Multiphysics Modelingin

FEMLAB 2.2Fall 2001

COMSOL

Contents

• Introduction• Modeling in FEMLAB

– A first simple model of direct current conduction

• Influence of wave guide geometry on wave propagation– 3D Electromagnetics

• Reaction distribution in a monolithic reactor– Chemical engineering and transport phenomena

• Study of the stresses in a guyed mast– Preview of the upcoming structural mechanics module

• Support and courses

Why modeling ?

• Education– Accelerates understanding

• Saves time and money– Rapid prototyping

• Safety– Spares equipment

• Fun?

Our company

• Founded in 1986 by two Ph.D. Students at the Royal Institute of Technology

• Developed several products within the Matlab family

• 95 employees in offices in Sweden, Finland, Norway, Denmark, USA, Germany, UK and France

• We want to provide user-friendly and powerful software for modeling in education, research, design, and development

Our first FEMLAB model

• Shows the main steps of the modeling process in FEMLAB

• Highlights– Single physics– 2D and 3D drawing tools– Several subdomains with different

properties– Post processing including boundary

integration– M-file features

Problem definition

V = 1

V = 0

V = 0

V

Outflow 2

Outflow 1

How is the current distributed between outflows 1 and 2 ?

Results

Integrate current density

Integrate current density

Summary of the modeling process

• Draw Mode• Boundary Mode• Subdomain Mode• Mesh Mode• Post Mode

Study of waveguide geometry in 3D

• How does the geometry influence the reflection of the wave?

• How is the mode of the traveling wave changed in the waveguide ?

• Exemplifies the use of FEMLAB in prototyping

• Shows the new 3D Electromagnetics Module

Problem definition

Incomingwave

Transmittedwave

x(xE) - k2E = 0

nx(xE) + ikEt = 2ikEinc

Is there a change in mode ? What is the dependency between the frequency andthe reflection coefficient?

Results

InOut

propagating wave standing wave

A frequency of 8.1 GHz gives minimal reflection, 7 %

The incoming TE11-mode is transformed to a TE10-wave

Results: S-parameters

Frequency (Hz)

minimal reflection

|S21|2

Results: S-parameters

• The S-parameter S21 (for open-ends) is:

• This can be computed as boundary integrals in the FEMLAB GUI

input throughflow Powerouput throughflow Power

21S

Reaction distribution in a monolithic reactor

• To which extent is the catalyst utilized ?

• How will the catalyst degrade due to temperature effects ?

• Exemplifies the use of FEMLAB in chemical reaction engineering design

• Shows the new version of the chemical engineering module

Problem definition

(-Dc + cv) = 0

(-Dc) + kc = 0

Inlet

Outlet

Porouscatlyst

Free fluid

Results

• Substantial depletion within the catalyst at a given z-position

• Utilization of the catalyst is not optimal

• Depletion along the z-axis gives a fairly good reactor performance

Socket for a guyed mast

• Minimize transport and material costs• Minimize weight and maximize

mechanical strength• Study the distribution of stresses in a

suggested design• Decide if we should pursue the work

based upon the suggested design, which implies a displacement below 0.1 mm at the thinnest part

Socket in a guyed mast

Guyed mast for telecom

Problem definition

z

no displacementin z-direction

Psymmetry

symmetry

¼ is modeled due to symmetry

2

ut2c u = K

Navier’s equations

ResultsVon Misses stresses and displacement

Maximum stress and displacement

max stress

Support & courses

• Experienced engineering staff

• Searchable FAQ database

• Extensive technical:support@femlab.com

• Download minicourse, apply for on-site minicourse or attend to our courses

• Developer Zone

Next step

• Download white papers, articles product sheets etc.

• Try FEMLAB yourself at hands-on seminars or trials

• Apply for on-site seminars and hands-on seminars

• Run tutorials and models at www.femlab.com