Koca, Kemal
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K. Kemal
Koca, Kemal
Koca, Kemal
Job Title
Dr. Öğr. Üyesi
Email Address
kemal.koca@agu.edu.tr
Main Affiliation
02.06. Makine Mühendisliği
Status
Current Staff
Website
ORCID ID
Scopus Author ID
Turkish CoHE Profile ID
Google Scholar ID
WoS Researcher ID
Sustainable Development Goals
1
NO POVERTY
1
Research Products
7
AFFORDABLE AND CLEAN ENERGY
14
Research Products
8
DECENT WORK AND ECONOMIC GROWTH
1
Research Products
9
INDUSTRY, INNOVATION AND INFRASTRUCTURE
1
Research Products
11
SUSTAINABLE CITIES AND COMMUNITIES
2
Research Products
13
CLIMATE ACTION
2
Research Products
14
LIFE BELOW WATER
1
Research Products
17
PARTNERSHIPS FOR THE GOALS
1
Research Products
Documents
32
Citations
876
h-index
16
Documents
28
Citations
742
Scholarly Output
15
Articles
14
Views / Downloads
249/6
Supervised MSc Theses
0
Supervised PhD Theses
0
WoS Citation Count
163
Scopus Citation Count
173
WoS h-index
9
Scopus h-index
9
Patents
0
Projects
2
WoS Citations per Publication
10.87
Scopus Citations per Publication
11.53
Open Access Source
7
Supervised Theses
0
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| Journal | Count |
|---|---|
| Process Safety and Environmental Protection | 4 |
| Arabian Journal for Science and Engineering | 1 |
| Energies | 1 |
| Energy Conversion and Management | 1 |
| Engineering Applications of Artificial Intelligence | 1 |
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Now showing 1 - 10 of 15
Article Measurements of Flow Characterization Revealing Transition to Turbulence Associated With the Partial Flexibility-Based Flow Control at Low Reynolds Number(Springer Heidelberg, 2025) Koca, Kemal; Keskin, Sinem; Sahin, Rumeysa; Veerasamy, Dhamotharan; Genc, Mustafa SerdarIn order to comprehend the flow characteristics of both controlled and uncontrolled SD7062 wind turbine airfoils with local flexible membrane material throughout a variety of angles of attack at a Reynolds number of 1.05 x 105, an experimental investigation was conducted. The time-dependent force measurement, the hot-wire experiment with a boundary layer and glue-on probes, and the oil-flow visualization technique were all utilized in the present study to measure the flow over the airfoil and examine the laminar-turbulent transition, laminar separation bubble, and the impact of a special flow control method that uses flexibility. A comprehensive intermittency analysis by utilizing hot-wire results was employed to obtain the flow physics effects of the local flexibility the first in the literature. The key results of the experiment demonstrated that the stall was delayed from alpha = 10 degrees to 12 degrees by the local flexibility. The hot-wire results are dedicated to laminar, transitional and turbulent regions and the transition phenomena at different locations over the suction surface of the airfoil in the analysis graphs. As demonstrated by the results of the oil-flow visualization experiment, in the uncontrolled case, the laminar separation bubble formed over the airfoil at alpha = 8 degrees between x/c = 0.16 and x/c = 0.42. The use of flexible membrane material over the airfoil provided that the oscillation of this material triggered the transition to turbulence and a bypass transition, which resulted in the reattached flow.Article Citation - WoS: 18Citation - Scopus: 19Passive Flow Control Application Using Single and Double Vortex Generator on S809 Wind Turbine Airfoil(MDPI, 2023) Ozden, Mustafa; Genc, Mustafa Serdar; Koca, KemalThe current study is aimed at investigating the influences of vortex generator (VG) applications mounted to the suction and pressure surfaces of the S809 wind turbine airfoil at low Reynolds number flow conditions. Both single and double VG applications were investigated to provide technological advancement in wind turbine blades by optimizing their exact positions on the surface of the airfoil. The results of the smoke-wire experiment for the uncontrolled case reveal that a laminar separation bubble formed near the trailing edge of the suction surface, and it was moved towards the leading edge as expected when the angle of attack was increased, resulting in bubble burst and leading-edge flow separation at & alpha; = 12 & DEG;. The u/U-& INFIN;, laminar kinetic energy and total fluctuation energy contours obtained from the numerical study clearly show that both the single and double VG applications produced