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Öğe A comprehensive review of battery thermal management systems for electric vehicles(Sage Publications Ltd, 2022) Çetin, İrfan; Sezici, Ekrem; Karabulut, Mustafa; Avci, Emre; Polat, FikretTrying to prevent and mitigate carbon emissions and air pollution is one of the biggest challenges for the technological development of the automobile industry. In addition, the automobile industry has stepped up research and field applications of electric vehicles as the European Union encourages the restriction of the use of conventional fuel-powered vehicles such as diesel and gasoline vehicles. However, the cycle life, environmental adaptability, driving range, and charging time of the battery currently used in electric vehicles are far beyond comparison with internal combustion engines. Therefore, studies have focused on batteries, and battery thermal management systems (BTMSs) have been developed. Battery performance is highly dependent on temperature and the purpose of an effective BTMS is to ensure that the battery pack operates within an appropriate temperature range. Ensuring that the battery operates in the appropriate temperature range is vital for both efficiency and safety. To determine the best convenient BTMS for several types of battery packs attached to many factors such as volumetric constraints, installation costs, and working efficiency. The maximum temperature rise and the maximum temperature difference are the basic parameters to analyze the efficiency of the BTMS. Most of the research about thermal management has focused on especially air cooling, liquid cooling, and phase change material (PCM) cooling methods. In this study, different BTMSs (air cooling, liquid cooling, PCM cooling, etc.) were examined and their advantages and disadvantages were compared, usage restrictions in today's technology, requirements, and studies on this subject were reported.Öğe A comprehensive study on the influences of different types of nano-sized particles usage in diesel-bioethanol blends on combustion, performance, and environmental aspects(Pergamon-Elsevier Science Ltd, 2021) Agbulut, Umit; Polat, Fikret; Saridemir, SuatThis paper aims to discuss the influences of the doping of different types of nanoparticles into the bioethanol-diesel fuel blends on the combustion, performance, and emission aspects. In this viewpoint, the tests are performed at a constant engine speed of 2400 rpm under the varying engine loads from 3 to 12 Nm with the gaps of 3 Nm. Test engine is fuelled with conventional diesel fuel (DF), the binary form of 90% diesel fuel and %10 ethanol (DF90E10), and then separately 100 ppm aluminium oxide (Al2O3) nanoparticles (DF90E10 + A100), and 100 ppm titanium oxide (TiO2) nanoparticles (DF90E10 + T100) into DF90E10 test fuel. In the results, DF90E10 increases brake specific fuel consumption (BSFC) by 6.25% and drops the brake thermal efficiency (BTE) by 2.1% in comparison to those of conventional DF. However, it is noticed that nanoparticles-doped DF90E10 test fuels are being pulled back the worsened performance results thanks to their higher surface to volume ratio, higher cetane number, higher calorific value, superior thermal properties, catalyst role of the accelerating chemical reactions in combustion proces, and high energy density of nanoparticles. Accordingly, BSFC is dropped by 2.25% and 1.26% whilst BTE is enhanced by 3.48% and 2.94% for DF90E10 + A100 and DF90E10 + T100 test fuels, respectively as compared to those of DF. Thanks to the excess oxygen content of ethanol and oxygen-donating catalyst role of nanoparticles, carbon monoxide (CO) is reduced by 14.29%, 25%, and 21.43%, and hydrocarbon (HC) is reduced by 21.32%, 30.15%, and 26.47% for DF90E10, DF90E10 + A100, and DF90E10 + T100, respectively as compared to those of conventional DF. NOx emission increases by 3.6% for DF90E10, and then nitrogen oxides (NOx) are reduced by 3.02%, and 1.57% for DF90E10 + A100 and DF90E10 + T100 due to the higher thermal conductivity value of nanoparticles and improving engine performance characteristics. On the other hand, the highest in-cylinder pressure (CPmax) and heat release rate (HRRmax) values, and longer ignition delay are generally noticed for the diesel-ethanol binary blend due to the lower cetane number, lower energy density and higher viscosity. In conclusion, this paper is proving that the doping of nanoparticles into the biofuels is presenting very satisfying results in pulling back the worsened engine characteristics arising from using diesel-biofuel binary blends. (C) 2021 Elsevier Ltd. All rights reserved.