Tutorial Steady state and transient thermal .pdf


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Nom original: Tutorial_Steady_state_and_transient_thermal.pdf
Titre: FLUX2D
Auteur: POLITEHNICA University of Bucharest, EPM_NM Lab

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CAD Package for Electromagnetic and Thermal
Analysis using Finite Elements

FLUX 10
®

2D Application
Tutorial of steady
state
and transient thermal

Copyright – July 2009

FLUX is registered mark.

FLUX software
FLUX Tutorials

: COPYRIGHT CEDRAT/INPG/CNRS/EDF
: COPYRIGHT CEDRAT

This tutorial was updated on 1 July 2009
Ref.: K205-B-10-EN-02/05

CEDRAT
15 Chemin de Malacher - Zirst
38246 MEYLAN Cedex
FRANCE
Phone: +33 (0)4 76 90 50 45
Fax: +33 (0)4 56 38 08 30
Email: cedrat@cedrat.com
Web: http://www.cedrat.com

CONVENTIONS USED

To make this tutorial easier to read, we use the following typeface conventions:
• All comments are written in the same way as this sentence.
• All dialogue text between the user and FLUX2D is written in courier font:

Name of the region to be created:
magnet ↵
Colour of this region:
MAGENTA
Select a surface or a menu item:
Quit
[q]uit ↵
Below are presented the conventions used for the dialogue between the user and FLUX2D:
Italic text
Bold text ↵
magnet ↵
[q]uit ↵
<B>old text
<M>AGENTA

Messages or questions displayed on the screen by FLUX2D.
User input to FLUX2D, such as the coordinates of a point.
The ↵ character symbolizes the Return/Enter key.
You only have to enter enough of the response to remove any ambiguity
between the responses you want and other valid ones. In which case enter
the character shown in square brackets [ ].
FLUX2D menu input. Make a selection by clicking on the menu item with
the mouse or, if there is no ambiguity, by entering the first character of the
word (shown in angled brackets < >).

<COILR>
FLUX2D graphical input, such as selecting a line or a point.



The reply is by default. To enter a default response, simply press the
Return/Enter key.

- REMARK The files corresponding to different cases studied in this tutorial are available
in the folder:

... \ Doc_examples \ Examples2D
\ThermalApplications
The correspondent applications are ready to be solved. This allows you to
adapt this tutorial to your needs.
• If you are not familiar with FLUX2D yet, we advise you to run through this
entire tutorial and to refer, if necessary to the given cases.
• If you are already a FLUX2D user, we advise you to redo only
the PREFLUX 2D, SOLVER_2D and POSTPRO_2D sections, in order to
discover the new possibilities of FLUX2D.

FLUX2D®10

TABLE OF CONTENTS

TABLE OF CONTENTS

PART A: DESCRIPTION OF THE STUDY

1

1.

REALIZED STUDY ....................................................................................................3

2.

PROBLEM DESCRIPTION........................................................................................5
2.1

The geometry ................................................................................................................5

2.2

The regions....................................................................................................................8

2.3

Mesh..............................................................................................................................9

2.4

The materials...............................................................................................................10

2.5

The sources.................................................................................................................11

2.6

The boundary conditions .............................................................................................11

2.7

The initial temperature. The ambient temperature not defined yet..............................11

2.8

Time steps (for thermal transient only) ........................................................................11

PART B: EXPLANATION OF CASE 1
3.

4.

13

PREFLUX 2D: ENTERING THE GEOMETRY, THE MESH AND THE
PHYSIC ................................................................................................................... 15
3.1

Starting FLUX2D .........................................................................................................15

3.2

Starting PREFLUX 2D .................................................................................................18

3.3

Entering the geometry .................................................................................................21

3.4

Building the mesh ........................................................................................................58

3.5

Creating the regions and assigning physical properties ..............................................67

3.6

Creating the TRA file .......................................................... Erreur ! Signet non défini.

3.7

Saving data and leaving PREFLUX 2D .......................................................................95

SOLVER_2D: SOLVING THE PROBLEM ............................................................... 96
4.1

Starting the solver........................................................................................................96

Tutorial of Steady State and Transient Thermal

PAGE A

TABLE OF CONTENTS

5.

4.2

Choosing the problem ................................................................................................. 97

4.3

Configuration of the solving options ............................................................................ 98

4.4

Running the solver ...................................................................................................... 99

POSTPRO_2D: ANALYSIS OF THE RESULTS....................................................102
5.1

Starting POSTPRO_2D............................................................................................. 102

5.2

Choosing the problem ............................................................................................... 103

5.3

Display of the results as charts ................................................................................. 105

5.4

Computation of local and global quantities ............................................................... 110

5.5

Variation of a local quantity along a path .................................................................. 117

5.6

Saving the results in a text file .................................................................................. 122

5.7

Leaving POSTPRO_2D............................................................................................. 123

PART C: EXPLANATION OF CASE 2
6.

7.

9.

