Makine ve Metal Teknolojileri Bölümü Koleksiyonu

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https://hdl.handle.net/20.500.12514/171

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Chemical characterization of waste tire pyrolysis products
(International Advanced Researches and Engineering Journal, 2021) Uğuz, Gediz; Ayanoğlu, Abdulkadir
The significance of tire disposal, an attractive waste to convert into burning oil or absorber etc.,has been increasing day by day. However, if it does not change into a useful form, it will damagethe nature and the living things. Thus, pyrolysis, a well-known method, which is used to convertrecycle tire waste into gas, liquid and char. On the other hand, the waste pyrolysis oil or wastetire oil (WTO) has a substantial avaliable calorific value similar to those of fossil fuels. Due topyrolysis reaction, high amount of sulfur is detected in the WTO; therefore, another step ofexplosion applied to WTO to decrease sulfur and also re-upgrade quality of oil with suchcatalysts as Calcium Oxide (CaO) and Natural Zeolite (NZ) at a ratio from 2 to 10 with anincrease of 2 for each step, individually. It is noticed that distillation test is a key analysis forseparation discrimination of rich or lean quality fuel. As a consequence of mixture of catalystWTO reactions, the best curve was observed at a 10% CaO-WTO mixture which was close todiesel#2 and the mixture was separated into two new fuels as light (Gasoline Like Fuel orabbreviated as GLF) and heavy one (Diesel Like Fuel or shortened as DLF) due to temperaturedifferences. According to distillation, FT-IR, NMR and UV–vis were used to analyze WTO,GLF and DLF for defining their characterization as well. Thus, the characterization result data ofsamples have quasi-equivalent with standard petroleum in open literature, and can be combustedin engine as well.
THERMAL ANALYSIS OF DIFFERENT REFUSE DERIVED FUELS SAMPLES
(DoiSerbia, 2021) Ayas, Gizem; Öztop, Hakan F.
As a result of the activities carried out by people to maintain their daily lives in different places such as homes, hospitals, hotels or workplaces, waste consisting of furniture, paint, batteries, food waste, sachets, bottles, fabrics, and fibers with the heterogeneous structure is called municipal solid waste. Secondary fuels with higher heating value, which are generated by recycling of non-recyclable and reusable wastes in municipal solid wastes, are called as refuse derived fuel (RDF). In this study, RDF1 (taken in December, winter season) and RDF2 (taken in June, summer season) samples obtained from different dates were used. The ultimate, proximate, calorific value, X-ray fluorescence, thermogravimetric analysis, and differential scanning calorimetry analysis were performed for these samples. Combustion characterization from RDF samples was investigated in the applied analyzes. The results of the content analysis made were examined separately and compared with the thermogravimetric analysis and differential thermal analysis combustion graph curves. It was revealed that the RDF1 sample had a better combustion compared to the RDF2 sample, as the ash amount and content obtained as a result of the combustion also supported other data. In addition, the results of the analysis show how different the RDF samples taken from the same region in two different months are different from each other.
Thin-Layer Drying Modeling in the Hot Oil-Heated Stenter
(International Journal of Thermophysics, 2020) Ünal, Fatih; Akan, Ahmet Erhan
Although the drying processes have an important place in the textile industry in terms of drying or various textile finishing applications, they are considered as an expensive process in terms of energy and time consumed. Therefore, it is of great importance to simulate with mathematical models the drying behavior of a stenter (ram machine), one of the most preferred convection dryers in the textile industry. For this purpose, in this study, modeling was attempted of the drying behavior of 67 % Cotton + 33 % Polyester containing Thessaloniki knit fabrics, using experimental data obtained from drying processes performed in 9 different drying operations in a 10-chamber hot oil-heated stenter and 12 different empirical and semi-empirical thin-layer models that are frequently used in the literature. R2 values from regression analysis were evaluated as the primary factor in the model fit selection. According to the results obtained, it was understood that the Diffusion Approach model with R2 values ranging from 0.9991 to 0.9999, Two Term Model with R2 values ranging from 0.9995 to 0.9999, and the Modified Henderson and Pabis model with R2 values ranging from 0.9995 to 0.9999 gave the most appropriate results upon simulating drying behavior. In this regard, this study, which contains explanatory information on the drying behavior in a stenter, is thought to be useful to researchers.
