Lattice Boltzmann method to study the water-oxygen distributions in porous transport layer (PTL) of polymer electrolyte membrane (PEM) electrolyser

Anodic porous transport layer (PTL) plays a pivotal role in the performance of the polymer electrolyte membrane (PEM) water electrolyser. In this study, Shen-Chen Lattice Boltzmann Method (SC-LBM) is implemented to study the invasion patterns (IP) of O2 in a water saturated anodic PTL. Multiphase flow patterns in anodic PTL obtained with the LBM simulations are validated with the experiment results. Simulations are conducted for varied Capillary number (Ca) and Bond number (Bo) to study the competitiveness between the capillary, viscous forces and gravity. A dimensionless number (φ) is defined to develop a set of optimized parameters to enhance O2 removal. The O2 saturations along the normalized length reveal importance of void space microstructure in PTL. Thus, positive and negative porosity gradients are implemented from catalyst layer (CL) to water flow channel to understand invasion patterns. The results inspire to consider a random micro porous layer (MPL) near the CL to minimize the accumulation of O2. Such parametric analysis and pore structure studies is a promising technique for the optimisation of the O2 removal process.