Öğe Current practices, potentials, challenges, future opportunities, environmental and economic assumptions for Türkiye's clean and sustainable energy policy: A comprehensive assessment(Elsevier Ltd, 2023) Ağbulut, Ümit; Yıldız, Gökhan; Bakır, H.; Polat, Fikret; Biçen, Yunus; Ergün, Adem; Gürel, Ali EtemIn today's world, most countries including Türkiye have met their electricity demand at a dominant rate by burning fossil-based fuels in thermal power plants. However, fossil-fuel reserves have been rapidly depleted, resulting in high volatility in these fuels’ markets, as well as alarming environmental, and economic problems for the governments. In recent years, many governments have started to face these problems and have rapidly transitioned to renewable and alternative carbon-free energy sources in their electricity production variety. However, these belated steps have failed to mitigate the increment in global greenhouse gas emissions against the rapid growth of population and energy demand. In recent years, Türkiye has put a noteworthy challenge to mitigate its dominant use of fossil fuels, reducing its energy dependence, sustaining its economic development, and mitigating the carbon footprint. From this point of view, it is witnessed that many power plants have been established, many of them are currently under construction, especially to produce more electricity in a sustainable way. Accordingly, the present study aims to comprehensively discuss Türkiye's energy production policy, energy potential and reserves, challenges, future opportunities, and the impacts of the energy sector on the economic and environmental issues for the country. In this framework, it is well-noticed that the country's future energy production policy has been reasonably changed in order to achieve positive economic and environmental outcomes in the medium and long term. © 2023 Elsevier LtdÖğe The effect of outer container geometry on the thermal management of lithium-ion batteries with a combination of phase change material and metal foam(Elsevier, 2024) Kursun, Burak; Toklu, Ethem; Polat, Fikret; Balta, MehmetThe use of PCM for thermal management of the batteries has an important place among passive cooling methods because it does not require pump or fan power. In battery cooling applications with PCM, it was aimed to increase the thermal conductivity of the PCM and to cool the battery better by using fins, nanoparticles, and metal foam. The novelty of this study is to investigate the effect of outer container geometry on battery temperature in battery cooling with PCM + metal foam composition. In this direction, five different container geometries affecting the heat transfer by conduction and convection were analyzed. The parametric study was carried out for different values of convection heat transfer coefficient, heat generation in the battery, PCM amount, and porosity. The lowest battery temperature for a given discharge time was obtained in triangular container geometry. With the use of a triangular container, the battery temperature was reduced between 0.4 % and 14.42 % compared to the use of a circular container, depending on the parameter values. The analysis findings revealed that the outer container geometry is more effective in the thermal management of the battery for conditions with low convection heat transfer coefficient and high heat generation.Öğe Effects of high-dosage copper oxide nanoparticles addition in diesel fuel on engine characteristics(Pergamon-Elsevier Science Ltd, 2021) Agbulut, Umit; Saridemir, Suat; Rajak, Upendra; Polat, Fikret; Afzal, Asif; Verma, Tikendra NathThis paper examines the effect of adding high dosage of copper oxide (CuO) nanomaterials (<77 nm) directly to conventional diesel fuel. The performance of the fuel with CuO added is assessed using a single cylinder, naturally aspirated, direct injection, air-cooled diesel engine. Examined were the char-acteristics of combustion and emissions for blends of 1000 and 2000 ppm CuO nanoparticles. The CuO blends were tested in the speed range between 2000 and 3000 rpm at intervals of 250 rpm. The CuO nanoparticles have