Three-dimensional thermo-fluid electrochemical modeling of planar SOFC stacks

A simulation tool for modeling planar solid oxide fuel cells is demonstrated. The tool combines the versatility of a commercial computational fluid dynamics simulation code with a validated electrochemistry calculation method. Its function is to predict the flow and distribution of anode and cathode gases, temperature and current distributions, and fuel utilization. A three-dimensional model geometry, including internal manifolds, was created to simulate a generic, cross-flow stack design. Similar three-dimensional geometries were created for simulation of co-flow, and counterflow stack designs. Cyclic boundary conditions were imposed at the top and bottom of the model domains, while the lateral walls were assumed adiabatic. The three cases show that, for a given average cell temperature, similar fuel utilizations can result irrespective of the flow configuration. Temperature distributions however, which largely determine thermal stresses during operation, are dependent on the chosen design geometry/flow configuration. The co-flow case had the most uniform temperature distribution and the smallest thermal gradients, thus offers thermo-structural advantages over the other flow cases.