A Distributed Parameter Model for a Solid Oxide Fuel Cell: Simulating Realistic Operating Conditions

We present a detailed multiphysics model capable of simulating the dyn\udamic behavior\udof a solid oxide fuel cell (SOFC). This model includes a description of a\udll the important physical\udand chemical processes in a fuel cell: fluid flow, mass and heat trans\udfer, electronic and ionic\udpotential fields, as well as the chemical and electrochemical react\udions. The resulting highly\udnonlinear, coupled system of differential equations is solved using a fi\udnite volume discretization.\udOur interest lies in simulating realistic operating conditions with the obj\udective of high efficiency\udoperation at high fuel utilization. While there are a number of studies\udin the literature that\udpresent multiphysics models for SOFCs, few have focused on simulat\uding operating conditions\udthat are necessary if SOFC systems are to realize their promise of h\udigh efficiency conversion of\udchemical energy to electrical energy. In this report we present s\udimulation results at operating\udconditions that approach the required ranges of power density an\udd overall efficiency. Our results\udinclude a) the temperature and composition profiles along a typical f\uduel cell in a SOFC stack, b)\udthe dynamic response of the cell to step changes in the available inpu\udt variables. Since models\udsuch as the one presented here are fairly expensive computationa\udlly and cannot be directly used\udfor online model predictive control, one generally looks to use simplifie\udd reduced order models\udfor control. We briefly discuss the implications of our model results o\udn the validity of using\udreduced models for the control of SOFC stacks to show that avoid\uding operating regions where\udwell-known degradation modes are activated is non-trivial without u\udsing detailed multiphysics\udmodels