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 mu-CT. Numerical water saturation distributions are compared to experimental mu-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 mu-CT reconstructions. Results reveal that CFM simulations showed 56-95.7% agreement in the liquid water voxels when compared to the mu-CT simulations for saturations in the range of 29-92.3%. Gas transport simulations are then performed on mu-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 mu-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. (C) The Author(s) 2018. Published by ECS.