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Öğe Biodiesel production from anchovy (engraulis encrasicolus) oil and its effect on diesel engine performance and emissions(Gazi Universitesi Muhendislik-Mimarlik, 2016) Sekmen, Y.; Sen, S.The interest in biodiesel as an alternative fuel increases due to increasing awareness of the depletion of fossil fuel resources, concerns about the environment, recycling of waste products, and restrictions imposed on exhaust emissions. Biodiesel can be produced from vegetable oils, animal fat or waste cooking oil. Main advantages of biodiesel may be summarized as; biodegradable, sulphur-free, Non-poisonous, consisting oxygen and high cetane number and lubricity. In this study, in order to identify performance and exhaust emission characteristics of a four-stroke, single cylinder diesel engine were operated with anchovy oil based biodiesel, diesel fuel and their blends (volumetrically 5, 20, 50 and 100%) at full load and various engine revolutions. We have noted that, increasing the proportion of the biodiesel in the mixture with respect to petroleum based diesel fuel, the specific fuel consumption increases 5-12%, while engine torque decrease %2-6. The emission analyses show that the CO, HC and smoke emission decrease while NOx emissions increase.Öğe Biodiesel production from waste melon seeds and using it as alternative fuel in direct injection diesel engine(Elsevier Sci Ltd, 2010) Aktas, A.; Sekmen, Y.; Sekmen, P.Melon seeds containing similar to 30% oil are wasted after the fruit is consumed. The chemical and physical properties of melon seed oil are very similar to vegetable oils used as biodiesel fuel. There are no studies regarding the use of melon seed oil or its esters as fuel in literature. In this study, oil was extracted from waste melon seeds and transformed to melon seed oil methyl ester (MSOME) by transesterification process. This fuel is used in a four stroke single cylinder direct injection diesel engine, and its effects on performance and emissions were investigated for various engine speeds at full load. In addition, diesel fuel no. 2 and soy bean oil methyl ester (SOME) is used as fuel under the same operating conditions for comparison purposes. According to the experiment results, specific fuel consumption is found to be more in both biodiesel fuels compared to diesel fuel, and the engine torque is 1-6% lower with MSOME and 3-5% with SOME compared to diesel fuel. Exhaust gas temperature is lower with MSOME and SOME than with diesel fuel. Furthermore, it is found that CO and HC emissions and smoke density are generally lower in both biodiesel fuels. However, NOx emission is slightly higher for SOME and MSOME than that for diesel fuel.Öğe The effect of heating and cooling temperatures on rapid cooling time and particle number in auto glass tempering process(Gazi Universitesi Muhendislik-Mimarlik, 2014) Akçay, M.; Sekmen, Y.; Gölcü, M.In terms of tempering quality, controlling and applying of heating and rapid cooling processes are very important in the glass tempering process. In this study, auto glass tempering process was implemented in the prototype glass tempering unit which was designed specifically, exchange of cooling time and particle number was investigated according to heating and cooling temperatures. Without going out of standards, it was aimed to determine the tempering conditions which are needed to keep the energy consumption at minimum in glass tempering process. Glasses that were heated to three different average surface temperatures (Th=620, 650 and 680°C) were rapidly cooled to four different average surface temperatures (Tc=70, 250, 300 and 400°C). The distance between the nozzle and the glass surface is H, the distance between the nozzle axes is S. It was considered 2Öğe The effects of advance fuel injection on engine performance and exhaust emissions of a diesel engine fuelled with biodiesel(2008) Aktas, A.; Sekmen, Y.Biodiesel is an oxygenated, sulphur-free, non-toxic, biodegradable and renewable alternative diesel fuel. It is known that CO, HC and smoke emissions of biodiesel are lower than those of diesel fuel. It is used without any significant setting and modification in diesel engines. Fuel injection timing is one of the significant parameters affecting the performance and emissions in diesel engines. By optimising fuel injection parameters, improvement in fuel economy as well as reduction in harmful exhaust emissions can be effected. In this study, the effects of fuel injection advance on engine performance and exhaust emissions were investigated experimentally in a fourstroke single cylinder direct injection diesel engine fuelled with biodiesel. Engine torque, brake power, specific fuel consumption, exhaust gas temperatures, CO, HC and NOx emissions were measured for injection timings of 24.9, 26.6 and 28.5°CA at full load. By increasing injection timing to 26.6°CA when running on biodiesel, engine torque and brake power increased by about 6%, and 8% improvement in specific fuel consumption were observed. In addition, it was also determined that CO and HC emissions decreased while NOx emissions increased by between 4-11%.