Introduction to COMSOL Multiphysics€¦ · • Introduction to COMSOL Multiphysics –...
Transcript of Introduction to COMSOL Multiphysics€¦ · • Introduction to COMSOL Multiphysics –...
General Outline • Introduction to COMSOL Multiphysics
– Microconnector Bump Demo • COMSOL Simulations Lecture 1: Electroanalysis
– Cyclic Voltammetry Demo • COMSOL Hands-on Exercise 1
– Chronoamperometry (Cottrell Equation) • COMSOL Simulations Lecture 2 : Current Distribtions
– Wire Electrode Demo • COMSOL Hands-on Exercise 2
– Decorative Plating
About COMSOL • HQ in Stockholm • 22 offices • 500 employees • 20 000 licenses, 100 000 users
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Why Simulate? • Conception and understanding
– Enables innovation
• Design and optimization – Achieve the highest possible
performance
• Testing and verification – Virtual testing is much faster
than testing physical prototypes
Simulation of current density in a chlor-alkali cell, showing variation across the surfaces of each electrode.
Simulating with COMSOL Multiphysics® • Electrical, mechanical, fluid, and
chemical simulations
• Multiphysics – include and couple all relevant physical effects
• Single physics in one integrated environment
• Cross-disciplinary product development
Complete Simulation Environment
Model Builder Provides instant access to any part of the model settings • CAD/Geometry • Materials • Physics • Mesh • Solve • Results
Graphics
COMSOL Desktop® Straightforward to use, the Desktop gives insight and full control over the modeling process
Some Terms • Module
– Add-on to the license you buy – contains additional functionality such as Physics Interfaces, Solvers and Material Libraries • Physics Interface
– Taylor made user-interface for setting up equations (related to a specific physics field) • Application
– The file (xxx.mph) that contains your model tree, defined using: • Global definitions • Components (the actual model, with geometry, local defintitions, physics interfaces, and mesh) • Studies (the numerical solvers) • Results (post processing)
• Materials – For linking parameters used in physics interfaces to data from the Material Library
• Application Library – Library of solved tutorial and benchmark examples.
• App – A user-interface, wrapped around your Application, that you create yourself for sharing your work to less experienced modelers
Under the Hood • Most physics interfaces use the Finite Element Method (FEM) for discretizing and
solving the problems • Boundary Element and other formulations also available for certain physics • Finite Element formulations use an open weak-form syntax, visible (and hackable)
for the user • Various different solvers are available:
– Stationary, Time-Dependend and Frequency Domain – Fully Coupled vs Segragated approaches for coupled probles – Iterative (Multigrid) or Direct – Parametric Sweeps – Adaptive Mesh Refinement – Cluster computing
Electrochemistry Products • batteries • fuel cells
• electroplating • other related surface processes
• corrosion analysis • corrosion prevention
• electrolysis • electrodialysis • electroanalysis
• All products rest on the same physics, but the user interfaces are tailored to the requirements of particular applications.
The Electrochemistry Interfaces • Current Distribution interfaces
– Generic electrochemical cell modeling – Nernst-Planck equations – Flat or porous electrodes – Arbitrary number of reactions – Double-layer effect
• Electroanalysis • Nernst-Planck-Poisson Equations • Battery Interfaces • Corrosion interfaces • Electrodeposition interfaces
The Battery Interfaces • Concentrated electrolyte theory used in all battery
interfaces (except Single Particle Battery) • Lithium-Ion Battery
– Charge balances in the electrodes and electrolyte – Material balances for the salt – Energy balance including electrochemical reactions – Material balance of intercalating species in electrode
particles – Solid electrolyte interface (SEI) on electrode particles
Settings for electrode reactions in the lithium-ion battery interface
The Battery Interfaces • Battery with Binary Electrolyte
– Similar to the Lithium-Ion Battery interface – Generic interface for batteries with concentrated binary
electrolytes • Lead-Acid Battery
– Porosity variation within electrodes coupled to electrode reactions and material balances
– Material balance for the salt in the electrolyte • Single Particle Battery
– Simplified generic battery interface – Each electrode is treated as a single ”particle” – For larger geometries, battery packs, or shorter
simulation times
Typical set of nodes of the Lead-Acid Battery interface for creating a model
The Batteries & Fuel Cells Material Library • Literature data for the most common electrode
and electrolyte materials: – Electrolyte conductivities – Equilibrium potentials – Diffusion coefficients – Activity coefficients – Transport numbers – Densities – Heat capacities*
*All listed properties not available for all listed materials
The Corrosion/Electrodeposition Interfaces • Dissolving/Depositing Electrode Species
– Keep track of reacted material per m2 of electrode surface in time-dependent simulations
• Predefined couplings to geometry deformations
Specifying the deposition of copper on an electrode surface in the user interface
Initial and corroded geometry due to galvanic corrosion of a magnesium alloy. Modeled using a deforming geometry (moving mesh/ale).
The Chemical Species Transport Interfaces • Transport of Diluted Species
– Diffusion, migration, and convection – Fick’s law/Nernst-Planck equations – Multiple species
• Transport of Diluted Species in Porous Media • Electrophoretic Transport • Nernst-Planck-Poisson Equations • Batteries & Fuel Cells:
– Transport of Concentrated Species • Maxwell-Stefan equations • Typically used for gas phase diffusion
– Reacting flow interfaces • Use Surface Reactions to model intermediate species on
electrode surfaces • Coupling features to electrochemistry
– Flat electrodes (molar fluxes) – Porous electrodes (molar sources/sinks)
Heat Transfer and Fluid Flow • Laminar flow • Porous media flow • Heat transfer
– Solids, fluids, and porous media • Coupling features
– Joule heating and heat from electrochemical reactions
– All Electrochemistry interfaces contain predefined heat source variables to be used for coupling to Heat Transfer interfaces
– Predefined mass sources and fluxes for coupling Electrochemistry to Fluid Flow
Demo: Microconnector Bump • Electrolyte flows over electrolyte
surface • Electrode covered by photoresist with
holes • Cell working at high overpotentials
and under diffusion control
• The goal is a well shaped, uniform bump
• What is the impact of the convective flow?
Model Details • Geometry
– 2D, includes hole in photoresist, and diffusion layer
• Mass transport – Transport of Diluted Species – Concentration set to 0 at electrode – Bulk concentration towards bulk electrolyte
• Momemtum transfer
– Laminar flow – Specified bulk velocity