Yapıcı, Ekin
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Yapıcı, Ekin Özgirgin
Özgirgin Yapıcı, Ekin
Ozgirgin Yapici, Ekin
Yapici, Ekin Ozgirgin
Özgirgin Yapıcı, Ekin
Ozgirgin Yapici, Ekin
Yapici, Ekin Ozgirgin
Job Title
Doç. Dr.
Email Address
ekinozgirgin@cankaya.edu.tr
Main Affiliation
06.06. Makine Mühendisliği
Makine Mühendisliği
06. Mühendislik Fakültesi
01. Çankaya Üniversitesi
Makine Mühendisliği
06. Mühendislik Fakültesi
01. Çankaya Üniversitesi
Status
Current Staff
Website
ORCID ID
Scopus Author ID
Turkish CoHE Profile ID
Google Scholar ID
WoS Researcher ID
Files
Sustainable Development Goals
13
CLIMATE ACTION
2
Research Products
8
DECENT WORK AND ECONOMIC GROWTH
0
Research Products
3
GOOD HEALTH AND WELL-BEING
0
Research Products
15
LIFE ON LAND
0
Research Products
17
PARTNERSHIPS FOR THE GOALS
0
Research Products
14
LIFE BELOW WATER
0
Research Products
4
QUALITY EDUCATION
0
Research Products
11
SUSTAINABLE CITIES AND COMMUNITIES
0
Research Products
6
CLEAN WATER AND SANITATION
0
Research Products
10
REDUCED INEQUALITIES
0
Research Products
9
INDUSTRY, INNOVATION AND INFRASTRUCTURE
1
Research Products
12
RESPONSIBLE CONSUMPTION AND PRODUCTION
1
Research Products
2
ZERO HUNGER
0
Research Products
1
NO POVERTY
0
Research Products
7
AFFORDABLE AND CLEAN ENERGY
11
Research Products
5
GENDER EQUALITY
0
Research Products
16
PEACE, JUSTICE AND STRONG INSTITUTIONS
0
Research Products
This researcher does not have a Scopus ID.
This researcher does not have a WoS ID.
Scholarly Output
17
Articles
11
Views / Downloads
1519/1111
Supervised MSc Theses
3
Supervised PhD Theses
0
WoS Citation Count
65
Scopus Citation Count
72
WoS h-index
2
Scopus h-index
2
Patents
0
Projects
0
WoS Citations per Publication
3.82
Scopus Citations per Publication
4.24
Open Access Source
6
Supervised Theses
3
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| Journal | Count |
|---|---|
| Hittite Journal of Science and Engineering | 2 |
| Isı Bilimi ve Tekniği Dergisi | 2 |
| Journal of Cleaner Production | 1 |
| JOURNAL OF CLEANER PRODUCTION | 1 |
| Journal of Mechanical Science and Technology | 1 |
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17 results
Scholarly Output Search Results
Now showing 1 - 10 of 17
Conference Object Design, Production, Theoretical And Experimental Analysis Of Parabolic Trough Solar Collector With Sun Tracking Mechanism(2017) Özgirgin Yapıcı, Ekin; Ünver, Eymen; Çelik, Damla; Tercan, Furkan; Ünalan, Emre; Taşkan, GökhanArticle Citation - WoS: 1Citation - Scopus: 1Numerical Investigation for Enhancement of Heat Transfer in the Cooling Water Jacket of CI Engine(Taylor & Francis inc, 2025) Altug, Hakan; Yapici, Ekin OzgirginDiesel engines are essential in heavy industries and agriculture, especially in vehicles like tractors that operate under challenging conditions, often causing engine faults. Effective thermal management systems are vital for faultless operation preventing overheating, extending engine life, reducing emissions, and improving efficiency. The core of these systems is the water jacket around the cylinder head, which regulates temperatures, facilitates lubrication, prevents friction-related faults, increase durability and thermal performance of the engine. Computational Fluid Dynamics techniques are crucial for analyzing engine thermal behavior and designing cooling systems with complex flows. This study simulates the engine block's temperature distribution under extreme conditions to prevent overheating and improve thermal performance. Geometrical modifications, such as optimizing outlet water ports are employed to achieve enhanced thermal performance by reducing the temperature of coolant. 3D model of the engine block is developed using STAR CCM+ to calculate water temperatures, flow rates and outlet pressures. Numerical validation is conducted with a test bench, and three geometric improvements are analyzed for temperature distribution and heat transfer coefficient. Results showed that, 6.2% improvement on thermal performance is achieved based on the average coolant temperatures and 10% enhancement is achieved in terms of heat transfer coefficient values.Article Performance Analysis of a Flat Plate Solar Collector Utilizing Different Nanofluids(Korean Soc Mechanical Engineers, 2025) Topak, Aysu Deniz; Yapici, Ekin OzgirginGiven the risks of fossil fuel utilization, interest in renewable energy sources like solar power is growing, particularly with solar collectors. Flat plate solar collectors are common in solar thermal applications, though conventional heat transfer fluids have low