small eddies, and those eddies in the double VG case led the flow to be reattached at the trailing edge of the suction surface and to gain more momentum by energizing. This situation was clearly supported by the results of aerodynamic force; the double VG application caused the lift coefficient to increase, resulting in an enhancement of the aerodynamic performance. A novel finding is that the VG at the pressure surface caused the flow at the wake region to gain more energy and momentum, resulting in a reattached and steadier flow condition.Conference Object Hybrid Renewable Energy to Greener and Smarter Cities: A Case Study of Kayseri Province(Springer Science and Business Media Deutschland GmbH, 2024) Bekçi, Eyüp; Koca, KemalIn this study, a hybrid energy system was implemented to fulfill the electricity requirements of the trams operating in Kayseri province. The tram's annual electricity consumption data was acquired on a monthly basis from the local electricity company in Kayseri. Utilizing the obtained data, energy and cost simulations were conducted employing the Homer-Pro program. The primary objective of this investigation is to enhance sustainability while satisfying electricity demands with minimal carbon emissions. Consequently, the established hybrid energy system incorporates renewable energy sources, specifically wind, solar, and biomass energy, with the inclusion of batteries for energy storage. Furthermore, generators and converters are integrated for energy conversion purposes. The study encompasses a detailed cost analysis to identify the most economically efficient hybrid energy system, determined through optimization studies. Through this research, it is anticipated that the implementation of such a system will significantly diminish carbon emissions in Kayseri, contributing to a substantial increase in sustainability. © 2024 Elsevier B.V., All rights reserved.Article Citation - WoS: 14Citation - Scopus: 17Convenient Site Selection of a Floating PV Power Plant in Türkiye by Using GIS-Fuzzy Analytical Hierarchy Process(Springer Heidelberg, 2024) Karipoglu, Fatih; Koca, Kemal; Ilbahar, EsraFloating photovoltaics (FPVs) are appearing as a promising and an alternative renewable energy opinion in which PV panels are mounted on floating platforms in order to produce electricity from renewable energy on water such as seas, dams, rivers, oceans, canals, fish farms, and reservoirs. So far, such studies related to the body knowledge on financial, technical, and environmental aspects of installation of FPV have not been performed in Turkey while expanding steadily in other countries. In this study, suitable site selection for installation of FPV power plants on three lakes in Turkey was studied by performing geographic information system (GIS) and the fuzzy analytic hierarchy process (FAHP) as multi-criteria decision-making (MCDM) method. This detailed study revealed that the criterion of global horizontal irradiance (GHI) was determined as the most crucial criterion for the installation of FPV on Beysehir Lake, Lake of Tuz, and Van Lake. Additionally, it was clearly seen that the Beysehir Lake had the highest value approximately 52% among other lakes for installation, that is why Beysehir Lake is selected as the best option for installation of an FPV system with this multi-criteria approach.Article Citation - WoS: 14Citation - Scopus: 16Investigation of the Effect of Hidden Vortex Generator-Flap Integrated Mechanism Revealed in Low Velocities on Wind Turbine Blade Flow(Pergamon-Elsevier Science Ltd, 2023) Ozden, Mustafa; Genc, Mustafa Serdar; Koca, KemalIn this study, the flap and vortex generator (VG) mechanisms which were employed separately in aircraft were used as integrated first in literature. In this mechanism, the flap motion triggered and activated the VGs when it was needed at low speeds. Thus, this flap mechanism eliminated the unnecessary drag force generation when VGs were not needed. Numerical simulations which were validated with experimental data were employed in the study. In the first step, the flow characteristics formed on the S809 airfoil with 4 different flap angles ( beta = 30 degrees, 20 degrees, 10 degrees, 0 degrees) were investigated without the VG. Then, those flow structures formed on the S809 airfoil with both flap and VG were examined under the same conditions. According to the results, utilizing flap and VGs together had a positive impact