Numerical modeling of a proton exchange membrane fuel cell with tree-like flow field channels based on an entropy generation analysis

This paper presents a three-dimensional numerical modeling of a PEM fuel cell with tree-like flow field channels. Four different tree-like configurations are considered for the study based on a statistical analysis of the veins of the leaves of different trees. The number of bifurcations of the vein and their inclination are considered as parameters for the characterization. Four different configurations are the most recurrent, corresponding to one level of bifurcation at 37° and 74° and two levels of bifurcation at 37° and 74°. The model considers a complete solution of the mass, momentum, energy, and electrochemical equations. An entropy generation analysis is developed as a post processing once the solution of the models is obtained. Because new geometries for the channel configuration in the bipolar plates are introduced, special attention is considered for the entropy generation due to mass flow. Results indicate that the configuration with two levels of bifurcation at 37° is efficient at removing water from the cathode channels, resulting in a good current density production. In addition, a better performance of the PEM fuel cell (higher current density production and lower entropy production) is obtained by increasing the number of bifurcations.