DBPapers
DOI:10.5593/SGEM2013/BD4/S17.009

COMPUTATIONAL FLOW MODELING OF A SULFIDE-DRIVEN FUEL CELL: THE CATHODE CELL WITH EJECTOR MIXER

S. Vlaev, D. Georgiev, V. Beshkov
Monday 5 August 2013 by Libadmin2013

References: 13th SGEM GeoConference on Energy And Clean Technologies, www.sgem.org, SGEM2013 Conference Proceedings, ISBN 978-619-7105-03-2 / ISSN 1314-2704, June 16-22, 2013, 69 - 76 pp

ABSTRACT

Oxydation of sulfide from Black Sea water for energy generation by sulfide-driven fuel cell is considered. A serious problem is the slow cathode oxygen reduction reaction (ORR): 2O2 + 8H+ +8e- = 4H2O. A solution is found by designing a cell with forcedcirculation by means of ejector. A cathode chamber with cylindrical coaxial electrode is proposed. Regarding the transport properties of the cathode area, the flow regime in the cathode compratment is studied. The aim of the study is to formulate a flow model of the cathode cell and to characterize the flow field in view of increasing the cell potential for enhanced oxygen reduction. The task is solved by numerical modeling and simulation. Commercial computational flow dynamics (CFD) software was used. A two-phase quasi-homogeneous mixture model is formulated and used in couple with k-ϵ turbulence model. The key parameters of the flow field, i.e. pressure and fluid velocity distribution, as well as energy dissipation rate are determined and visualized. The results are compared with reference data from the literature. The model can be combined with the current distribution model (Ohm’s law for ionic conduction), the electrode kinetic expressions (Butler-Volmer) and a diffusion convection equation for the ionic transport and can be implemented for complete description of current distribution and cell voltage thus promoting future analyses of the energy-storage system

Keywords: Fuel Cell, Cathode, Flow field analysis, CFD