Integrated thermal engineering analyses with heat transfer at periphery of planar solid oxide fuel cell

Chyou, Yau-Pin; Chung, Tsang-Dong; Chen, Jong-Sheng; Shie, Ri-Fong

doi:10.1016/j.jpowsour.2004.07.001

Cited by 45 publications

(30 citation statements)

References 10 publications

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“…As a consequence, the Nusselt number could be taken to Nu = 3.68 (i.e. the asymptotic value corresponding to a flow confined in channel) [46,47]. It is worth noting that fluids heat conductivities i depend on the gas composition along the cell (Fig.…”

Section: Gas Temperatures For Convective Heat Exchangesmentioning

confidence: 99%

Modelling of solid oxide steam electrolyser: Impact of the operating conditions on hydrogen production

Laurencin

Kane

Delette

et al. 2011

Journal of Power Sources

122

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Section: Gas Temperatures For Convective Heat Exchangesmentioning

confidence: 99%

Modelling of solid oxide steam electrolyser: Impact of the operating conditions on hydrogen production

Laurencin

Kane

Delette

et al. 2011

Journal of Power Sources

122

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“…The larger temperature and current gradients are in good agreement with the numerical studies which estimates quantitatively higher gradients indeed. 6,15,17 The boost in the up-segment's current production attributed to the high local temperature (Fig. 12) can be elaborated through the impedance analysis in a wide frequency range.…”

Section: Resultsmentioning

confidence: 99%

Processes Involving in the Temperature Variations in Solid Oxide Fuel Cells In-Situ Analyzed through Electrode-Segmentation Method

Aydın

Nakajima

2015

J. Electrochem. Soc.

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We aim to mitigate the spatial temperature variations contributing to the thermal stresses in solid oxide fuel cells. We thus analyze the involving processes through spatial temperature, current, and impedance variations in-situ measured by the electrode-segmentation method in a microtubular solid oxide. We find that, despite the preheating, the excess air flow commonly supplied in the practical applications for the convective cooling is the prevailing factor on the temperature variations causing a significant temperature gradient in the air inlet region, that poses a high risk of mechanical failure. In terms of the flow configuration, counter-flow shows larger temperature and current variations. The impedance variations clarify the impact of the temperature distribution on the current variations. Namely, high temperature in the fuel upstream accompanied with the high hydrogen concentration boosts the local current density, thus, results in larger Nernst-loss in the downstream wherein temperature is lower as well. We conclude that the excess air flow indirectly contributes to the thermal stresses and thus we recommend the reduction of the excess flow. The thermal stresses are accounted for the mechanical failure of solid oxide fuel cells (SOFC).1-3 To resist the thermal stresses at maximum achievable electrochemical performance, SOFCs are designed in various forms, for instance flat-tubular, tubular, and planar, etc. For in-situ investigating the properties spatially varying regardless of the SOFC form, microtubular SOFCs (mt-SOFCs) are quite practical owing to the simple form. Besides, a mt-SOFC with a small diameter can represent a unit gas flow channel in other forms. We thus elaborate the temperature, current, and concentration variations in mt-SOFCs.A mt-SOFC fundamentally consists of three main components, anode, electrolyte, and cathode. The cell fabrication requires sequential high temperature heat-treatment processes (1473-1673 K) for each component, thus, the induction of the residual stresses to the cell is inevitable.1,2,4,5 Because the components are made of distinct ceramicbased materials, they possess diverse intrinsic coefficients of thermal expansion (CTE). Selimovic et al. reports the CTEs of Ni/YSZ, 8YSZ, and LSM as 13 × 10 −6 , 10 × 10 −6 , 11 × 10 −6 1/K, respectively. The CTE and temperature are the main parameters determining the thermal strain of materials as Eq. 1 stateswhere ε th is the thermal strain, α (1/K) the CTE, T (K) temperature, and T ref (K) the stress-free reference temperature. According to Eq. 1, even a small difference among the CTEs of the components can result in thermal stresses due to the high operation temperature of mtSOFCs. 1,2,4,6,7 The cell components are hence required to be made of materials featuring similar CTEs. Even if the materials exhibit similar CTEs, longitudinal temperature variations over the cell surface induce thermal stresses.1-4,6-9 While a cell is operating with hydrogen and -excess air-, due to the electrochemical hydrogen oxidation reaction (HOR...

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“…A pilha pode ser formada por várias unidades de células. CHYOU et al [31] focaram seu estudo no design térmico de unidades de PaCOS, empregando materiais isolantes para redução de perdas por calor. Uma metodologia computacional foi empregada para caracterizar uma PaCOS planar típica (Figura 9a), utilizando um modelo bidimensional (Figura 9b) de elementos finitos para análise termomecânica em processos iterativos e bidimensional (Figura 9c) para adaptação a processos de RP.…”

Section: Fabricação De Pilhas a Combustível Por Rpunclassified

Prototipagem rápida de pilhas a combustível de óxido sólido

Hotza

2009

Matéria (Rio J.)

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Tecnologias de Prototipagem Rápida (Rapid Prototyping, RP) permitem a fabricação automática de peças com geometria complicada a partir de dados de Projeto Auxiliado por Computador (Computer Aided Design, CAD). A peça tridimensional é construída por consolidação de pó em camadas (processo "aditivo" ou "generativo"). Por isso, estas técnicas estão freqüentemente chamadas de fabricação de forma livre sólida ou fabricação em camadas. Em geral, uma abordagem de 5 etapas do desenvolvimento de produto é comumente aplicada: criação de um modelo de CAD, conversão do modelo de CAD em formato STL, fatiamento do arquivo STL em camadas de seção transversal, fabricação do produto, e finalmente acabamento superficial do produto. Técnicas de RP têm muitos benefícios sobre métodos tradicionais para geração de modelos, ferramentaria e construção de peças de produção de qualidade. Por exemplo, em contraste com processos "subtrativos" (furação, moagem, desbaste) os métodos "aditivos" de RP permitem a fabricação de produtos com estrutura complexa de poros internos que não podem ser fabricados por outros métodos. Técnicas de RP podem diminuir significativamente o tempo de fabricação de pilhas a combustível de óxido sólido (PaCOS) com pequena despesa de operação e reduzido custo de produto quando aplicadas corretamente. Tecnologias como Sinterização Seletiva a Laser (Selective Laser Sintering, SLS), Manufatura de Objetos Laminados (Laminated Object Manufacturing, LOM) e Impressão 3D (3D Printing, 3DP) podem ser usadas para fabricação de protótipos de pilhas a combustível, em particular na configuração planar.

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Integrated thermal engineering analyses with heat transfer at periphery of planar solid oxide fuel cell

Cited by 45 publications

References 10 publications

Modelling of solid oxide steam electrolyser: Impact of the operating conditions on hydrogen production

Modelling of solid oxide steam electrolyser: Impact of the operating conditions on hydrogen production

Processes Involving in the Temperature Variations in Solid Oxide Fuel Cells In-Situ Analyzed through Electrode-Segmentation Method

Prototipagem rápida de pilhas a combustível de óxido sólido

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