Simulation of Surface Reactions and Multiscale Transport Processes in a Composite Anode Domain Relevant for Solid Oxide Fuel Cells

Abstract

There are various transport phenomena (gasphase species, heat, and momentum) occurring at different length scales in anodesupported solid oxide fuel cells (SOFCs), which are strongly affected by catalytic surface reactions at active triplephase boundaries (TPBs) between the void space (for gas), Ni (catalysts for electrons), and YSZ (an electrolyte material for ions). To understand the multiscale chemicalreacting transport processes in the cell, a threedimensional numerical calculation approach (the computational fluid dynamics (CFD) method) is further developed and applied for a composite domain including a porous anode, fuel gas flow channel, and solid interconnect. By calculating the rate of microscopic surfacereactions involving the surfacephase species, the gasphase species/heat generation and consumption related to the internal reforming reactions have been identified and implemented. The applied microscopic model for the internal reforming reactions describes the adsorption and desorption reactions of six gasphase species and surface reactions of 12 surfaceadsorbed species. The predicted results are presented and analyzed in terms of the gasphase species and temperature distributions and compared with those predicted by employing the global reaction scheme for the internal reforming reactions.