the potential to accelerate the process of combustion by supplying molecules of oxygen and acting as a catalyst. The CuO enhances the thermal conductivity of the test fuels and in-creases heat dissipation from the combustion chamber. Experimental results show exhaust gas tem-perature (EGT) is reduced as well as unburnt hydro-carbons (HC) and oxides of carbon and nitrogen (CO and NOx). For CuO additions of 1000 and 2000 ppm, CO emissions fell by 14.6% and 20.8%, HC emissions by 6.2% and 13.4%, and NOx emissions by 4%, and 4.7%. Both blends of CuO increased the heating value of the diesel fuel. Brake-specific fuel consumption (BSFC) dropped by 4.5% and 8% while brake thermal efficiency (BTE) increased by 5.5% and 14.6% for 1000-CuO and 2000-CuO, respectively. On the other hand, nanoparticles accelerated the chemical reactions and the ignition delay (ID) period was shortened by 3.03% and 5.45% for CuO additions of 1000, and 2000 ppm, respectively. It was also observed that CuO nanoparticles up to 2000 ppm can be suspended in diesel fuel without clogging the filter on the injection system. (c) 2021 Elsevier Ltd. All rights reserved.Öğe Exergetic and exergoeconomic assessments of a diesel engine operating on dual-fuel mode with biogas and diesel fuel containing boron nitride nanoparticles(Springer, 2024) Uysal, Cuneyt; Agbulut, Umit; Topal, Halil Ibrahim; Karagoz, Mustafa; Polat, Fikret; Saridemir, SuatThis study investigates the exergetic and exergoeconomic analyses of a diesel engine operated on dual-fuel mode with fuelled both diesel fuel-boron nitride nanofuel and biogas purchased commercially. The experiments were performed for diesel fuel, diesel + 100 ppm boron nitride nanoparticle, diesel + 100 ppm boron nitride nanoparticle + 0.5 L min-1 biogas, diesel + 100 ppm boron nitride nanoparticle + 1.0 L min-1 biogas and diesel + 100 ppm boron nitride nanoparticle + 2.0 L min-1 biogas at various engine loads (2.5 Nm, 5.0 Nm, 7.5 Nm, and 10.0 Nm) and fixed crankshaft speed of 1500 rpm. The obtained experimental data were used to realize exergetic and exergoeconomic analyses. Among the fuels considered in this study, diesel + 100 ppm boron nitride nanoparticle nanofuel had the best exergetic and exergoeconomic results. As a result, at engine load of 10 Nm, the exergy efficiency of test engine and specific exergy cost of crankshaft work were obtained to be 29.12% and 124.86 US$ GJ-1 for diesel + 100 ppm boron nitride nanoparticle nanofuel, respectively. These values were 27.35% and 125.19 US$ GJ-1 for diesel fuel, 25.50% and 141.92 US$ GJ-1 for diesel + 100 ppm boron nitride nanoparticle + 0.5 L min-1 biogas, 23.10% and 156.33 US$ GJ-1 for diesel + 100 ppm boron nitride nanoparticle + 1.0 L min-1 biogas, and 21.09% and 171.92 US$ GJ-1 for diesel + 100 ppm boron nitride nanoparticle + 2.0 L min-1 biogas, respectively. It is clear that biogas addition to combustion made worse the exergetic and exergoeconomic performances of test engine. As a conclusion, it can be said that diesel + 100 ppm boron nitride nanoparticle nanofuel can be used as alternative fuel to D100 in terms of exergy and exergoeconomics.Öğe Experimental assessment of the influences of liquid-solid-gas fuel blends on DI-CI engine behaviors(Elsevier, 2022) Polat, Fikret; Yeşilyurt, Murat Kadir; Ağbulut, Ümit; Karagöz, Mustafa; Sarıdemir, SuatThis study aims to deeply investigate the effects of the boron nanoparticles reinforced diesel fuel along with various biogas (BG) flow rates (0.5, 1, and 2 L/min) on the engine performance and emission characteristics of a diesel engine. The tests were carried out using a single-cylinder, four-stroke, direct injection, compression-ignition engine at a constant engine speed of 1500 rpm and under the varying engine loads from 2.5 to 10 Nm with gaps of 2.5 Nm. In the results, it is seen that EGT started to decrease in both the addition of boron nanoparticles and the addition of biogas compared to that of conventional diesel fuel (DF). EGT reduced by 8.6% for DF+Boron test fuel, 14.4% for DF+Boron+ 0.5 BG, 21% for DF+Boron+ 1 BG, and 23.4% for DF+Boron+ 2 BG. Compared to diesel fuel, CO, NOx, and HC emissions decreased with the addition of nanoparticles at all loads. However, as the amount of biogas increased, CO and HC emissions increased, but NOx emissions decreased. CO emission dropped by 22.2% for DF+Boron test fuel, however, increased