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    Design and fabrication of novel anode flow-field for commercial size solid oxide fuel cells
    (Elsevier, 2017) Canavar, Murat; Timurkutluk, Bora
    In this study, nickel based woven meshes are tested as not only anode current collecting meshes but also anode flow fields instead of the conventional gas channels fabricated by machining. For this purpose, short stacks with different anode flow fields are designed and built by using different number of meshes with various wire diameters and widths of opening. A short stack with classical machined flow channels is also constructed. Performance and impedance measurements of the short stacks with commercial size cells of 81 cm(2) active area are performed and compared. The results reveal that it is possible to create solid oxide fuel cell anode flow fields with woven meshes and obtain acceptable power with a proper selection of the mesh number, type and orientation. (C) 2017 Elsevier B.V. All rights reserved.
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    Effects of mesh and interconnector design on solid oxide fuel cell performance
    (PERGAMON-ELSEVIER SCIENCE LTD, 2015) Canavar, Murat; Kaplan, Yuksel
    In this study, three different nickel based meshes are investigated as an anode side current collector and flow-field for solid oxide fuel cells (SOFCs) to reduce the fabrication cost. The same meshes are also tested on the conventional interconnectors with machined gas channels for comparison. Eight different short stacks are installed for this purpose. The characterizations of the short stacks are achieved via performance tests together with electrochemical impedance spectroscopy analyses. The experimental results reveal that the woven nickel mesh provides the required current collection and can act as an anode flow-field. It is also found that the spot welding of this mesh significantly improves the cell performance due to the enhanced contact between the mesh and the interconnector. Therefore, the spot welded nickel mesh can be directly employed on the anode interconnector as an effective anode current collector and flow-field without machining gas channels to reduce the SOFC cell/stack fabrication cost. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
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    Investigation of micro-tube solid oxide fuel cell fabrication using extrusion method
    (PERGAMON-ELSEVIER SCIENCE LTD, 2016) Mat, Abdullah; Canavar, Murat; Timurkutluk, Bora; Kaplan, Yuksel
    Extrusion is one of the most effective and inexpensive methods used in the production of ceramic tubes for tubular or micro-tubular solid oxide fuel cell (SOFC) applications. In this method, the parameters such as the viscosity of the ceramic slurry, the extrusion speed and the die temperature need to be optimized for a high performance. In this study, anode supported micro-tubular solid oxide fuel cells are successfully fabricated via a specially designed vertical-type piston extruder machine. The die design enables the production of micro-tubular SOFCs with outer diameters from 3 to 4.5 mm. The die temperature is determined to be the most important process parameter and the suitable die temperature is ranging 40-70 degrees C depending on the slurry content. The electrolyte layer is coated on the anode support tube by vacuum assist dip coating technique and co-sintering is applied with a home-made porous sintering apparatus to avoid dimensional anomalies. The effects of the parameters such as the composition of the electrolyte solution, the vacuum pressure and the immersion time on the electrolyte thickness are investigated. It is found that the electrolyte thickness decreases when the immersion time and vacuum pressure are reduced. Moreover, the thickness of the electrolyte is found to be depended on the content of the electrolyte solution. The effect of the pre-sintering temperature on the electrolyte quality is also investigated. The sintering temperatures of 1000 degrees C and 1100 degrees C provide a similar and desired electrolyte microstructure. A peak power density of 140 mW cm(-2) is obtained at 700 degrees C from the final cell. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
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    Investigation of temperature distribution and performance of SOFC short stack with/without machined gas channels
    (PERGAMON-ELSEVIER SCIENCE LTD, 2016) Canavar, Murat; Mat, Abdullah; Celik, Selahattin; Timurkutluk, Bora; Kaplan, Yuksel
    Solid oxide fuel cells (SOFCs) generate clean energy via electrochemical reactions at high operating temperatures. The distribution of the electrochemical reactions in the cell depends on the flow field design of the interconnectors. The non-uniform distribution of the reactions due to the flow field design may cause the development of thermal stresses which may lead to micro or macro cracks in the cell and thus a significant performance loss even a cell failure. In this study, the effects of operating current densities and fuel flow rates on the temperature profile within the cell and the cell performance are experimentally investigated for two different flow-field designs with Crofer 22 APU interconnectors, i.e. Design I and Design II. Design I, which mimics the conventional interconnector structure, has machined gas channels and porous nickel mesh at the anode side for the distribution of hydrogen and the collection of the current generated in the cell while at the anode side of Design II, only wire woven nickel mesh is employed. The experimental results indicate that Design II provides much more uniform temperature distributions under 20-40 A current loads and 1-2 NL/min H-2 flow rates when compared to those of Design I. Furthermore, Design II exhibits a higher peak power density than Design I at an operation temperature of 800 degrees C. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
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    Katı oksit yakıt pili için stak geliştirilmesi
    (Niğde Üniversitesi / Fen Bilimleri Enstitüsü, 2013) Canavar, Murat; Kaplan, Yüksel
    Bu tezde, interkonektör geometrisinin ve elek yapısının Katı Oksit Yakıt Pili (KOYP) tekli stak performansı üzerindeki etkileri deneysel olarak incelenmiştir. Deneyler gaz debileri, çalışma sıcaklıkları, test süreleri ve sıkıştırma basınçları sabit tutularak aynı şartlar altında yapılmıştır. Öncelikle kanallı interkonektörler üzerinde en iyi akım toplayıcı elek tespit edilmiştir. Daha sonra kanalsız interkonektörler üzerinde aynı eleklerin reaksiyon gazlarını dağıtma özellikleri araştırılmıştır ve en iyi akış dağıtıcı eleğin akım toplama özelliği iyileştirilmiştir. Çalışmaların neticesinde çoklu stak konfigürasyonu belirlenmiş ve stak imal edilmiştir.