Thermal Radiation and Effects on Transport Processes in Solid Oxide Fuel Cells

2008 ◽  
Vol 39 (5) ◽  
pp. 453-467 ◽  
Author(s):  
Hong Liu ◽  
Jinliang Yuan ◽  
Bengt Sunden
Author(s):  
J. D. J. VanderSteen ◽  
J. G. Pharoah

Solid oxide fuel cell (SOFC) technology has been shown to be viable, but its profitability has not yet been seen. To achieve a high net efficiency at a low net cost, a detailed understanding of the transport processes both inside and outside of the SOFC stack is required. Of particular significance is an accurate determination of the temperature distribution because material properties, chemical kinetics and transport properties depend heavily on the temperature. Effective utilization of the heat can lead to a substantial increase in overall system efficiency and decrease in operating cost. Despite the extreme importance in accurately predicting temperature, the majority of SOFC modeling work ignores radiative heat transfer. SOFCs operate at temperatures around or above 1200 K, where radiation effects can be significant. In order to correctly predict the radiation heat transfer, participating gases must also be included. Water vapour and carbon dioxide can absorb, emit, and scatter radiation, and are present at the anode in high concentrations. This paper presents a thermal transport model for analyzing heat transfer and improving thermal management within planar SOFCs. The model was implemented using a commercial computational fluid dynamic (CFD) code and includes conduction, convection, and radiation in a participating media. It is clear from this study that radiation must be considered when modelling solid oxide fuel cells. The effect of participating media radiation was shown to be minimal in this geometry, but it is likely to be more important in tubular geometries.


2005 ◽  
Vol 3 (1) ◽  
pp. 62-67 ◽  
Author(s):  
J. D. J. VanderSteen ◽  
J. G. Pharoah

Solid oxide fuel cell (SOFC) technology has been shown to be viable, but its profitability has not yet been seen. To achieve a high net efficiency at a low net cost, a detailed understanding of the transport processes both inside and outside of the SOFC stack is required. Of particular significance is an accurate determination of the temperature distribution because material properties, chemical kinetics, and transport properties depend heavily on the temperature. Effective utilization of the heat can lead to a substantial increase in overall system efficiency and decrease in operating cost. Despite the extreme importance in accurately predicting temperature, the SOFC modeling community appears to be uncertain about the importance of incorporating radiation into their models. Although some models have included it, the majority of models ignore radiative heat transfer. SOFCs operate at temperatures around or above 1200 K, where radiation effects can be significant. In order to correctly predict the radiation heat transfer, participating gases must also be included. Water vapor and carbon dioxide can absorb, emit, and scatter radiation, and are present at the anode in high concentrations. This paper presents a simple thermal transport model for analyzing heat transfer and improving thermal management within planar SOFCs. The model was implemented using a commercial computational fluid dynamic code and includes conduction, convection, and radiation in a participating media. It is clear from this study that radiation must be considered when modeling solid oxide fuel cells. The effect of participating media radiation was shown to be minimal in this geometry, but it is likely to be more important in tubular geometries.


Author(s):  
James M. Daggett ◽  
Neal P. Sullivan ◽  
Robert J. Kee ◽  
Huayang Zhu ◽  
Anthony M. Dean

Biofuels are receiving significant interest as a source for sustainable, locally produced hydrocarbon fuels. While solid-oxide fuel cells (SOFCs) can operate efficiently on biomass fuel streams, their use can prove problematic if process conditions are not carefully monitored, as carbon-deposit formation presents a significant risk. In this study, we examine the chemistry and transport processes underway when SOFC anodes are exposed to ethanol-steam mixtures. Through use of a unique Separated-Anode Experiment, this study decouples anode chemistry processes from charge-transfer, cathode-activation, and other electrochemical processes in an effort to focus on ethanol decomposition in SOFC environments. Experiments are combined with numerical simulations that include Dusty-Gas transport modeling within the anode pore structure, and elementary, multi-step heterogeneous and homogeneous chemical kinetics mechanisms representing fuel conversion within the anode. Process windows for deposit-free operation are postulated, and alternate anode architectures that minimize the risk of deposit formation are discussed.


2013 ◽  
Vol 10 (2) ◽  
Author(s):  
Jinliang Yuan ◽  
Guogang Yang ◽  
Bengt Sunden

There are various transport phenomena (gas-phase species, heat, and momentum) occurring at different length scales in anode-supported solid oxide fuel cells (SOFCs), which are strongly affected by catalytic surface reactions at active triple-phase boundaries (TPBs) between the void space (for gas), Ni (catalysts for electrons), and YSZ (an electrolyte material for ions). To understand the multiscale chemical-reacting transport processes in the cell, a three-dimensional numerical calculation approach (the computational fluid dynamics (CFD) method) is further developed and applied for a composite domain including a porous anode, fuel gas flow channel, and solid interconnect. By calculating the rate of microscopic surface-reactions involving the surface-phase species, the gas-phase species/heat generation and consumption related to the internal reforming reactions have been identified and implemented. The applied microscopic model for the internal reforming reactions describes the adsorption and desorption reactions of six gas-phase species and surface reactions of 12 surface-adsorbed species. The predicted results are presented and analyzed in terms of the gas-phase species and temperature distributions and compared with those predicted by employing the global reaction scheme for the internal reforming reactions.


ChemInform ◽  
2006 ◽  
Vol 37 (51) ◽  
Author(s):  
P.-W. Li ◽  
L. Schaefer ◽  
M. K. Chyu

2019 ◽  
Vol 7 (1) ◽  
pp. 1901-1908 ◽  
Author(s):  
Thinh X. Ho ◽  
Pawel Kosinski ◽  
Alex C. Hoffmann ◽  
Ivar Wærnhus ◽  
Arild Vik

2013 ◽  
Vol 51 (2) ◽  
pp. 125-130 ◽  
Author(s):  
Sun-Min Park ◽  
Hae-Ran Cho ◽  
Byung-Hyun Choi ◽  
Yong-Tae An ◽  
Ja-Bin Koo ◽  
...  

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