PAGE B

124

SOLVER_2D: PARAMETRIC SOLVING PROCESS .............................................126
6.1

Starting the solver ..................................................................................................... 126

6.2

Choosing the problem ............................................................................................... 127

6.3

Defining the parameters ............................................................................................ 129

6.4

Running the solving process ..................................................................................... 137

POSTPRO_2D: ANALYSIS OF THE RESULTS....................................................141
7.1

Starting POSTPRO_2D............................................................................................. 141

7.2

Choosing the problem ............................................................................................... 141

7.3

Analysis of the results ............................................................................................... 142

7.4

Leaving POSTPRO_2D............................................................................................. 156

PART D: EXPLANATION OF CASE 3
8.

FLUX2D®10

157

PHYSICAL PROPERTIES FOR TRANSIENT THERMAL APPLICATION.............159
8.1

Starting PREFLUX 2D............................................................................................... 159

8.2

Creating RADIATOR3 problem ................................................................................. 159

8.3

Creating the TRA file................................................................................................. 168

8.4

Saving data and leaving PREFLUX 2D..................................................................... 168

SOLVER_2D: SOLVING THE PROBLEM .............................................................169
9.1

Starting the solver ..................................................................................................... 169

9.2

Choosing the problem ............................................................................................... 169

9.3

Running the solver .................................................................................................... 170

Tutorial of Steady State and Transient Thermal

FLUX2D®10

TABLE OF CONTENTS

10. POSTPRO_2D: ANALYSIS OF THE RESULTS.................................................... 175
10.1 Starting POSTPRO_2D .............................................................................................175
10.2 Choosing the problem ...............................................................................................175
10.3 Display of the results as charts..................................................................................178
10.4 Computation of local and global quantities................................................................185
10.5 Temperature variation along a path...........................................................................192
10.6 Leaving POSTPRO_2D .............................................................................................200
10.7 Conclusion.................................................................................................................200

Tutorial of Steady State and Transient Thermal

PAGE C

FLUX2D®10

PART A: DESCRIPTION OF THE STUDY

PART A: DESCRIPTION OF THE STUDY

TUTORIAL OF STEADY STATE AND TRANSIENT THERMAL

PAGE 1

PART A: DESCRIPTION OF THE STUDY

PAGE 2

FLUX2D®10

TUTORIAL OF STEADY STATE AND TRANSIENT THERMAL

FLUX2D®10

PART A: DESCRIPTION OF THE STUDY
REALIZED STUDY

1. REALIZED STUDY

The aim of this tutorial is to discover the most important commands of FLUX software – section
FLUX2D, in the study of a simple example of thermal steady state and transient problem,
corresponding to the heating of a thyristor du to the switching losses of 100 W. The thyristor is
placed on a radiator that is fixed to a chassis by a holding device. The thyristor - radiator assembly is
surrounded by air. Convection and radiation to the surrounding air direct the thermal exchange. The
thermal transfer to the chassis is modeled as thermal exchange.

THYRISTOR

RADIATOR

CHASSIS

We will carry out three simulations to study the thermal behavior of the device:


Case 1: The radiator is entirely surrounded by air. The simulation is carried out under thermal
steady state conditions.



Case 2: The radiator is fixed to a chassis. The coefficient of thermal transfer towards the chassis
varies between 5 W/m2/°C and 1500 W/m2/°C, the reference value being set at 20 W/m2/°C.
The thickness of the thyristor varies between 10 mm and 17 mm, with a reference value of
14 mm. The simulation is carried out under thermal steady state conditions.



Case 3: The radiator is entirely surrounded by air. The simulation is carried out under thermal
transient state conditions.

TUTORIAL OF STEADY STATE AND TRANSIENT THERMAL

PAGE 3

PART A: DESCRIPTION OF THE STUDY
REALIZED STUDY

FLUX2D®10

These three cases will allow you to discover the main programs and commands of FLUX2D:


Case 1 is a thermal steady state problem, introduces FLUX2D main programs:
PREFLUX 2D: definition of the geometry and building of the mesh, definition of the materials
and the assignment of the physical properties and boundary conditions
- SOLVER_2D: solving of the problem
- POSTPRO_2D: analysis of the results
-



Case 2 differs from Case 1 only by the thermal transfer coefficient to the chassis and the
thickness of the thyristor, quantities parameterized using the SOLVER_2D program. In this case,
you will use:
- SOLVER_2D: parameterized solving of the problem
- POSTPRO_2D: analysis of the results



Case 3 is similar to Case 1, but this case is a thermal transient problem. The geometry, the mesh
and the materials are the same as for Case 1. In this case, you will use:
- PREFLUX 2D: redefinition of the physical properties of the regions and of the boundary
conditions
- SOLVER_2D: solving of the problem
- POSTPRO_2D: analysis of the results

PAGE 4

TUTORIAL OF STEADY STATE AND TRANSIENT THERMAL

FLUX2D®10

PART A: DESCRIPTION OF THE STUDY
PROBLEM DESCRIPTION

2. PROBLEM DESCRIPTION

2.1 The geometry
All the dimensions of the geometry are given in [mm]. The thickness of the device is equal to
40 mm. The geometry of the radiator is obtained by a geometrical transformation duplicating the
points of the central cooling rib.
30
10 (case 1 and 3)
10-17 (case 2)

point of (0, 0) coordinates

THYRISTOR

RADIATOR
15

radius = 3 mm
50

10

radius = 2 mm

64

Central rib

The geometry contains two surface regions and four line regions. One of the line regions models the
thermal transfer to the chassis. The THICK parameter characterizes the thyristor thickness.

