PNNL

Abstract

In order to efficiently develop and optimize planar SOFC stacks to meet technical performance targets, it is desirable to perform numerical experiments on the effects of geometry, material properties, operational parameters, and thermal-mechanical loading. The computations with representative baseline designs, validated by experimental data, have been used to develop better understanding of the stack behavior while avoiding costly and time-consuming experiments. In order to model the coupled physics associated with an SOFC stack, the simulation tool SOFC-MP was developed. This modeling tool combines the versatility of a commercial multi-physics code and a validated electrochemistry calculation routine to predict the gas flow distributions, current distribution, temperature field, and power output for stack-level simulations. The fundamental building blocks of the modeling and simulation tools are electrochemical models, heat and mass transfer simulations, computational mechanics, and experimental data. The modeling tools were then used to evaluate challenging issues anticipated for cell scale-up. A systematic methodology was developed for quantifying the thermal and electrical performance improvements available with pressurized operation. For SOFC cathode contact materials and stack development, a sintering model was developed to explore/optimize the load distribution within the stack as a function of cathode contact densification and strength. The modeling tools developed were also used in studying current material development and degradation challenges. The mechanical durability of the surface scale present on metallic interconnects was evaluated for its ability to resist scale growth-induced spallation. The developed design methodology and stack analytical procedures have been documented as an ASME design basis for distribution within the SECA program. This report discusses technical progress made in FY 2010.