Comsol简易教程（有例子，适合入门学习）.pdf-资料库

COMSOL Multiphysics ™ M n i i c o u r s e V E R S I O N 3 . 3

How to contact COMSOL: Benelux COMSOL BV Röntgenlaan 19 2719 DX Zoetermeer The Netherlands Phone: +31 (0) 79 363 4230 Fax: +31 (0) 79 361 4212 info@femlab.nl www.femlab.nl Denmark COMSOL A/S Diplomvej 376 2800 Kgs. Lyngby Phone: +45 88 70 82 00 Fax: +45 88 70 80 90 info@comsol.dk www.comsol.dk Finland COMSOL OY Lauttasaarentie 52 FIN-00200 Helsinki Phone: +358 9 2510 400 Fax: +358 9 2510 4010 info@comsol.fi www.comsol.fi France COMSOL France WTC, 5 pl. Robert Schuman F-38000 Grenoble Phone: +33 (0)4 76 46 49 01 Fax: +33 (0)4 76 46 07 42 info@comsol.fr www.comsol.fr Germany FEMLAB GmbH Berliner Str. 4 D-37073 Göttingen Phone: +49-551-99721-0 Fax: +49-551-99721-29 info@femlab.de www.femlab.de Italy COMSOL S.r.l. Via Vittorio Emanuele II, 22 25122 Brescia Phone: +39-030-3793800 Fax: +39-030-3793899 info.it@comsol.com www.it.comsol.com Norway COMSOL AS Søndre gate 7 NO-7485 Trondheim Phone: +47 73 84 24 00 Fax: +47 73 84 24 01 info@comsol.no www.comsol.no Sweden COMSOL AB Tegnérgatan 23 SE-111 40 Stockholm Phone: +46 8 412 95 00 Fax: +46 8 412 95 10 info@comsol.se www.comsol.se Switzerland FEMLAB GmbH Technoparkstrasse 1 CH-8005 Zürich Phone: +41 (0)44 445 2140 Fax: +41 (0)44 445 2141 info@femlab.ch www.femlab.ch United Kingdom COMSOL Ltd. Studio G8 Shepherds Building Rockley Road London W14 0DA Phone:+44-(0)-20 7348 9000 Fax: +44-(0)-20 7348 9020 info.uk@comsol.com www.uk.comsol.com United States COMSOL, Inc. 1 New England Executive Park Suite 350 Burlington, MA 01803 Phone: +1-781-273-3322 Fax: +1-781-273-6603 COMSOL, Inc. 1100 Glendon Avenue, 17th Floor Los Angeles, CA 90024 Phone: +1-310-689-7250 Fax: +1-310-689-7527 COMSOL, Inc. 744 Cowper Street Palo Alto, CA 94301 Phone: +1-650-324-9935 Fax: +1-650-324-9936 info@comsol.com www.comsol.com For a complete list of international representatives, visit www.comsol.com/contact Company home page www.comsol.com COMSOL user forums www.comsol.com/support/forums COMSOL Multiphysics Minicourse © COPYRIGHT 1994–2006 by COMSOL AB. All rights reserved Patent pending The software described in this document is furnished under a license agreement. The software may be used or copied only under the terms of the license agreement. No part of this manual may be photocopied or reproduced in any form without prior written consent from COMSOL AB. COMSOL, COMSOL Multiphysics, and COMSOL Script are trademarks of COMSOL AB. Other product or brand names are trademarks or registered trademarks of their respective holders. Version: COMSOL 3.3 Sept. 2006