to be 5.6%, 16.7%, and 36.1% for DF+Boron+ 0.5 BG, DF+Boron+ 1 BG, and DF+Boron+ 2 BG respectively. NOx emission reduced by 4.9%, 8.6%, 10.7%, and 14.8% for DF+Boron, DF+Boron+ 0.5 BG, DF+Boron+ 1 BG, and DF +Boron+ 2 BG respectively. In comparison to that of conventional DF, the brake specific fuel consumption (BSFC) value decreased by 8.42% for DF+Boron test fuel due to high energy content of nanoparticles, but it increased by 10.94% for DF+Boron+ 0.5 BG, 28.01% for DF+Boron+ 1 BG, and 60.2% for DF+Boron+ 2 BG. In addition, brake thermal efficiency BTE value increased by 8.04% for boron-added test fuel, but it declined by 9.41% for DF+Boron+ 0.5 BG, 19.38% for DF+Boron+ 1 BG, and 32.2% for DF+Boron+ 2 BG as compared to that of DF. In the conclusion, it is noticed that the engine characteristics have worsened by the introduction of biogas into the cylinder, but these worsened characteristics can be improved with the presence of boron nitride nanoparticles. (c) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.Öğe An experimental assessment on dual fuel engine behavior powered by waste tire-derived pyrolysis oil - biogas blends(Elsevier, 2022) Karagöz, Mustafa; Polat, Fikret; Sarıdemir, Suat; Yeşilyurt, Murat Kadir; Ağbulut, ÜmitThis paper is intended to investigate the usability of waste tire pyrolysis oil along with diesel and biogas dual fuel in the CI engines. In this framework, the waste tire chips are firstly pyrolyzed in the study, and then are volumetrically blended into the conventional diesel fuel (DF) at the ratio of 20%. The biogas flow rate changes as 0.5, 1, and 2 L/min when the engine is fuelled by P20 test fuel. Throughout the experiments, the engine runs at a fixed engine speed of 1500 rpm under 2.5, 5, 7.5 and 10 Nm. In the results, it is noticed that the unburnt emissions such as CO and HC considerably increases with the presence of pyrolysis oil and biogas in the cylinder due to the lack of oxygen and lower heating value of these fuels. However, the NOx firstly rises with the dieselpyrolysis oil blends by 2.21% but then pulls back with the introduction of biogas to the combustion chamber. It drops by 2.29%, 4.93%, and 11.14% for P20 + 0.5 BG, P20 + 1 BG, and P20 + 2 BG test fuels, respectively in comparison to that of DF. On the other hand, the engine performance worsens with the pyrolysis oil due to the lower energy content. Accordingly, the increment on BSFC is found to be 9.28%, 25.15%, 42.51%, and 67.68%, and the reduction on BTE is found to be 8.47%, 17.72%, 25.52%, and 33.48% for P20, P20 + 0.5 BG, P20 + 1 BG, and P20 + 2 BG test fuels, respectively. It is concluded that even if they worsen the engine performance and exhaust emissions, the burning of waste products in the forms of pyrolysis oil and biogas as fuel substitutions in CI engines seems a very promising way in terms of waste management, disposal the huge volume of waste products from the nature, and protection of rapidly depletion fossil fuel reserves.Öğe Experimental evaluation of the impacts of diesel-nanoparticles-waste tire pyrolysis oil ternary blends on the combustion, performance, and emission characteristics of a diesel engine(Elsevier, 2022) Polat, FikretIn the present research, pyrolytic oil is obtained from the waste tire chips, and then acid washing process, clay and calcium oxide process, distillation process, and oxidative sulfur removal processes are used to improve its properties. Then it is blended into conventional diesel fuel with/without Al2O3 nanoparticles, and the performance, combustion, and emission characteristics of a single-cylinder, air cooled, and naturally aspired diesel engine are discussed in this study. Tests were performed at varying engine loads from 3 to 12 Nm with the gaps of 3 Nm under a constant engine speed of 2400 rpm. In this study, three types of fuels were tested, namely D100 (100% diesel fuel), P10 (90% diesel fuel and 10% pyrolytic oil), and P10 + 1 g Al2O3 (obtained by adding 1 g of Al2O3 nanoparticles to P10 fuel). The addition of Al2O3 nanoparticles increased the brake thermal efficiency while reducing the maximum in-cylinder pressure, heat release rate, specific fuel consumption, exhaust gas temperature, hydrocarbon emissions, NOx emissions, and CO emissions compared to other test fuels. Namely, with the addition of Al2O3 nanoparticles, BTE was improved by 4.51% and 1.59% compared to P10 and pure