Master Degree / Yüksek Lisans Tezleri

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

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Author: search.filters.author.Rodriguez, Alvaro DiezLanguage: search.filters.language.en

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Now showing 1 - 4 of 4
  • Master Thesis
    An Adaptive Neuro-Fuzzy Approach for Modeling the Effects of Water-In Emulsion on Diesel Sprays
    (Izmir Institute of Technology, 2016) Yavuz, Bekir Kağan; Rodriguez, Alvaro Diez; Saplıoğlu, Kemal
    This thesis is prepared as an outcome of the Energy Engineering Master of Science program at Izmir Institute of Technology, IZTECH, in Turkey. The main purpose of this study is to analyse the effects of water content in diesel fuel spray behaviours using adaptive neuro-fuzzy inference system models (ANFIS) for compression ignition engines. The investigations are carried out using numerical models of ANFIS in MATLAB R2011a, generating simulations from training and test datasets based on recent experimental studies from the literature. The thesis primarily tests the use and the fitness of ANFIS models, modifying the neural network structure so that the simulations acceptably reach the experimental results accurately. Then secondarily, the simulation is used to investigate the effects of parameters originally not available in the related study. The investigation mainly focusses on water in diesel emulsions from pure diesel to an emulsion with 20% water content. Operational conditions such as chamber ambient pressure, injection pressure, chamber ambient temperature are also investigated to find their effects over spray penetration. It was found that the increase of water content in the diesel fuel did not have a relevant effect at very low and very high temperatures, however at medium-high temperatures it increased spray penetration. Furthermore, it was observed that the increase of chamber ambient pressure and chamber ambient temperature reduced the spray penetration as expected.
  • Master Thesis
    A Numerical Study of Waste Heat Recovery Potential of the Exhaust Gases From a Power Generation Diesel Engine
    (Izmir Institute of Technology, 2017) Boz, Buket; Rodriguez, Alvaro Diez
    Recently, producing and using energy in an efficient way is one of the challenges through the world. Additionally, the severe environmental issues regarding global warming and ozone depletion have risen. Having taken into consideration two aspects, waste heat recovery systems can be an effective solution to solve some of these problems. This study presents the waste heat recovery potential applied to stationary internal combustion engines. Through the work, three different diesel engines’ exhaust gases are applied as the heat sources. Three Organic Rankine Cycle (ORC) configurations are designed, a Simple Organic Rankine Cycle and Regenerative Organic Rankine cycle which are thermally powered by exhaust gases and Pre-heating and Regenerative Organic Rankine Cycle with the usage of exhaust gas and the engine cooling water as the heat sources. In order to assess the differences between the chemical classes regarding the ozone depletion and global warming potential, eight candidate working fluids are chosen. A selecting procedure is created to obtain the most appropriate working fluid for the suitable cycle configuration. The first law of thermodynamic analysis is conducted with the variations of the working fluids, heat sources and the cycle designs in order to accomplish the greatest thermal efficiency with the most suitable working fluid and the configuration. It was found that it is possible to achieve a high thermal efficiency outcome using zero ozone depletion and global warming potential fluids under the Regenerative Organic Rankine configuration.
  • Master Thesis
    Cogeneration Sustainability Study for the Izmir Institute of Technology
    (Izmir Institute of Technology, 2017) Ahmad, Awais; Rodriguez, Alvaro Diez
    In this study, feasibility of Cogeneration/Combined Cycle System will be evaluated for the Izmir Institute of Technology. Turkish Energy Policy lacks some key factors which need to be highlighted for achieving Energy targets. The first aim of this study is to compare the policies and implementation of combined cycle systems of Turkey with Europe and to analyze the steps carried out by European Countries to achieve sustainability. The main objective of this study includes the implementation of a combined cycle system based on the data collection from the authorities of the Institute to analyze the deficiencies of existing system and to propose a more efficient system for meeting the energy demand. Two systems were taken in consideration, a gas turbine and a reciprocating engine based combined cycle system, detailed energy analysis with emissions and cost analysis were presented to determine what case provides the best solution to meet the energy demand.
  • 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.