TUTORIAL OF STEADY STATE AND TRANSIENT THERMAL

PAGE 5

FLUX2D®10

PART A: DESCRIPTION OF THE STUDY
PROBLEM DESCRIPTION

SURFTHYR

RADLOW

PAGE 6

THYRISTOR

RADIATOR

RADHIGH

CHASSIS

TUTORIAL OF STEADY STATE AND TRANSIENT THERMAL

FLUX2D®10



PART A: DESCRIPTION OF THE STUDY
PROBLEM DESCRIPTION

The geometric parameter is:
Parameters
THICK



Description
Thyristor thickness

The geometric transformations are:
Transformations
SYM
TRANS_X_MINUS
TRANS_X_PLUS



Value (mm)
10 (Case 1 and Case 3); 10 - 17 (Case 2)

Description
Symmetry type transformation
Translation along X axis toward minus
Translation along X axis toward plus

Type
AFFIN_LINE_2PT
TRANS_VEC
TRANS_VEC

The coordinates of the points that define the central cooling rib (right-hand side half) are:
X (mm)

Y (mm)

0

0

0

- 15

0

- 50

2

- 48

2

- 15

5

- 12

5

0

The coordinates that define the rest of the radiator outline are:
X (mm)

Y (mm)

- 32

0

32

0

The other points are obtained by a geometric transformation.


The coordinates of the points that define the thyristor are:
X (mm)

Y (mm)

- 15

0

15

0

15

THICK

- 15

THICK

TUTORIAL OF STEADY STATE AND TRANSIENT THERMAL

PAGE 7

FLUX2D®10

PART A: DESCRIPTION OF THE STUDY
PROBLEM DESCRIPTION

2.2 The regions
The computation domain of the thermal field consists of two surface regions and four line regions.
Region’s name
THYRISTOR
RADIATOR
SURFTHYR
RADLOW
CHASSIS
RADHIGH

PAGE 8

Description
Thyristor
Radiator
Thyristor – air exchange surface
Radiator – air exchange surface
Radiator – chassis thermal transfer surface (in cases 1 and 3
this region is replaced by air)
Radiator – air exchange surface, placed between thyristor and
chassis

Type of region
Surface region
Surface region
Line region
Line region
Line region
Line region

TUTORIAL OF STEADY STATE AND TRANSIENT THERMAL

FLUX2D®10

PART A: DESCRIPTION OF THE STUDY
PROBLEM DESCRIPTION

2.3 Mesh
The mesh is built by using the automatic mesh generator. The mesh point associated to the points of
the geometry is presented in the next table.
Type of MESH_POINT
MEDIUM

Size (mm)
2

The MEDIUM mesh point is associated to all the points of the geometry.
The mesh of the geometry is represented in the next figure.

Mesh of the study domain

TUTORIAL OF STEADY STATE AND TRANSIENT THERMAL

PAGE 9

FLUX2D®10

PART A: DESCRIPTION OF THE STUDY
PROBLEM DESCRIPTION

2.4 The materials
The problem that we are going to study contains the following materials:


aluminum (ALU material) in the RADIATOR surface region. Its characteristics are:
-

thermal conductivity, linearly dependent on the temperature:

k = k0 (1 + a T)
k0 = 204 W/m/°C
a = -3 ⋅ 10-4 °C-1

-

specific heat, linearly dependent on the temperature. This property is used only in thermal
transient analysis:
RoCp = RoCp0 (1 + a T)
RoCp0 = 2.32⋅106 J/m3/°C
a = 0.003

On the surface of the radiator is imposed a thermal exchange by means of the line regions around
the radiator: RADHIGH, RADLOW and CHASSIS. The thermal exchange for radiator is
characterized by:
-

convection exchange coefficient

Ce conv = 20 W/m2/°C

This value corresponds to medium ventilation of the radiator.


radiation exchange coefficient

Ce rad = 0.8

silicon (SILICON material) in the THYRISTOR region. Its characteristics are:
-

thermal conductivity
specific heat

k = 78 W/m/°C
RoCp = 1.75 ⋅ 106 J/m3 /°C

The specific heat property is used only in the thermal transient analysis.
The surface of the thyristor is less ventilated then the radiator surface. Thus, thermal exchange
property is imposed to the SURFTHYR line region around the thyristor.
The thermal exchange for thyristor is characterized by:
-

PAGE 10

convection exchange coefficient
radiation exchange coefficient

Ce conv = 5 W/m2/°C
Ce rad = 0.9

TUTORIAL OF STEADY STATE AND TRANSIENT THERMAL

FLUX2D®10

PART A: DESCRIPTION OF THE STUDY
PROBLEM DESCRIPTION

2.5 The sources
The thyristor dissipates a total power of 100 W through the THYRISTOR surface region.
The other regions have no heat sources.

