Modeling of mass and charge transport in a solid oxide fuel cell anode structure by a 3D lattice Boltzmann approach

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• 作者：Hedvig Paradis ; Martin Andersson ; Bengt Sundén
• 刊名：Heat and Mass Transfer
• 出版年：2016
• 出版时间：August 2016
• 年：2016
• 卷：52
• 期：8
• 页码：1529-1540
• 全文大小：1,613 KB
• 刊物类别：Engineering
• 刊物主题：Engineering Thermodynamics and Transport Phenomena
  Industrial Chemistry and Chemical Engineering
  Thermodynamics
  Physics and Applied Physics in Engineering
  Theoretical and Applied Mechanics
  Engineering Fluid Dynamics
  
• 出版者：Springer Berlin / Heidelberg
• ISSN：1432-1181
• 卷排序：52

文摘

A 3D model at microscale by the lattice Boltzmann method (LBM) is proposed for part of an anode of a solid oxide fuel cell (SOFC) to analyze the interaction between the transport and reaction processes and structural parameters. The equations of charge, momentum, heat and mass transport are simulated in the model. The modeling geometry is created with randomly placed spheres to resemble the part of the anode structure close to the electrolyte. The electrochemical reaction processes are captured at specific sites where spheres representing Ni and YSZ materials are present with void space. This work focuses on analyzing the effect of structural parameters such as porosity, and percentage of active reaction sites on the ionic current density and concentration of H₂ using LBM. It is shown that LBM can be used to simulate an SOFC anode at microscale and evaluate the effect of structural parameters on the transport processes to improve the performance of the SOFC anode. It was found that increasing the porosity from 30 to 50 % decreased the ionic current density due to a reduction in the number of reaction sites. Also the consumption of H₂ decreased with increasing porosity. When the percentage of active reaction sites was increased while the porosity was kept constant, the ionic current density increased. However, the H₂ concentration was slightly reduced when the percentage of active reaction sites was increased. The gas flow tortuosity decreased with increasing porosity.List of symbolsAVSurface area to volume (m2/m3)bParticle distribution function, ion/electron transportCConcentration (mol/m3)D_eEffective diffusivity (m2/s)D_effAverage effective diffusivity (m2/s)D_KeffEffective Knudsen diffusivity (m2/s)d_pParticle diameter (m)eBase velocity in the lattice Boltzmann modelEActivation energy (kJ/mol)EActual voltage (V)EeqEquilibrium voltage (V)fParticle distribution function, momentum transportFFaraday’s constant (96,485 A s/mol)gParticle distribution function, mass transporthParticle distribution function, heat transportiCurrent density (A/m2)LPorous domain length (m)MMolecular weight (g/mol)pPressure (atm)QHeat flow (J/s)RGas constant [8.3145 J/(mol K)]ReReynolds number (–)R_jReaction rate (mol/s)SEntropy (J/mol K)TTemperature (K)tTime (s)uVelocity vector (m/s)u, vVelocity (m/s)x, y, zPosition (m)