Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Effects of Methanol on Species Concentrations in N-Heptane Flames(Izmir Institute of Technology, 2019) M. Alazreg, Abdalwahab Rashed; İnal, FikretFuel oxygenate additives have been used as an alternative method to reduce the combustion emissions. The effects of methanol addition on n-heptane oxidation were investigated for one-dimensional, atmospheric pressure, laminar, premixed, fuel-rich flame at an equivalence ratio of 2.10. The Detailed Chemical Kinetic Modeling approach has been used to obtain information about the combustion characteristics of n-heptane and n-heptane/methanol flames. A detailed chemical kinetic mechanism was generated by merging two mechanisms of n-heptane (with the formation of polycyclic aromatic hydrocarbons (PAHs)) and methanol. The Master Mechanism consists of 4480 reactions and 945 species. Model validation was carried out using the experimental data available in the literature for different combustion systems. The Master Mechanism was investigated for the combustion of n-heptane and n-heptane/methanol flames using reaction sensitivity, rate of production, and reaction pathway analyses. The mole fraction profiles of low-molecular-weight stable species, single ring aromatics, and PAHs have been predicted by the model. Good agreements between the modeling and experimental results of species mole fractions for both flames have been achieved. The mole fractions of low-molecular-weight species, aromatics, and PAHs were reduced as the methanol was added to n-heptane flame. Acetylene, propargyl radical, and vinylacetylene have been found as important species for the formation of the first aromatic ring and PAH species. Model reduction was also carried out using directed relation graph method. The Reduced Mechanism consists of 1113 reactions and 156 species. The Reduced Mechanism was in a good agreement with the Master Mechanism in terms of the species mole fraction predictions of the n-heptane/methanol flame.Master Thesis Detailed Chemical Kinetic Modeling of N-Heptane Flame(Izmir Institute of Technology, 2018) Değirmenci, Emre; İnal, FikretTo understand the complex combustion characteristics of gasoline, n-heptane is used as one of the two major reference fuels. The emissions resulted from incomplete combustion are one of the main issues caused from usage of high amount of fossil fuels in transportation and energy generation sectors. The main purpose of this study is to model one-dimensional premixed, laminar, burner-stabilized fuel-rich n-heptane flame to understand its combustion characteristics in mainly fuel-rich conditions. Detailed chemical kinetic modeling technique was used to get high amount of information about the ignition characteristics of n-heptane and formation nature of emissions. A detailed chemical kinetic mechanism was generated by combining several mechanisms from the literature that related with possible products of fuel-rich n-heptane combustion. The detailed mechanism consists of 4185 reactions and 893 species. Validations of the model were done with various experimental data available in the literature such as premixed laminar flames and jet stirred reactors. After generating the kinetic model, detailed investigation of the n-heptane flame was done by using rate of production, reaction sensitivity and reaction pathway analyses. One of the attributes of fuel-rich flames, Polycyclic aromatic hydrocarbon (PAH) formation kinetics were also investigated. Acetylene (C2H2), propargyl radical (C3H3), and vinylacetylene (C4H4) were found as the main precursors of the first aromatic ring and PAH formation as a result of pathway and rate of production analyses. The generated model was able to predict most of the major, minor and trace components that formed in the flame that modeled. A reduced model was also generated by using directed relation graph with error propagation (DRGEP) mechanism reduction technique on the detailed mechanism. The reduced mechanism consists of 1879 reactions and 359 species. The species mole fraction predictions of detailed and reduced mechanism were very close to each other. Most of the species formed in the flame were predicted by the reduced mechanism with less computational afford than detailed mechanism.