A 3-dimensional planar SOFC stack model
|
|
- Bernadette Patterson
- 5 years ago
- Views:
Transcription
1 A 3-dimensional planar SOFC stack model Michel Bernier, James Ferguson and Raphaèle Herbin 1 Introduction A fuel cell converts chemical energy to electrical energy through electro-chemical reactions at the anode and cathode in much the same way as an ordinary battery. However, a fuel cell is continuously replenished with fuel and can therefore never go dead the way conventional batteries do. Like a battery, the voltage produced by the chemical reactions is typically on the order of a volt. To produce an appreciable amount of power to operate household devices or industrial equipment, the electrochemical cells must be connected in series and parallel. Such collections of cells are called stacks. Solid oxide fuel cells (SOFC) differ from other fuel cell technologies in that the electrolyte is a solid. This provides many advantages. There is no corrosive liquid to contain as in molten carbonate or phosphoric acid fuel cells nor is there any consumption of the electrolyte eleminating the need for electrolyte replenishment. Since fuel cells typically operate with gases as fuel and oxidant, SOFCs can be constructed without moving parts which often leads to high reliability. The principal disadvantage of SOFCs is their operating temperature. Since these cells typically operate from to selection of materials which are stabile, durable and compatible is a difficult task. Differing coefficients of thermal expansion, interdiffusion of materials used for the anode, electrolyte and cathode, and stresses caused by temperature gradients are the major engineering problems faced in the design of SOFCs. Towards this end the prediction of temperature distribution within SOFC stacks is crucial to the successful design of SOFC systems. The number of cathode-electrolyte-anode structures representing a positive electrode, electrolyte and negative electrode (PEN) in a planar stack may number as many as with up to channels on each side of apen structure (i.e fuel channels). The calculation of the three dimensional distributions which resolve the Université de Provence, 1353 Marseille, France, work sponsored by Gaz de France and ADEME Boise State University, Idaho, 83725, U.S.A. Université de Provence, 1353 Marseille, France 1
2 detail of the channels and PEN structures is beyond the capability of present computers. As a consequence the influence of the channels and PEN structure on the distribution of, voltage, current, fuel and air distribution is achieved through modelling. Interconnection Plate Anode Stack Electrolyte Cathode Interconnection channels Figure 1 : Stack geometry The approach adopted here is to model a sub-unit of the stack named a unit cell using conventional conservation equations and constitutive laws resolving geometric details of the PEN structure and channel geometry and use the resulting model to determine parameters which are required to model the full stack, so as to determine the behaviour of the temperature, voltage, fuel and air distributions at the stack scale. A unit cell is taken to be the smallest geometrically repeating unit which can be used to construct a stack. Figure 2 illustrates unit cells for the co-, counter-, and cross-flow geometries and gives their typical dimensions. CO-COUNTER FLOW GEOMETRY CROSS FLOW GEOMETRY PEN Electrolyte Anode "! %$ "! %& "! Cathode Figure 2 : Unit cell geometries for the co-, counter-, and cross- flow THe next sections develop the governing equations for the temperature, voltage, current, fuel species and oxidant species distributions in a three dimensional stack,
3 %$ examine the limiting behaviour asthe number of unit cells increases and describe a solution procedure. 2 The SOFC stack model 2.1 Thermal Energy Conservation Unit cell effective properties approach In this section the thermal energy equation describing the temperature distribution of an SOFC stack is developed from the unit cell model (see also [6]). Following this approach provides relationships and definitions establishing a connection between parameters in the stack model and results from unit cell computations. Figure 3 : Thermal heat flux on the unit cell Conservation of thermal energy states that the sum of fluxes over a control volume surface equals the heat produced in the control volume at steady state (see figure 3). Considering the control volume to be a unit cell, thermal energy conservation can be written as : eff Considering a unit cell for which &, the average heat flux across a face of the cell must equal the heat flux at the stack level. Therefore, using Fourier s law of conduction for the cell flux, the effective conductivity ' at the stack level to the parent material conductivity )( in the unit cell is found to be -.+/1032,87 +* 0165 (, -+9:;032 * 01 5! " (1)
4 The ratio ( represents a shape factor which accounts for the curvature and concentration of adiabats (heat flows paths) in the unit cell geometry for fluxes flowing in the direction. Similar computations are performed for the and directions. Applying the constitutive equation (1) to the thermal energy conservation for the 2 stack yields : 5 eff & Homogeneization techniques Homogeneization techniques have been used over the past twenty years to try and model composite materials made out of fine microstructures as homogeneous materials. The set of equations which describes the behaviour of a stack at the cell level is nonlinear and therefore not so easy to homogenize. However, the homogeneization techniques may be used to solve the linear systems which arise at one point of a given iterative procedure. we shall give here as an example the homogeneized model for the temperature equation. As seen previously, the conservation of thermal energy states that 5 &, where. Instead of computing an effective conductivity as was proposed above, we now try to analyse the behaviour of the temperature as grows, where the subscript denotes the number of cells of the stack. Assume here, for simplicity, that the channel temperatures are known and denoted by and, (depending on the space variable). Then the thermal equations written at the cell level write : 5 & "!$&% ' on air channel wall "!$&% ' on fuel channel wall T N homogenized solution (from unit cell computations) T fine grid solution on the whole stack Number of unit cells Figure : comparison between thermal distributions calculated by both methods 600
5 A mathematical result which was shown in [1] proves that at point may be approached by the algebraic expression: where, and are computed from unit cell calcultations (see [1]). Figure compares the temperature distribution computed by the homogeneization technique and by solving the exact model on a very fine discretisation grid on the whole stack. Note that these distributions were both computed by part of the software which is described in section 3.2. The error between the two solutions decreases when grows. This method is adapted to solve the thermal problem in the 3D stack model. 2.2 Thermal sinks and sources The heat source & at the stack level incorporates each of the heat producing or heat absorbing mechanisms observed at the unit cell level ; in the SOFC stack, two of the source terms produce heat (& ohm and & el ) while the other two absorb heat (& ref and & ch ). The source term is decomposed as & & ohm & el & ref & ch Ohmic heating (& ohm ) : is the major source of heat in a fuel cell. Ohmic heat is generated throughout the solid structure since electrical current flows thoughout this region. The two regions which dominate the heat production are the interconnect and electrolyte. The electrolyte ohmic heat production is included in el. Only the interconnect is considered here. As in the unit cell model, the ohmic heat production is given by ohm eff Electro-chemical Heat generation (& el ) : includes effects of ohmic heat dissipation in the electrolyte plus heat generated by electro-chemical reactions at the electrode-electrolyte interfaces. At the stack-level of modelling these heat sources are 2-dimensional in nature (assuming a thin electrolyte for the ohmic heating). Channel cooling (& ch ) : the air and fuel channels which permeate the SOFC stack provide the principal means by which the temperature of the stack is maintained. To model the heat transfer between the fluid and channel walls an expression of the form ch is assumed. Expressions for and is found by equating these expressions to the actual heat transfered in a unit cell (see [2]), similar to the computation of the effective conductivities. Heat Reforming loss( & ref ) : methane is a component of fuel used to drive SOFCs but it is not oxidized directly. Therefore methane is converted catalytically with to and through the reactions :