2.6 The boundary conditions
Special thermal exchange conditions are used on all the external boundaries of the computation
domain. This type of boundary conditions is imposed implicitly if the boundaries are line regions
and the associated type of region is of thermal exchange type. Thus, there is no condition to be
defined explicitly by the user in this application.
Note:
In order to carry out a parametric analysis with geometric parameters, the boundary
conditions should be necessarily be defined on line regions.

2.7 The initial temperature. The ambient temperature not
defined yet
In thermal transient problem the initial temperature of the device is set to 20° C.
The ambient temperature not yet imposed by the boundary conditions on certain boundaries is of
20° C.

2.8 Time steps (for thermal transient only)
The initial time step is set to 60 seconds. Subsequent time step values are not limited. The duration
of the study is limited to 5000 s. This value is reached in 16 time steps.

TUTORIAL OF STEADY STATE AND TRANSIENT THERMAL

PAGE 11

PART A: DESCRIPTION OF THE STUDY
PROBLEM DESCRIPTION

PAGE 12

FLUX2D®10

TUTORIAL OF STEADY STATE AND TRANSIENT THERMAL

FLUX2D®10

PART B: EXPLANATION OF CASE 1
PROBLEM DESCRIPTION

PART B: EXPLANATION OF CASE 1

TUTORIAL OF STEADY STATE AND TRANSIENT THERMAL

PAGE 13

PART B: EXPLANATION OF CASE 1
PROBLEM DESCRIPTION

PAGE 14

FLUX2D®10

TUTORIAL OF STEADY STATE AND TRANSIENT THERMAL

FLUX2D®10

PART B: EXPLANATION OF CASE 1
PREFLUX 2D: ENTERING THE GEOMETRY, THE MESH AND THE PHYSIC

3. PREFLUX 2D: ENTERING THE GEOMETRY,
THE MESH AND THE PHYSIC

This chapter lists the commands used to build the geometry of the device and the mesh of the
computation domain and to create and assign the physical properties. This is the first step to study a
device by finite element method with FLUX2D.

3.1 Starting FLUX2D
FLUX2D uses several programs managed by a supervisor. To activate it on WINDOWS, you have
to click on the menus in the following figure.
Start, Programs, Cedrat, FLUX 10

TUTORIAL OF STEADY STATE AND TRANSIENT THERMAL

PAGE 15

FLUX2D®10

PART B: EXPLANATION OF CASE 1
PREFLUX 2D: ENTERING THE GEOMETRY, THE MESH AND THE PHYSIC

The FLUX Supervisor window is then displayed.
Menu bar
Tool bar

Directory
manager

Project
Files

Program
manager

My programs
FLUX View

The different parts of the FLUX Supervisor window are described hereafter.
Part
Menu bar

Toolbar

Program manager

Function
Windows commands for FLUX
• File
• Display
• Versions
• Tools
• Help
Icons for common tasks in FLUX
• User version
• Compress/Decompress a project
• Options (memory, license, etc.)
• Help (link to online Users Guide for FLUX)
Displays the FLUX modules
The different modules are grouped by “family” in different
folders. Each module is shown as an item in the tree.
You can expand a folder by clicking on the

PAGE 16

sign.

TUTORIAL OF STEADY STATE AND TRANSIENT THERMAL

FLUX2D®10

PART B: EXPLANATION OF CASE 1
PREFLUX 2D: ENTERING THE GEOMETRY, THE MESH AND THE PHYSIC

You can start a module by double-clicking on its name, e.g.,
Geometry.

My programs

Links to other programs, such as:
• DOS Shell
• Windows Explorer
You can add links to other programs here, as you wish.

Directory manager

Displays the computer’s directory.

Files

Displays project files.

FLUX View

Displays:
• the model geometry for the selected 2D project file
(*.TRA)
• the FLUX View logo, if no problem is selected

The FLUX2D supervisor window is displayed.
First, you should create a new directory to work in it and access your new working directory by
selecting
it
in
the
supervisor
window
in
the
Directory
manager
(e.g., C:\users\customers\cedrat).
Now, you can run any FLUX2D program by double-clicking with the mouse on the corresponding
menu.

TUTORIAL OF STEADY STATE AND TRANSIENT THERMAL

PAGE 17

FLUX2D®10

PART B: EXPLANATION OF CASE 1
PREFLUX 2D: ENTERING THE GEOMETRY, THE MESH AND THE PHYSIC

3.2 Starting PREFLUX 2D
To run PREFLUX 2D, in the tree at the left, in Construction, you should double-click on the
following menu.