diesel fuel, respectively. According to this, the BSFC value increased by 4.29% for P10 test fuel and then is reduced by 2% for P10 + 1 g Al2O3 test fuel as compared with conventional diesel fuel. Compared to diesel fuel, the CO, NOx, and HC emission values deteriorated by 17.5%, 5.69%, and 18.6%, respectively, with the addition of pyrolysis oil, and these deteriorated properties were improved by 10%, 6.82%, and 13.95%, respectively, with the addition of Al2O3 nanoparticles. In the light of this study, it was observed that while waste tire pyrolysis oil worsened engine performance, emission, and combustion characteristics, these deteriorations could be improved with nano Al2O3 supplementation. (c) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.Öğe Improvement of worsened diesel and waste biodiesel fuelled-engine characteristics with hydrogen enrichment: A deep discussion on combustion, performance, and emission analyses(Elsevier, 2024) Saridemir, Suat; Polat, Fikret; Agbulut, UmitDue to the strict emission policies, fuel researchers are dedicated to mitigating the tailpipe emissions from internal combustion engines (ICEs). Therefore, researchers have considered biodiesel as the best alternative to conventional diesel fuel (D) for a while. However, many scientific papers experimentally announced that the use of biodiesel significantly worsens engine behaviors. In this framework, hydrogen enrichment has become a very reasonable option in order to minimize the reverse influences of biodiesel-fuelled engine characteristics. In this direction, waste cooking of 25% (B25) was volumetrically blended to D and reference data was collected. Then, 15 and 30 Lpm hydrogen was introduced from the intake manifold by mixing with air along with B25 test fuel to observe the changes from the hydrogen effect. Tests were performed on a three-cylinder, water-cooled diesel engine at constant engine speed (2000 rpm) and variable engine loads (15, 30, 45 and 60 Nm). In the results, it is witnessed that BSFC (brake specific fuel consumption) for B25 fuel increased by 8.23% as compared D fuel. However, along with the introduction of 15 and 30 Lpm hydrogen to B25 fuel, the BSFC value dropped by 17.58%, and 30.75%, respectively. In a similar way, B25 test fuel reduces BTE (brake thermal efficiency) by 7.54% as compared to D fuel. However, the hydrogen introduction of 15 and 30 Lpm (Litre per minute) along with B25 fuel improves the BTE value by 10.19%, and 17%, respectively. On the other hand, the inclusion of 15 Lpm and 30 Lpm H2 to B25 fuel provided a reduction of 23.75% and 45.59% for HC (Hydrocarbon) emissions, and 53.1% and 62.6% for NOx (Nitrogen oxide) emissions, respectively. In conclusion, it is seen that deteriorations in combustion, performance, and emission characteristics resulting from the use of biodiesel can be minimized by using hydrogen for ICEs.Öğe Influence of A Novel Catalysis on The Pyrolysis Yields Obtained by Two Different Reactors(2020) Toklu, Ethem; Polat, Fikret; Kılınçel, MertIn the present study mixtures of polymeric and cellulosic biomass materials were pyrolized in the presence of two different catalysts (sepiolite and aluminium bauxite) in various ratios by two different reactors; a rotary kiln reactor (RKR) and a fixed bed pyrolysis reactor (FBR). The results were compared to determine the effects of pyrol ysis parameters such as catalysts, feedstock and reactor types on the energy content of the final products. First, the polymeric and cellulosic materials were mixed at certain ratios and thus the mixtures were prepared. Then, thermally activated catalysts were added to these mixtures. At the end of the experiments, certain properties such as higher heating value (HHV), the elemental concentrations, particle size and size surface areas of the end products (for solid and liquid phases) were calculated and analysed. The HHV of the liquid products from bauxite added mixture in RKR and FBR was 42.74 MJ/kg and 40.95 MJ/kg respectively. Besides the HHV of the oil products from sepiolite added mixture in RKR and FBR was 41.28 MJ/kg and 38.94 MJ/kg respectively. These values are same and close to HHV of the conventional diesel (42.7 MJ/kg). However no considerable effect seen on HHV of char products from catalyst added mixtures. On the other hand, due to the SEM images the char products it can be clearly concluded that com paring with FBR, RKR had the better performance on pyrolysis of the biomass mixtures.