Non-Continuum Mass Transport in Solid Oxide Fuel Cell Anodes by the Lattice Boltzmann Method

At the length scales and temperatures present in a typical SOFC, both continuum and non-continuum transport of fuel and product species are important. Fuel and product transport through a representative, microscopic, two-dimensional (2D) channel present in the porous anode of a solid oxide fuel cell (SOFC) is examined. Non-continuum transport, which can be broken down into the slip, transition and free molecular regimes, is modeled for a ternary system (H₂, H₂O, and N₂) using the Stefan-Maxwell (SM) model, the Dusty-Gas (DG) model and the lattice Boltzmann method (LBM). Results obtained show that the LBM can provide a suitable framework for continuum as well as non-continuum transport in a SOFC up to the transition regime. LBM can also handle complex porous geometries, which are currently intractable by other modeling approaches, e.g. SM and DG. However, further work is required to extend the range of application of the present LBM to the free-molecular flow regime.