Context
bar

Title
bar

Menus
bar

Menus and
toolbar

Graphic
scene
toolbar

Data tree

Graphic
scene

History

Status bar

The different parts of the PREFLUX 2D window are described below.
Element
Title bar

Menu bar

Function
General information:
• Software name and version number
• Name of the current project
Access to the different menus:
• Project, Application, View, Display, Select


PAGE 18

Geometry, Mesh, Physic, Tools, Help

TUTORIAL OF STEADY STATE AND TRANSIENT THERMAL

FLUX2D®10

PART B: EXPLANATION OF CASE 1
PREFLUX 2D: ENTERING THE GEOMETRY, THE MESH AND THE PHYSIC

Access to the toolbar corresponding to the contexts:
• Geometry, Mesh, Physic

Context bar

Tool and menu bar
Project

Access to the commands of Project menu:
• New, Open…, Save, Close, Exit

Tools

Access to the commands of Tools menu:
• Undo

Geometry

Access to the commands of Geometry context:
• Commands of creation of the geometric entities


Mesh

Physic




Access to the commands of Mesh context:
• Commands for the creation of mesh entities
• Actions on the mesh
• Check of the mesh
Access to the commands of Physic context:
• Commands for the creation of physic entities




Element
Toolbar of the graphic scene
View

Actions on the geometry
Check of the geometry

Actions on the physic
Check of the physic

Function
Access to the commands of the View menu:


Refresh view, Zoom, Zoom region



Standard 1 view, Standard 2 view, Opposite view,
Direction of view, View on X, View on Y, View
on Z, Four views mode.

Display
Access to the commands of Display menu:
• Display of coordinate systems, points, lines, faces,
volumes, surface regions, volume regions
Access to the commands of Display menu of the
Geometry context:
• Display of surface elements, points numbers, lines
numbers
TUTORIAL OF STEADY STATE AND TRANSIENT THERMAL

PAGE 19

FLUX2D®10

PART B: EXPLANATION OF CASE 1
PREFLUX 2D: ENTERING THE GEOMETRY, THE MESH AND THE PHYSIC

Access to the commands of Display menu of the
Mesh context:
• Display of mesh points, mesh lines, nodes, surface
elements
Access to the commands of Display menu of
Physic context:
• Display of non meshed coils
Access to the commands of the Select menu:
• Activate the selection filter, Select points, Select
lines, Select faces, Select volumes, Select surface
regions, Select volume regions

Selection

Element
Entities tree

History

PAGE 20

Function
Entities tree of the FLUX project.

Information concerning different
current actions (project evolution):
• Restoring of data during a
project opening,
• Comments about the current
actions,
• Advance
of
computation
during the solving process, …

TUTORIAL OF STEADY STATE AND TRANSIENT THERMAL

FLUX2D®10

PART B: EXPLANATION OF CASE 1
PREFLUX 2D: ENTERING THE GEOMETRY, THE MESH AND THE PHYSIC

3.3 Entering the geometry
The first step in the numerical modeling of an electromagnetic device is the description of the device
geometry and the computation domain.

3.3.1 Creating a new problem
Each time that you run a FLUX2D program, you should select the name of the problem to be treated
or define a new problem.
To create a new problem, you should use:
• either the menus below
Project
New


or the icon below:

Note:
The current project should be saved under a name chosen by the user. A periodic save of your
work is recommended. We chose in this tutorial to save the current project at the entry and at
the exit of the PREFLUX 2D program.
To save the current project under the Radiator name, you should use:


either the menus below:
Project
Save



or the icon below:

The Save window is then displayed and you must perform tasks 1 and 2 in the next figure.

1. Enter Radiator as
Preflu2D project name
2. Click on the Save
button to save the
PREFLUX 2D project

TUTORIAL OF STEADY STATE AND TRANSIENT THERMAL

PAGE 21

FLUX2D®10

PART B: EXPLANATION OF CASE 1
PREFLUX 2D: ENTERING THE GEOMETRY, THE MESH AND THE PHYSIC

3.3.2 Activating the Geometry command
Then, you should check that the Geometry context is selected.


by the icon:

PAGE 22

TUTORIAL OF STEADY STATE AND TRANSIENT THERMAL

FLUX2D®10

PART B: EXPLANATION OF CASE 1
PREFLUX 2D: ENTERING THE GEOMETRY, THE MESH AND THE PHYSIC

3.3.3 Definition of the THICK parameter
The coordinates of points, arcs and circles can be entered using geometrical parameters or
mathematical expressions that allow us to rapidly modify the geometrical dimensions.
A parameter is defined by a name, a comment and a mathematical expression.
The name of a parameter should start with a letter and can be longer than the standard length of
8 characters. However, it is recommended to use short names or abbreviations that can be easily
memorized.
Comments should briefly describe the parameter significance; comments should be shorter than
72 characters.
The mathematical expressions may contain:
• Constants;
• Arithmetic operators (+, -, *, /, **);
• Arithmetic functions admitted by FORTRAN (SQRT, LOG, SIN, …);
• Other parameters;
• Combinations of any of these.
Note:
Once defined, the parameters are independent of units; that is, the numerical value associated
with a parameter is not changed if the units are changed. Any units associated with the
parameter are taken from the coordinate system in which the parameter is defined. For
example, if a parameter value is defined as 10 in a coordinate system using millimeters as
units, the parameter value will be still 10 if the coordinate system units are changed to inches,
or meters, or kilometers, or any other unit. In this way, you can modify the scale of a
geometric feature without entering each point or item all over again. Parameters can be
created at any time during the geometry description.

