified for both non-flashing and flashing spray simulations and the results were compared with experimental ones. It is concluded that; discharge coefficient and spray initial angle have critical impacts on the numerical results.
  • Master Thesis
    Analysis of a Hydrogen Fueled Internal Combustion Engine
    (Izmir Institute of Technology, 2005) Kahraman, Erol; Özerdem, Mehmet Barış
    In the history of internal combustion engine development, hydrogen has been considered at several phases as a substitute to hydrocarbon-based fuels. Starting from the 70.s, there have been several attempts to convert engines for hydrogen operation.Together with the development in gas injector technology, it has become possible to control precisely the injection of hydrogen for safe operation. Since the fuel cell needs certain improvements before it is widely used in vehicles, the conventional internal combustion engine is to play an important role in the transition. This study examines the performance characteristics and emissions of a hydrogen fueled conventional spark sparkignition engine. Slight modifications are made for hydrogen feeding which do not change the basic characteristics of the original engine. Comparison is made between the gasoline and hydrogen operation and engine design changes are discussed. Certain remedies to overcome the backfire phenomena are attempted.