SOFC多尺度多场耦合和性能演化理论研究

Multiscale & Multiphysics Theory and Modeling on SOFC Performances and Degradations

针对本研究主攻一体化电池结构SOFC和使用以甲烷为代表的碳基燃料的科学技术目标,经过对目前理论与模拟研究现状的系统全面考虑,我们在研究的前两年着重开展了一些必需的基础理论和模拟研究,以弥补现状的不足。本报告侧重介绍本课题在如下方面开展的创新性理论研究与所取得的成果:(1)获得精度与Dusty-gas Model精度相当的物种流量解析表达式;(2)获得能解释实验结果的Ni颗粒生长理论模型;给出三相线长度随Ni颗粒生长变化的理论关系;(3)获得能解释实验结果的多孔复合电极有效电导率理论模型;(4)建成微管SOFC多尺度多物理场耦合的二维模型;给出关键材料组分、微结构和工作参数对微管SOFC性能的影响,指明可具有合理力学性能的材料组分、微结构和工作参数。这些研究为后期的系统全面理论模拟研究奠定了良好基础。

The overall objective of our 973 program is to conduct basic research on solid oxide fuel cells （SOFCs） with nano--composite electrode structures and using methane fuel as a representative of general fossil fuel. Based on this objective and considering the deficiency of the available theory and modeling technique, we carried out the corresponding theory and modeling activities to fill the gap. This report summaries some of our key findings on the following topics： （1） Obtaining analytical decoupled expressions for the fluxes of multi--component gas species with accuracy comparable to the coupled Dusty--Gas Model= （2） Developing a theoretical model for the Ni agglomeration that is capable of explaining the experimental data. Moreover, using this model to establish the relationship between the TPB length and the growth of Ni particlesI （3） Developing models for the effective electrical conductivities of nano-- composite electrode and explaining the experimental data （4） Building multi--scale and multi--physics numerical 2D model for micro-- tubular SOFC. Based on this numerical tool, conducting simulation study on the effects of key material composition, microstructure and operating parameters on the performance of micro--tubular SOFC. The simulation results are used to identify the material composition, microstructure and operating parameters with desirable mechanical properties. The above results provide a solid basis for a systematical and thorough theoretical and modeling study in the future activity of the program.