Yazar "Celik, M. Bahattin" seçeneğine göre listele
Listeleniyor 1 - 13 / 13
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe CO and C3H8 oxidation activity of Pd/ZnO nanowires/cordierite catalyst(Pergamon-Elsevier Science Ltd, 2016) Sen, Mehmet; Emiroglu, A. Osman; Celik, M. BahattinUsing nanowires grown on monolith cordierite as catalyst wash-coat is a new concept. ZnO nanowires array has different pore-region diffusion of reactants in the catalyst media because it can have greater effective porosity and average diffusion length scale than traditional catalyst carrier. Also, thickness of ZnO nanowires array is less than conventional wash coat. ZnO nanowires were grown on monolith cordierite channels, and Pd was impregnated on the nanowires. The catalyst structure was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and atomic absorption spectrometry (AAS). The activity performance of Pd/ZnO nanowires catalyst for C3H8 and CO was examined under lean, stoichiometric and rich conditions. T50 was achieved under stoichiometric condition of gas mixture for C3H8 and CO at 400 degrees C and 235 degrees C, respectively. (C) 2016 Elsevier Ltd. All rights reserved.Öğe Combustion and emission characteristics of isoamyl alcohol-gasoline blends in spark ignition engine(Elsevier Sci Ltd, 2020) Uslu, Samet; Celik, M. BahattinNowadays, the evaluation of waste products has gained importance. The fusel oil, which is obtained as a waste product in sugar factories, has a high proportion of isoamyl alcohol. Alcohols having a high-octane number give lower emission values when used as fuel. In this study, isoamyl alcohol was used at high compression ratio (CR) to improve performance and emissions in a spark ignition (SI) engine. The experiments were performed at full load, different CRs (8.0:1, 8.5:1 and 9.0:1) and different speeds (2600, 2800, 3000 and 3200 rpm) using different fuels A0 (%100 gasoline), A10 (%10 isoamyl alcohol-%90 gasoline), A20 (%20 isoamyl alcohol-%80 gasoline) and A30 (%30 isoamyl alcohol-%70 gasoline). According to the obtained results, exhaust emissions decreased with using of isoamyl alcohol compared the using of gasoline at all CRs. With the use of A30, carbon monoxide (CO), nitrogen oxides (NOx) and hydrocarbon (HC) emissions decreased by approximately 12.2%, 35.6% and 6.45%, respectively compared to gasoline. The cylinder gas pressures (CGP) and heat release rates (HRR) were recorded for each CR and fuel blend. Moreover, by increasing the CR, brake thermal efficiency (BTE) increased about 2.67% with A20 compared to gasoline on 9.0:1 CR. Furthermore, torque and effective power also increased by 2.03% and 2.51% with A20, respectively.Öğe THE DETERMINATION OF OPTIMUM INJECTION PRESSURE IN AN ENGINE FUELLED WITH SOYBEAN BIODIESEL/DIESEL BLEND(Vinca Inst Nuclear Sci, 2014) Celik, M. Bahattin; Simsek, DoganIn this study, the optimum blend rate and injection pressure in a four-stroke, single cylinder, direct injection diesel engine using soybean methyl ester were investigated experimentally. The tests were conducted at two stages. Firstly, the engine was tested with diesel fuel, B25 (25% biodiesel + 75% diesel fuel), B50, B75, and B100 fuels at full load and at a constant speed. According to the test results, it was determined that the most suitable fuel was B25 in terms of performance and emission. Secondly, the engine was tested at different loads with diesel fuel at original injection pressure and with B25 at different injection pressures (160, 180, 200, 220, and 240 bar) for comparison. It was determined from tests performed with B25 that the most suitable injection pressure in terms of performance and emissions was 220 bar. The specific fuel consumption and power values of the B25 were found to be nearly the same as those of diesel fuel at 220 bar injection pressure. In addition, HC, CO, and smoke emissions were reduced by about 33%, 9%, and 20%, respectively. On the other hand, NO emission increased by about 12%.Öğe The effect of tire derived fuel/diesel fuel blends utilization on diesel engine performance and emissions(Elsevier Sci Ltd, 2012) Dogan, Oguzhan; Celik, M. Bahattin; Ozdalyan, BulentThe aim of the present study is to evaluate the effect of tire-derived fuel (TDF) on engine performance and exhaust emissions in a diesel engine. For this aim, the raw tire derived pyrolytic oil was refined and six test fuels, TDF10 (contains 10% tire derived fuel and 90% diesel fuel in volume basis), TDF30, TDF50, TDF70, TDF90 and neat diesel fuel, were prepared to test in a diesel engine. Tests were performed in a single cylinder, four stroke, unmodified, and naturally aspirated DI high speed diesel engine at full load and four engine speeds (1400 rpm, 2000 rpm, 2600 rpm, and 3200 rpm) by using six test fuels. The experimental test results showed that the DI diesel engine can run with the TDF fuel blends up to TDF90. The smoke opacity, unburned hydrocarbon, and carbon monoxide emissions reduced while nitrogen oxides emissions increased with the increasing TDF content in the fuel blends. In addition, TDF fuel content in the fuel blends does not have a significant impact on the engine output torque, the engine power, brake specific fuel consumption (BSFC) and brake thermal efficiency (BTE) with respect to those of the reference diesel fuel. (C) 2011 Elsevier Ltd. All rights reserved.