6 7 7 Reaction R3 is heat absorbing and is kinetically controlled. Reaction is slightly exothermic and is sufficiently fast that it can be assumed to be at chemical equilibrium (see []). 2.3 Electrical Problem The electrical potential equation, which describes the variation of electrical potential in a SOFC stack model is developed in the same way as in the thermal problem. The equation is developed by considering the current fluxes and potential distribution on the unit cell. In this way essential parameters required in the stack model can be related to the unit cell and computed. Finally the conservation of electrical energy principle states : 5. The electric potential is assumed to be proportional to the gradient of the stack potential, namely : eff, where eff is an effective conductivity related to the material and geometry of the unit cell. Electrochemicals reactions and potential jump At electrolyte/electrodes interfaces, two reactions are taken into account : Across electrolyte layers, the potential increases due to the electrochemical reactions occuring at the electrode-electrolyte interfaces. The magnitude of the potential jump is given by : jump Nernst loss The Nernst potential Nernst is a function only of the reactant distributions, on one side, on the other. For both reactions and, the Nernst Voltage is given by : $% Nernst 6 where for! ", and for! $ ". If both reactions occur at the anode-electrolyte interface then &%(' Nernst )% Nernst. The loss term loss, is composed of : the ohmic loss across electrolyte, the anode and cathode activation polarization losses, and the anode and cathode diffusion losses. 2. Channel transport mechanism Conservation law for the mass flux ( 7 ) writes : 5 +* 7, where * 7 is the production rate of species ; The species concentrations,, are studied in the channels. The diffusion of the reactants in the porous anode and cathode was carefully studied at the cell level in []. At the stack level,
7 / / 5 5 use is made of these results by stating that the concentration of a given species at an interface is proportional to the concentration on the same section in the channel, where the proportion is computed by the cell model results. The conservation of the electrons must be written at the interfaces where the electrochemical reactions occur. Hence the mass flux is related to the electric current by Faraday s law. (see [] for more details). In the gas channels, the thermal flux is mainly convective in the gas flow direction, and conductive from the channel to solid parts. Hence, in the two channels, the expression for the flux is : species where is the heat conductivity and 7 is the heat capacity of gas. 3 Solution procedure 3.1 Finite Volume discretization Following [5] we choose here the finite volume method to discretize the set of non linear equations obtained from the above model. The advantage of a finite volume method over a finite difference method is that the discretization of the flux is conservative and consistent even in the case of discontinuous diffusion coefficients (see [5]). The finite volume method is also somewhat simpler to implement than the finite element method in the case of jump conditions such as those encountered in the SOFC model (see [5]). Here we use a three dimensional non uniform parallelepipedic mesh. For the sake of simplicity, we shall present here the finite volume method in the two-dimensional case. Let us consider the following thermal problem : 5 & in solid parts "! &% ' (2) on boundaries where is the solid component of stack temperature, and is the gas temperature, % the heat transfert coefficient, and & is the source term. The principle of the finite volume method is to write the flux balance over a discretization cell (or control volume) 7 ; for equation (2) this yields : - / - /! &
8 % where n is a outward pointing normal vector. M L u I u I M u M L u L Figure 5: local notations With the notations shown in figure 5, the interface flux can be formulated on each side of the interface between the control volumes and by : Imposing the continuity on the approximation value of the flux yields I By similar computations, Fourier boundaries conditions are discretized by : &% 3.2 Software configuration Three computer codes are developed for the simulation software Heol2D which performs a two dimensional simulation of a simplified model in order to compare the numerical results obtained when using homogeneisation results against those obtain from a cell model. Stack3D which is the computing kernel for the three dimensional simulation. XHeol which is the graphic interface used for the analysis of the results from Heol2D and Stack3D. All three parts of the software were written in C under the Unix system. The software is portable on any Unix machine and was already tested on Irix (SGI), SunOS (Sun Microsystems) and HP-Unix (Hewlett Packard). The graphical interface uses the Motif and X11 libraries. The computer programs are written in a modular way so that a computational method of a subsystem for the stack model may be replaced by another without any effect on the rest of the code. Similarly, all geometrical data (width and thickness of the various parts of the unit cell, number of cells
9 ), physical parameters (material conductivites, reaction rates and operating conditions (temperature and mass fractions of the reactants at the inlet, gas velocities ) are defined in external files, which are directly accessible to the user, without recompiling the code itself. The Stack3D part contains the treatment of all electrochemical, thermal and mass equations. It also takes into account the reforming and shift reactions, the diffusion losses and the overpotentials. It contains a unit cell module which allows the computation of the effective parameters when this approach is chosen, and of the homogeneisation coefficients otherwise. Heol Packages INPUT DATA Operating conditions Unit cell geometry Stack geometry Gas parameters Voltage parameters Model data Materials model Electrochemical reactions model LibMath Package Linear system treatment STACK3D Package Thermal problem treatment Electrical problem treatment Mass problem treatment LibMesh Package Mesh treatment XHeol Package Figure 6 : Heol architecture OUTPUT DATA XHeol format data TASF format The use of the software requires the definition of the various parameters through the various input files, as shown in Figure. Once the code is run, the results are stored in output files which are directly accessed by the graphical interface XHeol. Conclusions A three dimensional planar stack simulation code is developed using modelling techniques and recent mathematical and numerical techniques. The software is modular and portable, and is designed to be a user-friendly tool for the optimization of SOFC configurations. Références [1] Ph. BATOUX and M. BERNIER and R. HERBIN, Numerical simulation of heat and current conduction using homogeneisation techniques, in preparation.