Öğe Investigation of the effects of different nanoparticle-reinforced liquids on the cooling performance of the battery thermal management system(Springer Heidelberg, 2024) Celik, Kemal; Polat, Fikret; Kilincel, MertElectric vehicles are gaining importance in the transportation sector as an environmentally friendly option to replace fossil fuels and reduce carbon footprint. Battery packs, which are the power source of electric vehicles, are high-cost and thermally sensitive components. The temperature rising and temperature distribution of battery packs during charging and discharging processes affect their performance, life, and safety. Therefore, an effective cooling system is required to keep the operating temperature of the battery packs in the optimum range and to ensure homogeneous temperature distribution. In this study, a battery module containing 18 cylindrical lithium-ion batteries was placed in a labyrinth-type cooling channel. The cooling channel is made of copper. Pure water, boron nitride (BN)-water nanofluid, and titanium dioxide (TiO2)-water nanofluid were passed through the cooling channel and the thermal performances of the cooling fluids were compared. Concentrations of 0.1% by mass of BN-water nanofluid and 0.1% by mass of TiO2-water nanofluid were used. Experiments were carried out at 1C charge and 1C, 2C, and 3C discharge rates to test the battery pack under different operating conditions. In all experiments, the inlet flow rate of the refrigerants was kept constant at 790 ml/min and the inlet temperature at 25 degrees C. According to the experimental results, it was seen that BN-water nanofluid provides better cooling performance compared to other fluids and makes the temperature distribution of the battery module more homogeneous. This study aims to contribute to the development of battery thermal management systems in electric vehicles.Öğe Kentsel katı atıkların termal işlenmesinin enerji optimizasyonu(Düzce Üniversitesi, 2018) Polat, Fikret; Toklu, EthemKentsel katı atık içeriği bölgeden bölgeye, ülkeden ülkeye, ilden ile hatta aynı il için yıldan yıla göre bile değişiklik gösterdiği için, literatürde farklı menülerde hazırlanmış kentsel katı atığın pirolizine ait veri bulunmamaktadır. Bu çalışmada kentsel katı atıklardan enerji üretim teknolojileri hakkında detaylı literatür taraması yapılmış, sıcaklığın termal bertaraf yöntemlerinden piroliz işleminin sonucunda elde edilecek son ürün miktarlarına ve özellikle metan gazı miktarına olan etkisini araştırmak üzere deneyler yapılmıştır. Ayrıca döner fırın piroliz reaktörü nümerik olarak modellenmiş, kütle, enerji, momentum ve ısı transferi denklemleri türetilmiştir. Aynı zamanda üç farklı çap/boy oranında tasarlanan piroliz reaktörü için sonlu elemanlar modeli oluşturulmuş, 2015 yılı Kocaeli ili çevre durum raporundan alınan verilerle giriş sıcaklığı, partikül boyutu ve dönme hızlarında farklı değerler denenerek toplamda 81 adet hesaplamalı akışkanlar dinamiği analizi yapılmıştır. Maksimum metan gazı miktarının elde edildiği analiz şartlarına göre Kocaeli ilinin kentsel katı atıklardan elde edilebilecek enerji potansiyeli hesaplanmıştır. Metan miktarı açısından sonlu elemanlar analizi ile deneysel verilerin birbiriyle örtüştüğü ve buna bağlı olarak da Kocaeli ilindeki kentsel katı atıkların piroliz işlemine tabi tutulmaları halinde meydana gelecek gaz ürünlerden sadece metan gazının değerlendirildiğinde bile üretilebilecek yıllık elektrik enerjisinin yaklaşık 156 GWh olduğu hesaplanmıştır.Öğe Kentsel katı atıkların termoliz yöntemi ile işlenmesinin termodinamik analizi(Düzce Üniversitesi, 2015) Polat, Fikret; Toklu, EthemGünümüzde kentlerin en büyük sorunlarından biri, sanayileşme neticesinde elde edilen ilerlemeyle doğru orantılı olarak yaşam standartları yükselirken önlenemeyen nüfus artışının da doğal kaynakların tükenmesine ve çevrenin artan katı atık miktarı yüzünden hızla kirlenmesine sebep olmasıdır. Tüketim alışkanlıklarının değişmesi neticesinde kişi başına üretilen katı atık miktarı her geçen gün artmaktadır. Bu sorun atıkların bertarafında kullanılan teknolojilerin ekonomik ve çevre dostu olması ile ilgili endişeleri arttırmaktadır ve konuyla ilgili araştırmalar giderek artmaktadır. Tüm dünyada sürdürülebilir kalkınma yaklaşımı kapsamında; atıkların çevre ve insan