Numerical analysis of reactant transport in novel tubular polymer electrolyte membrane fuel cells

In the present work, a numerical analysis of three novel PEM fuel cells with tubular geometry was conducted. Three different cross sections were considered for the PEM, namely: circular, square and triangular. Similar boundary and operational conditionswere applied for all the geometries. First the obtained polarization curve for basic architecture fuel cells was validated with experimental data and then the results of the three novel tubular architectures were compared with basic conventional geometry. The results showed that for the case of V=0.4 volts, circular and square tubular models gives up to 27.5 and 8 percent outlet current density more than the base model, whereas the triangular model predicts a decrease of 14.37 percent compared to the base model. Because the square tubular and in particular the circular tubular models do not have sharp edges, uniform reactioncan take place over the entire catalyst layer of the cathode and anode electrodes, and therefore the distribution of the hydrogen, oxygen and water is uniform. Also, circular geometry, due to use of all the reaction surface and lack of dead zones, produces higher power outputs. The temperature distribution in a lateral direction in the reaction zone for all three configurations indicates that the maximum temperature for the circular tubular has the lowest values in comparison to the other two cases, which results from a uniform surface reaction for this geometry. The results presented in this paper can be used for designing novel architecture of fuel cells.