10 [2] M. BERNIER. Simulation d un coeur de pile au gaz naturel Phd thesis, Université de Provence. [3] M. BERNIER, E. GEHAIN, and R. HERBIN. Stack and cell modelling with sofc3d: a computer program for the 3d simulations of solid oxide fuel cells. In B. Thorstensen, editor, Proc. of the 2nd European SOFC Forum, 1996, Oslo - Norway, v1, , [] J.R. FERGUSON, J.M. FIARD, and R. HERBIN. Three-dimensional numerical simulation for various geometries of solid oxide fuel cells. J. of Power Sources 58, , [5] J.M. FIARD and R. HERBIN. Comparison between finite volume and finite element methods for an elliptic system arising in chemistry. Comp. Meth. in App. Mech. and Engin., 115, , 199. [6] K. NISANCIOGLU and H. KAROLIUSSEN. Cell and stack optimization by modeling. In Proc. 1st European SOFC Forum, 199, Lucerne - Switzerland, 199. [7] A.L. LEE. Internal reforming development for solid oxide fuel cells. Rep. Institute of Gas Technology, 1987.
Prof. Mario L. Ferrari
Sustainable Energy Mod.1: Fuel Cells & Distributed Generation Systems Dr. Ing. Mario L. Ferrari Thermochemical Power Group (TPG) - DiMSET University of Genoa, Italy Lesson II Lesson II: fuel cells (electrochemistry)
More informationBasic overall reaction for hydrogen powering
Fuel Cell Basics Basic overall reaction for hydrogen powering 2H 2 + O 2 2H 2 O Hydrogen produces electrons, protons, heat and water PEMFC Anode reaction: H 2 2H + + 2e Cathode reaction: (½)O 2 + 2H +
More informationModeling as a tool for understanding the MEA. Henrik Ekström Utö Summer School, June 22 nd 2010
Modeling as a tool for understanding the MEA Henrik Ekström Utö Summer School, June 22 nd 2010 COMSOL Multiphysics and Electrochemistry Modeling The software is based on the finite element method A number
More informationSCIENCES & TECHNOLOGY
Pertanika J. Sci. & Technol. 22 (2): 645-655 (2014) SCIENCES & TECHNOLOGY Journal homepage: http://www.pertanika.upm.edu.my/ Numerical Modelling of Molten Carbonate Fuel Cell: Effects of Gas Flow Direction
More informationModeling of Liquid Water Distribution at Cathode Gas Flow Channels in Proton Exchange Membrane Fuel Cell - PEMFC
Modeling of Liquid Water Distribution at Cathode Gas Flow Channels in Proton Exchange Membrane Fuel Cell - PEMFC Sandro Skoda 1*, Eric Robalinho 2, André L. R. Paulino 1, Edgar F. Cunha 1, Marcelo Linardi
More informationBasic overall reaction for hydrogen powering
Fuel Cell Basics Basic overall reaction for hydrogen powering 2H 2 + O 2 2H 2 O Hydrogen produces electrons, protons, heat and water PEMFC Anode reaction: H 2 2H + + 2e Cathode reaction: (½)O 2 + 2H +
More informationMultidimensional, Non-Isothermal, Dynamic Modelling Of Planar Solid Oxide Fuel Cells
Multidimensional, Non-Isothermal, Dynamic Modelling Of Planar Solid Oxide Fuel Cells K. Tseronis a, I. Kookos b, C. Theodoropoulos a* a School of Chemical Engineering and Analytical Science, University
More informationElectrochemical and thermo-fluid modeling of a tubular solid oxide fuel cell with accompanying indirect internal fuel reforming
CHAPTER 3 Electrochemical and thermo-fluid modeling of a tubular solid oxide fuel cell with accompanying indirect internal fuel reforming K. Suzuki 1, H. Iwai 2 & T. Nishino 2 1 Department of Machinery
More informationSolid Oxide Fuel Cell Material Structure Grading in the Direction Normal to the Electrode/Electrolyte Interface using COMSOL Multiphysics
Solid Oxide Fuel Cell Material Structure Grading in the Direction Normal to the Electrode/Electrolyte Interface using COMSOL Multiphysics M. Andersson*, B. Sundén, Department of Energy Sciences, Lund University,
More informationAdvanced Analytical Chemistry Lecture 12. Chem 4631
Advanced Analytical Chemistry Lecture 12 Chem 4631 What is a fuel cell? An electro-chemical energy conversion device A factory that takes fuel as input and produces electricity as output. O 2 (g) H 2 (g)
More informationIntroduction Fuel Cells Repetition
Introduction Fuel Cells Repetition Fuel cell applications PEMFC PowerCell AB, (S1-S3) PEMFC,1-100 kw Toyota Mirai a Fuel Cell Car A look inside The hydrogen tank 1. Inside Layer of polymer closest to the
More informationForced Convectional Heat Transfer in Solid Oxide Fuel Cells: An Analytical Treatment.