sağlığı açısından bir tehdit olmaktan çıkıp, ekonomi için bir girdiye dönüştürülmesini amaçlayan atık yönetim stratejileri benimsenmektedir. Entegre katı atık yönetimi, kaynakta atık azaltma, yeniden kullanım, geri dönüşüm ve geri kazanım uygulamaları ile başlayıp, oluşan atığın toplanması ve nihai bertarafı ile son bulan bir prosestir. Atıkları enerjiye dönüştürmek için çeşitli teknolojiler mevcuttur. Bu teknolojilerin başlıcaları düzenli depolama, yakma, piroliz, gazifikasyon ve anaerobik çürütmedir. Düzenli depolama atıkların mühendislik esaslarına göre depolanmasıdır. Oluşan depo gazı enerji üretiminde kullanılır. Yakma teknolojisinde, atıklar kontrollü olarak ısı geri kazanımı sağlanarak yakılırlar ve buhar türbinleri kullanılarak elektrik üretimi gerçekleştirilir. Gazlaştırma teknolojisi ilk aşamada piroliz içerir daha sonra bunu yüksek sıcaklıklı reaksiyonlar takip eder ve düşük molekül ağırlıklı gazlar üretilir. Üretilen gaz içten yanmalı motorlar veya boylerler kullanılarak enerji üretimi için değerlendirilir. Bu çalışmada kentsel katı atıklardan enerji üretim teknolojileri hakkında detaylı literatür taraması yapılmış, tezin birinci bölümünde, çalışmanın önemi, amacı ve kapsamı açıklanmıştır. İkinci bölümde katı atık konusu ile ilgili tanımlar yapılmış ve birbirleriyle kıyaslanılmıştır. Daha sonra kentsel katı atık bertaraf metotları geri kazanım, düzenli depolama, termal dönüşüm teknolojileri ve biyolojik dönüşüm teknolojileri sırasıyla anlatılmıştır. Bunlardan enerji geri kazanımı sağlayan teknolojiler özellikle termal bertaraf yöntemlerinden pirolizin termodinamik analizi yapılmıştır. Son bölümde sonuçlar değerlendirilmiş ve öneriler yapılmıştır.Öğe Performance and emission behaviors of a CI engine fueled by waste feedstocks at varying compression ratios(Sage Publications Ltd, 2022) Polat, FikretThe main objective of this study is to observe the effects of compression ratio (CR) variation on the engine performance and exhaust emission characteristics of a single-cylinder diesel engine fueled by waste fusel oil (F), waste cooking oil biodiesel (BD), and waste tire pyrolysis oil (P). For this purpose, Diesel RK software was used and the analyzes were performed at varying CRs of 18.3, 20.3, and 22.3. Analyzes were carried out at 2400 rpm constant engine speed, and varying engine loads (3, 6, 9, and 12 Nm). In the results, it is noticed that as the CR increased, BSFC (Brake Specific Fuel Consumption) value also increased for all test fuels. However, at low loads (3 and 6 Nm), the BSFC value decreased as the compression ratio increased after CR20.3. While the maximum BSFC value was obtained to be 560.55 g/kWh for P20 fuel at 3 Nm for CR20.3, the minimum one was achieved to be 46.76 g/kWh for neat diesel fuel at 12 Nm for 18.3. As the CR increased, the BTE (Brake thermal efficiency) value decreased for all test fuels at nearly all loads. However, at low loads (3 and 6 Nm), it is observed that the BTE improved as the CR increased after CR20.3. While maximum BTE was calculated to be 32.07% for P10F10 fuel at CR18.3 compression ratio at 12 Nm load, minimum one was achieved to be 15.36% for P20 at 3 Nm load for CR20.3. In addition, the NOx increased at all loads as CR increased for all test fuels. The maximum NOx value for P20 was recorded to be 1300 ppm at 12 Nm load and CR22.3. A minimum NOx was detected as 144. 56 ppm for P10F10 at 3 Nm, and CR18.3. In conclusion, the paper has proved that the experimental results are well-fitting with those of simulation software.Öğe Role of hydrogen-enrichment for in-direct diesel engine behaviours fuelled with the diesel-waste biodiesel blends(Pergamon-Elsevier Science Ltd, 2024) Alcelik, Necdet; Saridemir, Suat; Polat, Fikret; Agbulut, UmitCarbon footprint indicates the total amount of greenhouse gases released into the atmosphere by individuals, institutions and countries. The widespread use of fossil fuels is a big player which increases the carbon footprint. Therefore, switching to sustainable alternatives in energy production and consumption is an effective step in combating climate change, as well as efforts to prevent the depletion of fossil fuels. In this regard, although biodiesels offer a solution to the depletion of fossil fuels, with this advantage, the effects of production processes and use on environmental sustainability should be taken into consideration. Many scientific studies