Three-dimensional dynamic modeling and transport analysis of solid oxide fuel cells under electrical load change

Title
Three-dimensional dynamic modeling and transport analysis of solid oxide fuel cells under electrical load change
Authors
이종호윤경중이상혁배용균홍종섭
Keywords
SOFC; Solid oxide fuel cell; Dynamic modeling; Electrical load trip; Dynamic response; Transport phenomena
Issue Date
2018-06
Publisher
Energy conversion and management
Citation
VOL 165-418
Abstract
The aim of this study is to elucidate the transient behavior of thermodynamic variables in a solid oxide fuel cell (SOFC) upon electrical load change, which can be used for optimizing cell microstructure and developing a reliable SOFC stack design. To overcome the insufficient durability and large performance degradation, SOFC technologies still need reliable cell microstructure and stack design prior to their market deployment. This is of significant concerns when considering actual operating conditions, in particular, sudden and severe electrical load change. Enhancing the dynamic stability of SOFC is essential to improve its durability under the electrical load change. To meet the needs, the local thermodynamic state and thermo-fluid environment should be examined in detail, which requires high-fidelity numerical simulations. In this study, a physical model is developed to resolve temporally and spatially reactions and transport phenomena taking place inside planar, anode-supported SOFC stacks. The model is validated by using in-house experimental measurements of a current response profile upon electrical load change. Then, the dynamic response of thermodynamic variables upon electrical load change is investigated by assuming potentiodynamic conditions. The results of this study show that the electrical current responds excessively to the potential steps and recovers its magnitude asymptotically to the quasi-steady state. A relaxation time is needed for its dynamic response and recovery. This is explained by the time-dependent variation of the electrochemical reaction zone and species transport in the anode. The former reacts quickly to electrical load change, influencing the hydrogen concentration, while the latter shows time-delay, affecting the diffusion of hydrogen between the reaction zone and fuel channel. The time-delay required for the response of hydrogen diffusion corresponds to the relaxation time neede
URI
http://pubs.kist.re.kr/handle/201004/67531
ISSN
0196-8904
Appears in Collections:
KIST Publication > Article
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