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Spray Characteristics of Emulsified Biodiesel-Diesel Blends in a Constant Volume Combustion Chamber
(01. Izmir Institute of Technology, 2020) Özkol, Ünver; Özkol, Ünver; Özkol, Ünver; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Over the last decades, various studies have been carried out by the researchers to find out an alternative fuel that can overcome emission problems caused by diesel fuel which affect the environment and human health significantly. Due to emulsified biodiesel-diesel blend (EBB) fuels are being a possible alternative fuel for diesel, in this study, it was aimed to investigate the macroscopic spray parameters such as spray penetration length and cone angle of different EBB fuels, namely B20W15 and B20W5, containing 15% and 5% water by volume, respectively. In order to examine the spray characteristics of B20W15 and B20W5, the experiments were carried out by means of constant volume combustion chamber and utilizing shadowgraph technique with a high-speed camera. Experiments were performed with 600 bar and 800 bar injection pressure while the ambient pressure was 0 bar, 5 bar and 10 bar, respectively. After experiments were fulfilled, the recorded images of test fuels were processed via ImageJ program. The results showed that stability of the emulsion can be obtained when HLB value was 8 and surfactant concentration was 5% by volume. It was understood that increment in water concentration in the emulsion caused deterioration in emulsion stability while it led higher viscosity, higher density, longer spray penetration lengths and narrower cone angles. It was observed that B20W5 resulted wider spray cone angles and shorter spray penetration lengths than B20W15 under 0,5 and 10 bar chamber pressure with injections pressures of 600 and 800 bar. Also, it was understood that both EBB lead longer spray penetration lengths and narrower spray cone angles compared to reference diesel while they lead vice versa compared to reference biodiesel. The reason of spray geometry difference between diesel and EBB fuels can be associated with the higher viscosity and density of EBB fuels compared to diesel. As a result, considering that B20W5 reduce the use of fossil fuels, and no significant difference compared to diesel in terms of spray geometry, it can be said that B20W5 may be a promising alternative fuel for the futur
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; Rodriguez, Alvaro Diez; Saplıoğlu, Kemal; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
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.
Stochasting reactor model for surrogate diesel fuels
(Izmir Institute of Technology, 2015) Sandal, Gökçen; Mobedi, Moghtada; Diez Rodriguez, Alvaro; Mobedi, Moghtada; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
The objective of this thesis is to develop of various surrogate fuels with computational engine simulation tools based on stochastic reactor models (SRMs) in direct injection engines (DI). The SRM is based on probability density function (PDF) approach which has important ability to calculate complex reactions, energy equations and mass transfer. It is also successful to control the effects of inhomogeneities and turbulence with low computational cost. Since the diesel fuel is very complex to solve in numerical tools, surrogate fuels were tested in this study. N-heptane, n-heptane / toluene and n-heptane / isooctane mixtures were used as surrogate fuels due to their physical and chemical properties were very close to diesel fuel. These fuels were tested under different injection timings and the calculated results were compared with an experimental study’s data. Comparison of ignition delay results demonstrate a good agreement between theoretical and experimental data, but soot formations were different when compared to literature and reference study. Fuel properties, structures or discrepancy between engine operating conditions and numerical model could be the cause of these differences.

Master Degree / Yüksek Lisans Tezleri

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