Öğe Energy saving in a deep well pump with splitter blade(2006) Gölcü, M.; Pancar, Y.; Sekmen, Y.Design parameters, like blade number, blade outlet angle and impeller outlet diameter, affect pump performance and energy consumption. Deep well pumps with splitter blades (DWPwsb) are manufactured to achieve energy saving and improve efficiency. Splitter blades are generally located at the centerline of the main blades. Blade number and blade discharge angle should be conveniently determined when splitter blades are used on the impellers. In this study, impellers having different numbers of blades (z = 5, 6, 7) with and without splitter blades (35%, 60% and 80% of the main blade length) were tested in a deep well pump. Tests have been conducted on a total of 12 impellers, and the characteristics of deep well pumps without splitter blade (DWPwosb) and DWPwsb were obtained experimentally. These results show that splitter blades cause negative effects on pump performance in impellers with blade numbers of 6 and 7. When the splitter blade is added to the impeller with the blade number of 5, the efficiency increases with flow up to 10 l/s flow rate, after which it decreases as the splitter blade length increases. The highest efficiency and the lowest energy consumption were obtained in DWPwsb with 80% of the main blade length. At the best efficiency point (b.e.p), an energy saving of 6.6% and an improvement of 1.14% in efficiency were achieved. An analysis of the additional cost of the splitter blade and the application in an agricultural area were performed. © 2005 Elsevier Ltd. All rihgts reserved.Öğe Experimental investigation of cooling with multiple air jets on auto glass tempering(2012) Gölcü, M.; Yazici, H.; Akçay, M.; Köseoglu, M.F.; Sekmen, Y.Impinging air jets due to their high heat and mass transfer capacity are widely used for heating, cooling and drying applications in nowadays industry. This study aims to investigate auto glass tempering project. Heat transfer characteristics of heated glass plates during their cooling with mutually placed circular air jets have been experimentally investigated. 4 mm thick glass samples were used in the experiments. Cooling process has been performed with 16 mutually placed nozzles of 8 mm in diameter and 80 mm in length in staggered arrangement. Nozzles were made of seamless aluminum pipes. Experiments have been conducted for dimensionless jet to plate distances (H/D) between 1 and 10, and S/D ratios which represents dimensionless distance between nozzle axis, for 2?S/D?10. Reynolds number has been fixed at 30000 for all experiments. According to the results the highest average Nusselt number (Num) has been achieved for S/D=2 and H/D=4 with a value 123.3 and the lowest average Nusselt number was obtained for S/D=10 and H/D=10 with a value 58.6.Öğe EXPERIMENTAL INVESTIGATION OF TRANSIENT TEMPERATURE DISTRIBUTION AND HEAT TRANSFER BY JET IMPINGEMENT IN GLASS TEMPERING PROCESSING(Springer, 2015) Yazici, H.; Akcay, M.; Golcu, M.; Koseoglu, M. F.; Sekmen, Y.Heating and sudden cooling are among the most important processes affecting temper quality in the production period of tempered auto glass. In this study, heat transfer characteristics and cooling times during the sudden cooling process of tempered glass production have been experimentally investigated. Flat glass with dimensions of 50x50x4 mm has been heated up to 680 degrees C in the furnace and was then exposed to sudden cooling process until its surface temperature dropped to 70 degrees C. In the cooling process two mutually placed 8 cm long air jet nozzles with an internal diameter of 8 mm have been used. Experiments have been conducted for Reynolds numbers in the range of (20000 <= Re <= 40000) and for dimensionless jet to plate distances in the range of (1 <= H/D <= 10). Based on the above parameters cooling periods, local (Nu(x)), average (Nu(aver)) and stagnation point (Nu(stad))Nusselt numbers have been experimentally determined.