Öğe Experimental determination of suitable ethanol-gasoline blend rate at high compression ratio for gasoline engine(Pergamon-Elsevier Science Ltd, 2008) Celik, M. BahattinEthanol produced from biomass has high octane number and gives lower emissions. Therefore, it is used as alternative fuel in the gasoline engines. In this study, ethanol was used as fuel at high compression ratio to improve performance and to reduce emissions in a small gasoline engine with low efficiency. Initially, the engine whose compression ratio was 6/1 was tested with gasoline, E25 (75% gasoline + 25% ethanol), E50, E75 and E100 fuels at a constant load and speed. It was determined from the experimental results that the most suitable fuel in terms of performance and emissions was E50. Then, the compression ratio was raised from 6/1 to 10/1. The engine was tested with EO fuel at a compression ratio of 6/1 and with E50 fuel at a compression ratio of 10/1 at full load and various speeds without any knock. The cylinder pressures were recorded for each compression ratio and fuel. The experimental results showed that engine power increased by about 29% when running with E50 fuel compared to the running with EO fuel. Moreover, the specific fuel consumption, and CO, CO2, HC and NOx emissions were reduced by about 3%, 53%, 10%, 12% and 19%, respectively.(C) 2007 Elsevier Ltd. All rights reserved.Öğe An Overview of Utilization of Blast Furnace and Steelmaking Slag in Various Applications(Elsevier Science Bv, 2019) Oge, Mecit; Ozkan, Dervis; Celik, M. Bahattin; Gok, Mustafa Sabri; Karaoglanli, Abdullah CahitEver-increasing energy costs and environmental restrictions have compelled researchers to focus on the reutilization of vast amounts of industrial by-products such as blast furnace slag and steelmaking slag, in energy extensive and material extensive industries such as iron-steel production and construction. Attempts to reutilize these waste materials all around the world have yielded successful results up to date, such that, in some of these attempts they even surpassed their intended use as blend or replacement materials and became serious rivals to their industrial counterparts. Various ways to reutilize these waste materials have been explored up to date, including waste heat recovery, clinker substitute in cement production, and a number of comparatively more value added applications. The ongoing attempts have come to a point that pushes the limits for more technological uses such as alternative ceramic coating materials in surface engineering applications. In this regard, this review study aims to provide an overview of and a collective approach to various uses of blast furnace and steelmaking slag in diverse applications and fields, with a view to provide insight into the current attempts to optimize or improve their use, as well as emerging trends as to the potential use of these waste materials in higher value-added applications. (c) 2019 Elsevier Ltd. All rights reserved.Öğe Performance and emission prediction of a compression ignition engine fueled with biodiesel-diesel blends: A combined application of ANN and RSM based optimization(Elsevier Sci Ltd, 2020) Aydin, Mustafa; Uslu, Samet; Celik, M. BahattinIn the present study, the performance and emission parameters of a single cylinder diesel engine powered by biodiesel-diesel fuel blends were predicted by Artificial Neural Network (ANN) and optimized by Response Surface Methodology (RSM). The data to be used for ANN and RSM applications were obtained by using biodiesel/diesel fuel blends at different engine loads and various injection pressures. ANN model has been developed to predict the outputs such as brake thermal efficiency (BTE), brake specific fuel consumption (BSFC), exhaust gas temperature (EGT), nitrogen oxides (NOx), hydrocarbons (HC), carbon monoxide (CO) and smoke regarding engine load, biodiesel ratio and injection pressure. A feed-forward multi-layer perceptron network is used to show the correlation among the input factors