CONDENSATION ANALYSIS OF THE INSULATION OF WALLS IN MARDIN PROVINCE ACCORDING TO DIFFERENT LOCATIONS
(2019) Ünal, Fatih
In this study, condensation and vapor diffusion caused by different positioned insulation in the wall were analyzed for Mardin province. In the analysis, according to the 2008 standard of TS 825, the MATLAB calculation program was used with the Glaser graphing method and graphical user interface (GUI). Extruded polyurethane foam was used as the insulation material and normal unreinforced concrete was chosen as the wall. Evaporation and condensation values were determined by creating 6 different wall models with the same insulation thickness of 20 cm and an unreinforced concrete wall was covered with 2 cm plaster on the inside with a 3 cm thickness on the outside. The data obtained for 2 cm and 4 cm insulation thicknesses are presented in tables and the results are interpreted for Mardin province. Consequently, it was seen that the worst wall structure in terms of condensation and evaporation was obtained in the middle insulated wall and later in the interior insulated wall structure. The externally insulated wall did not show any condensation.
Fuels properties, characterizations and engine and emission performance analyses of ternary waste cooking oil biodiesel-diesel-propanol blends
(SUSTAINABLE ENERGY TECHNOLOGIES AND ASSESSMENTS, 2019) Bencheikh, Kamel; Atabani, A. E; Shobana, Sutha; Mohammed, M. N.; Uguz, Gediz; Arpa, Orhan; Kumar, Gopalakrishnan; Ayanoglu, Abdulkadir; Bokhari, Awais
Application of biodiesel synthesized from waste-based raw materials with numerous solvents (higher chain alcohols) in diesel engines is a topic of great interest. This article examines the effect of biodiesel-diesel-propanol ternary blends. Physio-chemical properties, fatty acids composition (FAC), FT-IR, TGA, DSC, NMR along with some selected engine and emissions performance parameters were examined. Biodiesel was produced from waste cooking oil and exhibits excellent FAC that yields kinematic viscosity, cetane number, oxidation stability, higher heating value and iodine value of 3.93mm(2)/s, 58.88, 7.43 h, 39.45 MJ/kg and 64.92 g/100 g. Propanol blended biodiesel depicted an affirmative improvement in cold flow properties and decremented density. FT-IR and NMR results confirms the existence of biodiesel-diesel-propanol and prove their qualities as reliable methods. DSC and TGA results confirm that propanol reduces the onset and crystallization temperatures of the blends. Engine and emissions performance revealed that propanol addition further increased brake specific energy consumption (BSEC) and brake specific fuel consumption (BSFC) and reduced carbon monoxide (CO), exhaust gas temperature (EGT), nitrogen oxides (NOx) and smoke. This study proves the feasibility of the ternary blends with rewarding benefits in cold flow properties and densities besides acceptable engine and emissions performance results.
Experimental analysis and modeling of the thermal conductivities for a novel building material providing environmental transformation
(Energy Sources, Part A: Recovery, Utilization and Environmental Effects, 2021) Ünal, Fatih; Koçyiğit, Fatih; Koçyiğit, Şermin
In this study, a mathematical equation was developed to determine the thermal conductivity of the materials by producing porous heterogeneous materials with expanded vermiculite aggregates, waste basalt powder, and the mixture of molten tragacanth added building materials. Experimental thermal conductivity of the samples was determined by using the hot wire method. Experimental thermal conductivity of the samples produced varied between 0.196 W/mK and 0.522 W/mK depending on the expanded vermiculite ratio, the ratio of waste basalt powder, and the ratios of tragacanth and cement. In addition, the developed mathematical thermal conductivity ranges from 0.201 W/mK to 0.455 W/mK. The experimental values deviated from the values in the developed model in the range of 3–19%. This equation was developed based on the porosity ratio of the produced samples, the density and thermal conductivity of the materials in the samples. The thermal conductivity results obtained by the experimental and theoretically developed equation were compared with each other and it was observed that the results were compatible.