Ionics 9 (2003) 83 Forced Convectional Heat Transfer in Solid Oxide Fuel Cells: An Analytical Treatment. F.A. Coutelieris 1, A.K. Demin 2, S.L. Douvartzides 1 and P.E. Tsiakaras 1 1 University of Thessalia,
More informationModeling of a one dimensional Anode supported high temperature tubular SOFC
International Journal of ChemTech Research CODEN (USA): IJCRGG, ISSN: 0974-4290, ISSN(Online):2455-9555 Vol.10 No.6, pp 784-792, 2017 Modeling of a one dimensional Anode supported high temperature tubular
More informationParameter Effects on Transport Phenomena in Conjunction with Internal Reforming Reactions in Intermediate Temperature SOFCs
1909 10.1149/1.2729303, The Electrochemical Society Parameter Effects on Transport Phenomena in Conjunction with Internal Reforming Reactions in Intermediate Temperature SOFCs Jinliang Yuan a,*, Wei Guo
More informationBatteries (Electrochemical Power Sources)
Batteries (Electrochemical Power Sources) 1. Primary (single-discharge) batteries. => finite quantity of the reactants 2. Secondary or rechargeable batteries => regeneration of the original reactants by
More informationDirect Energy Conversion: Fuel Cells
Direct Energy Conversion: Fuel Cells References and Sources: Direct Energy Conversion by Stanley W. Angrist, Allyn and Beacon, 1982. Fuel Cell Systems, Explained by James Larminie and Andrew Dicks, Wiley,
More informationCeramic Processing Research
Journal of Ceramic Processing Research. Vol. 8, No. 3, pp. 224-228 (2007) J O U R N A L O F Ceramic Processing Research Computer modeling of single-chamber SOFCs with hydrocarbon fuel Jeong-Hwa Cha 1,2,
More informationElectrochemical Cell - Basics
Electrochemical Cell - Basics The electrochemical cell e - (a) Load (b) Load e - M + M + Negative electrode Positive electrode Negative electrode Positive electrode Cathode Anode Anode Cathode Anode Anode
More informationThree-Dimensional Computational Fluid Dynamics Modeling of Solid Oxide Electrolysis Cells and Stacks
INL/CON-08-14297 PREPRINT Three-Dimensional Computational Fluid Dynamics Modeling of Solid Oxide Electrolysis Cells and Stacks 8 th European SOFC Forum Grant Hawkes James O Brien Carl Stoots Stephen Herring
More informationElectrochemistry. Goal: Understand basic electrochemical reactions. Half Cell Reactions Nernst Equation Pourbaix Diagrams.
Electrochemistry Goal: Understand basic electrochemical reactions Concepts: Electrochemical Cell Half Cell Reactions Nernst Equation Pourbaix Diagrams Homework: Applications Battery potential calculation
More informationComputational Fluid Dynamics Modelling of. Solid Oxide Fuel Cell Stacks
Computational Fluid Dynamics Modelling of Solid Oxide Fuel Cell Stacks by Robert Takeo Nishida A thesis submitted to the Department of Mechanical and Materials Engineering in conformity with the requirements
More informationLecture 29: Forced Convection II
Lecture 29: Forced Convection II Notes by MIT Student (and MZB) As discussed in the previous lecture, the magnitude of limiting current can be increased by imposing convective transport of reactant in
More informationThis section develops numerically and analytically the geometric optimisation of
7 CHAPTER 7: MATHEMATICAL OPTIMISATION OF LAMINAR-FORCED CONVECTION HEAT TRANSFER THROUGH A VASCULARISED SOLID WITH COOLING CHANNELS 5 7.1. INTRODUCTION This section develops numerically and analytically
More informationNUMERICAL ANALYSIS ON 36cm 2 PEM FUEL CELL FOR PERFORMANCE ENHANCEMENT
NUMERICAL ANALYSIS ON 36cm 2 PEM FUEL CELL FOR PERFORMANCE ENHANCEMENT Lakshminarayanan V 1, Karthikeyan P 2, D. S. Kiran Kumar 1 and SMK Dhilip Kumar 1 1 Department of Mechanical Engineering, KGiSL Institute
More informationModeling of the 3D Electrode Growth in Electroplating
Modeling of the 3D Electrode Growth in Electroplating Marius PURCAR, Calin MUNTEANU, Alexandru AVRAM, Vasile TOPA Technical University of Cluj-Napoca, Baritiu Street 26-28, 400027 Cluj-Napoca, Romania;
More informationPerformance Simulation of Passive Direct Methanol Fuel Cell
International Journal of Advanced Mechanical Engineering. ISSN 50-334 Volume 8, Number 1 (018), pp. 05-1 Research India Publications http://www.ripublication.com Performance Simulation of Passive Direct
More informationFUEL CELLS: INTRODUCTION
FUEL CELLS: INTRODUCTION M. OLIVIER marjorie.olivier@fpms.ac.be 19/5/8 A SIMPLE FUEL CELL Two electrochemical half reactions : H 1 O H + + H + e + + e H O These reactions are spatially separated: Electrons:
More informationFINITE ELEMENT METHOD MODELLING OF A HIGH TEMPERATURE PEM FUEL CELL
CONDENSED MATTER FINITE ELEMENT METHOD MODELLING OF A HIGH TEMPERATURE PEM FUEL CELL V. IONESCU 1 1 Department of Physics and Electronics, Ovidius University, Constanta, 900527, Romania, E-mail: ionescu.vio@gmail.com
More informationNumerical Investigation of Convective Heat Transfer in Pin Fin Type Heat Sink used for Led Application by using CFD
GRD Journals- Global Research and Development Journal for Engineering Volume 1 Issue 8 July 2016 ISSN: 2455-5703 Numerical Investigation of Convective Heat Transfer in Pin Fin Type Heat Sink used for Led
More informationFUEL CELLS in energy technology (4)
Fuel Cells 1 FUEL CELLS in energy technology (4) Werner Schindler Department of Physics Nonequilibrium Chemical Physics TU Munich summer term 213 Fuel Cells 2 Nernst equation and its application to fuel
More informationSOFC modeling considering hydrogen and carbon monoxide as electrochemical reactants
SOFC modeling considering hydrogen and carbon monoxide as electrochemical reactants Andersson, Martin; Yuan, Jinliang; Sundén, Bengt Published in: Journal of Power Sources DOI: 10.1016/j.jpowsour.01.1.1
More informatione - Galvanic Cell 1. Voltage Sources 1.1 Polymer Electrolyte Membrane (PEM) Fuel Cell
Galvanic cells convert different forms of energy (chemical fuel, sunlight, mechanical pressure, etc.) into electrical energy and heat. In this lecture, we are interested in some examples of galvanic cells.