and the output factors. The RSM is applied to find the optimum engine operating parameters with the purpose of simultaneous reduction of emissions, EGT, BSFC and increase BTE. The obtained results reveal that the ANN can correctly model the exhaust emission and performance parameters with the regression coefficients (R-2) between 0.8663 and 0.9858. It is seen that the maximum mean relative error (MRE) is less than 10%, compared with the experimental results. The RSM study demonstrated that, biodiesel ratio of 32% with 816-W engine load and 470 bar injection pressure are the optimum engine operating parameters. It is found that the ANN with RSM support is a good tool for predict and optimize of diesel engine parameters powered with diesel/biodiesel mixtures.Öğe Performance improvement and emission reduction in small engine with low efficiency(Maney Publishing, 2007) Celik, M. BahattinBecause air cooled small engines have very low compression ratio and fixed ignition timing, and work on slightly rich mixtures, their specific fuel consumption and emission values are very high. In this study, some modifications were made to improve performance and to reduce emissions in a small engine. The compression ratio of this engine was raised from 5 : 1 to 10 : 1, the ignition system was powered and the ignition timing was converted to be variable. The modified engine was operated with lean mixtures at high compression ratio. The test results showed that the power of the modified engine was higher than that of the standard engine by similar to 32%. At the same time, the specific fuel consumption and the HC emissions were reduced by similar to 36 and 31% respectively. According to these results, it can be said that there is the potential of performance improvement and emission reduction in the small engines without using any fuel injection system and exhaust control system which increase cost of engine.Öğe The Relation Between Meteorological Factors and Pollutants Concentrations in Karabuk City(Gazi Univ, 2007) Celik, M. Bahattin; Kadi, IbrahimKarabuk, situated in the northwest of Turkey, is among the cities which suffer most from the air pollution in Turkey. Due to the heavy industrial foundations and the usage of low quality coal for heating purposes, air pollution has been the primary environmental problem in Karabuk. Meteorological factors are known to be effective in decreasing air pollution, but the meteorological properties of Karabuk do not allow for the diminishment of air pollution. In this study, the relationship between SO2 and particulate matter; and wind speed, relative humidity and air temperature has been investigated from 1998 to 2001 on the bases of 24-hour continuous measurements. The relationship between air pollution and the meteorological factors was statistically analyzed. According to the results of the analysis, for some years, there is a moderate and weak level relation between meteorological factors and particulate matter concentrations in Karabuk city.Öğe Room and high temperature wear behaviors of steelmaking slag coating and WC-reinforced composite coatings(Elsevier Science Sa, 2020) Oge, Mecit; Karaoglanli, A. Cahit; Celik, M. BahattinSteelmaking slag (SmS) powder and commercial WC-reinforced composite powders (NiCrBSi/WC (50/50) and WC/Co (88/12)) were deposited on the AISI 316 L stainless steel substrates by atmospheric plasma spraying (APS), and high velocity oxy fuel (HVOF) spraying techniques. The microstructures as well as the room and high temperature wear performances of the fabricated coatings were comparatively evaluated to assess the usability of steelmaking slag, an industrial by-product of steelmaking industry, as an alternative protective coating material against room and high temperature sliding wear. The friction-wear tests of all coatings against Al2O3 abrader were performed on a high-temperature ball-on-disk tribometer at room temperature and elevated temperatures (250 degrees C-500 degrees C) under 5 and 10 N normal loads. The powders, as-sprayed and worn samples were characterized by X-ray diffraction (XRD), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) techniques and a 3D optical surface profiler. The SmS coating structure displayed the highest porosity which was followed by NiCrBSI-WC and WC-Co coatings. WC-Co coating exhibited the lowest specific wear rates until being damaged at 500 degrees C due to severe decarburization. NiCrBSi-WC and SmS coatings withstood the 500 degrees C wear test and NiCrBSi-WC coating slightly outperformed SmS coating under high load whereas SmS coating displayed lower wear rates under low load. SmS coating's stable oxide-rich structure acted in the favor of the coating's wear performance. The slight increase in the wear rate of SmS coating with the increase of temperature from 250 degrees C to 500 degrees C is believed to be induced by the large temperature gradients between the real contact areas and their surroundings. Overall, plasma sprayed SmS coating exhibited promising results when compared with its commercial HVOF sprayed WC-reinforced composite counterparts.