Virtual Liquid Water Intrusion in Fuel Cell Gas Diffusion Media

A cluster based full morphology (CFM) model is developed to predict liquid water intrusion in GDLs. The CFM model is used to simulate water intrusion into a dry GDL microstructure obtained from μ-CT. Numerical water saturation distributions are compared to experimental μ-CT reconstructions of the same GDL sample at varying saturation levels. A quantitative validation of the CFM model results is then provided by studying the number of voxels in the image that contain water in both the CFM model results and the μ-CT reconstructions. Results reveal that CFM simulations showed 56–95.7% agreement in the liquid water voxels when compared to the μ-CT simulations for saturations in the range of 29–92.3%. Gas transport simulations are then performed on μ-CT and CFM partially saturated GDLs in order to study the validity of the CFM model images to estimate transport properties of partially saturated GDLs. A maximum error of 20% was observed between the predicted effective diffusivities obtained from CFM simulations and those obtained directly from simulations on the μ-CT data for saturations below 40%. Effective diffusivity predictions from the CFM simulations agree well with in-plane effective diffusivities in literature while the through-plane effective diffusivities were underpredicted by a factor of 2.