Bipolar plate flow channel modeling

Abstract

Proton Exchange Membrane Fuel Cell (PEMFC) is a type of fuel cell that has gained popularity in the transportation sectors due to its high specific power and clean by-products produced. The work presented in this report aims to create a representative Computational Fluid Dynamics (CFD) model of a commercial fuel cell using the ANSYS Fluent software. Potentiostatic boundary condition was used in the numerical simulation and the current density calculated by the model was compared with experimental data obtained from accredited research papers. Firstly, a single flow channel computer aided design (CAD) model was created using SOLIDWORKS and input into ANSYS Fluent to investigate the detailed simulation parameters required to achieve simulation results close to another single flow channel model. Next, two separate PEMFC CAD models containing the serpentine and parallel flow channels with an active area of 5mm x 5mm were modeled using SOLIDWORKS and input into ANSYS Fluent with parameters obtained from experiments. The current density calculated by the model is validated with experimental results to determine the accuracy of the simulation model. The contact resistance is adjusted to match the simulation results obtained with the experimental results. With the development of an accurate simulation model, novel flow channel designs modeled using SOLIDWORKS are input into the simulation model to investigate the influence of flow channel design on the PEMFC performance. Based on performance indicators such as the evenness of oxygen distribution across the cathode flow channels, current density and the power density obtained, it is observed that derivatives of the serpentine flow channel design are the best performing designs. Lastly, a sensitivity analysis was conducted to investigate how changes in the porosity of the GDL, CL and relative humidity of cathode reactant gases affects the performance of the PEMFC. The simulation results shows that relative humidity has the greatest impact on the performance of the PEMFC.