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Öğe Analysis and Optimization of the Performances of the Tandem Blade Radial Compressor Using the CFD(Mdpi, 2024) Soylemez, Mustafa Erturk; Behcet, Rasim; Parlak, ZekeriyaCentrifugal compressors are frequently used in both military and commercial areas because they can be easily manufactured and reach high-pressure compression ratios. The factor that limits the performance and operating range of compressors is flow instability. Many ideas have been put forward for performance improvement, but tandem blade radial compressors, which do not require an extra air system, have attracted the most interest. In this study, computational fluid dynamics (CFD) analyses were carried out on various parameters of the tandem blade (TB) radial compressor, and an optimization study was carried out to find the best design using a genetic algorithm on a whole operating curve. It was investigated how these parameters affected the efficiency and total pressure ratio between the determined lower and upper limits. The numerical analyses of the optimum design obtained as a result of the iterations were carried out. As a result of the iterations, three optimum designs were obtained and numerical analysis was carried out according to one of them, and then they were compared with the results in the literature. The general agreement of computational fluid dynamics and the literature data served as a validation for the computational approach. The error rates between the numerical analysis results and the experimental results in the literature were calculated for different flow rates and were found to be 1.98% as the highest and 0.35 as the lowest. The work carried out in this article will provide a valuable reference for future advanced tandem blade compressor designs.Öğe Comparison of exhaust emissions of biodiesel-diesel fuel blends produced from animal fats(Pergamon-Elsevier Science Ltd, 2015) Behcet, Rasim; Oktay, Hasan; Cakmak, Abdulvahap; Aydin, HuseyinThe present paper examines two biodiesels named as fish oil methyl ester (FOME) and chicken oil methyl ester (CFME) produced from low-cost waste fish and chicken oils using the transesterification method, and their fuel properties were compared to EN 14214 and ASTM D6751 biodiesel standards. Then, each methyl esters were blended with the commercial diesel fuel (D2) with a ratio of 20% on volume basis, respectively and two fuel samples named as FOB20 (20% Fish Oil Methyl Ester and 80% D2 fuel) and CFB20 (20% chicken oil methyl ester and 80% D2 fuel) were obtained. An experimental study for investigating the effects of the blended fuels on engine performance and its exhaust emissions was performed by using a single cylinder, four stroke, direct injection and air-cooled diesel engine at different speeds under full load. According to the test results, it was observed that the brake power, torque values and the carbon monoxide (CO), unburnt hydrocarbon (UHC) and carbon dioxide (CO2) concentrations of blended fuels decreased while the NOx concentration and brake specific fuel consumption (bsfc) values increased compared to diesel fuel. (C) 2015 Elsevier Ltd. All rights reserved.Öğe Diesel engine applications for evaluation of performance and emission behavior of biodiesel from different oil stocks(Wiley-Blackwell, 2015) Behcet, Rasim; Aydin, Huseyin; Ilkilic, Cumali; Iscan, Bahattin; Aydin, SelmanExtensive researches on alternative fuels have been carried out since the fossil-based fuels are limited. Many of these studies have ever been on the usability of vegetable oils in diesel engines. In the current work, biodiesel were produced from waste fish oil (FOB), hazelnut oil (HOB), rapeseed oil (ROB), and waste cooking oil (WCOB) by transesterification method. The same optimized variables of 6:1 methanol/oil molar ratio (mol/mol), 0.4% sodium methoxide concentration (wt.%), 60 degrees C reaction temperature, 1000 rpm agitation speed and 2 h reaction time conditions were performed for biodiesel production from all kinds of above mentioned oils. Some of the important chemical and physical properties of test fuels were found. Without making blends with diesel fuel, pure biodiesels were used in a diesel engine in order to clarify how their usage effects on engine performance and exhaust emission parameters. When compared with those of diesel fuel, average torque and power were reduced while brake specific fuel consumption was increased for biodiesels. Besides, carbon monoxide (CO), hydrocarbon (HC) emissions were considerably lower for biodiesel usage while oxides of nitrogen (NOx) emissions were higher than that of diesel fuel. Furthermore, emissions of carbon dioxide (CO2) and smoke opacity were reduced for biodiesel usage. Oxygen (O-2) contained in the exhaust gases were higher for biodiesels while they contain more oxygen molecules in their structure. (c) 2014 American Institute