On-Design and Off-Design Performance Prediction for a Planar Solid Oxide Fuel Cell Stack

摘要

Multiple cells or 'stack' models are usually developed from the cell models assuming that performance of a stack is a linear extension of a single cell performance. This work presents a three-dimensional cell model able to describe the stack performance more accurately. The model is based on an two dimensional cell model developed earlier by the author. The two dimensional, rather detailed cell model was obtained by writing the constitutive laws in the solid part of the cell for heat and conservation of heat and mass in the air and fuel channels. It included comprehensive representation of resistive cell losses, reaction kinetics for the reforming reaction and heat conduction through the solid part of the cell. The finite volume method was employed for the calculations. For this study, the two-dimensional cell model is further improved and a third dimension (in the stacking direction) is introduced. This allows a modelling of the stack performance which accounts for cell-to-cell interaction effects, i.e., the cells in the stack communicate thermally with each other. Some selected case studies will be presented to give an idea about the capabilities of this approach to the stack mathematical modelling. The results clearly show importance of three dimensional modelling while predicting both on-design and off-design performance behaviour of the stack.