Performance and Stress Analysis of Flat-Tubular Solid Oxide Fuel Cells Fueled with Methane and Hydrogen

Solid oxide fuel cell (SOFC) is a promising power generation technology with high efficiency and can operate with a wide range of fuels. Although H₂ delivery and storage are still hurdles, natural gas is readily accessible through existing pipeline infrastructure and therefore stands as a viable fuel candidate for SOFC. Owing to the high operating temperature, the methane in natural gas can be directly reformed in the anode of an SOFC. However, mechanical failure remains a critical issue and hinders the prevalence of traditional planar SOFCs. A novel flat-tubular structure with symmetrical double-sided cathodes was previously proposed to improve mechanical durability. In this work, the performance of a methane-fueled SOFC with symmetrical double-sided cathodes is analyzed with a numerical multiphysics model. The distributions of different physical fields in the SOFC are investigated. Special attention is paid to stress analysis, which is closely related to the mechanical stability of an SOFC. Furthermore, the CH₄-fueled and H₂-fueled SOFCs are also compared in terms of the distribution of thermal stress. A lower first principal stress is observed for CH₄-fueled flat-tubular SOFC, demonstrating a reduced probability of mechanical failures and potentially extended lifespan.