thermal conductivity. To improve efficiency, nanofluids are employed. This study involves thermal analysis of a solar collector system using different nanofluids prepared in laboratories. Design parameters of the collector and the impact of utilizing nanofluids with different concentrations on the thermal performance of collector system are investigated through both analytical and experimental approaches. Results show nanofluids enhance thermo-physical properties, improving collector efficiency even at low concentrations. Comparing commonly used oxides (Al2O3) and rarely used nitrides (AlN), AlN-based nanofluids showed superior thermal properties. Additionally, MXene-water nanofluid with MAX (Ti3AlC2) synthesized from Titanium (II) hydride further increased efficiency. Experimental results demonstrated up to a 55.3 % efficiency improvement for nanofluids over water.Article Investigation Of Working Temperature Effect On Micro-Cogeneration Application Of Proton Exchange Membrane Fuel Cells(2018) Budak, Yağmur; Özgirgin Yapıcı, Ekin; Devrim, YılserI n this study, micro-cogeneration application is used to increase the efficiency of Proton Exchange Membrane Fuel Cell (PEMFC) systems and effect of different operation temperatures on system performance is observed. For this reason, two different PEMFC systems were comparatively studied operating at 70o C and 160o C, respectively. Micro-cogeneration system design has done considering experimentally determined current density, power and temperature values. Since the amount of heat extracted from each PEMFC system is different related to the operating temperatures, different heat transfer fluids have been used for the cooling systems. These systems are designed for utilization of electricity and hot water for Atılım University Hydrogen Energy Laboratory. Heat loss calculation is made for the laboratory and thermal energy needed for heating the laboratory is calculated. Parallel to the design calculations, simple payback times for PEMFCs with micro-cogeneration applications were determined. LT-PEMFC and HT-PEMFC systems have 402 W and 456 W thermal powers respectively and 87.4 % and 92.8 % total cogeneration efficiencies were calculated for each system respectively. For each system maximum water temperatures and flow rates are calculated as a result of micro-cogeneration application. HT-PEMFC system has found to be capable of higher amount of heating. Even LT-PEMFC system has a lower thermal power and efficiency; it is determined to be more economical and has a lower pay pack time then HT-PEMFC system. For both systems, necessary number of stacks to be used for laboratory heating is calculated as four.Article Experimental Study and Theoretical Investigation of High Temperature Proton Exchange Membrane Fuel Cell Micro-Cogeneration Application(Turkish Soc thermal Sciences Technology, 2018) Yapıcı, Ekin; Devrim, Yilser; Ozgirgin Yapici, Ekin; Makine MühendisliğiIn this study, a house hold micro-cogeneration system is designed using high temperature proton exchange membrane (HTPEM) fuel cell. HTPEM type fuel cells gain the highest interest lately, due to their advantages in terms of increasing efficiency and power quality, reducing harmful emissions and flexibility of operation with respect to the other fuels. The micro-cogeneration system involves producing both electrical energy and hot water and/or vapor together in an economical way, utilizing single fuel (HTPEM fuel cells) for household applications. During the operation of the fuel cell, for high efficiency and stable power production, the access heat of the stack should be removed constantly and the temperature of the stack should be held stable. Heat recovered from the designed innovative cooling system is used for acquiring energy for heating water. This way, thermal efficiency is almost doubled compared to simple cycle. In the scope of this study, 225 W HTPEM fuel cell stack is designed and tested at 160 degrees C operation temperature with hydrogen gas and air. During operation, for homogenous distribution of temperature among the cells, for a short start up period leading to a fast required steady state temperature and for constantly removing the access heat produced in the cell, the cell stack is cooled by using a cooling fluid (Heat Transfer Oil 32- Petrol Ofisi). Selection of insulation material type and thickness for the cell stack is done using natural convection and radiation loss calculations. For the most efficient operating conditions, micro-cogeneration system water inlet and exit temperatures, water and cooling