A Numerical Parametric Study on the Impacts of Mass Fractions of Gas Species on PEMFC Performance

Proton exchange membrane fuel cell (PEMFC) has attained increasing interest during the past decade owing to operating at low temperatures, generating higher efficiency power and having low pollutant emissions. Many parameters including operating temperatures, pressures and mass fraction of gas species affect PEMFC efficiency. In this work, a 3D Computational Fluid Dynamics approach is employed to study the influences of hydrogen mass fraction (0.1-0.6), oxygen mass fraction (0.1-0.2) and cathode water mass fraction (0.1-0.26) on the cell performance at 0.4-0.8 V. The numerical results using ANSYS Fluent reveal that decreasing hydrogen mass fraction and increasing water mass fraction augment the current density at 0.4 and 0.6 V. Besides, decreasing oxygen mass fraction from 0.2 to 0.16 also enhances the cell performance whereas the current density remains almost constant with further decreasing oxygen mass fraction. The highest current density of 2.30 A/cm² is achieved with mass fraction of oxygen of 1.6 and the current density increases by 82.5% compared to the base model at 0.4 V. However, the pressure drop of channels is not significantly affected by modifying mass fractions of gases. It is found that determining the optimum value of each species mass fraction at the anode and cathode plays a crucial role in the development of the cell efficiency.