Energy and exergy analysis of an industrial corn dryer operated by two different fuels
(International Journal of Exergy, 2021) Ünal, Fatih
In this study, the data obtained after converting an industrial horizontal type corn dryer that meets its drying air temperature from coal to natural gas was compared by thermodynamic analyses. Before starting the drying process, it was assumed that the corn type DKC6050 with 24-25% corn inlet humidity dries when it reaches approximately 14% corn outlet humidity, which is the storage condition after the drying process. Energy and exergy efficiencies, drying rates, unit drying costs, specific moisture extraction rate, and specific energy consumption values of the analysed systems were determined using the data obtained from the experiments carried out at 90, 100 and 110 C drying temperatures. On the other hand, it was also determined that the unit drying cost was approximately 0.1-0.45 €/kg and the specific energy consumption was less than approximately 1,000-8,000 kJ/kgwater. Also, emission values released to the environment were calculated for both systems based on the amount of energy required for drying.
Lpg Yakıtlı Endüstriyel Yatay Tip Mısır Kurutma Tesisinin Enerji ve Maliyet Analizi
(Dicle Üniversitesi Mühendislik Fakültesi Mühendislik Dergisi, 2020) Ünal, Fatih; Bulut, Hüsamettin; Kahraman, Ahmet
Bu çalışmada kurutma havasının ısıtılmasında LPG kullanılan yatay tip mısır kurutma tesisinin kurutma odasına farklı kurutma havası giriş sıcaklıkları ile elde edilen sonuçlara bağlı olarak enerji ve maliyet analizleri yapılmıştır. Kurutma sürecinde, sisteme sabit hava debisinde farklı sıcaklıklarda (85°C, 90°C ve 95°C) kurutma havası gönderilerek belirlenen düğüm noktalarında sıcaklık(°C), bağıl nem(%) ve hava hızı(m/s) ölçülmüştür. Sistemde belirlenen 6 adet düğüm noktasından elde edilen verilere bağlı olarak yapılan enerji ve maliyet analizinde kurutma havası giriş sıcaklığı, ısıtıcı giriş havasının sıcaklığı ve bağıl nem değişimlerinin yakıt sarfiyatı, enerji verimliliği ve birim kurutma maliyet üzerindeki etkileri değerlendirilmiştir. Sonuç olarak, kurutma giriş havası sıcaklığının artmasının enerji verimliliğini düşürdüğü, birim kurutma maliyetini ve yakıt sarfiyatını artırdığı tespit edilmiştir. Isıtıcı giriş havasının bağıl neminin artması ile yakıt sarfiyatının ve birim kurutma maliyetinin arttığı ve enerji verimliliğinin düştüğü tespit edilmiştir.
Whisker Behavior and Tool Wear in Cutting of Unidirectional SiC Whisker Reinforced Plastics
(Elsevier Science Pub., July, 1996) Jamal ElDeen AFAGHANI; K. Yamaguchi
This study concerns the cutting process of unidirectional Sic whisker-reinforced plastic composite. The effects of the grain size of the polycrystalline diamond tool and the Sic whisker orientation on the tool wear were investigated. The tool with fine grain size exhibited higher wear rates. The greatest tool wear was with the composite having longitudinal alignment of whiskers. The cutting processes of various orientations of whiskers were observed by scanning electron microscopy at low speed using a specially designed device. Moreover, models were proposed for cutting the Sic whisker-plastic composite and for wear of sintered diamond tools.
Tear-off Wear Mechanism of Sintered Diamond Tool in Cutting SiC Particle-strengthened Epoxy Composite
(Elsevier Science Pub., 1997-06) Afaghani, Jamal Eldeen; Yamaguchi, Katsumi; Nakamoto, T.
This study concerns the wear of sintered diamond tools in the cutting of SiC-particle–epoxy composites. The effects of the SiC particle size, volume ratio in the composite and diamond grain size of the cutting tool on tool wear were investigated. The experimental work has shown that a coarse-grained diamond tool exhibits higher wear resistance than a corresponding fine-grained tool. Greater tool wear was obtained in cutting the composites that had coarser particles and a higher volume ratio of SiC. Moreover, it was found that the tool wear increases drastically when the SiC particles are larger than the tool grains. A wear model of the tool was proposed, in which the tool is worn mainly by the ‘tear-off’ mechanism of the diamond grains. This model could explain the experimental results by comparing the pushing force of an SiC particle with the tear-off resistance of the diamond grains of the tool. Finally, a fatigue-like empirical curve was established. This curve can be used to predict the wear of the tool during cutting of the composite. q 1997 Elsevier Science S.