Öğe Experimental investigation of transient temperature distribution and heat transfer by jet impingement in glass tempering processing(Shiraz University, 2015) Yazici, H.; Akcay, M.; Golcu, M.; Koseoglu, M.F.; Sekmen, Y.Heating and sudden cooling are among the most important processes affecting temper quality in the production period of tempered auto glass. In this study, heat transfer characteristics and cooling times during the sudden cooling process of tempered glass production have been experimentally investigated. Flat glass with dimensions of 50x50x4 mm has been heated up to 680 °C in the furnace and was then exposed to sudden cooling process until its surface temperature dropped to 70 °C. In the cooling process two mutually placed 8 cm long air jet nozzles with an internal diameter of 8 mm have been used. Experiments have been conducted for Reynolds numbers in the range of (20000le;Rele;40000) and for dimensionless jet to plate distances in the range of (1le;H/Dle;10). Based on the above parameters cooling periods, local (Nux), average (Nuaver) and stagnation point (Nustag) Nusselt numbers have been experimentally determined. © Shiraz University.Öğe Mathematical modeling of a SI engine cycle with actual air-fuel cycle analyses(Association for Scientific Research, 2007) Sekmen, P.; Sekmen, Y.The performance of an engine whose basic design parameters are known can be predicted with the assistance of simulation programs into the less time, cost and near value of actual. However, inadequate areas of the current model can guide future research because the effects of design variables on engine performance can be determined before. In this study, thermodynamic cycle and performance analyses were simulated for various engine speeds (1800, 2400 ve 3600 1/min) and various excess air coefficients (EAC) (0.95-1.05) to crank shaft angle (CA) with 1 degree increment at full load and 8:1 constant compression ratio (CR) of a SI engine with four stroke, single cylinder and natural aspirated. Brake mean effective pressure, power, thermal efficiency, specific fuel consumption (sfc), etc engine performance parameters were calculated; the values of peak cylinder pressures and temperatures and positions of them were determined by the present program. Variations of these parameters with crank angle, engine speed and excess air coefficient were presented graphically. The calculated results show good agreement with literature. Simulation program is usable to set for varies load, compression ratios, and engine sizes. © Association for Scientific Research.Öğe Prediction of performance and smoke emission using artificial neural network in a diesel engine(Association for Scientific Research, 2006) Sekmen, Y.; Gölcü, M.; Erduranli, P.; Pancar, Y.The fuel injection pressure is one of the significant operating parameters affects atomization of fuel and mixture formation; therefore, it determines the performance and emissions of a diesel engine. Increasing the fuel injection pressure decrease the particle diameter and caused the diesel fuel spray to vaporize quickly. However, with decreasing fuel particles their inertia will also decrease and for this reason fuel can not penetrate deeply into the combustion chamber. In this study, artificial neural-networks (ANNs) are used to determine the effects of injection pressure on smoke emissions and engine performance in a diesel engine. Experimental studies were used to obtain training and test data. Injection pressure was changed from 100bar to 300bar in experiment (standard injection pressure of test engine is 150bar). Injection pressure and engine speed have been used as the input layer; smoke emission, engine torque and specific fuel consumption have been used as the output layer. Two different training algorithms were studied. The best results were obtained from LevenbergMarquardt (LM) and Scaled Conjugate gradient (SCG) algorithms with 11 neurons. However, The LM algorithm is faster than the SCG algorithm, and its error values are smaller than those of the SCGs. For the torque with LM algorithm, fraction of variance (R2) and mean absolute percentage error (MAPE) were found to be 0.9927 and 7.2108%, respectively. Similarly, for the specific fuel consumption (SPC), R2 and MAPE were calculated as 0.9872 and 6.0261%, respectively. For the torque with SCG algorithm, R 2 and MAPE were found to be 0.9879 and 9.0026%, respectively. Similarly, for the specific fuel consumption (SPC), R2 and MAPE were calculated as 0.9793 and 8.7974%, respectively. So, these ANN predicted results can be considered within acceptable limits and the results show good agreement between predicted and experimental values. © Association for Scientific Research.
