Numerical simulation of flow distribution for external manifold design in solid oxide fuel cell stack

In this study, a three dimensional model is constructed to investigate the flow distributions and the pressure variations for a 40-cell solid oxide fuel cell (SOFC) stack. Computational fluid dynamics (CFD) is used to optimize the design parameters of external manifold in the stack. The model consists of equations for the network with chamber structure of manifold. Simulation results indicate that the flow uniformity strongly depends on geometric shapes of manifold, including the joined position between tube and manifold, the dimension of manifold and the number of tubes. The ratio of flow velocity which describes the uniformity of flow distribution can be decreased by optimizing the geometrical structure of manifolds. In addition, it is found that the flow distribution can be intensively influenced by the gas resistance of the stack, which is closely related to the configuration of interconnect channels. The results summarize the importance of structure design of external manifold for stack performance. The numerical results are in good agreement with the experimental measurement in a 40-cell stack.