Tunçbilek Termik Santralinin Ekserji Analizi
(Tesisat Mühendisliği Dergisi, 2014-09-20) ÜNAL, Fatih; ÖZKAN, Derya Burcu
Bu çalışmada Türkiye’de çalışmakta olan Tunçbilek Termik Santrali, ünite ekipmanlarının her birinin termodinamik analizi yapılarak değerlendirilmiştir. Termik santral ünitesinde belirlenen yirmi yedi düğüm noktasının termodinamik özelliklerine bağlı olarak enerji ve ekserji değerleri hesaplanmıştır. Bulunan sonuçlar ile ekipmanların ayrı ayrı enerji ve ekserji dengeleri kurularak ortalama kayıp ve tahrip olan enerji ve ekserjiler hesaplanmış, kayıp enerji oranı ve yok olan ekserji oranı bulunmuştur. Çalışmanın sonuçları grafik olarak verilmiştir. Buna göre, en yüksek enerji kaybı oranı ve en yüksek ekserji kaybı oranı olan ekipman sırasıyla %71,1 ve %79,5 ile kazan olarak bulunmuştur. Elde edilen termodinamik özellikler yardımıyla Termik Santral’in ısıl ve ikinci yasa verimleri sırasıyla %32,3 ve %75,1 olarak bulunmuştur.
EXERGO ECONOMIC ANALYSIS OF THE GROUND SOURCE HEAT PUMP FOR COOLING SEASONS IN THE MARDIN PROVINCE
(Yıldız Technical University, 2014-04-05) ÜNAL, Fatih; TEMİR, Galip
Nowadays, the effective and efficient use of energy has become an indispensable necessity due to energy sources gradually are decreasing and energy prices are increasing. In this study the experimental results of vertical type ground source heat pump pump for cooling seasons for a test site which is 120 m2 experimental ground area in Midyat/Mardin. After examining the results of studies energy, exergy and eksergo economic analysis was performed over the system. According to the analysis of the system it was determined that the compressor cooling process is of 3,704 kW best heat loss, 1.6539 kW the highest exergy loss, 0.4658 $/h and cost rate associated with capital investment, 0.7464 $/h and the high cost of exergy, exergy loss 44,72% rate of 38.43% and values eksergo economic factors. For this reason, it is inevitable that the planned improvements should be carried out primarily compressor. As a result; our system is quite effective in both reduce energy consumption and reducing greenhouse gas emissions.
Thermodynamic Analysis of Cooling with Vertical Type Ground Source Heat Pump: Mardin Case Study
(International Knowledge Sharing Platform, 2017-02-20) ÜNAL, Fatih; TEMİR, Galip
In this study, for experimental area with a ground area of 120 m2 determined in district Midyat of province Mardin in the hot climate zone of Turkey, analysis of energy and exergy are applied to the system by investigating the results of experimental studies for the cooling season of vertical type ground source heat pump integrated with fan coil system. Instant data records were taken in the cooling process (01.07.2013 / 31.10.2013) for the 11 node points determined in the installed system. In the analysis of experimental data through immediate data recording, the COP value of the system was 3.70, the energy loss was 3,125 kW, the loss of exergy was 3,698 kW, the energy efficiency was 83.88% and the second law efficiency was 21.31%. In the cooling season, the element that works with the least energy efficiency in the system and the loss of highest exergy is designated as compressor. In this context, it has been determined that priority should be given to compressor for improvement studies to be considered. As a result, it has been determined that the use of vertical type ground source heat pump system for cooling purposes is suitable for Mardin Province.