of Chemical Engineers Environ Prog, 2014 34: 890-896, 2015Öğe Effect of different types of fuels tested in a gasoline engine on engine performance and emissions(Pergamon-Elsevier Science Ltd, 2021) Yakin, Ahmet; Behcet, RasimIn this study, three different fuels named G100 (pure gasoline), E20 (volume 20% ethanol and 80% gasoline blend) and ES20 (20% sodium borohydride added ethanol solution and 80% gasoline) were used to test in a gasoline engine. First of all, G100 fuel, E20 and ES20 blended fuels, respectively, were tested in a gasoline engine and the effects of fuels on engine performance and exhaust emissions were investigated experimentally. Experiments were carried out at full load and at five different engine speeds ranging from 1400 to 3000 rpm, and engine performance and exhaust emission values were determined for each test fuel. When the test results of the engine operated with E20 and ES20 blended fuels are compared with the test results of the engine operated with gasoline; engine torque of E20 blended fuel increased by 1.87% compared to pure gasoline, while engine torque of ES20 blended fuel decreased by 1.64%. However, the engine power of E20 and ES20 blended fuels decreased by 2.02% and 5.10%, respectively, compared to the power of pure gasoline engine, while their specific fuel consumption increased by 5.02% and 6.57%, respectively, compared to pure gasoline fueled engine. On the other hand, CO and HC emissions of the engine operated with E20 and ES20 blended fuels decreased compared to the pure gasoline engine, while CO2 and NOx emissions increased. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.Öğe Effects of fuels produced from fish and cooking oils on performance and emissions of a diesel engine(Pergamon-Elsevier Science Ltd, 2014) Behcet, Rasim; Yumrutas, Recep; Oktay, HasanIn this study, two fuels called as FOME (Fish Oil Methyl Ester) and COME (Cooking Oil Methyl Ester) were produced from waste fish and cooking oils using the transesterification method. Commercial D2 (Diesel fuel) and two fuel samples obtained by blending the FOME and COME with the D2 with a ratio of 25% on volume basis were used as fuels in a Diesel test engine. An experimental study was performed for investigating the performance and exhaust emissions of the Diesel engine using the fuels. According to the test results, it was observed that the fish oil based fuel indicated better performance and exhaust emission parameters than those of cooking oil. Results clearly showed that the engine power and torque values were lower than those of the Diesel fuel with values of 3.05% and 1.25% for FB25, and 4.07% and 2.2% for CB25, respectively. Also, brake specific fuel consumption for the produced fuels increased up to 5.69% compared to Diesel fuel. However, HC and CO emission reductions compared to the Diesel fuel were found to be around 16.24% and 19.81%, respectively. But, the amount of increase in NOx emissions for the same biodiesel fuels reached up to 17.2%. (C) 2014 Elsevier Ltd. All rights reserved.Öğe Evaluation as fuel diesel engine of methyl esters derived from waste animal fats(Sage Publications Inc, 2015) Behcet, RasimThe purpose of this study is to convert waste animal fats, which are harmful to the environment and human health, into biodiesel fuel and to investigate the using of biodiesel as fuel in diesel engines. For this reason, fish fat methyl ester (FFME) and chicken fat methyl ester (CFME) have been produced by transesterification method from fish fat and chicken fat. After that, methyl esters have been used as fuel in a single-cylinder, four stroke, direct injection and air-cooled diesel engine; and the effects of fuels on engine performance and exhaust emissions have been comparatively investigated with standard diesel fuel (D2). Engine tests show that the performance parameters of biodiesel fuels do not differ greatly from those of the diesel fuel. Slight power losses, combined with an increase in the fuel consumption, are experienced with the animal fat based biodiesel fuels. On the other hand, exhaust emissions (HC and CO) of FFME and CFME fuels were lower than those of diesel fuel. Taken into account of good fuel combustion characteristics and positive effects on the environment, it can be concluded that FFME and CFME fuels can be used as an alternative to diesel fuel.