at low wind speeds. Moreover, due to the flap and vortex generator integrated mechanism closed up to be not unnecessary drag formation at high wind speeds, thus those structures increased further to the positive effect with the increasing wind velocity. In terms of energy output, it was shown that this novel idea provided more energy output in this study.Article Citation - WoS: 44Citation - Scopus: 43Nuclear Energy Consumption, Energy Access and Energy Poverty: Policy Implications for the COP27 and Environmental Sustainability(Elsevier Sci Ltd, 2023) Bashir, Muhammad Farhan; Ma, Beiling; Sharif, Arshian; Ao, Tong; Koca, KemalThe ever-increasing energy resource demand and subsequent environmental challenges mean that policymakers have shifted their focus to nuclear energy to address energy and environmental issues due to its unlimited potential. The current study investigates the role of nuclear energy consumption to unveil contextual information and report novel evidence concerning the significance of energy and environmental policies. This research is a novel attempt to outline methodological and topical contributions, thematic analysis, co-citation analysis, and country-collaboration analysis. As energy and environmental solutions have been prioritized within sustainable development goals, our research approach would allow policymakers and researchers to understand the extent to which nuclear energy can provide solutions towards environmental sustainability and identify research limitations to overcome by future studies. Moreover, our extensive analysis allows us to argue that nuclear energy impacts energy demand and is the most critical factor in fulfilling environmental commitments under regional and international environmental agreements.Article Citation - WoS: 1Citation - Scopus: 1Role of Partial Flexibility on Flow Evolution and Aerodynamic Power Efficiency Over a Turbine Blade Airfoil(MDPI, 2024) Koca, Kemal; Genc, Mustafa SerdarIn this study, the aerodynamic performance of a cambered wind turbine airfoil with a partially flexible membrane material on its suction surface was examined experimentally across various angles of attack and Reynolds numbers. It encompassed physical explanation at the pre/post-stall regions. The results of particle image velocimetry revealed that the laminar separation bubble was diminished or even suppressed when a local flexible membrane material was employed on the suction surface of the wind turbine blade close to the leading edge. The results of the deformation measurement indicated that the membrane had a range of flow modes. This showed that the distribution of aerodynamic fluctuations due to the presence of LSB-induced vortices was reduced. This also led to a narrower wake region occurring. Aerodynamic performance improved and aerodynamic vibration significantly lowered, particularly at the post-stall zone, according to the results of the aerodynamic force measurement. In addition to the lift force, the drag force was enormously reduced, corroborating and matching well with the results of PIV and deformation measurements. Consequently, significant benefits for a turbine blade were notably observed, including aerodynamic performance enhancement, increased aerodynamic power efficiency, and reduced aerodynamic vibration.Article Citation - WoS: 1GIS-AHP Approach for a Comprehensive Framework to Determine the Suitable Regions for Geothermal Power Plants in Izmir, Turkiye(Konya Teknik Univ, 2024) Koca, Kemal; Karipoglu, Fatih; Ozturk, Emel ZerayGeothermal energy is gaining more reputation and importance around the world. Correspondingly, suitable location selection is a critical step and has become necessary for the successful installation and operation of geothermal power plants. This study investigated suitability of & Idot;zmir region, located in the Aegean part of T & uuml;rkiye, in terms of geothermal power plants applications by using the combination of Geographical Information System and Analytic Hierarchy Process. Based on the request of power plants, thirteen important criteria were evaluated under three main categories named as physical (C1), environmental (C2) and technical (C3). Moreover, expert's opinions were taken into consideration to calculate the importance of these criteria. Key results showed that & Idot;zmir was suitable for geothermal power plants. The final suitability map layer pointed out that %8.73 (1.037 km2) of total area