Master Degree / Yüksek Lisans Tezleri

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

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Subject: search.filters.subject.Gasoline Direct Injection

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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
    Experimental Investigation of Gdi Injectoer
    (Izmir Institute of Technology, 2015) Abuzahra, Fakhry; Rodriguez, Alvaro Diez
    Among the challenges in the internal combustion - spark ignition Gasoline Direct Injection (GDI) engines stayed under spotlight for its ability to be developed in terms of fuel conversion efficiency and emission contaminants. Spray analysis is of great importance for the combustion operation and it is a prerequisite for improving the mixing capabilities of the air/fuel mixture. Momentum flux measurement technique is one of the most interesting approaches that aims to study the spray structure which can be a complement for high-speed imaging and Phase Doppler Anemometry (PDA) analysis. In the present study, two GDI single-hole research injectors, Magneti Marelli with Length to Diameter parameter (L/D)=1; 3 are investigated by means of momentum flux, global and local, under both low and high temperatures. The flash-boiling phenomenon is triggered when static pressure is below fuel saturation pressure at the same temperature which drastically affects the spray structure in terms of decrement in the penetration rate accompanied with an enlargement in the cone angle. N-heptane is used as a fuel under a temperature range 30-120 C, vessel ambient pressure range 40 303 KPa ,energizing time 1500 -3000 distance for the global momentum 5--40 mm and two horizontal planes for local momentum flux 10; 30 mm. Results of high-speed imaging were integrated in terms of cone angle and penetration rate. Furthermore, the results of this study can verify the Computational Fluid Dynamic (CFD) numerical analysis and provide wealthy understanding of the spray evolution.