TUTORIAL OF STEADY STATE AND TRANSIENT THERMAL

PAGE 23

FLUX2D®10

PART B: EXPLANATION OF CASE 1
PREFLUX 2D: ENTERING THE GEOMETRY, THE MESH AND THE PHYSIC

The THICK parameter allows us to quickly modify the thyristor thickness.
Follow the program sequence below:
• either select the following menus:
Geometry
Geometric Parameter
New


or click on the following icon:



or in the tree at the left, in the Data tab:
click with the right button of the mouse, in Geometry, Geometric tools, on
Geometric Parameter

The following contextual menus appear.

Select New


or double click on Geometric Parameter in the tree.

The New Geometric Parameter window is then displayed and to create the geometric
parameter THICK, you must perform tasks 1 to 5 in the next figure.
1. Enter THICK as Name of
Parameter
2. Enter Thyristor
thickness as Comment
3. Enter 10 as Algebraic
expression for the parameter
4. Click on the OK button to
create the parameter
5. Click on the Cancel button
to quit this window

The geometric THICK parameter is then created.
Note:
You can enter the name of the projects, regions and parameters in lowercase or uppercase.
They will automatically be converted to uppercase.
Note:
The parameter 1 is PI (value 3.141592 …).
Parameters can be defined at any moment during the construction of the geometry.
PAGE 24

TUTORIAL OF STEADY STATE AND TRANSIENT THERMAL

FLUX2D®10

3.3.4

PART B: EXPLANATION OF CASE 1
PREFLUX 2D: ENTERING THE GEOMETRY, THE MESH AND THE PHYSIC

Entering the points and lines of the radiator

Points can be entered as a set of two coordinates (X and Y, or R and θ, or R and Y) in a specified
coordinate system, or using geometric transformations. To define the coordinates of the points we
can use numbers, parameters or Fortran expressions.
As the points are entered, PREFLUX 2D automatically and arbitrarily assigns a reference number to
each point. You can use these reference numbers to select points, but they are not automatically
displayed. If you wish to see them on your screen, you should use the Display, Display
points numbers command.
You may notice that the points on your screen are not assigned the same numbers as the ones we use
for convenience in this tutorial. Please do not be worried about this discrepancy. Whenever, we use
a point number in our instructions, for example, to select a certain point, we will also include a short
description about the location of that point, so that you can choose the proper one from your own
screen.
Finally, you may notice that as more points are entered, individual points become difficult to
distinguish. When you want to enlarge a selected area of the screen, use the View, Zoom Region
menu or the icon

to see a specific point or feature.

After using the Zoom Region command, activate the View, Zoom All menus or the icon
to display an overview of all the geometric features you have entered so far. If you want to see
additional information about a specific point or any other geometric feature, select the feature from
the screen and then click with the right button of the mouse and activate the Edit menu.
First, we will enter the points of the radiator. We will start with the points of the right-hand side half
of the central cooling rib (see table below). They will allow us to create the first lines. These points
are not parameterized. We will enter these points as a set of coordinates in the XY1 coordinate
system.
Point

X (mm)

Y (mm)

P1

0

0

P2

0

- 15

P3

0

- 50

P4

2

- 48

P5

2

- 15

P6

5

- 12

P7

5

0

TUTORIAL OF STEADY STATE AND TRANSIENT THERMAL

PAGE 25

FLUX2D®10

PART B: EXPLANATION OF CASE 1
PREFLUX 2D: ENTERING THE GEOMETRY, THE MESH AND THE PHYSIC

The sequence of commands can be repeated as many times as needed. The answer provided for the
previous point is proposed by default (value between brackets). If this one is appropriate, you should
simply validate it by pressing the Return/Enter key ↵.
To create a point, you should use:
• either the following menus:
Geometry
Point
New


or the following icon:



or in the tree at the left, in the Data tab:
click with the right button of the mouse, in Geometry, Geometric Entities,
on Point

The following contextual menus appear.

Select New


or double click on Point in the tree.

The New Point window is then displayed and to create the first point, you must perform tasks 1 to
6 in the next figure.
1. Select the Geometric Definition
tab
2. Select Point defined by its
Parametric Coordinates as
Type of the Point
3. Select XY1 as Coordinate System for
definition
4. Enter 0 for the First coordinate
5. Enter 0 for the Second coordinate
6. Click on the OK button to create the
point

The point number 1 is then created.

PAGE 26

TUTORIAL OF STEADY STATE AND TRANSIENT THERMAL

FLUX2D®10

PART B: EXPLANATION OF CASE 1
PREFLUX 2D: ENTERING THE GEOMETRY, THE MESH AND THE PHYSIC

To create the second point, you must perform tasks 1 to 3 in the next figure.

1. Enter 0 for the First coordinate
2. Enter -15 for the Second coordinate
3. Click on the OK button to create the
point

The point number 2 is then created.

TUTORIAL OF STEADY STATE AND TRANSIENT THERMAL

PAGE 27

FLUX2D®10

PART B: EXPLANATION OF CASE 1
PREFLUX 2D: ENTERING THE GEOMETRY, THE MESH AND THE PHYSIC

Then you must create all the other points, from P3 to P7, listed in the previous table.
Finally, to create the last point of the previous table, P7, you must perform tasks 1 to 4 in the next
figure.

