多物理场耦合作用下平板式固体氧化物燃料电池的蠕变损伤行为

Damage and Creep Behavior in Planar Solid Oxide Fuel Cell by Modeling of Multiphysics Coupled

利用COMSOL Multiphysics软件建立了电化学-气体流动-物质传递-温度相耦合的多物理场模型,将多物理场数值计算得到的不均匀温度场分布作为热载荷施加至ABAQUS模型中,基于由Wen-Tu蠕变延性耗竭模型开发的蠕变损伤子程序,研究了固体氧化物燃料电池(SOFC)的蠕变损伤行为,预测了蠕变裂纹演化过程。结果表明,SOFC各构件蠕变变形与损伤在运行初期迅速增大后基本保持不变,下连接体最先达到临界损伤值,是潜在危险区域,最容易发生失效;50000h后,SOFC出现2处蠕变损伤,最大裂纹发生于下连接体与阴极材料交界且距空气流道入口1.1 mm处,长度为1.6 mm,为非贯穿裂纹,较整体结构尺寸相比损伤较小不会发生气体泄漏,可以满足40000 h的商业安全运行要求。

A multiphysics-coupling model of solid oxide fuel cell(SOFC)was proposed via a software named COMSOL Multiphysics for the establishment of coupled fields of electrochemical-gas,flow-matter and transfer-temperature.The inhomogeneous temperature distribution obtained from the numerical analysis was applied to the corresponding model build by ABAQUS as a thermal load,and the creep damage subroutine developed based on the Wen-Tu creep ductile depletion model was used to analyze the creep damage of SOFC.The creep damage behavior of SOFC was investigated and the creep crack propagation was predicted.The results show that the creep deformation and damage of SOFC components firstly increase and then remain unchanged.The lower connector is the first to reach the critical damage value,which is the potential dangerous area and is the most likely to failure.After 50000 h,two creep damages occur in SOFC.The maximum crack is 1.6 mm as the non-penetrating crack that occurs at the junction of 1.1 mm in the air inlet of the lower connector and the cathode material.Compared with the overall structure size,the smaller crack will not cause gas leakage,thus meeting the requirement of commercial safe operation for 40000 h.