The effects of operating parameters on the performance of proton exchange membrane fuel cells

A two-dimensional computational proton exchange membrane fuel cells (PEMFCs) model is presented to investigate the effects of operating parameters such as overall ohmic resistance, cathode side charge transfer coefficient, operating pressure, and fuel cell temperature on PEMFCs. A single phase, compressible and isothermal flow of reactant-product mixture in the air-side electrode of PEM fuel cell with straight gas channel is considered. The mixture is composed of three species: oxygen, water vapor and nitrogen. The model presented in this paper is a typical three-layer that consists of cathode-side gas flow channel, cathode-side gas diffusion layer and cathode-side catalyst layer. For the present computation the assembly of the software packages Gambit+Fluent is used to solve this predictive model through SIMPLE algorithm and the modeling results are illustrated via local current density curve, oxygen sink curve and performance curves including I-V and I-P curves. The results reveal that the net transport of reacting species through porous layers toward the catalyst layer and also the performance of PEMFC can be enhanced by increasing cathode side charge transfer coefficient, operating pressure and operating temperature. Also the overall ohmic resistance (sigma) is investigated which is the structural parameter that has the most significant influence on PEMFC performance.