More informationGrading the amount of electrochemcial active sites along the main flow direction of an SOFC Andersson, Martin; Yuan, Jinliang; Sundén, Bengt
Grading the amount of electrochemcial active sites along the main flow direction of an SOFC Andersson, Martin; Yuan, Jinliang; Sundén, Bengt Published in: Journal of the Electrochemical Society DOI: 10.1149/2.026301jes
More informationFuel Cell Activities in MME Waterloo
Fuel Cell Activities in MME Waterloo Xianguo Li and Roydon Fraser Fuel Cells and Green Energy Research Group Department of Mechanical & Mechatronics Engineering University of Waterloo, Waterloo, Ontario,
More informationIn all electrochemical methods, the rate of oxidation & reduction depend on: 1) rate & means by which soluble species reach electrode surface (mass
Voltammetry Methods based on an electrolytic cell Apply potential or current to electrochemical cell & concentrations change at electrode surface due to oxidation & reduction reactions Can have 2 or 3
More informationOverview of electrochemistry
Overview of electrochemistry 1 Homogeneous Heterogeneous Equilibrium electrochemistry (no current flows) Thermodynamics of electrolyte solutions: electrolytic dissociation thermodynamics and activities
More informationELECTROCHEMICAL SYSTEMS
ELECTROCHEMICAL SYSTEMS Third Edition JOHN NEWMAN and KAREN E. THOMAS-ALYEA University of California, Berkeley ELECTROCHEMICAL SOCIETY SERIES WILEY- INTERSCIENCE A JOHN WILEY & SONS, INC PUBLICATION PREFACE
More informationMulti-physics Simulation of a Circular-Planar Anode-Supported Solid Oxide Fuel Cell
Multi-physics Simulation of a Circular-Planar Anode-Supported Solid Oxide Fuel Cell Keyvan Daneshvar *1, Alessandro Fantino 1, Cinzia Cristiani 1, Giovanni Dotelli 1, Renato Pelosato 1, Massimo Santarelli
More informationChapter 22. Bulk Electrolysis: Electrogravimetry and Coulometry. Definition. Features of Bulk Electrolysis Cells
Chapter 22 Bulk Electrolysis: Electrogravimetry and Coulometry Definition Bulk Electrolysis deals with methods that involve electrolysis producing a quantitative change in oxidation state Example: In a
More informationD DAVID PUBLISHING. 1. Introduction. Akira Nishimura 1, Masashi Baba 1, Kotaro Osada 1, Takenori Fukuoka 1, Masafumi Hirota 1 and Eric Hu 2
Journal of Energy and Power Engineering () - doi:./-/.. D DAVID PUBLISHING Temperature Distributions in Single Cell of Polymer Electrolyte Fuel Cell Simulated by an D Multi-plate Heat-Transfer Model and
More informationChemistry: The Central Science. Chapter 20: Electrochemistry
Chemistry: The Central Science Chapter 20: Electrochemistry Redox reaction power batteries Electrochemistry is the study of the relationships between electricity and chemical reactions o It includes the
More informationTutorial 11. Use of User-Defined Scalars and User-Defined Memories for Modeling Ohmic Heating
Tutorial 11. Use of User-Defined Scalars and User-Defined Memories for Modeling Ohmic Heating Introduction The purpose of this tutorial is to illustrate the use of user-defined scalars (UDS) and user defined
More informationCFD study of gas mixing efficiency and comparisons with experimental data
17 th European Symposium on Computer Aided Process Engineering ESCAPE17 V. Plesu and P.S. Agachi (Editors) 2007 Elsevier B.V. All rights reserved. 1 CFD study of gas mixing efficiency and comparisons with
More informationDevelopment of Bifunctional Electrodes for Closed-loop Fuel Cell Applications. Pfaffenwaldring 6, Stuttgart, Germany
Development of Bifunctional Electrodes for Closed-loop Fuel Cell Applications S. Altmann a,b, T. Kaz b, K. A. Friedrich a,b a Institute of Thermodynamics and Thermal Engineering, University Stuttgart,
More informationModeling, Simulation and Optimization of a Cross Flow Molten Carbonate Fuel Cell
Modeling, Simulation and Optimization of a Cross Flow Molten Carbonate Fuel Cell P. Heidebrecht 1, M. Mangold 2, M. Gundermann 1, A. Kienle 2,3, K. Sundmacher 1,2 1 Otto-von-Guericke-University Magdeburg,
More informationElectrolysis and Faraday's laws of Electrolysis
Electrolysis and Faraday's laws of Electrolysis Electrolysis is defined as the passage of an electric current through an electrolyte with subsequent migration of positively and negatively charged ions
More informationNernst voltage loss in oxyhydrogen fuel cells
Nernst voltage loss in oxyhydrogen fuel cells Jinzhe Lyu (Division for Experimental Physics, School of Nuclear Science & Engineering, National Research Tomsk Polytechnic University, Lenina Ave. 43, Tomsk,
More informationMAGNETIC FIELD INFLUENCE ON ELECTROCHEMICAL PROCESSES
MAGNETIC FIELD INFLUENCE ON ELECTROCHEMICAL PROCESSES 1. Introduction Tom Weier, Jürgen Hüller and Gunter Gerbeth Electrochemical reactions play an important role in various types of industrial processes
More informationIII. Transport Phenomena
III. Transport Phenomena Lecture 17: Forced Convection in Fuel Cells (I) MIT Student Last lecture we examined how concentration polarisation limits the current that can be drawn from a fuel cell. Reducing
More informationi i ne. (1) i The potential difference, which is always defined to be the potential of the electrode minus the potential of the electrolyte, is ln( a
We re going to calculate the open circuit voltage of two types of electrochemical system: polymer electrolyte membrane (PEM) fuel cells and lead-acid batteries. To do this, we re going to make use of two