Thermodynamic Analysis of Heating with Solar Assisted Vertical Type Ground Source Heat Pump: Mardin Case Study
(International Knowledge Sharing Platform, 2017-02-20) ÜNAL, Fatih
In this study, for experimental area with a ground area of 120 m2 determined in district Midyat of province Mardin in the hot climate zone of Turkey, analysis of energy and exergy are applied to the system by investigating the results of experimental studies for the heating season of solar assisted vertical type ground source heat pump integrated with fan coil system. Solar energy is used with the aim of sustaining the heat pump system. Instant data records were taken in the heating process (01.10.2013 / 31.03.2014) for the 14 node points determined in the installed system. In the analysis of experimental data through immediate data recording, the COP value of the system was 3.61, the energy loss was 8.9952 kW, the loss of exergy was 6.2673 kW, the energy efficiency was 64.52% and the second law efficiency was 24.51%. In the heating season, solar energy's rate of meeting energy need of the heat pump system was found to be 9.75%. The elements with the most loss of exergy in the system are designated as collectors and compressors. In this context, it has been determined that priority should be given to compressor for improvement studies to be considered. As a result, it has been determined that the system examined for Mardin Province is appropriate.
Comparison of Energy and Cost Analysis of Two Different Industrial Corn Drying Plants Using Solid Fuel
(IJARSET, 2018-08-01) ÜNAL, Fatih; BULUT, Hüsamettin; KAHRAMAN, Ahmet
In this study, the energy and cost analyzes of two different corn drying plants using solid fuel in the heating of drying air are performed. In the evaluated drying processes, corn which has high humidity, dried to a value below 15% relative humidity which is the storage humidity. In the drying process, thermodynamic properties such as temperature, relative humidity and air velocity of the node points determined in the systems were measured. The continuous operating temperatures of the facilities specified for analyzes were taken into account. In the analyzes, measurements were made for the drying air inlet temperatures of drying plants which was drying temperature of 70°C and 112°C. Based on the results obtained at the determined nodes, the influences on the inlet temperature of the drying air, the thermal value of the fuel, the fuel consumption, the energy efficiency and the unit drying cost have been evaluated. As a result, it has been found that the increase in inlet air temperature reduces boiler efficiency and energy efficiency, increases unit drying cost and fuel consumption. It has been found that high thermal value fuel usage has an important role in decreasing drying time as it allows working at high temperatures.
An Applıcatıon Of Exergoeconomic Analysıs For Power Plants
(Vinča Institute of Nuclear Sciences, 2018-06-23) Ünal, Fatih
Currently, energy resources are rapidly consumed. Therefore, scientists and engineers study the effective use of energy. In the present study, a thermodynamic and exergoeconomic analysis was performed in a thermal power plant in Turkey. The study involved determining the thermodynamic properties of 27 node points in a thermal power plant unit, and this was followed by calculating energy and exergy values of every node. Mean exergy costs were calculated by establishing energy and exergy balances of the equipment with respect to the calculated results. Subsequently, lost and damaged energies and exergies were calculated, and exergoeconomic factors were determined. The equipments were compared with each other on a graph based on the obtained results. The maximum rate of exergy loss and cost of exergy destruction corresponded to 79.5% and 886,66 $/h, respectively. The maximum exergy losses in a thermal power plant occurred in the boiler, turbine groups, condenser, heating group, pumps, and auxiliary groups. The highest and second highest law efficiencies of the studied thermal power plant corresponded to 32.3% and 28.5%, respectively. The study also involved presenting suggestions for improvement. Additionally, exergoeconomic analyses were conducted while considering the power plants’ investment and equipment maintenance costs. It is expected that the calculation method and the obtained results can be applied to other thermal power plants.
Energy, exergy and exergoeconomic analysis of solar assisted vertical ground source heat pump system for heating season
(Springer, 2018-08-05) Ünal, Fatih; Temir, Galip; Köten, Hasan
The purpose of this study is to evaluate the experimental performance of a solar assisted vertical ground source heat pump system (VGSHP) for the winter climatic conditions of Mardin, which is in the South-Eastern Anatolia region of Turkey. For this aim, an experimental analysis was performed on solar assisted VGSHP system, which was designed to meet the heating needs of an experimental room, during the heating season (10.01.2013/03.31.2014). The experimentally obtained results were used to calculate energy, exergy and exergoeconomic analyses of the system and its components. The energy efficiency, exergy efficiency and exergoeconomic factors of the entire system were 67.36 %, 27.40 % and 60.51 %, respectively. In this study, the system was proposed for disseminating the use of alternative technologies supported by renewable energy systems and it has been tested for the first time in Mardin to meet its heating needs with convectional systems. The experimental results showed that the proposed solar assisted VGSHP system can be used for residential heating in Mardin and similar regions. As a result, it has been detected that the system is very effective in both reducing energy consumption and decreasing emissions of green-house gases.
