LTNE APPROACH AND SIMULATION FOR ANODE-SUPPORTED SOFCS

Fuel cells are promising for future energy systems, since they are energy efficient and, when hydrogen is used as fuel, there are no emissions of greenhouse gases. Fuel cells have during recent years various improvements, however the technology is still in the early phases of development, this can be noted by the lack of dominant design both for singe fuel cells, stacks and for entire fuel cell systems. In this study a CFD approach (COMSOL Multiphysics) is employed to investigate the effect on temperature distribution from inlet temperature, oxygen surplus, ionic conductivity and current: density for an anode-supported intermediate temperature solid oxide fuel cell (IT-SOFC). The developed model is based on the governing equations of heat-, mass- and momentum transport. A local temperature non equilibrium (LTNE) approach is introduced to calculate the temperature distribution in the gas- and solid phase separately. The results show that the temperature increasing along the flow direction is controlled by the degree of surplus air. It is also found that the ohmic polarization in the electrolyte and the activation polarization in the anode and cathode have major influence on the performance. If a count flow approach is employed the inlet temperature for the fuel stream should be close to the outlet temperature for the air flow to avoid a too high temperature gradient.