More informationApplications of Voltaic Cells
Applications of Voltaic Cells Lesson 4 chapter 13 Objective You will be able to explain how the development of the voltaic cell had affected society. Dry Cells Since voltaic cells are not portable, dry
More informationModelling fuel cells in start-up and reactant starvation conditions
Modelling fuel cells in start-up and reactant starvation conditions Brian Wetton Radu Bradean Keith Promislow Jean St Pierre Mathematics Department University of British Columbia www.math.ubc.ca/ wetton
More informationPolarization analysis and microstructural characterization of SOFC anode and electrolyte supported cells
Polarization analysis and microstructural characterization of SOFC anode and electrolyte supported cells Lanzini A., Leone P., Santarelli M., Asinari P., Calì M. Dipartimento di Energetica. Politecnico
More informationChapter 18. Electrochemistry
Chapter 18 Electrochemistry Section 17.1 Spontaneous Processes and Entropy Section 17.1 http://www.bozemanscience.com/ap-chemistry/ Spontaneous Processes and Entropy Section 17.1 Spontaneous Processes
More informationIntroduction to Solid Oxide Fuel Cells. Solid Oxide Fuel Cell (SOFC)
Introduction to Solid Oxide Fuel Cells Basics Electrochemistry Microstructure Effects Stacks Solid Oxide Fuel Cell (SOFC) CATHODE: (La,Sr)(Mn)O 3 (LSM) LSM-YSZ ELECTROLYTE: ANODE: Y-doped ZrO 2 (YSZ) Ni-YSZ
More informationDocumentation of the Solutions to the SFPE Heat Transfer Verification Cases
Documentation of the Solutions to the SFPE Heat Transfer Verification Cases Prepared by a Task Group of the SFPE Standards Making Committee on Predicting the Thermal Performance of Fire Resistive Assemblies
More informationDr. V.LAKSHMINARAYANAN Department of Mechanical Engineering, B V Raju Institute of Technology, Narsapur, Telangana,, India
Parametric analysis performed on 49 cm 2 serpentine flow channel of PEM fuel cell by Taguchi method (Parametric analysis performed on PEMFC by Taguchi method) Dr. V.LAKSHMINARAYANAN Department of Mechanical
More informationNumerical simulation of fluid flow in a monolithic exchanger related to high temperature and high pressure operating conditions
Advanced Computational Methods in Heat Transfer X 25 Numerical simulation of fluid flow in a monolithic exchanger related to high temperature and high pressure operating conditions F. Selimovic & B. Sundén
More informationComputational model of a PEM fuel cell with serpentine gas flow channels
Journal of Power Sources 130 (2004) 149 157 Computational model of a PEM fuel cell with serpentine gas flow channels Phong Thanh Nguyen, Torsten Berning 1, Ned Djilali Institute for Integrated Energy Systems,
More information17.1 Redox Chemistry Revisited
Chapter Outline 17.1 Redox Chemistry Revisited 17.2 Electrochemical Cells 17.3 Standard Potentials 17.4 Chemical Energy and Electrical Work 17.5 A Reference Point: The Standard Hydrogen Electrode 17.6
More informationDMFC Models and Applications - A Literature Survey, Part I
Proceedings of the 2014 International Conference on Industrial Engineering and Operations Management Bali, Indonesia, January 7 9, 2014 DMFC Models and Applications - A Literature Survey, Part I S. Patrabansh,
More informationOn heat and mass transfer phenomena in PEMFC and SOFC and modeling approaches
On heat and mass transfer phenomena in PEMFC and SOFC and modeling approaches J. Yuan 1, M. Faghri 2 & B. Sundén 1 1 Division of Heat Transfer, Lund Institute of Technology, Sweden. 2 Department of Mechanical
More informationThe effect of heat transfer on the polarizations within an intermediate temperature solid oxide fuel cell
Advanced Computational Methods and Experiments in Heat Transfer XII 3 The effect of heat transfer on the polarizations within an intermediate temperature solid oxide fuel cell M. Navasa, M. Andersson,
More informationNovel Devices and Circuits for Computing
Novel Devices and Circuits for Computing UCSB 594BB Winter 2013 Lecture 3: ECM cell Class Outline ECM General features Forming and SET process RESET Variants and scaling prospects Equivalent model Electrochemical
More informationlect 26:Electrolytic Cells
lect 26:Electrolytic Cells Voltaic cells are driven by a spontaneous chemical reaction that produces an electric current through an outside circuit. These cells are important because they are the basis
More informationUgur Pasaogullari, Chao-Yang Wang Electrochemical Engine Center The Pennsylvania State University University Park, PA, 16802
Computational Fluid Dynamics Modeling of Proton Exchange Membrane Fuel Cells using Fluent Ugur Pasaogullari, Chao-Yang Wang Electrochemical Engine Center The Pennsylvania State University University Park,
More informationGalvanic Cells Spontaneous Electrochemistry. Electrolytic Cells Backwards Electrochemistry
Today Galvanic Cells Spontaneous Electrochemistry Electrolytic Cells Backwards Electrochemistry Balancing Redox Reactions There is a method (actually several) Learn one (4.10-4.12) Practice (worksheet)
More informationIV. Transport Phenomena. Lecture 23: Ion Concentration Polarization
IV. Transport Phenomena Lecture 23: Ion Concentration Polarization MIT Student (and MZB) Ion concentration polarization in electrolytes refers to the additional voltage drop (or internal resistance ) across
More informationOxidation-Reduction Review. Electrochemistry. Oxidation-Reduction Reactions. Oxidation-Reduction Reactions. Sample Problem.