ENERGY CONSUMPTION OF DEFROSTING PROCESS IN NO-FROST REFRIGERATORS
(Yildiz Technical University Press, 2018) ÖZKAN, Derya Burcu; ÜNAL, Fatih
Refrigerators have high energy consumption because they consume energy throughout the day, and they are used in all residences and in most offices. Designing more efficient models and, thus, decreasing the energy consumption of refrigerators have become necessary, owing to the global energy scarcity. The purpose of this study was to decrease energy consumption and increase the efficiency of the defrosting process in no-frost refrigerators. The defrosting process plays an important role in the energy consumption of no-frost refrigerators. The amount of energy needed for defrosting and the time it takes are important factors for manufacturers in terms of energy performance. Recently, a theoretical correlation was developed as a function of the frost thickness, heat flux, and frost density for estimating the defrosting time of an evaporator fin surface. The melting time of the frost on the fin was calculated by a mathematical model and compared to results that were obtained experimentally. The results were differed from the actual melting time as 4.7%.
Energy, exergy and exergoeconomic analysis of solar-assisted vertical ground source heat pump system for heating season
(KOREAN SOC MECHANICAL ENGINEERS, 2018) Unal, Fatih; Temir, Galip; Koten, Hasan
The purpose of this study is to evaluate the experimental performance of a solar assisted vertical ground source heat pump system (VGSHP) for the winter climatic conditions of Mardin, which is in the South-Eastern Anatolia region of Turkey. For this aim, an experimental analysis was performed on solar assisted VGSHP system, which was designed to meet the heating needs of an experimental room, during the heating season (10.01.2013/03.31.2014). The experimentally obtained results were used to calculate energy, exergy and exergoeconomic analyses of the system and its components. The energy efficiency, exergy efficiency and exergoeconomic factors of the entire system were 67.36 %, 27.40 % and 60.51 %, respectively. In this study, the system was proposed for disseminating the use of alternative technologies supported by renewable energy systems and it has been tested for the first time in Mardin to meet its heating needs with convectional systems. The experimental results showed that the proposed solar assisted VGSHP system can be used for residential heating in Mardin and similar regions. As a result, it has been detected that the system is very effective in both reducing energy consumption and decreasing emissions of green-house gases.
Perspective of safflower (Carthamus tinctorius) as a potential biodiesel feedstock in Turkey: characterization, engine performance and emissions analyses of butanol–biodiesel–diesel blends
(Taylor and Francis Ltd., 2017) Al-Samaraae R.R.; Atabani A.E.; Uguz G.; Kumar G.; Arpa O.; Ayanoglu A.; Mohammed M.N.; Farouk H.
Safflower (Carthamus tinctorius) is widely farmed in Turkey. This study investigates the physicochemical properties of safflower biodiesel and its blends with Euro diesel and butanol. A polynomial curve-fitting method was used to predict kinematic viscosity and density of the ternary blends. Furthermore, characteristics such as DSC, FT-IR, UV-Vis and TGA were adopted to evaluate the influence of butanol addition on biodiesel–diesel blends. Engine performance parameters such as BP, torque and BSFC and emissions such as CO, HC, NOx and EGT were studied. Safflower methyl ester satisfied both EN 14214 and ASTM D 6751 standards regarding viscosity, flash point and density. However, iodine value was quite high. Oxidation stability fails to satisfy either standard. This is due to the high level of unsaturated fatty acids (91.05%). A reduction in BP, torque, HC and CO coupled with an increase in BSFC, NOx emissions and EGT was observed for all blends compared to Euro diesel. Overall, all blends appear to be good alternatives to biodiesel–diesel blends. This work supports that biodiesel can be blended with diesel and butanol as ternary blends (up to 20%) for use as a fuel in compression ignition (CI) engines. Therefore, combustion characteristics of blends shall be further investigated. © 2017 Informa UK Limited, trading as Taylor & Francis Group

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