1. Enter 5 for the First coordinate
2. Enter 0 for the Second coordinate
3. Click on the OK button to create the
point
4. Click on the Cancel button to quit this
window

The following image should appear on your screen.

The points can be deleted, modified, visualized, propagated or extruded. In order to verify the
dimensions, the computation of the distance between two points is accessible (Geometry,
Verify, Compute distance between Points). For a better view of the points created so
far, you should click on View, Zoom All or click on the icon

.

Note:
To modify a point, you should click on Geometry, Point, Edit, and select the point to
be modified. To delete a point, you should click on Geometry, Point, Delete and select
the point to be deleted. To delete a point linked to a line, you should select Geometry,
Point,
Force
Delete,
then
select
the
point
to
be
deleted.

PAGE 28

TUTORIAL OF STEADY STATE AND TRANSIENT THERMAL

FLUX2D®10

PART B: EXPLANATION OF CASE 1
PREFLUX 2D: ENTERING THE GEOMETRY, THE MESH AND THE PHYSIC

When the coordinates of a point are modified, all the geometric entities containing this point (lines,
surfaces, ...) will automatically be updated.
To create closed surfaces, the points should be connected with lines. The order in which the lines are
created is not important. Likewise, it is not important that all the points be defined before entering
the lines. In this version of PREFLUX 2D lines may be drawn as straight segments or arcs. Several
options explained in the table below are available to create the arcs.
Menu Command
Segment defined by
Starting and
Ending Points
Arc defined by
Starting, Middle
and Center Points
Arc defined by its
Angle, Starting
and End Points
Arc defined by
Center
Coordinates,
Starting and End
Points
Arc defined by
Starting, Ending
and Center Points
Arc defined by its
Radius, Starting
and Ending Points
Propagated from an
other line
Extruded from a
point

Explanation
Line defined by selecting two points

Arc defined by 3 points (within a selected coordinate system)

Arc defined by 2 points and an angle (within a selected
coordinate system)
Arc defined by 2 points and coordinates of the center (within a
selected coordinate system)

Arc defined by 2 points and center point (within a selected
coordinate system)
Arc defined by two points and a radius (within a selected
coordinate system)
Line defined by propagation
Line defined by extrusion

FLUX2D continuously checks if the lines are entered correctly. A new line intersecting or
superposed on an existing line is not allowed. To connect three points along the same straight line,
you should define two different lines.

n° 1

TUTORIAL OF STEADY STATE AND TRANSIENT THERMAL

n° 2

n° 3

PAGE 29

FLUX2D®10

PART B: EXPLANATION OF CASE 1
PREFLUX 2D: ENTERING THE GEOMETRY, THE MESH AND THE PHYSIC



Defining the straight lines

We will create the six lines of the right-hand side of the central cooling rib of the radiator by
activating the following commands:
• either select the following menus:
Geometry
Line
New


or click on the following icon:



or in the tree at the left, in the Data tab:
click with the right button of the mouse, in Geometry, Geometric Entities, on Line

The following contextual menus appear.

Select New


or double click on Line in the tree.

For each line, you should select a starting point and an ending point.
The New Line window is then displayed.

PAGE 30

TUTORIAL OF STEADY STATE AND TRANSIENT THERMAL

FLUX2D®10

PART B: EXPLANATION OF CASE 1
PREFLUX 2D: ENTERING THE GEOMETRY, THE MESH AND THE PHYSIC

The six straight line connect the following points P6 and P7, P7 and P1, P1 and P2, P2 and P3, P4
and P5, P5 and P2, as presented in the figure below.
2

1

3

6

4

5

To create the first line, you must perform tasks 1 to 4 in the next figure.

1. Select the Geometric
Definition tab
2. Select Segment defined
by Starting and
Ending Points as Type of
the line
3. Select the first point with the
in the Graphic scene
mouse
4. Select the second point with the
mouse

Tutorial of Steady State and Transient Thermal

in the Graphic scene

PAGE 31

PART B: EXPLANATION OF CASE 1
PREFLUX 2D: ENTERING THE GEOMETRY, THE MESH AND THE PHYSIC

FLUX2D®10

The line number 1 is then created.
The program sequence for the creation of straight lines can be repeated as many times as needed.
We leave it by clicking on the Cancel button.
Note:
To delete an incorrect line, you should click on Geometry, Line, delete and then to
select the line to be deleted. If this line is connected to a surface region, you should use the
Force Delete menu, then select the line to be deleted. This last operation supposes the
deletion of all the faces linked to this line.
command we will display an overview of the lines that
Using the View, Zoom All or the icon
define the right-hand side half of the fixed part of the contactor, as presented below.

PAGE 32

Tutorial of Steady State and Transient Thermal

FLUX2D®10



PART B: EXPLANATION OF CASE 1
PREFLUX 2D: ENTERING THE GEOMETRY, THE MESH AND THE PHYSIC

Defining the arcs

We continue with the creation of the two arcs that connect points P6 and P5, P3 and P4, as presented
in the figure below.
We have to select the points in counter-clockwise direction with respect to the arc curvature. The
radius of the first arc is 3 mm and the radius of the second arc is 2 mm.

