CFD Modeling to Investigate the Performance of PEM Fuel Cells Affected By Cathodic Pressure

The proton exchange membrane (PEM) fuel cell is a promising energy conversion device.  However, the cost and durability of a PEM fuel cell are major challenges needed to be overcome before it will be widely used. The simulation is crucial for the design and optimization of practical devices based on deep understanding of coupled transport phenomena inside the fuel cell. It is widely known that the slower reaction in the cathode is a limiting factor and the cathodic operating pressure has a strong influence on the cell performance. In this paper, an open-source code OpenFOAM is employed to simulate the transport phenomena and electrochemical reactions in PEM fuel cells. The basic governing equations for continuity, momentum, mass and energy transfer are solved with appropriate source terms using a computational fluid dynamics (CFD) method.  A steady state and three-dimensional (3D) model is applied for single flow channels and multi-functional layers, i.e., bipolar plates, gas diffusion layers (GDLs), catalyst layers (CLs) and electrolyte. The distributions of gas compositions, pressure, temperature, activation loss, cell voltage and current density are captured and presented. The O₂ partial pressure on the reaction sites resulting from transport and inlet pressure suggests an influence on the cell performance. The influence of removal of the inert gas N₂ and production of H₂O vapor on the O₂ partial pressure is considered based on the multi-species transport model. To verify the accuracy of the simulation approach, comparisons between the computed results and literature data have been conducted.