have shown that engine performance remains below standards with biodiesel. The availability of hydrogen as an energy carrier in cylinder to overcome the above -mentioned negative situations has recently become a popular topic for fuel researchers. In this work, the diesel-biodiesel fuels were blended proportionally and tested on a threecylinder water-cooled in -direct diesel engine at varying loads (15, 30, 45, and 60 Nm) and a constant engine speed of 2200 rpm for observing the effects of test fuels on combustion, performance, and emissions characteristics of diesel engine. First of all, conventional diesel fuel (D) was used to obtain reference data, and then B20 fuel obtained by mixing waste cooking oil with 20 % by volume of diesel fuel was used. The remaining 4 fuels are test fuels obtained by giving hydrogen from the intake manifold at different flow rates (10, 20, 30, and 40 L/min) in addition to B20 fuel. These fuels are called B20 + 10 Lpm H 2 , B20 + 20 Lpm H 2 , B20 + 30 Lpm H 2 and B20 + 40 Lpm H 2 , respectively. As a result, the BSFC of B20 fuel increased by 8.78 % compared to diesel fuel, and then the addition of hydrogen dropped the BSFC value by 8.8 %, 13.02 %, 17.16 %, and 22.12 % for B20 + 10 Lpm H 2 , B20 + 20 Lpm H 2 , B20 + 30 Lpm H 2 , and B20 + 40 Lpm H 2 , respectively. Hydrogen enrichment also had a positive impact on BTE. Although the BTE dropped by 6.14 % in B20 fuel compared to diesel, it increased by 4.51 %, 5.05 %, 5.62 %, and 7.12 % in B20 + 10 Lpm H 2 , B20 + 20 Lpm H 2 , B20 + 30 Lpm H 2 and B20 + 40 Lpm H 2 fuels, respectively. The addition of 10, 20, 30, and 40 Lpm H 2 to B20 fuel reduced NOx emissions by 31.25 %, 33.08 %, 38.87 %, and 41.46 %, respectively, and also reduced CO emissions by 17.47 %, 30.73 %, 51.8 % and 59.04 % respectively.Öğe Structural and Thermal Analyses of F Class Gas Turbine Compressor Blade(2022) Gerengi, Mustafa; Polat, FikretGas turbines are used extensively for aircraft propulsion, land-based power generation, and industrial applications. They are consist of many parts. One of the important parts is the blade and disc. Blade and disc are individual components that make up the compressor section. That is why all effects on these components directly affect the unit itself. For that reason engineering calculations on such critical parts are important. Some power plants and gas turbines failed regarding wrong engineering calculations. One of them happened two years ago on GE (General Electric) 9FB gas turbine in Turkey. Some turbine blades have broken and created high-cost damage on the unit. Some engineering calculations have been failed regarding side running conditions. For that reason, this study has been performed to protect and verify the engineering value of AEN 94.3A F-type gas turbine side running conditions. In this study, the structural and thermal analysis of the final stage compressor rotor blade and disc, which are currently used on-site, was performed by using the ANSYS program. Initially, basic knowledge of blade and disc design drawings were reviewed and design steps of the existing 3D (Three dimensions) blade and disc configuration were described. For that reason, a 3D model of the existing compressor blade and the disc has been done in the SolidWorks design program. Later on, this model was transferred to the ANSYS program and analyzed. In the analysis, the parameters formed in the blade geometry were determined. By creating a design geometry with the selected parameters, the stress of the existing blade under operating conditions was examined. All external parameters in this study were taken from an F-type gas turbine operation under real field conditions. The stresses obtained from different regions on the blade were examined. After the thermal and structural analysis, obtained results have been compared with side engineering measurements. By comparison, it was observed and verified that the unit normal side running condition is safe and engineering calculations are sufficient. In this study before starting the analysis, general information about gas turbines has been presented. Gas turbines have been briefly introduced and then, the basic operation principles of turbines have been explained. As it is known, gas turbines are shaped based on thermodynamic principles. In this study, engineering thermodynamics in gas turbines is briefly explained as well.
