Yazar "Karakoc, T. Hikmet" seçeneğine göre listele

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    Application of Artificial Neural Network (ANN) method to exergy analysis of thermodynamic systems
    (Ieee Computer Soc, 2009) Yoru, Yilmaz; Karakoc, T. Hikmet; Hepbasli, Arif; Wani, MA; Kantardzic, M; Palade, V; Kurgan, L; Qi, Y
    Exergy is a way to sustainable development and may be defined as the maximum theoretical useful work, while exergy analysis identifies the sources, the magnitude and the causes of thermodynamic inefficiencies within each system component. By using the ANN, exergy results can be obtained easily including closer results. The results were solved by CogeNNexT code developed by authors and Fast ANN (FANN) Library is implemented to this C++ code. The main objective of the present study is namely (i) to apply the ANN method to exergy analysis of thermodynamic systems by presenting the performance of the ANN method and (ii) to emphasize the definition of ANN inputs. It may be concluded that most of thermodynamic systems can be trained and analyzed by using the ANN method. It is expected that this study would be very beneficial to those dealing with the intelligent systems of the future.
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    Dynamic energy and exergy analyses of an industrial cogeneration system
    (Wiley, 2010) Yoru, Yilmaz; Karakoc, T. Hikmet; Hepbasli, Arif
    The study deals with the energetic and exergetic analyses of a cogeneration (combined heat and power, CHP) system installed in a ceramic factory, located in Izmir, Turkey. This system has three gas turbines with a total capacity of 13 MW, six spray dryers and two heat exchangers. In the analysis, actual operational data over one-month period are utilized. The so-called CogeNNexT code is written in C++ and developed to analyze energetic and exergetic data from a database. This code is also used to analyze turbines, spray dryers and heat exchangers in this factory. Specifications of some parts of system components have been collected from the factory. Based on the 720 h data pattern (including 43 200 data), the mean energetic and exergetic efficiency values of the cogeneration system are found to be 82.3 and 34.7%, respectively. Copyright (C) 2009 John Wiley & Sons, Ltd.
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    Exergetic analysis of an aircraft turbofan engine
    (John Wiley & Sons Ltd, 2007) Turgut, Enis T.; Karakoc, T. Hikmet; Hepbasli, Arif
    The main objective of the present study is to perform an exergy analysis of a turbofan kerosene-fired engine with afterburner (AB) at sea level and an altitude of 11000 m. The main components of this engine include a fan, a compressor, a combustion chamber, a turbine, an AB and an exhaust. Exergy destructions in each of the engine components are determined, while exergy efficiency values for both altitudes are calculated. The AB unit is found to have the highest exergy destruction with 48.1% of the whole engine at the sea level, followed by the exhaust, the combustion chamber and the turbine amounting to 29.7, 17.2 and 2.5%, respectively. The corresponding exergy efficiency values for the four components on the product/fuel basis are obtained to be 59.9, 65.6, 66.7 and 88.5%, while those for the whole engine at the sea level and an altitude of 11000 m are calculated to be 66.1 and 54.2%. Copyright (c) 2007 John Wiley & Sons, Ltd.
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    Exergoeconomic analysis of an aircraft turbofan engine
    (Inderscience Enterprises Ltd, 2009) Turgut, Enis T.; Karakoc, T. Hikmet; Hepbasli, Arif
    This study deals with an exergoeconomic analysis of an aircraft turbofan engine utilising the kerosene as fuel. A new parameter is developed to define the trust cost rate. The cost of exergy destruction, the relative cost difference and the exergoeconomic factor are investigated. The variation of the relative cost difference and exergoeconomic factor according to the operating and maintenance costs and the annual operating hour are also studied. For a high by-pass and high thrust rated engine, the cost rate of thrust is obtained to be 304.35 $(hkN)(-1) for the hot thrust and 138.96 $(hkN)(-1) for the cold thrust, respectively.
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    Exergy analysis of a turbofan aircraft engine
    (Inderscience Enterprises Ltd, 2009) Turgut, Enis T.; Karakoc, T. Hikmet; Hepbasli, Arif; Rosen, Marc A.
    An exergy analysis is reported for a General Electric turbofan engine (the CF6-80) using sea-level data. The effects on exergy efficiencies and exergy destructions are investigated of modifying the isentropic efficiencies of turbomachinery components. The most irreversible units in the system are found to be the fan and the core engine exhaust, with exergy loss rates of 47.3 MW and 35.9 MW, respectively, and the combustion chamber, with an exergy destruction rate of 31.5 MW. The exergy efficiencies of the fan and the core engine exhausts are found to be 12.9 and 12.7%, respectively.