were determined as highly suitable regions in terms of installation. In addition, the obtained suitability map layer was compared with actual geothermal power plants. Based on the comparison study, power plants in Seferihisar were moderately suitable for geothermal power plants while the location of Bal & ccedil;ova power plant was highly suitable. Regarding the suitability assessment in the present study, the location of Dikili power plants had the least suitability score.Article Citation - WoS: 21Citation - Scopus: 22Experimental Flow Control Investigation Over Suction Surface of Turbine Blade With Local Surface Passive Oscillation(Pergamon-Elsevier Science Ltd, 2022) Koca, Kemal; Genc, Mustafa Serdar; Veerasamy, Dhamotharan; Ozden, MustafaImpact of the local flexible membrane (LFM) on aerodynamic phenomena including the formation of a laminar separation bubble (LSB) and transition to turbulence was experimentally investigated over the suction surface of a Clark-Y airfoil first time in literature. The experiments such as aerodynamic force measurement, smoke-wire flow visualization and hot-film tests were carried out at the free-stream velocity of U infinity = 3.2 m/s, U infinity = 6.4 m/s, U infinity = 9.6 m/s, U infinity = 12.8 m/s, and Reynolds number based upon on the chord length was Rec = 3.5 x 104, Rec = 7.0 x 104, Rec = 1.05 x 105 and Rec = 1.4 x 105, respectively. The experimental angle of attack was set at 0 degrees = alpha <= 20 degrees. In detailed intermittency analysis by the hot-film sensor over the uncontrolled airfoil, it was seen that the LSB and transition to turbulence formed close to the trailing edge at a lower angle of attack, and it moved towards the leading edge when increasing the angle of attack simultaneously. Employing LFM on the suction surface obviously affected the progress of these flow phenomena. In the results of smoke-wire flow visualization, either the size of the laminar separation bubble (LSB) was reduced or its presence was suppressed at lower in-cidences. The aerodynamic force measurement results also supported those behaviors. In particular, at lower incidences, the negative effects of LSB were mitigated, resulting in the presence of a more stable lift curve. Additionally, it was clearly observed that utilizing LFM ensured positive effects, especially at the pre-and the post-stall regions in terms of fewer fluctuations at the CL curve, meaning that less aerodynamic vibration and noise on wind/hydro turbine could be obtained.Article Citation - WoS: 11Citation - Scopus: 11Biogas Intake Pressure and Port Air Swirl Optimization to Enhance the Diesel RCCI Engine Characteristics for Low Environmental Emissions(Elsevier, 2024) Dalha, Ibrahim B.; Koca, Kemal; Said, Mior A.; Rafindadi, Aminu D.Exhaust emission and combustion control in RCCI (reactivity-controlled compression ignition) focused mainly on the direct-injected fuel parameters, urging to investigate the advantages of port-fuel intake parameters. The engine was modified for port injection of Biogas at the valve and RCCI mode. The influence of port swirl ratio (PSR, 0 - 80%) and biogas injection pressure (BIP, 1 - 4 bar) on the diesel RCCI combustion and emissions was tested and optimized at varied loads and 1600 rpm in a port injection at the valve (PIVE) approach. Established kinetic mechanisms were combined with multi-objective optimization to further investigate, predict, and analyze emissions occurrence and trade-offs for reduced environmental impacts. The results show that the radiation absorption triggered by increased CO2 lowers combustion temperature, resulting in prolonged ignition. Setting the airflow to swirl lowers the in-cylinder pressure at elevated BIP while raising the heat generated across the BIPs. Increasing the PSR slows the combustion while BIP speeds up the process. BIP and PSR show great trade-off reduction ability among all emission parameters. The optimum unburned hydrocarbon, nitrogen oxide, particulate, and carbon monoxide emissions for the injection at the valve were found to be 109.58, 0.577, and 2.336 ppm, and 0.103%, respectively, at low-load, low-BIP, and high-PSR. The emissions were lowered by 6.58, 91.26, 80.65, and 13.45% compared to the premixed RCCI mode, respectively. Therefore, introducing lowpressure biogas amid high swirling air at the valve elevates the in-cylinder condition while lowering the emissions, mitigating their environmental implications.
