In this study a complete two-dimensional model for proton exchange membrane (PEM) fuel cells was used to investigate the effect of using different obstacles on the performances, current density and gas concentration for different Aspect Ratios. The proposed model is a full cell model, which includes all the parts of the PEM fuel cell, flow channels, gas diffusion electrodes, catalyst layers and the membrane. Also a series of tests are carried out to investigate and validate the numerical results of the polarization curve under the normal conditions. A PEM fuel cell with active area and Nafion 117 membrane with 4mg Pt for the anode and cathode is employed as a membrane electrode assembly. The results show that the predicted polarization curves by using this model are in good agreement with the experimental results. Also the results show that the local current density reduces more obviously at a higher overpotential than at a lower overpotential because of the more obvious reflection phenomena in the downstream region. At lower operating voltage conditions, the overall cell performance decreases as the aspect ratio decreases.
کلید واژگان :PEM fuel cell, rectangular obstacle, triangle obstacle, numerical modeling, current density, gas concentration
ارزش ریالی : 600000 ریال
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