Virtual Liquid Water Intrusion in Fuel Cell Gas Diffusion Media

Abstract

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.

Developments in X-ray tomography characterization for electrochemical devices

“…A micro-CT dataset of a dry GDL was used by Sabharwal et al to build a full morphology model, which simulated liquid water intrusion into the GDL. Results of the simulation showed good agreement with experimentally obtained wet GDL datasets, highlighting that the model constructed was efficient at predicting liquid water saturation in the GDL [131]. Other demonstrations of imagebase modelling have included a number of studies using X-ray CT datasets to understand water evaporation in GDLs [132,133].…”

Liquid water in cathode gas diffusion layers of PEM fuel cells: Identification of various pore filling regimes from pore network simulations

“…In this context, the present paper is an attempt to clarify the mechanisms leading to the occurrence of liquid water in the cathode gas diffusion layer (GDL) from numerical simulations. As pointed out for instance in [4], GDLs are integral part of PEM-FCs and play a key role for the distribution of the reactant from the channel to the catalyst layer (CL) as well as for removing the water produced in the CL. Due to its significance, the water issue in GDLs has been the subject of many experimental and numerical studies.…”

Alkaline Water Electrolysis at 25 A cm−2 with a Microfibrous Flow‐through Electrode

“…However, it is possible the gas bubbles can be larger than the D throat of the Ni MF and Ni-Cu NW felts, increasing the resistance to bubble removal (Figure 4). As predicted by both the bubble size vs. [64,65] and experimental observations [66,67] for bubble transport within NW and MF felts could provide more detailed analytical results that enable a quantitative connection between bubble transport phenomena and OER performance.…”