Multiscale Modeling Subatomic Modeling Electron structures Quantum Mechanics

Multiscale Modeling Subatomic Modeling Electron structures (Quantum Mechanics) Atomistic Modeling Molecular Dynamics (Classical Force Fields) Continuum Modeling Elasticity, Thermal expansion Electric conductivity Microstructure Modeling Transport Processes in Porous Media Multi-Component Modeling Single Cell Stack Process Integration

Prior Work Multi-component modeling Multi-species reactive flows Heat transfer Electro-chemistry Fuel Cell Stacks A numerical study of cell to cell variations in a SOFC stack, A. Burt, I. Celik, R. Gemmen, A. Smirnov, Journal of Power Sources, vol. 126, pp. 76 -87, 2004 Fuel-Cell Simulator Interface, A. Smirnov, H. Zhang, A. Burt, I. Celik, Journal of Power Sources, vol. 138, pp 187 -193, 2004 Multi-Physics Simulations of Fuel Cells Using Multi-Component Modeling A. Smirnov, A. Burt, I. Celik, Journal of Power Sources, V. 158, pp. 295 -302, 2006

Electrons: SCF, DFT, LTMO Provide binding forces for atomistic modeling. Provides electric conductivity and elasticity tensors for the continuum modeling. Molecules: MD/GCMC Provides thermal conductivity and Thermal expansion coefficients Chemical reactions Continuum Materials: FEA Electric conductivity Heat transfer Thermal expansion Composite Materials: FEA/CFD, MC, GA Porosity Micro-structure Diffusivity

Inter-Scale Coupling 1 M: Sub-nano level (ab-initio) modeling Seif-Consistent Field Density Functional Theory. 1 M -> 2 P: Nano-level properties: Classical interaction potentials 1 M -> 3 P: Micro-level properties: Electical conductivity, elasticity tensors. 2 P -> 2 M: Nano-level modeling: Molecular dynamics (slow, transient) Grand Canonical Monte-Carlo (fast, steady-state) 2 M -> 3 P: Micro-level properties: Thermal expansion coefficients Heat transfer coefficients 3 P -> 4 M: Porous micro-structure modeling FEM/CFD Evolutionary Optimization

Fundamental problems Sulfur Poisoning and Carbon Clogging: Clogging A technical challenge or a fundamental problem? What can be wrong with SOFC? - No moving parts - No flowing liquids - No way to clean/flush the system! - All successful electrochemical devices so far are using some kind of liquids: -- car batteries -- MCFC -- PEM FC -- Even us! Second law of Thermodynamics: Keeping entropy low can be expensive. We can't hope to clean up tons of air that is being filtered through SOFC. Our way is to find a catalyst resistant to all the dirt. The alternative may be to find a flush mechanism.