Electrochemical Analysis And Numerical Modeling Of Solid Oxide Fuel Cell

Fuel Cells are a highly efficient, environmentally benign method of electric power production. Among fuel cells, Solid Oxide Fuel Cells (SOFCs) are drawing keen worldwide attention for its flexibility in design and high generating efficiency in respect of all solid constitution compared to other fuel cell systems. The transport phenomena and electrochemical reaction inside solid oxide fuel cells which determine the output performance of the cells are coupled together. And therefore, the emphasis of the numerical simulation work is placed on the development of the operating conditions to improve the species distribution of the flow field with fruition of advanced output performance of the cell.The fundamental of solid oxide fuel cells is given out and the irreversible factors of activation, concentration and ohm polarizations are deduced on the basis of dynamic-electrochemistry principles, in addition, the causations and the effect on the output performance of the cell is accounted. The current transport inside the cell is substituted for an equivalent ladder circuit model, and thereby the whole transport path is reduced to one-dimensional as well as the computation.This numerical modeling work employed Computational Fluid Dynamics(CFD) packages FLUENT and its preprocessor Gambit as tools, hydrogen fueled planar single solid oxide fuel cells as object, then constructed the mass conservation, momentum conservation, energy conservation and species conservation equations with respects of the basic characters and rules of fluid flow inside solid oxide fuel cells. Subsequently the work analyzed the relationship between the operating conditions and the improvement of the temperature distribution, the output performance as well as the utilization of fuel, which might in consequence, contributes some guidelines to the optimization of practical operation for solid oxide fuel cells. What's more, this dissertation gives out as result the current density distribution at electrode/electrolyte interface and thus reflected the couple character of electrochemistry and the flow states inside the cell.At last, this dissertation focused for the output voltage under specified current on the simulation of a model fueled with the composition of hydrogen, water vapor and argon, and then compared the simulation results with those experimental ones under a similar model and the same working conditions as published previously in literature. Good accordance revealed the validity of the numerical simulation of this work.