Three-dimensional and Transient Modeling of a PEM Fuel Cell with the Pin - type flow Field

In the present study, a three-dimensional and transient model of a proton exchange membrane (PEM) fuel cell with pin-type flow field is investigated. The governing equations, including the mass, momentum, species, charge and energy conservation equation along with electrochemical reactions, are numerically solved to investigate the transient behavior of the fuel cell. The results associated with the current density, chemical species and velocity distributions, along with the streamline pattern clarify the basic concept of the transport phenomena in the PEM fuel cells. The numerical results show that using the pin-type flow field, increase the oxygen transfer rate into the catalyst layer which results to an increase in the current density average value. As the transient time of the fuel cell is about few seconds, its start-up process is very quick. During this transient time, the operating parameters of the fuel cell such as current density, mole fraction of the reactants and pressure of the fuel cell reach to their steady state condition.