A CFD Simulation for an Air Breathing PEMFC for Power Source Portable Applications

Air breathing PEM fuel cells are a promising and a potential power source for portable applications. The challenges that air breathing fuel cells has to overcome in order to be used in portable applications and to be cost competitive are related to the ability to use logistic fuels, to the prevention of cathode contamination with impurities from the used air (supplied by active or passive methods), to the reduction of the size and weight.

In this context, the development of a mathematical model for a better understanding of the fundamental processes and characteristics associated with air breathing cathode operation is required. The three-dimensional model developed in this paper based on the ANSYS Multiphysics software was used to analyse the influence of the factors that influence the PEM fuel cell performance (flow field configuration, operating conditions). Regarding the flow field configuration a 3 step-serpentine was used for the anode channel and parallel channels were used in the cathode side for the forced air supply. In this respect, for the cathode side channels, the width, depth and the space between two adjacent channels was varied (1 mm, 1.5 mm, and 2 mm) in order to see their influence on the uniformity of the reactant distribution (particularly water) and on heat management. Regarding the operating parameters that can have a significant influence on the performance, our numerical analysis took into consideration the air flow rate, the humidity and temperature and the results are discussed in the paper. The analysis was intended to identify critical parameters and give an insight into physical mechanisms that can influence this type of air breathing PEM fuel cell.