Ph.D. Proposal Presentation by
Benjamin M. Dempsey
Wednesday, July 13, 2005
(Dr. David McDowell , Chair)
"Modeling of Linear Cellular Material Solid Oxide Fuel Cells"
As the world's energy needs continue to grow, alternative energy conversion devices will be needed to more effectively utilize our planet's limited resources; fuel cells will likely be a part of that plan. For years, the high power densities that could be obtained from honeycomb-type structures have driven the search for technologies that could fabricate these unique structures. Linear Cellular Materials (LCMs) are honeycomb-like structures that can be used in Solid Oxide Fuel Cell (SOFC) stacks. LCMs are extruded using powder precursors and chemical reactions to obtain near fully dense cells with thicknesses as low as 50-100 microns. The honeycomb-like structures can be composed of various materials including metal alloys and electrolytic ceramics. For the specific case of the fuel cell, an electronic and ionic conducting metal oxide paste is extruded.
The goal of this research is to explore possible geometries and process routes for LCM SOFCs that may achieve structural integrity goals for post-processed residual stress and associated damage, as well as in-service resistance to thermo-mechanical stresses; Process models will address chemical reduction, sintering, viscoplasticity, and porosity and temperature dependent elasticity of the phases. Analyses to be employed for exploring in-service integrity will consider fuel and air flow, various modes of heat transfer, electrical performance in energy conversion and associated heat generation, as well as temperature dependent elasto-viscoplasticity of the phases. Maps of process conditions and SOFC geometry effects on initial residual stresses and potential damage mechanisms will be developed to support fabrication.