fluid flow rates, convenient pipe diameter and pump power calculations are done to finalize the design. With the cogeneration system designed during the studies, by recovering the access heat of the insulated HTPEM cell stack, district water with initial temperature of 15-20 degrees C is heated around 50 degrees C. Data gathered during studies indicate that fuel cell micro-cogeneration application is highly viable.Conference Object Yüksek Sıcaklık Pem Yakıt Hücresi Mikro-Kojenerasyon Sistemi Tasarımı(2016) Devrim, Yılser; Üregen, Nurhan; Özgirgin Yapıcı, EkinMaster Thesis Nanopartiküller ve Farklı Geometrilere Sahip Kanatçıklar Kullanarak Borularda Isı Transferi İyileştirme(2025) Eğerci, Neslihan; Yapıcı, Ekin Özgirgin; Türkoğlu, HaşmetEnerji, havacılık ve otomotiv gibi sektörlerde mühendislik uygulamaları geliştirmek, ısı transfer verimliliğini artırmak için yaratıcı yöntemler gerektirir. Isı transfer yüzey alanını genişleterek, ısı eşanjörlerindeki boru kanatçıkları termal performansı artıran temel parçalardır. Ancak, tipik kanatçık tasarımlarının en iyi performansı göstermesini engelleyen birkaç kısıtlama vardır. Nanopartiküller, akışkan özelliklerini ve termal iletkenliği artırarak daha etkili ısı iletimi sağlar. Geleneksel soğutma sıvılarından daha fazla termal iletkenlik sunarak, nanofluidlerin kullanımı boru kanatçık sistemlerinde ısı transferini artırır. Bu çalışmanın amacı, farklı geometrilerde kanatçıklı bir boru tasarımı yaparak en etkili tasarımda farklı konsantrasyonlarda sabit boyutta nanoakışkanlar kullanarak ısı transferini incelemektir. Kanatçık çalışması için çeşitli konfigürasyonlar incelendi (üçgen, dikdörtgen ve daire). Üçgen kanatçıklı borunun en uygun olduğu çalışmalar sonucunda bulundu. Üçgen kanatçıklı yapıya farklı konsantrasyonlarda nano akışlar eklendi. Sonuç olarak en iyi nano akış konsantrasyonu ve geometri yapısı bulundu. En iyi nanoakış Al₂O₃-TiO₂ ve konstrasyonu %10-6' dır. En iyi geometri üçgen yapılı fin olarak bulunmuştur.Article Citation - WoS: 2Citation - Scopus: 2Analysis of Heat Transfer Enhancement in Tubes With Capsule Dimpled Surfaces and Al2o3-Water Nanofluid(Turkish Soc thermal Sciences Technology, 2022) Ibrahim, Mahmoud Awni A. Haj; Turkoglu, Hasmet; Yapici, Ekin OzgirginThis study aims to numerically investigate and evaluate the enhancement of heat transfer by new capsule dimples on tube surfaces for flow of water and Al2O3-water nanofluid with different concentrations, under uniform surface heat flux. The originality of this work lies in combining two passive heat transfer enhancement methods such as geometrical improvements and nanofluids together. Capsule dimples with different depths were considered. Al2O3- water nanofluid was modeled as a single-phase flow based on the mixture properties. The effects of dimple depth and nanoparticle concentrations on Nusselt number, friction factor and performance evaluation criteria (PEC) were studied. Numerical computations were performed using ANSYS Fluent commercial software for 2000-14000 Reynolds number range. It was found that when laminar, transient and fully developed turbulent flow cases are considered, increase in the dimple depth increases the Nusselt number and friction factor for both pure water and Al2O3-water nanofluids cases. Also, the friction factor increases as dimple depth increases. Results show that increase in PEC is more pronounced in the laminar region than in the transition region, it starts to decrease for turbulent flows. For nanofluid, PEC values are considerably higher than pure water cases. The variation of PEC for capsule dimpled tubes are dependent on flow regimes and dimple depths. Increasing the nano particle volume concentration and dimple depth in laminar flows increase the PEC significantly.Article Numerical investigation on the performance of a small scale solar chimney power plant for different geometrical parameters(2020) Özgirgin Yapıcı, Ekin; Nsaif, Osama; Aylı, EceIn recent decades, demand for energy has been significantly increased, and considering environmental impacts and the degrading nature of fossil fuels, clean and emission-free renewable energy production has attracted a great deal of attention. One of the most promising renewable energy sources is solar energy due to low cost and low harmful emissions, and from the 1980s, one of the most beneficial applications of solar energy is the utilization of solar chimney power plants (SCPP). A SCPP is a simple and reliable system that consists of three main components; a solar collector, a chimney (tower) and a turbine to utilize electrical