1 Electrochemistry Oxidation-Reduction Review Topics Covered Oxidation-reduction reactions Balancing oxidationreduction equations Voltaic cells Cell EMF Spontaneity of redox reactions Batteries Electrolysis
More informationModeling the Behaviour of a Polymer Electrolyte Membrane within a Fuel Cell Using COMSOL
Modeling the Behaviour of a Polymer Electrolyte Membrane within a Fuel Cell Using COMSOL S. Beharry 1 1 University of the West Indies, St. Augustine, Trinidad and Tobago Abstract: In recent years, scientists
More informationMASS TRANSFER COEFFICIENTS DURING AERATION BY A SELF-ASPIRATING IMPELLER
th European Conference on Mixing Warszawa, - September MASS TRANSFER COEFFICIENTS DURING AERATION BY A SELF-ASPIRATING IMPELLER Czesław Kuncewicz, Jacek Stelmach Lodz University of Technology, Department
More informationSUPPLEMENTARY INFORMATION
doi:10.1038/nature17653 Supplementary Methods Electronic transport mechanism in H-SNO In pristine RNO, pronounced electron-phonon interaction results in polaron formation that dominates the electronic
More informationState-Space Modeling of Electrochemical Processes. Michel Prestat
State-Space Modeling of Electrochemical Processes Who uses up my battery power? Michel Prestat ETH-Zürich Institute for Nonmetallic Materials Head: Prof. L.J. Gauckler Outline Electrochemistry Electrochemical
More informationNeuroPhysiology and Membrane Potentials. The Electrochemical Gradient
NeuroPhysiology and Membrane Potentials Communication by neurons is based on changes in the membrane s permeability to ions This depends on the presence of specific membrane ion channels and the presence
More informationFigure 1. Schematic of Scriber Associates Model 850C fuel cell system.
Objective of the fuel cell experiments: To familiarize the working principles and performance characteristics of proton exchange membrane fuel cells. Experimental Procedures Instrumentation A Scriber Associates
More informationA Current-Voltage Model for Hydrogen Production by Electrolysis of Steam Using Solid Oxide Electrolysis Cell (SOEC)
15 th International Conference on Environmental Science and Technology Rhodes, Greece, 31 August to 2 September 2017 A Current-Voltage Model for Hydrogen Production by Electrolysis of Steam Using Solid
More informationThe Apparent Constant-Phase-Element Behavior of a Disk Electrode with Faradaic Reactions
Journal of The Electrochemical Society, 154 2 C99-C107 2007 0013-4651/2006/1542/C99/9/$20.00 The Electrochemical Society The Apparent Constant-Phase-Element Behavior of a Disk Electrode with Faradaic Reactions
More informationComputational Analysis of Heat Transfer in Air-cooled Fuel Cells
Proceedings of ASME 2011, 5th International Conference on Energy Sustainability & 9th Fuel Cell Science, Engineering and Technology Conference, ESFuelCell2011 August 7-10, 2011, Washington, DC, USA ESFuelCell2011-54794
More informationAir Flow Modeling and Performance Prediction of the. Integrated-Planar Solid Oxide Fuel Cell IP-SOFC
Applied Mathematical Sciences, Vol. 7, 2013, no. 96, 4775-4788 HIKARI Ltd, www.m-hikari.com http://dx.doi.org/10.12988/ams.2013.36296 Air Flow Modeling and Performance Prediction of the Integrated-Planar
More informationelectrodeposition is a special case of electrolysis where the result is deposition of solid material on an electrode surface.
