Diploma Project - Poster

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Diploma Project - Poster

  1. 1. PROTON EXCHANGE MEMBRANE FUEL CELL (PEMFC) MODELING and SIMULATION using COMSOL MULTIPHYSICS Ercüment SÖNMEZ – Coşkun TOPRAK Supervisor : Prof. Dr. Mustafa DEMİRCİOĞLU Ege University, Engineering Faculty, Department of Chemical Engineering, 35100 Bornova, İZMİR ABSTRACT ÖZET ABSTRACT/ÖZET Energy generation and consumption plays an important role worldwide in both the advancement of modern technology and the Enerjinin üretimi ve tüketimi; teknolojinin gelişimi ve global ekonomiye etkiyen eğilimler üzerinde büyük rol oynamaktadır. Fosil trends on global economy. Fossil fuel sources have been drastically used during last century which has caused a series of yakıt kaynakları son yüzyıl içerisinde büyük ölçeklerde kullanılmış olup, etkileri ciddi çevresel sorunlara neden olmaktadır. Sonuç environmental problems. As a concequence, alternative energy sources have been sought to diminish these problems. Research olarak, bu sorunları azaltmak için alternatif enerji kaynakları üzerinde çalışmalar devam ediyor. Yakıt hücreleri üzerindeki on fuel cell technology has been boomed recently to supply a response both economically and environmentally solutions to the araştırmalar; artan enerji talebine, hem ekonomik hemde çevresel etki yönünden bir cevap olabilmesi için, son zamanlarda artış increasing energy demand. In this project, the effects of various design parameters and operating conditions on PEM fuell cell göstermiştir. Bu projede, PEM yakıt hücresinin performansını etkileyen çeşitli çalışma koşulları ve tasarım değişkenleri üzerinde performance have been studied by using a pionering software “COMSOL Multiphysics” which requires integrated engineering çalışılmış olup; diğer mühendislik dalları ile etkileşimli ve ileri derecede mühendislik bilgisi gerektiren ve bu konuda öncü bir yazılım disciplineand sound knowledge. olan “COMSOL Multiphysics”kullanılmıştır. AC/DC MODULE ACOUSTICS MODULE CHEMICAL ENGINEERING MODULE EARTH SCIENCE MODULE Contains built‐in application modes and  Models single and coupled processes  Simulates electrical components and  Analyzes CFD,mass and energy balances  boundary settings for the modeling of  for geologic and environmental  devices that depend on electrostatics,  coupled to chemical reaction kinetics.  acoustic wave propagation in solids and  phenomena particularly based around  magnetostatics and electromagnetic  Incorporates a plethora of application  stationary fluids.  sub‐surface flow.  quasi‐statics applications, particulary  modes for the field of the transport  coupled to other physics. phenomena including ionic transport  Generator Flow Duct Centrifugal Pump  Discrete Fracture and multicomponent diffusion. COMSOL HEAT TRANSFER MODULE COMSOL MULTIPHYSICS MEMS MODULE A finite‐element based program for simulating unlimited multiphysics and single‐physic applications. It incorporates Represents coupled processes in micro‐ Consists of advanced application modes  easy‐to‐use application interfaces, complete control over meshing and powerful solvers. COMSOL Multiphysics electro‐mechanical and microfluidic  for the analysis of heat transfer by  also offers an extensive and well‐managed interface to MATLAB and its toolboxes for a large variety of devices. Incorporates specific  conduction, convection, and radiation. programming, preprocessing and post‐processing possibilities. multiphysics couplings for applications  Specific for industrial applications such  Similar interfaces are offered with COMSOL Multiphysics which are COMSOL Script, such as electroosmotic flow, film  as electronics cooling and process  COMSOL Reaction Engineering Lab. Brake Disc of  a Car Comb Drive damping, and fluid‐structure interaction. engineering.  RF MODULE CAD IMPORT MODULE STRUCTUAL MECHANICS MODULE MATERIAL LIBRARY Characterizes electromagnetic fields,  Internal material property database with more than  Performs classical stress‐strain analyses  Facilities the reading of most  currents, and waves for RF, microwave,  2500 materials and 20000 properties. The database  with full multiphysics capabilities.  industry‐standard CAD formats.  optical and other high frequency  contains temperature dependence of electrical, thermal,  Comprises nonlinear material models,  Includes add‐on packages that  devices. and structural properties of solid materials. large deformation and contact abilities;  support the file formats for specific  all able to be freely coupled to other  CAD programs geometry kernels. Communication  physics. Microwave Oven Car Wheel Rim Mast FUEL CELL PEM FUEL CELL A fuel cell is an energy generation device that converts hydrogen and PEM fuel cell use a solid polymer membrane (a thin plastic film) as the oxygen into usable electric power by way of simple chemical reactions. As a electrolyte. This polymer is permeable to protons when it is saturated simple electrochemical device, a fuel cell does not actually burn fuel, with water, but it does not conduct electrons. ‐ ‐ ‐ ‐ allowing it to operate pollution‐free. The only emissions produced by a fuel cell are pure water and