energy. Recently, by the advancement in computer technology, the use of CFD methodology for studying SCPP has become an extensive, robust and powerful technique. In light of the above, in this study, numerical simulations of a SCPP through three-dimensional axisymmetric modeling is performed. A numerical model is created using CFD software, and the results are verified with an experimental study from the literature. After ensuring good agreement with the experiments, chimney's and collector's geometric parameters effects and different configurations effects on SCPP performance, simultaneously and additively is investigated. The study introduces an insight to the performance enhancement methods and finding the best configuration of a SCPP model, which will be the basis of a detailed prototyping process. Based on the numerical results, the best configuration of the SCPP has been found as the diverging chimney which enhances the generated power. The results of the study showed that the chimney height and collector radius increase has a positive effect on the power output and efficiency of the system, but when construction and material costs are also considered, each has an optimal value. The maximum impact on the performance is found to be by the chimney tower radius and the collector height and inclination are found to have optimum values considering performance. According to the obtained results, the best performance for the SCPP was obtained with 3.5 m chimney height, 30 cm tower diameter, 400 cm of collector diameter with 6 cm height and zero inclination angle. By the correct selection of the dominant performance parameter which can be done by correctly interpreting the results of this study, "the best" design of a SCPP real scale prototype considering maximum power requirement can be done. (C) 2020 Elsevier Ltd. All rights reserved.Article Citation - WoS: 52Citation - Scopus: 58Numerical Investigation on the Performance of a Small Scale Solar Chimney Power Plant for Different Geometrical Parameters(Elsevier Sci Ltd, 2020) Yapici, Ekin Ozgirgin; Ayli, Ece; Nsaif, OsamaIn recent decades, demand for energy has been significantly increased, and considering environmental impacts and the degrading nature of fossil fuels, clean and emission-free renewable energy production has attracted a great deal of attention. One of the most promising renewable energy sources is solar energy due to low cost and low harmful emissions, and from the 1980s, one of the most beneficial applications of solar energy is the utilization of solar chimney power plants (SCPP). A SCPP is a simple and reliable system that consists of three main components; a solar collector, a chimney (tower) and a turbine to utilize electrical energy. Recently, by the advancement in computer technology, the use of CFD methodology for studying SCPP has become an extensive, robust and powerful technique. In light of the above, in this study, numerical simulations of a SCPP through three-dimensional axisymmetric modeling is performed. A numerical model is created using CFD software, and the results are verified with an experimental study from the literature. After ensuring good agreement with the experiments, chimney's and collector's geometric parameters effects and different configurations effects on SCPP performance, simultaneously and additively is investigated. The study introduces an insight to the performance enhancement methods and finding the best configuration of a SCPP model, which will be the basis of a detailed prototyping process. Based on the numerical results, the best configuration of the SCPP has been found as the diverging chimney which enhances the generated power. The results of the study showed that the chimney height and collector radius increase has a positive effect on the power output and efficiency of the system, but when construction and material costs are also considered, each has an optimal value. The maximum impact on the performance is found to be by the chimney tower radius and the collector height and inclination are found to have optimum values considering performance. According to the obtained results, the best performance for the SCPP was obtained with 3.5 m chimney height, 30 cm tower diameter, 400 cm of collector diameter with 6 cm height and zero inclination angle. By the correct selection of the dominant performance parameter which can be done by correctly interpreting the results of this study, "the best" design of a SCPP real scale prototype considering maximum power requirement can be done. (C) 2020 Elsevier Ltd. All rights reserved.
