不同流道布置的平板式固体氧化物燃料电池蠕变损伤研究

Creep Damage of Planar Solid Oxide Fuel Cell with Different Arrangements of Flow Channels

固体氧化物燃料电池(Solid oxide fuel cell,SOFC)长期在高温下运行,蠕变不可避免,蠕变变形会导致损伤,产生裂纹,不同流道布置对平板式SOFC蠕变损伤会产生显著的影响。建立平板式SOFC多物理场模型,将COMSOL多物理场数值模型计算得到的不均匀温度场作为热载荷施加到ABAQUS模型中,再基于Wen-Tu蠕变延性耗竭模型开发了蠕变损伤子程序,研究平板式SOFC同流、逆流、交叉流道设计下的蠕变行为。结果表明,平板式SOFC在同流、逆流、交叉流道设计下分别运行19 800 h、24 000 h、78 500 h后达到蠕变损伤临界值,裂纹萌生均位于上连接体处;运行50 000 h后同流条件下出现两处裂纹,逆流条件下出现四处裂纹,交叉流道布置下未出现裂纹;采用交叉流道布置可最大化平板式SOFC工作寿命。结论可为实现长期、高效、稳定运行的平板式SOFC优化设计提供理论依据。

During the long-time operation of solid oxide fuel cell(SOFC)under high temperature condition,creep deformation of component of SOFC is inevitable and will lead to damage and crack.Different fuel-air-channel designs will have significant impacts on the creep damage of SOFC.A multiphysics-coupled model of planar SOFC is developed.The non-uniform temperature distribution calculated by multiphysics-coupled finite element model in COMSOL is applied to ABAQUS model as a heat load.Based on Wen-Tu creep ductility depletion model,a creep damage subroutine is developed to study the creep behavior of planar SOFC under the fuel-air-channel designs of co-flow,counter-flow and cross-flow.The results show that the creep damage of the planar SOFC reaches the critical value after 19800 h,24000 h and 78500 h of operation in the co-flow,the counter-flow and the cross-flow channel designs,respectively.Besides,among the channel designs mentioned above,the creep crack initiation is located at the upper interconnector.After 50000 h of operation,there are two cracks and four cracks occurred in the co-flow and the counter-flow designs,respectively.However,there is no crack occurred in the condition of cross-flow channel design.The operation life of planar SOFC can be maximized by applying the cross-flow channel design.The conclusion can provide an important theoretical basis for the optimization design of planar SOFC to achieve long-term,efficient and stable operation.