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Mechanical failures in the operating stacks of solid oxide fuel cells (SOFCs) are frequently related to thermal stresses generated by a temperature gradient and its variation. In this study, a computational fluid dynamics (CFD) model is developed and further applied in full-size SOFC stacks, which are fully coupled and implemented for analysis of heat flow electrochemical phenomena, aiming to predict thermal stress distribution. The primary object of the present investigation is to explore features and characteristics of the thermal stress influenced by electrochemical reactions and various transport processes within the stacks. It is revealed that the volume ratio of the higher thermal stress region differs nearly 30% for different stack flow configurations; the highest probability of potential failure appears in the cell cathodes; the more cells applied in the stack, the greater the difference in the predicted temperature/thermal stress between the cells; the counter-flow stack performs the best in terms of output power, but the predicted thermal stress is also higher; the cross-flow stack exhibits the lowest thermal stress and a lower output power; and although the temperature and thermal stress distributions are similar, the differences between the unit cells are bigger in the longer stacks than those predicted for shorter stacks. The findings from this study may provide a useful guide for assessing the thermal behavior and impact on SOFC performance.

A fully coupled electro-thermo-mechanical CFD model is developed and applied to illuminate the crucial factors influencing the overall performance of a solid oxide electrolysis cell (SOEC), particularly the configuration and geometry parameters of its inter-connector (IC), comprising ribs and channels. Expanding on a selected width ratio of 4:3, the gradient ribs/channels are further investigated to assess electrochemical and thermo-mechanical performance. It is elucidated that, while maintaining constant maximum temperature and thermal stress levels, employing a non-regular geometry IC with gradient channels may yield a 30% enhancement in hydrogen production. These nuanced explorations illuminate the complex interplay between IC configuration, thermal stresses, and electrolysis efficiency within SOECs.

A three-dimensional computational fluid dynamics (CFD) method coupled with multi-physics phenomena is developed and applied for a 10-cell full-scale SOEC stack in this study. Effects of gas flow patterns, operating temperature, and manifold configurations are simulated and analyzed for stack performance and thermal stress. It is demonstrated the hydrogen production and thermal stress obtained in cross-flow mode stack are about 8% and 36 MPa higher compared to that in other flow cases. Furthermore, it is found the temperature gradient is the predominant factor affecting the thermal stress distribution and failure probability. Lastly, a stack arrangement with 2-inlet and 1-outlet is proposed and analyzed to enhance gas distribution uniformity within the cell channels. The findings of this study hold significance as a reference for investigating the impact on the SOEC stack performance and thermal stress distribution.

In this work, a 3D multi-physics coupled model was developed to analyze the temperature and thermal stress distribution in a planar solid oxide fuel cell (SOFC) stack, and then the effects of different flow channels (co-flow, counter-flow and cross-flow) and electrolyte thickness were investigated. The simulation results indicate that the generated power is higher while the thermal stress is lower in the co-flow mode than those in the cross-flow mode. In the cross-flow mode, a gas inlet and outlet arrangement is proposed to increase current density by about 10%. The generated power of the stack increases with a thin electrolyte layer, but the temperature and its gradient of the stack also increase with increase of heat generation. The thermal stress for two typical sealing materials is also studied. The predicted results can be used for design and optimization of the stack structure to achieve lower stress and longer life.

Mechanical failures in the operating stacks of solid oxide fuel cells (SOFCs) are frequently related to thermal stresses generated by a temperature gradient and its variation. In this study, a computational fluid dynamics (CFD) model is developed and further applied in full-size SOFC stacks, which are fully coupled and implemented for analysis of heat flow electrochemical phenomena, aiming to predict thermal stress distribution. The primary object of the present investigation is to explore features and characteristics of the thermal stress influenced by electrochemical reactions and various transport processes within the stacks. It is revealed that the volume ratio of the higher thermal stress region differs nearly 30% for different stack flow configurations; the highest probability of potential failure appears in the cell cathodes; the more cells applied in the stack, the greater the difference in the predicted temperature/thermal stress between the cells; the counter-flow stack performs the best in terms of output power, but the predicted thermal stress is also higher; the cross-flow stack exhibits the lowest thermal stress and a lower output power; and although the temperature and thermal stress distributions are similar, the differences between the unit cells are bigger in the longer stacks than those predicted for shorter stacks. The findings from this study may provide a useful guide for assessing the thermal behavior and impact on SOFC performance. [ABSTRACT FROM AUTHOR]

A fully coupled electro-thermo-mechanical CFD model is developed and applied to illuminate the crucial factors influencing the overall performance of a solid oxide electrolysis cell (SOEC), particularly the configuration and geometry parameters of its inter-connector (IC), comprising ribs and channels. Expanding on a selected width ratio of 4:3, the gradient ribs/channels are further investigated to assess electrochemical and thermo-mechanical performance. It is elucidated that, while maintaining constant maximum temperature and thermal stress levels, employing a non-regular geometry IC with gradient channels may yield a 30% enhancement in hydrogen production. These nuanced explorations illuminate the complex interplay between IC configuration, thermal stresses, and electrolysis efficiency within SOECs. [ABSTRACT FROM AUTHOR]

A three-dimensional computational fluid dynamics (CFD) method coupled with multi-physics phenomena is developed and applied for a 10-cell full-scale SOEC stack in this study. Effects of gas flow patterns, operating temperature, and manifold configurations are simulated and analyzed for stack performance and thermal stress. It is demonstrated the hydrogen production and thermal stress obtained in cross-flow mode stack are about 8% and 36 MPa higher compared to that in other flow cases. Furthermore, it is found the temperature gradient is the predominant factor affecting the thermal stress distribution and failure probability. Lastly, a stack arrangement with 2-inlet and 1-outlet is proposed and analyzed to enhance gas distribution uniformity within the cell channels. The findings of this study hold significance as a reference for investigating the impact on the SOEC stack performance and thermal stress distribution. [ABSTRACT FROM AUTHOR]

In this work, a 3D multi-physics coupled model was developed to analyze the temperature and thermal stress distribution in a planar solid oxide fuel cell (SOFC) stack, and then the effects of different flow channels (co-flow, counter-flow and cross-flow) and electrolyte thickness were investigated. The simulation results indicate that the generated power is higher while the thermal stress is lower in the co-flow mode than those in the cross-flow mode. In the cross-flow mode, a gas inlet and outlet arrangement is proposed to increase current density by about 10%. The generated power of the stack increases with a thin electrolyte layer, but the temperature and its gradient of the stack also increase with increase of heat generation. The thermal stress for two typical sealing materials is also studied. The predicted results can be used for design and optimization of the stack structure to achieve lower stress and longer life. [ABSTRACT FROM AUTHOR]