Electrochemical Methods Electrochemical Deposition is known as electrodeposition - see CHEM* 1050 - electrolysis electrodeposition is a special case of electrolysis where the result is deposition of solid
More informationCHAPTER 7 NUMERICAL MODELLING OF A SPIRAL HEAT EXCHANGER USING CFD TECHNIQUE
CHAPTER 7 NUMERICAL MODELLING OF A SPIRAL HEAT EXCHANGER USING CFD TECHNIQUE In this chapter, the governing equations for the proposed numerical model with discretisation methods are presented. Spiral
More informationPerformance Analysis of a Two phase Non-isothermal PEM Fuel Cell
Performance Analysis of a Two phase Non-isothermal PEM Fuel Cell A. H. Sadoughi 1 and A. Asnaghi 2 and M. J. Kermani 3 1, 2 Ms Student of Mechanical Engineering, Sharif University of Technology Tehran,
More informationCHAPTER 17: ELECTROCHEMISTRY. Big Idea 3
CHAPTER 17: ELECTROCHEMISTRY Big Idea 3 Electrochemistry Conversion of chemical to electrical energy (discharge). And its reverse (electrolysis). Both subject to entropic caution: Convert reversibly to
More informationModeling the next battery generation: Lithium-sulfur and lithium-air cells
Modeling the next battery generation: Lithium-sulfur and lithium-air cells D. N. Fronczek, T. Danner, B. Horstmann, Wolfgang G. Bessler German Aerospace Center (DLR) University Stuttgart (ITW) Helmholtz
More informationSliding Mode Control for Stabilizing of Boost Converter in a Solid Oxide Fuel Cell
BUGARAN ACADEMY OF SCENCES CYBERNETCS AND NFORMATON TECHNOOGES Volume 13, No 4 Sofia 013 Print SSN: 1311-970; Online SSN: 1314-4081 DO: 10.478/cait-013-0060 Sliding Mode Control for Stabilizing of Boost
More informationUNIVERSITY OF CINCINNATI
UNIVERSITY OF CINCINNATI Date: I,, hereby submit this work as part of the requirements for the degree of: in: It is entitled: This work and its defense approved by: Chair: COMPUTATIONAL MODELING OF HEAT
More informationCalculations on a heated cylinder case
Calculations on a heated cylinder case J. C. Uribe and D. Laurence 1 Introduction In order to evaluate the wall functions in version 1.3 of Code Saturne, a heated cylinder case has been chosen. The case
More informationChapter 20 Electrochemistry
Chapter 20 Electrochemistry Learning goals and key skills: Identify oxidation, reduction, oxidizing agent, and reducing agent in a chemical equation Complete and balance redox equations using the method
More informationOn Analysis of Chemical Reactions Coupled Gas Flows in SOFCs
On Analysis of Chemical Reactions Coupled Gas Flows in SOFCs Jinliang YUAN 1,*, Guogang YANG 2, Bengt SUNDÉN 1 * Corresponding author: Tel.: ++46 (0)46 222 4813; Fax: ++46 (0) 46 222 4717; Email: jinliang.yuan@energy.lth.se
More informationChannel Shape Design of Solid Oxide Fuel Cells
Channel Shape Design of Solid Oxide Fuel Cells A Technical Report by Sagar Kapadia W. Kyle Anderson and Chad Burdyshaw UTC-CECS-SimCenter-2009-01 June 2009 GRADUATE SCHOOL OF COMPUTATIONAL ENGINEERING
More informationElectron Transfer Reactions
ELECTROCHEMISTRY 1 Electron Transfer Reactions 2 Electron transfer reactions are oxidation- reduction or redox reactions. Results in the generation of an electric current (electricity) or be caused by
More informationGraphene-based Electrodes for Electrochemical Energy Conversion
Graphene-based Electrodes for Electrochemical Energy Conversion September 23, 2014 AVS North California Chapter Prof. Min Hwan Lee School of Engineering Graphene for electrochemical devices Properties
More informationChapter 1 INTRODUCTION AND BASIC CONCEPTS
Heat and Mass Transfer: Fundamentals & Applications 5th Edition in SI Units Yunus A. Çengel, Afshin J. Ghajar McGraw-Hill, 2015 Chapter 1 INTRODUCTION AND BASIC CONCEPTS Mehmet Kanoglu University of Gaziantep
More informationsensors ISSN by MDPI
Sensors 008, 8, 1475-1487 Full Research Paper sensors ISSN 144-80 008 by MDPI www.mdpi.org/sensors Three-Dimensional Transport Modeling for Proton Exchange Membrane(PEM) Fuel Cell with Micro Parallel Flow
More informationBattery Design Studio Update
Advanced Thermal Modeling of Batteries Battery Design Studio Update March 20, 2012 13:30 13:55 New Features Covered Today 3D models Voltage dependent diffusion Let s start with brief introduction to Battery
More informationINTRODUCTION TO CATALYTIC COMBUSTION
INTRODUCTION TO CATALYTIC COMBUSTION R.E. Hayes Professor of Chemical Engineering Department of Chemical and Materials Engineering University of Alberta, Canada and S.T. Kolaczkowski Professor of Chemical
More informationNumerical simulation of proton exchange membrane fuel cell
CHAPTER 6 Numerical simulation of proton exchange membrane fuel cell T.C. Jen, T.Z. Yan & Q.H. Chen Department of Mechanical Engineering, University of Wisconsin-Milwaukee, USA. Abstract This chapter presents
More informationEVALUATION OF THE THERMAL AND HYDRAULIC PERFORMANCES OF A VERY THIN SINTERED COPPER FLAT HEAT PIPE FOR 3D MICROSYSTEM PACKAGES
Stresa, Italy, 25-27 April 2007 EVALUATION OF THE THERMAL AND HYDRAULIC PERFORMANCES OF A VERY THIN SINTERED COPPER FLAT HEAT PIPE FOR 3D MICROSYSTEM PACKAGES Slavka Tzanova 1, Lora Kamenova 2, Yvan Avenas
More informationBasic Concepts of Electrochemistry
ELECTROCHEMISTRY Electricity-driven Chemistry or Chemistry-driven Electricity Electricity: Chemistry (redox): charge flow (electrons, holes, ions) reduction = electron uptake oxidation = electron loss
More informationUnderstanding Impedance of Li-Ion Batteries with Battery Design Studio
Understanding Impedance of Li-Ion Batteries with Battery Design Studio Robert Spotnitz Battery Consultant Thursday July 6, 2017 16:40-17:10 Understanding Impedance Li-Ion Batteries with Battery Design
More information