A Distributed Resistance Analogy for Solid Oxide Fuel Cells

Abstract

A distributed resistance analogy for solid oxide fuel cells Beale, Steven; Zhubrin, S. V.Access and use of this website and the material on it are subject to the Terms and Conditions set forth at http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en Numerical Heat Transfer, Part B: Fundamenals, 47, 6, 2005 Publisher's version / la version de l'éditeur: This article maybe used for research, teaching and private study purposes. Any substantial or systematic reproduction, re-distribution, re-selling, loan or sub-licensing, systematic supply or distribution in any form to anyone is expressly forbidden.The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material. The method of distributed resistances is outlined for performance calculations in solid oxide fuel cells. The domain is discretized using a multiply shared space method. Both potentiostatic and galvanostatic conditions are considered. Mass transfer effects on the heat transfer coefficients and the Nernst potential are taken into consideration. Calculations, for one cell and for a 10-cell stack, are compared to those obtained using a detailed numerical method. Agreement is very good. It is concluded that the distributed resistance analogy may be used to predict transport phenomena in fuel cell stacks at a fraction of the computational cost required for conventional means.

Effective transport properties of the porous electrodes in solid oxide fuel cells

“…The porous composite anode and cathode electrodes used in solid oxide fuel cells (SOFCs) provide a particular challenge to the engineer who wishes to construct mathematical models at the cell/stack level [1,2]. It is of great importance, not only to employ wellconstructed microstructures, but also to possess accurate data for effective transport and electro-physical properties of the multi-phase porous systems used in SOFCs.…”

Two-Phase Flow and Mass Transfer Within the Diffusion Layer of a Polymer Electrolyte Membrane Fuel Cell

“…The purpose here is not to develop detailed models specific to any given design, but rather to reduce the two-phase mass transfer problem to a standard form so that fine-scale diffusion terms may be replaced by simple rate equations. This will enable the future construction of spreadsheet calculation procedures for single PEMFCs as well as CFD-based models for large stacks of cells, where prohibitively expensive fine-grid calculations may be replaced by rate terms (Beale and Zhubrin, 2005). At present, PEMFC stack design is seriously restricted by the inability of the CFD engineer to construct fine meshes within memory limitations and run times typical of present-day computers.…”

“…Conventional fuel cells, such as PEMFCs and solid oxide fuel cells (SOFCs) generally employ gaseous mixtures as reactants and products. Previous work (Beale, 2004) was concerned with single-phase mass transfer and the development of a single-phase SOFC stack model (Beale and Zhubrin, 2005) based on the distributed resistance analogy of Patankar and Spalding (1974). The PEMFC, however, relies on the membrane being hydrated in order to function effectively, and hence the problem is two-phase-with both liquid and gas present.…”

Effect of Porous Microstructural Properties on the Results of a Cell-Level Model in Solid Oxide Fuel Cells

“…It is imperative, not only to employ well-reconstructed microstructures, but also to access accurate data for effective physical and transport properties of the multi-phase and multi-layer electrodes used in SOFCs. The effective properties from such micro-scale porous media may readily be integrated into the macroscale cell/stack/hot-box models used in SOFCs (2,3). Therefore, the accurate and reliable techniques for the micro-structural reconstruction and computation of relevant physical and transport properties will lead to improvement in the overall design of SOFCs.…”