Starting point

Ending point

Ending point
Starting point

To open the New Line window, you should double click on Line in the tree.

Tutorial of Steady State and Transient Thermal

PAGE 33

FLUX2D®10

PART B: EXPLANATION OF CASE 1
PREFLUX 2D: ENTERING THE GEOMETRY, THE MESH AND THE PHYSIC

To create the arcs, you should follow the tasks 1 to 12 in the next figure.

1. Click on
the
Definition tab

Geometric

2. Select Arc defined by its
Radius,
Starting
and
Ending Points as type of line
3. Select XY1 as coordinate system
4. Type 3 as arc radius

5. Type 6 as number of starting point
or click on this cell, then click on
the arc starting point
6. Type 5 as number of ending point
or click on the arc ending point
7. Press on the Return/Enter key to
create the segment

8. Type 2 as arc radius
9. Type 3 as number of starting point
or click on the starting point
10. Type 4 as number of ending point
or click on the ending point
11. Press on the Return/Enter key to
create the segment
12. Click on Cancel to quit the arcs
creation sequence

PAGE 34

Tutorial of Steady State and Transient Thermal

FLUX2D®10

PART B: EXPLANATION OF CASE 1
PREFLUX 2D: ENTERING THE GEOMETRY, THE MESH AND THE PHYSIC

The following global view is displayed:
• by clicking on the icon
,
• or in the menu bar on:
View
Zoom all

Tutorial of Steady State and Transient Thermal

PAGE 35

FLUX2D®10

PART B: EXPLANATION OF CASE 1
PREFLUX 2D: ENTERING THE GEOMETRY, THE MESH AND THE PHYSIC

3.3.5

Creating the geometrical transformation of symmetry type

The left-hand side half of the cooling rib that is situated at the right-hand side of the central cooling
rib, can be easily built by using a geometrical transformation of symmetry type with respect to a
line.
To create a transformation, you should use:
• either the following menus:
Geometry
Transformation
New


or the following icon:



or in the tree at the left, in the Data tab:
click with the right button of the mouse, in Geometry, Geometric tools, on
Transformation

The following contextual menus appear.

Select New


or double click on Transformation in the tree.

The New Transformation window is then displayed.

PAGE 36

Tutorial of Steady State and Transient Thermal

FLUX2D®10

PART B: EXPLANATION OF CASE 1
PREFLUX 2D: ENTERING THE GEOMETRY, THE MESH AND THE PHYSIC

For the creation of the transformation, you will have to select the two points (P6 and P7) of the
straight line presented in the next figure. The symmetry transformation will be defined with respect
to this line.
P7

Line defined by two points
used to define the sy mmetry

P6

Tutorial of Steady State and Transient Thermal

PAGE 37

FLUX2D®10

PART B: EXPLANATION OF CASE 1
PREFLUX 2D: ENTERING THE GEOMETRY, THE MESH AND THE PHYSIC

To create the transformation SYM, you must perform tasks 1 to 8 in the next figure.

1. Type SYM as name of the geometric
transformation
2. Type
Symmetry
type
Transformation as associated
comment
3. Select Affine Transformation
with respect to a line
defined by 2 Points as type
of geometric transformation
4. Type 7 as number of the first point that
defines the transformation or click on
this cell, then click on the first point
defining the symmetry line
5. Type 6 as number of the second point
that defines the transformation or click
on the second point defining the
symmetry line
6. Type -1 as scaling factor
7. Click on OK to create the geometric
transformation
8. Click on Cancel to quit this window

The selection of points P7 and P6 can be performed graphically, with the mouse, replacing tasks 4 to
5 in the previous figure.

PAGE 38

Tutorial of Steady State and Transient Thermal

FLUX2D®10

3.3.6

PART B: EXPLANATION OF CASE 1
PREFLUX 2D: ENTERING THE GEOMETRY, THE MESH AND THE PHYSIC

Duplication of the central cooling rib faces

The faces that correspond to the right-hand side half of the central cooling rib of the radiator will be
duplicated using the SYM transformation already created. To do that, we should first construct the
faces of the right-hand side half of the rib. Then, we should propagate them using the SYM
transformation.
To construct the faces, you should use:
• either the following menus:
Geometry
Build
Build Faces


or the following icon:

PREFLUX 2D will automatically construct 2 faces. If you wish to visualize them on your screen,
you should click in PREFLUX 2D menu bar on:
Display
Display
Display Faces
Now, you should propagate the two faces displayed in the next figure.

Tutorial of Steady State and Transient Thermal

PAGE 39

PART B: EXPLANATION OF CASE 1
PREFLUX 2D: ENTERING THE GEOMETRY, THE MESH AND THE PHYSIC

FLUX2D®10

To propagate the faces, you should use:
• either the following menus:
Geometry
Propagate
Propagate Faces


or the following icon:



or in the tree at the left, in the Data tab:
click with the right button of the mouse, in Geometry, Geometric Entities, on Face

The following contextual menus appear.

Select Propagate Faces
The Propagate Faces window is then displayed.

PAGE 40

Tutorial of Steady State and Transient Thermal


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