heat. This also makes a fuel cell quiet, dependable, The fuel for the PEMFC is hydrogen and the charge carrier is the hydrogen and very fuel‐efficient. ion (proton). At the anode, the hydrogen molecule is split into hydrogen Fuel Hydrogen  Oxygen (O2)  ‐ ions (protons) and electrons. The hydrogen ions permeate across the ‐ (H2) İn the air A fuel cell has two electrodes, one positive and one negative, called the electrolyte to the cathode while the electrons flow through an external ++ PEMFC cathode and the anode. The reactions that produce electricity take place at circuit and produce electric power. Oxygen, usually in the air, is supplied ‐ the electrodes. Every fuel cell also has an electrolyte, which carries to the cathode and combines with the electrons and the hydrogen ions to ‐ electrically charged particles from one electrode to the other, and a produce water. The reactions at the electrodes are as follows: catalyst, which accelerates the reactions at the electrodes. 2H2      4H+ + 4e‐ Anode Reactions: ++ Cathode Reactions: O2 + 4H+ + 4e‐ Some types of fuel cell: 2H2O Used Fuel  Air + Water Vapor Recirculates Alkaline Fuel Cells (AFCs) Overall Cell Reactions: 2H2 + O2     2H2O Phosphoric Acid Fuel Cells (PAFCs) PEMFC General Properties Molten‐Carbonate Fuel Cells (MCFCs) Flow Field Plate Flow Field Plate Operating  SystemOutput Efficiency  Applications  Advantages Disadvantages Solid Oxide Fuel Cells (SOFCs) Temperature Anode Cathode Polymer Electrolyte Membrane Fuel Cells (PEMFCs) •Solid electrolyte  Catalyst Catalyst • Requires  • Back‐up power  reduces corrosion &  Direct Methanol Fuel Cells (DMFCs) expensive catalysts  • Portable power  (Platinum) (Platinum) electrolyte  • High sensitivity to  • Small  Proton Exchange Membrane management  40‐60% 50 ‐ 100°C  1kW – 250kW Zinc Air Fuel Cells (ZAFCs) fuel impurities  distributed  problems  electric  • Low temperature  generation  • Low temperature  Biological Fuel Cells (BFCs) Proton Exchange Membrane Fuel Cell (PEMFC) waste heat  • Transportation  • Quick start‐up  DRAW and MESH MODE MODELING PROCESS SUBDOMAIN MODE The model uses current balances, mass balances (Maxwell‐Stefan diffusion for reactant, water and nitrogen 2D design is selected using gas), and momentum balances (gas flow) to simulate a 2D PEM fuel cell’s behavior. rectangular coordinates. After Application Modes Module Dependent Variables Governing Equations specifying geometry (1) mesh As created in draw mode, three  COMSOL  Conductive Media DC  Solid Phase  Electromagnetics mode (2) is applied to control Multiphysics (Electrodes) Potential subdomains (1, 2, 3) are defined as  the distribution of elements anode, membrane, and cathode. In each COMSOL  Conductive Media DC Electrolyte  PEM MODELING Electromagnetics easily. A mesh is a partition of Multiphysics (Membrane) Potential Subdomain, material properties and  the geometry model into small Chemical Momentum  boundaries are determined freely. Darcy’s Law Pressure Engineering Module balance units of simple shapes. Dividing Maxwell‐Stafen Diffusion  Chemical  Mass Fraction of current geometry into meshes Mass balance and Convection Engineering Module H2 and H2O (Anode side) [Msa] (small shapes) provides full Maxwell‐Stafen Diffusion  ( 1) ( 2) Chemical  Mass Fraction of  control of boundaries and easy‐ Mass balance and Convection Engineering Module O2, H2O and N2 (Cathode side) [MSc] solve problem. PARAMETRIC INVESTIGATION BOUNDARY MODE SOLVE and POST MODE SOLVE MODE Electrodes Membrane Darcy MSa MSc COMSOL Multiphysics includes a set  Boundary Type Boundary Type Boundary Type Boundary Type Boundary Type of solvers for PDE‐based problems  1‐7,9,14‐ EI 11,12 EI 1 P 1 MF 13 F for linear and non‐linear equations.  16,18‐22 In post mode, given a solver/mesh  8 EP 10 ICF 4 P 4 CF 21 CF pair, a variety of tools are available  10 ICF 13  ICF 10 I/O 10 F 22 MF for data visualization. In PEM  13 ICF 13 I/O Modeling, power generation,  Various parameters such as temperature , pressure,  efficiency, geometry and raw 17 EP 21 P geometry/mesh, properties of used materials ( porosity,  material properties are analyzed . 22 P conductivity etc.) is investigated to analyze the effects on  CF : Convective Flow  EI : Electric Insulation  EP : Electric Potential  F : Flux PEM fuel cell performance. ICF : Inward Current Flow  I/O : Inflow/Outflow  MF : Mass Fraction P : Pressure DESIGNING & BUILDING FUEL CELLS, Colleen S. Spiegel , McGraw Hill Book Co. , 2007 ‐ INTRODUCTION TO CHEMICAL ENGINEERING COMPUTING, Bruce A. Finlayson, John Wiley Inc., 2006 ‐ CONTROL OF FUEL CELL POWER SYSTEMS (Priciples, Modeling, Analysis REFERENCES and Feedback Design)”, Jay T. Pukrushpan, Anna G. Stefanopoulou, Huei Peng, Springer, 2005 ‐ PROCESS MODELıNG AND SıMULATıON WıTH FıNıTE ELEMENT METHODS, William B. J. Zimmerman, World Scientific Publishing Co., 2004 ‐ FUEL CELL HANDBOOK, EG&G Technical Services, Inc., Seventh Edition, U.S. Department of Energy Office of Fossil Energy National Energy Technology Laboratory, November 2004 ‐ AN INTRODUCTION TO FUEL CELLS AND HYDROGEN TECHNOLOGY, Brian Cook, Heliocentris, December 2001

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