Figure 4. Fuel cell polarization curves of different porosity models.

The influence of a tubular structure PEMFC (proton exchange membrane fuel cell) with different flow patterns is investigated in this study. A complete 3D non-isothermal model is constructed for square and circular tubular PEMFCs, and the distribution of oxygen and water concentration in cathode channels, current density, power density and cell net power are studied. To this end, the four arrangements of tubular PEMFC are square chordal (SC), square peripheral (SP), circular chordal (CC) and circular peripheral (CP). The calculation of the effective area and boundary conditions remains the same when performing all four configurations. The consequent results show that for the tubular structure PEMFC, compared with the co-flow mode, the counter-flow mode has better performance and provides more power. Using a counter-flow pattern, the permeability of the species increases, so a more uniform reaction occurs at the cell. The entire performance of the SP and CP model is not as good as that of the SC and CC models because the SP and CP models have a higher flow velocity. Moreover, the SC model using the counter-flow pattern has the maximum predicted net power among the other models.