Öğe Evaluation of hydrogen-containing NaBH4 and oxygen-containing alcohols (CH3OH, C2H5OH) as fuel additives in a gasoline engine(Pergamon-Elsevier Science Ltd, 2022) Behcet, Rasim; Yakin, AhmetThe aim of this study is to obtain alternative fuels with hydrogen-containing (NaBH4) and oxygen-containing (ethanol, methanol) fuel additives and to test these fuels in a gasoline engine. For this purpose, each of the NaBH4 added ethanol and methanol solutions was added to pure gasoline at a volume of 10% and mixed fuels named SE10 and SM10 were obtained, respectively. The obtained SE10 and SM10 mixed fuels were tested in a spark ignition engine and the performance and emission effects of the fuels were compared with the pure gasoline fueled engine test data. When the test results of the mixture fuel engine were compared with the test results of the engine running with pure gasoline, the torque of the SE10 fuel engine decreased compared to the pure gasoline engine, while the torque of the SM10 blended engine increased. In addition, while the exhaust gas temperatures of both blended fuels decreased, their specific fuel consumption and thermal efficiency increased. On the other hand, adding NaBH4 doped ethanol and methanol solutions to pure gasoline resulted in better combustion, reductions in CO emissions of SE10 and SM10 blended fuels by 31.04% and 53.7%, but CO2 emissions increased by 11.20% and 19.51% respectively. In addition, NOx emissions of SE10 and SM10 blended fuels decreased by 15.17% and 8.73%, respectively. (C) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.Öğe Experimental investigation of the effect of a novel curved winglet vortex generator on heat transfer with a designed controller circuit(Elsevier France-Editions Scientifiques Medicales Elsevier, 2022) Goksu, Taha Tuna; Behcet, RasimIn the presented experimental study, twelve different double-sided curved blade vortex generators were produced at two blade angles (15 and 30 ) based on the turbulator blade angle, blade direction, and the placement of the turbulators in the pipe. After conducting smooth pipe studies, the curved structure's winglet components were mounted on the pipe at various angles and locations, and the effects on heat transfer and pressure drop were determined for Reynolds Numbers ranging from 16,210 to 41,470. The smooth pipe results obtained were compared with the results obtained from the numerical Gnielinski, Dittus-Boelter, Blasius, and Petukhov equations. In addition, a control circuit has been developed to ensure the precision and recording reliability of the results. The root mean square error (RMSE) and mean absolute percent error (MAPE) results obtained by the controller circuit were found to be in good agreement with the results of the experimental study. Considering the results obtained with the elements placed in the pipe, the highest increases in Nusselt number and friction factor compared to the smooth pipe were 173% and 592%, respectively. The most notable Nusselt number (Nu(a)/Nu(o)) and friction factor (f(a)/f(o)) increases were seen in the values of 3.41 and 6.92, respectively. The highest PEC value for the heat transfer improvement effect was approximately 1.79 for the low Reynolds Number value of 16,214. Among all the turbulators, the highest heat transfer increase was achieved with the double-sided opened blade (UD-30) type turbulator, while the lowest heat transfer increase effect was achieved with the one-bladed opened type (OC-15) turbulator. In terms of PEC, eight turbulators had a significant effect on all Reynolds values, but the remaining four had no effect.Öğe INVESTIGATION OF THE EFFECT OF DEAD-STATE TEMPERATURE ON THE PERFORMANCE OF BORON-ADDED FUELS AND DIFFERENT FUELS USED IN AN INTERNAL COMBUSTION ENGINE(Begell House Inc, 2024) Uckan, Irfan; Yakin, Ahmet; Behcet, RasimThis study aimed to investigate the exergy variations of five different fuels developed for internal combustion engines. Two of these fuels, i.e., boron-added fuels, were newly developed. In many previous studies, only one dead-state temperature was considered for exergy calculations. However, it is important to note that the deadstate temperature can vary. Therefore, the impact of changing the dead-state temperature on the exergy of the internal combustion engine becomes crucial. In this particular study, the exergy variations of the newly developed boron-added fuels ES12.5 and MS12.5, as well as gasoline blended with ethanol (E12.5), gasoline blended with methane (M12.5), and pure gasoline (B100) were examined. These variations were analyzed at different dead-state temperatures ranging from 273 K to 298 K. This study focused on examining the detailed changes in the exergy of exhaust gases emitted from the combustion process, specifically at the exhaust outlet, with respect to variations in the dead-state temperature. Furthermore, the impact of the dead-state temperature on various parameters commonly used in thermodynamic analyses, including improvement potential, productivity lack, and fuel depletion ratio were investigated. Through analysis, the study revealed significant variations in the exergy of internal combustion engines when the dead-state temperature was altered. These findings emphasized the importance of considering the dead-state temperature as a critical factor in understanding and optimizing the exergic performance of internal combustion engines.