论文部分内容阅读
The temperature uniformity and component concentration distributions in solid oxide fuel cells during operating processes can influence the cell electrochemical and thermal characteristics.A three-dimensional thermal-fluid numerical model including electrochemical reactions and water-gas-shift (WGS) reaction for a single channel solid oxide fuel cell was developed to study the steady-state characteristics,which include distributions of the temperature (T),temperature gradient (△T/△x),and fuel utilization.It was shown that the maximum temperature (Tmax) changed with operating voltage and the maximum temperature gradient ((△T/△x)max) occurred at the inlet of the channel of a solid oxide fuel cell by simulation.Moreover,the natural convection condition had a great influence on T and △T/△x.The thermal stress generated by temperature differences was the key parameter and increasing the convection heat-transfer coefficient can greatly reduce the thermal stress.In addition,the results also showed that there were lower temperature gradients and lower current density at high working voltage;therefore,choosing the proper operating voltage can obtain better cell performance.