Multiscale three-dimensional modeling of two-phase transport inside porous transport layers

Polymer Electrolyte Membrane Water Electrolyzers (PEMWE) depend on a porous transport layer (PTL) to remove gaseous oxygen from the catalyst layer produced by the oxygen evolution reaction. PEMWEs are a promising technology for energy production and storage. In this work, five PTLs are reconstructed from X-ray Tomography Scans to create real three-dimensional structures. During the geometry generation process, porosity and a pore size distribution were calculated. Two different numerical models were used to simulate physical properties and expected performance for the different PTL samples. First, a two-phase flow micro-scale ex-situ model was used to predict in-plane permeability, through-plane permeability, and oxygen evolution. Adaptive meshing and adaptive time scale was used to produce a more accurate prediction of bubble interaction with the solid structure and liquid water. Second, a macro-scale model of a real PEMWE was used to predict performance behavior for each PTL sample. Outcomes from this work will provide insight into PTL design for more efficient PEMWE operation.