Proton Exchange Membrane Fuel Cells: Geometric Scaling and Similarity Conditions

Abstract

In the present study, the similarity conditions in the proton exchange membrane fuel cells are investigated and the scaling effect on the polarization curve is analyzed. The steady-state two-dimensional, isothermal single-phase, and multi-species system of flow field's governing equations are utilized besides the ionic and electric potentials to predict numerically the fuel cell operation. Here, the finite-volume and cell-centered method is used as a numerical scheme. It is concluded that the similarity may exist in the performance of the fuel cells by considering some requirements. The results show that the scaling up the fuel cell with scaling size of SC makes the total current density SC times the based one, and the potential fields of the base and scaled fuel cells are similar. In addition, the effect of geometric scaling on different regions of the polarization curve is investigated for non-similar condition which shows that scaling-down the fuel cell amplifies the mass transport limiting region, and increases somewhat its maximum total current density.