Hae-Won Choi

Open-source computational model of a solid oxide fuel cell

The solid oxide fuel cell is an electro-chemical device which converts chemical energy into electricity and heat. To compete in todays market, design improvements, in terms of performance and life cycle, are required. Numerical prototypes can accelerate design and development progress. In this programme of research, a three- dimensional solid oxide fuel cell prototype, openFuelCell, based on open-source computational fluid dynamics software was developed and applied to a single cell. Transport phenomena, combined with the solution to the local Nernst equation for the open-circuit potential, as well as the Kirchhoff-Ohm relationship for the local current density, allow local electro-chemistry, fluid flow, multi-component species transport, and multi-region thermal analysis to be considered. The underlying physicochemical hydrodynamics, including porous- electrode and electro-chemical effects are described in detail. The openFuelCell program is developed in an object-oriented open- source C++ library. The code is available at http://openfuelcell.sourceforge.net/. The paper also describes domain decomposition techniques considered in the context of highly efficient parallel programming

Numerical and Experimental Analysis of a Solid Oxide Fuel Cell Stack

A numerical simulation of the Julich F-design solid oxide fuel cell stack is conducted by means of an original mathematical model. The model is implemented in the open source toolbox, OpenFOAM. This cell/stack level model is a key component of a programme to develop a fully integrated multi-scale fuel cell modelling capability, from nano-scale through to system level. It is intended to share the resulting software with other parties openly. Substantial experimental data is available for the Julich F-design; Stack configuration, flow conditions, interconnector geometries and porous electrode properties prescribed in the numerical model are based on field experiments. The numerical model generates distributions of fluid flow, species concentrations, current density and temperature. The results of the simulations are compared against experimental data obtained from short stacks.

Effective Transport Properties Accounting for Electrochemical Reactions of Proton-Exchange Membrane Fuel Cell Catalyst Layers

There has been a rapidly growing interest in three-dimensional micro-structural reconstruction of fuel cell electrodes so as to derive more accurate descriptors of the pertinent geometric and effective transport properties. Due to the limited accessibility of experiments based reconstruction techniques, such as dual-beam focused ion beam-scanning electro microscopy or micro X-Ray computed tomography, within sample micro-structures of the catalyst layers in polymer electrolyte membrane fuel cells (PEMFCs), a particle based numerical model is used in this study to reconstruct sample microstructure of the catalyst layers in PEMFCs. Then the reconstructed sample structure is converted into the computational grid using body-fitted/cut-cell based unstructured meshing technique. Finally, finite volume methods (FVM) are applied to calculate effective properties on computational sample domains.