Analytical and numerical investigation of flow distribution in PEMFC stacks

The flow distribution in the PEMFC stack is of significance to its performance and durability. To determine the flow uniformity criterion of the stack manifold, a "flow field analysis scheme" that combines theoretical analysis and numerical simulations has been employed. In the analysis, an analytical model is developed for the manifold flow system. Two dimensionless configuration parameters eta and lambda determining the flow distribution are clarified and the coefficient of variation (CV) has been quantitatively derived, which is the function of the combined variable eta.lambda. On this basis, a simple and explicit criterion for flow uniformity has been proposed (CV < 5% when eta lambda < 0.59). Additionally, the detailed numerical simulations systematically investigate the stack configuration parameters, further validating the aforementioned criterion. The pressure recovery phenomenon in the inlet header has inspired us to conceive the basic principles of the stack manifold design.