Öğe THE USAGE OF HYDROGEN FOR IMPROVING EMISSIONS AND FUEL CONSUMPTION IN A SMALL GASOLINE ENGINE(Turkish Soc Thermal Sciences Technology, 2011) Kosar, Murat; Ozdalyan, Bulent; Celik, M. BahattinAs small gasoline engines run on slightly rich mixture, and do not have catalytic converter, their specific fuel consumption and emission values are very high. When the gasoline engines are operated with pure hydrogen NOx emissions increase and the backfire occurs. In this study, a small engine was run with hydrogen at a suitable lean mixture without occurring backfire, and improvements on fuel consumption and emissions were aimed. Performance emissions and cylinder pressures of the engine were measured for hydrogen and gasoline. The specific fuel consumption and NOx emissions were reduced by about 57% and 66%, respectively at hydrogen operation. Moreover the values near zero for CO, CO2 and HC emissions were obtained. The test results showed that the small gasoline engine can operate with pure hydrogen at a suitable lean mixture without any backfire, and provide important improvements in emissions and fuel consumption without using any exhaust control system, electronic ignition system and fuel injection system which increase cost of engine.Öğe THE USE OF PURE ETHANOL AS ALTERNATIVE FUEL IN A SPARK IGNITION ENGINE(Gazi Univ, Fac Engineering Architecture, 2008) Celik, M. Bahattin; Colak, AlimBecause of increasing energy demand and environmental pollution, alternative fuels such as ethanol, methanol, natural gas, hydrogen and LPG have been used in spark ignition engines. Ethanol has an important place among the alternative fuels as its octane number is high, exhaust emission level is low and it is produced from biomass sources. In this study, the effect of the use of pure ethanol in an SI engine which has variable compression ratio on engine performance and emissions were investigated experimentally. In the experiments, a single cylinder, four stroke, spark ignition research engine which has a variable compression ratio was used. The experiments were performed by running the engine at the 6/1 compression ratio with gasoline and ethanol, and at the 8/1, 10/1 compression ratios with ethanol. The results showed that some decreases were obtained in CO, CO2 and NOx emissions without any noticeable power loss when ethanol was used instead of gasoline at the 6/1 compression ratio. By increasing the compression ratio (10/1), engine power was increased up to 25% with ethanol. CO, CO2 and NOx emissions were reduced about 41%, 21% and 26%, respectively. Moreover, HC emissions were increased about 40%. According to the results obtained, it can be said that using ethanol at high compression ratios in the engines significantly improves the engine performance and decreases the exhaust emissions.Öğe The use of pure methanol as fuel at high compression ratio in a single cylinder gasoline engine(Elsevier Sci Ltd, 2011) Celik, M. Bahattin; Ozdalyan, Bulent; Alkan, FarukThe methanol has greater resistance to knock and it emits lower emissions than neat gasoline. As single cylinder small engines have low compression ratio (CR), and they run with slightly rich mixture, their power are low and emission values are high. The performance can be increased at high CR if these engines are run with fuels which have high octane number. In this study, methanol was used at high CR to increase performance and decrease emissions of a single-cylinder engine. Initially, the engine whose CR was 6/1 was tested with gasoline and methanol at full load and various speeds. Then, the CR was raised from 6/1 to 8/1 and 10/1, gradually. The knock was not observed at the CRs of 8/1 and 10/1 when using methanol while the knock was observed at the CR of 8/1 when using gasoline. The knock was determined from the cylinder pressure-time curves. The results showed that some decreases were obtained in CO, CO2 and NOx emissions without any noticeable power loss when using methanol at the CR of 6/1. By increasing the CR from 6/1 to 10/1 with methanol, the engine power and brake thermal efficiency increased by up to 14% and 36%, respectively. Moreover, CO, CO2 and NOx emissions were reduced by about 37%, 30% and 22%, respectively. (C) 2010 Elsevier Ltd. All rights reserved.