C O N T E N T S Introduction 2 3 A Multiphysics Model Background . . . . . . . . . . . . . . . . . . . . . . . . . 4 The Steady Conduction-Current Problem . . . . . . . . . . . . . 5 The Heat Transfer Problem . . . . . . . . . . . . . . . . . . . 6 Getting Started . . . . . . . . . . . . . . . . . . . . . . . 7 Geometry Modeling. . . . . . . . . . . . . . . . . . . . . . 9 Material Settings for Conductive Media DC . . . . . . . . . . . . . 10 Boundary Settings for Conductive Media DC . . . . . . . . . . . . 12 Solving the Conductive Media DC Problem . . . . . . . . . . . . . 15 Visualization and Postprocessing . . . . . . . . . . . . . . . . . 15 Mesh Generation. . . . . . . . . . . . . . . . . . . . . . . 18 Solver Parameters . . . . . . . . . . . . . . . . . . . . . . 20 Adding Heat Transfer to the Model . . . . . . . . . . . . . . . . 21 Material Settings for Heat Transfer . . . . . . . . . . . . . . . . 22 Boundary Settings for Heat Transfer . . . . . . . . . . . . . . . 25 Solving the Coupled Problem . . . . . . . . . . . . . . . . . . 26 Visualization and Postprocessing . . . . . . . . . . . . . . . . . 26 Strong Coupling; Temperature-Dependent Material Properties . . . . . 27 Solving the Strongly Coupled Problem . . . . . . . . . . . . . . . 28 Visualization and Postprocessing . . . . . . . . . . . . . . . . . 29 Transient Multiphysics Simulation . . . . . . . . . . . . . . . . . 31 Initial Conditions . . . . . . . . . . . . . . . . . . . . . . . 31 Solver Parameters . . . . . . . . . . . . . . . . . . . . . . 32 Visualization and Postprocessing . . . . . . . . . . . . . . . . . 33 Extra Exercise: Capturing the Stiff Behavior . . . . . . . . . . . . . 36 Extra Exercise: Logical Expressions and Volume Integration . . . . . . . 38 Appendix A: Using the Built-In CAD Tools 40 Appendix B: The Equations 48 The Conductive Media DC Equation . . . . . . . . . . . . . . . 48 The Heat Transfer Equation . . . . . . . . . . . . . . . . . . . 49 C O N T E N T S | i

The Bidirectionally Coupled Problem . . . . . . . . . . . . . . . 50 ii | C O N T E N T S

C O M S O L M u l t i p h y s i c s M i n i c o u r s e C O M S O L M U L T I P H Y S I C S M I N I C O U R S E | 1

Introduction COMSOL Multiphysics offers a complete environment that allows you to perform all the steps in the modeling process. Its graphical user interface includes functions for CAD modeling, the import of drawings and images, definition of material properties and equations, mesh generation, solving the problem, visualization and postprocessing. Analyses in engineering design do not end with the computation of voltages, stresses, and velocity fields. Frequently you must perform extensive postprocessing on the computed output in order to arrive at useful engineering parameters such as impedance, quality factor, conversion factors, or rotation angles. During the examples in this minicourse you will quantify simulation results into hard engineering design numbers. The following introductory model gives an overview of basic modeling techniques and introduces the concepts of multiphysics in the 2-way coupling of heat transport and conduction currents. The model was inspired by simulations conducted by COMSOL Multiphysics customers within the areas of MEMS and electronics, but the concepts apply to all types of COMSOL Multiphysics models, whether from chemical engineering, structural mechanics, electromagnetics, or any other field. Enjoy your modeling! The COMSOL Team 2 | C O M S O L M U L T I P H Y S I C S M I N I C O U R S E

A Multiphysics Model This section shows you how to define and solve a first model in COMSOL Multiphysics. The simulated phenomena are steady conduction currents and heat generation in an aluminum film deposited on a silicon substrate. The model investigates the temperature in the device after the current is applied. The model exemplifies several steps that can be important in the modeling process. It also gives a quick overview of the features available for modeling in COMSOL Multiphysics’ graphical user interface. This example addresses the following important COMSOL Multiphysics features: • The use of predefined physics The definition and solution of a multiphysics problem Defining physical properties that depend on the solution itself The definition and solution of a strongly coupled and transient multiphysics problem The extraction of design numbers using the postprocessing tools The typical modeling steps include: 1 Definition of the geometry 2 Definition of the physics in the volume and at the boundaries 3 Meshing 4 Solving 5 Visualization 6 Postprocessing C O M S O L M U L T I P H Y S I C S M I N I C O U R S E | 3

Background A film of aluminum is deposited on a silicon substrate. The aluminum is approximately 0.1 mm thick with the pattern shown in the following picture. Aluminum deposit Input current Ground Silicon substrate Figure 1: Device layout The device’s width is roughly 2.4 mm, with a hole in the center with a diameter of approximately 0.45 mm. A constant current passes through the deposit starting at t=0. You wish to study the temperature distribution in the aluminum pattern as a function of time. You also want to evaluate the electrical power distribution as well as the total resistance over time. The problem couples two physical phenomena, a current balance and a heat balance. The electrical resistance increases with temperature, while the current density itself serves as a heat source through ohmic losses in the current conduction. This implies that the coupling between the two physics is a 2-way coupling. You cannot solve one problem separate from the other. 4 | C O M S O L M U L T I P H Y S I C S M I N I C O U R S E

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Comsol简易教程（有例子，适合入门学习）.pdf

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