CFD based two-phase modelling of proton exchange membrane fuel cell with interdigitated flow field

The flow field structure is an important factor determining proton exchange membrane fuel cell performance. A steady three-dimensional, two-phase and non-isotherm mathematical model based on computational fluid dynamics is proposed in this paper, and the model is applied to conduct numerical study on a single proton exchange membrane fuel cell with an interdigitated flow field and an electrode area of 6.4x6.5 cm(2). The distribution of gas flow field, temperature and local current density is numerically obtained, which also support some advantages of interdigitated flow fields such as fast water removal, forced convection, etc. In addition, the effects of anode and cathode relative humidity on the cell characteristics such as anode and cathode pressure loss, membrane electrical conductivity and cell performance are numerically analysed. The results indicate that keeping the relative humidity 100% of anode in-stream reactants constant and decreasing the relative humidity of cathode in-stream reactants (100, 80 and 60%) will enhance cell performance and increase pressure loss inside both anode and cathode; correspondingly, keeping the relative humidity 100% of cathode reactants constant and decreasing the relative humidity of anode reactants (100, 80 and 60%) will reduce cell performance and reduce pressure loss inside both anode and cathode. The membrane electrical conductivity can be much greatly affected by relative humidity of anode in-stream reactants; however, relative humidity of cathode has little effect on it.