Öğe Numerical investigation of the thermo-hydraulic performance of DNA inspired double and triple helix wire coils(Elsevier Science Sa, 2022) Goksu, Taha Tuna; Yilmaz, Ibrahim Halil; Behcet, RasimIn this study, DNA-inspired wire coil (WC) inserts, namely double wire coil (DWC) and triple wire coil (TWC), were proposed for promoting the thermo-hydraulic performance of a plain tube. Triangular-in-shape WC fitted tubes were modeled in Ansys Workbench and numerically solved in Ansys Fluent. WC inserts with pitches (0.056 m, 0.112 m, 0.168 m), side lengths (0.005 m, 0.006 m) and clearance distances (0.001 m, 0.002 m) were analyzed through a fully developed turbulent flow with the Reynolds number ranging from 6,406-26,647. Detailed model validations were performed using the empirical data and experimental studies in the literature and good agreements were statistically achieved. Results reveal that the proposed inserts can significantly increase the heat transfer performance and performance evaluation criterion (PEC) by almost up to fivefold and 103% compared to those of a plain tube, respectively. DWC increases the PEC by similar to 1.1 times the SWC fitted tube while TWC can increase the PEC by similar to 1.14 times. Increasing the number of WC beyond three would not add benefits to the PEC considerably.Öğe Second law analysis of an internal combustion engine for different fuels consisting of NaBH4, ethanol and methanol mixtures(Pergamon-Elsevier Science Ltd, 2024) Uckan, Irfan; Yakin, Ahmet; Behcet, RasimThis study was carried out to investigate the effects of NaBH4, which is not used as an internal combustion engine fuel in the literature, on system energy and exergy when used in internal combustion engines. In the study, fuels containing oxygen and hydrogen (MSG12.5, EG12.5, ESG12.5 and MG12.5) and pure gasoline (G100) were tested at different engine speeds and the changes in the energy and exergy analyzes of the system were inves-tigated. In the experimental study, the energy and exergy values of gasoline used as fuel were at the highest values with 33.21 kW and 35.62 kW, respectively, while the energy and exergy efficiencies were 27 % and 25 %, respectively. MG12.5 fuel used in the study showed the best performance among all fuels with 38 % energy efficiency and 35 % exergy efficiency. On the other hand, it was seen that boron added ESG12.5 % fuel was the second best fuel with 35 % energy efficiency and 33 % exergy efficiency. Another fuel, boron added MSG12.5 fuel, performed better than gasoline in terms of both energy and exergy efficiency. In addition, it was determined that more than 50 % of the exergy of the fuel entering the system was lost due to exergy destruction and the exergy destruction of the fuels used in the experiments was determined at least in MG12.5, ESG12.5, EG12.5 and G100, respectively.Öğe Testing sodium borohydride as a fuel additive in internal combustion gasoline engine(Pergamon-Elsevier Science Ltd, 2022) Yakin, Ahmet; Behcet, Rasim; Solmaz, Hamit; Halis, SerdarAdditives are added to conventional fuels to ensure complete combustion of fuels, increase engine performance and reduce harmful emissions from vehicles. Hydrogen and oxygen-containing fuel additives added to fossil-based internal combustion engine fuels improve the properties of the fuels and reduce vehicle-related emissions. Evaluation of mixed fuels created by adding different types of alcohol and nano-sized additives to motor fuels as an alternative fuel in motor vehicles is among the most researched scientific studies recently. In this study, alcohol-gasoline fuels (E5, M5), NaBH4-alcoholgasoline fuels (ES5, MS5), and pure gasoline were tested in a gasoline engine. Fuels used in engine tests; E5 fuel (5% by volume ethanol 95% gasoline blend), M5 fuel (5% by volume methanol 95% gasoline blend), ES5 fuel (5% by volume NaBH4-ethanol solution 95% gasoline blend), MS5 fuel (5% by volume NaBH4methanol solution 95% gasoline mixture) and pure gasoline. In the experiments, brake thermal efficiency, engine torque, specific fuel consumption, and exhaust gas temperature were measured and compared with pure gasoline. Compared to gasoline, the exhaust gas temperatures of all blended fuels decreased. On the other hand, there was an increase in engine torque values, except for ES5 fuel. At the same time, there was an increase in both specific fuel consumption and brake thermal efficiency. When the CO and HC emission values of the blended fuels are compared with the gasoline fuel values, the highest reduction in CO emissions occurred in ES5 blended fuel with 65.53%, while the highest decrease in HC emission was realized in E5 fuel with 19.09%. On the other hand, when NOx and CO2 emissions of E5, M5, ES5, MS5 mixed fuels are compared with gasoline, NOx emissions are 12.63%, 28.37%, 19.65%, respectively; decreased by 36.03% but CO2 emissions increased by 8.51%, 30.46%, 34.48%, 25.95% respectively.(c) 2022 Elsevier Ltd. All rights reserved.
