Mathematical modeling of transport phenomena in porous SOFC anodes

Abstract:In this study, a three-dimensional computational fluid dynamics (CFD) model is developed for an anode-supported planar SOFC from the Chinese Academy of Science Ningbo Institute of Material Technology and Engineering (NIMTE). The simulation results of the developed model are in good agreement with the experimental data obtained under the same conditions. With the simulation results, the distribution of temperature, flow velocity and the gas concentrations through the cell components and gas channels is presented and discussed. Potential and current density distributions in the cell and overall fuel utilization are also presented. It is also found that the temperature gradients exist along the length of the cell, and the maximum value of the temperature for the cross-flow is at the outlet region of the cell. The distribution of the current density is uneven, and the maximum current density is located at the interfaces between the channels, ribs and the electrodes, the maximum current density result in a large over-potential and heat source in the electrodes, which is harmful to the overall performance and working lifespan of the fuel cells. A new type of flow structure should be developed to make the current flow be OPEN ACCESSEnergies 2014, 7 81 more evenly distributed and promote most of the TPB areas to take part in the electrochemical reactions.

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“…For the porous electrodes, effective conductivity for electron/ion is estimated by Equation (22) [12]:…”

Section: Ion and Electron Transportmentioning

confidence: 99%

Three-Dimensional CFD Modeling of Transport Phenomena in a Cross-Flow Anode-Supported Planar SOFC

et al. 2013

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“…S i , the 4 Copyright © 2011 by ASME source term by the chemical reactions, is defined for the internal reforming reactions. Two approaches for defining the electrochemical reactions can be found in the literature, either as source terms in the governing equations [14][15] or as interface conditions defined at the electrode/electrolyte interfaces [16][17]. The later concept is employed in this study, because the thickness of the active layer is relatively thin [16][17].…”

Section: Mass Transportmentioning

confidence: 99%

Modeling Validation and Simulation of an Anode Supported SOFC Including Mass and Heat Transport, Fluid Flow and Chemical Reactions

Andersson

Yuan

Sundén

et al. 2011

ASME 2011 9th International Conference on Fuel Cell Science, Engineering and Technology

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Fuel cells are electrochemical devices that directly transform chemical energy into electricity, which are promising for future energy systems, since they are energy efficient and, when hydrogen is used as fuel, there are no direct emissions of greenhouse gases. The cell performance depends strongly on the material characteristics, the operating conditions and the chemical reactions that occur inside the cell. The chemical-and electrochemical reaction rates depend on temperature, material structure, catalytic activity, degradation and the partial pressures for the different species components. There is a lack of information, within the open literature, concerning the fundamentals behind these reactions. Experimental as well as modeling studies are needed to reduce this gap.In this study experimental data collected from an intermediate temperature standard SOFC with H 2 /H 2 O in the fuel stream are used to validate a previously developed computational fluid dynamics model based on the finite element method. The developed model is based on the governing equations of heat and mass transport and fluid flow, which are solved together with kinetic expressions for internal reforming reactions of hydrocarbon fuels and electrochemistry. This model is further updated to describe the experimental environment concerning cell design. Discussion on available active area for electrochemical reactions and average ionic transport distance from the anodic-to the cathodic three-phase boundary (TPB) are presented. The fuel inlet mole fractions are changed for the validated model to simulate a H 2 /H 2 O mixture and 30 % pre-reformed natural gas. Keywords: SOFC, Modeling, Validation, Active Area, IonicTransport Distance, COMSOL Multiphysics INTRODUCTION AND PROBLEM STATEMENTFuel cells (FCs) are promising due to advantages of higher efficiency and lower emissions of SO X , NO X and CO 2 than conventional power generation [1]. The solid oxide fuel cell (SOFC) is a high temperature fuel cell, which operates at 600-1000 ºC [2]. This temperature allows SOFCs to operate with different types of fuels from both fossil and renewable sources. It opens a way for an easier transition from conventional power generation with hydrocarbon based fuels to fuel cells with possibility for different fuels, especially SOFCs. Due to the increasing global awareness of that energy usage affects the environments, the interest of renewable energy has increased. SOFCs are generally more tolerant to contaminants than other fuel cells and the possibility to internally (as well as externally) reform the fuel make them interesting for renewable energy resources [1].Numerical results of SOFC models are only approximations of real conditions and the validation is an important and necessary step in the development of reliable and accurate computational models. A range of validity can be established between the developed model and experimental

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“…Despite some limited work published in this area (Zhang et al, 2005;Doherty et al, 2010;Kattke and Braun, 2010;Ameri and Mohammadi, 2011), demonstrations of system scale modelling and simulation of SOFCs using commercial simulation packages are scarce. Unfortunately, the current widely used, commercial process simulators, including Aspen Plus and Aspen HYSYS, do not include an inbuilt module for a SOFC unit (Zhang et al, 2005) that covers the associated transport and reaction phenomena (Hussain et al, 2007;Ho et al, 2009). There are several reasons for this situation.…”

Section: Introductionmentioning

confidence: 99%

Solid oxide fuel cell reactor analysis and optimisation through a novel multi-scale modelling strategy

Amiri

Vijay

Tadé

et al. 2015

Computers & Chemical Engineering

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Mathematical modeling of transport phenomena in porous SOFC anodes

Cited by 51 publications

References 17 publications

Three-Dimensional CFD Modeling of Transport Phenomena in a Cross-Flow Anode-Supported Planar SOFC

Three-Dimensional CFD Modeling of Transport Phenomena in a Cross-Flow Anode-Supported Planar SOFC

Modeling Validation and Simulation of an Anode Supported SOFC Including Mass and Heat Transport, Fluid Flow and Chemical Reactions

Solid oxide fuel cell reactor analysis and optimisation through a novel multi-scale modelling strategy

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