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Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version 3.2

Flomerics, Inc. January 2002

Flomerics Limited.

81 Bridge Road Hampton Court, Surrey, KT8 9HH

United Kingdom Tel: +44 (0) 181 941 8810 Fax: +44 (0) 181 941 8370

Flomerics Incorporated. 257 Turnpike Rd., Suite 100

Southborough, MA USA 01772

Tel: (508) 357-2012 Fax: (508) 357-2013

http://www.flomerics.com

Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version 3.2 1

Copyright This document is copyright and may not be reproduced by any method, translated, transmitted, or stored in a retrieval system without prior written permission of Flomerics Limited. Disclaimer While every effort is made to ensure accuracy, Flomerics Limited and Flomerics Inc. cannot be held responsible for errors or omissions, and reserve the right to revise this document without notice. Document Reference Document Number: FLOTHERM/ST/01/02 Issue 1.0 Software Version: FLOTHERM Version 3.2 Conditions of Use This document is issued along with FLOTHERM software for use under the terms and conditions of the license agreement between the user’s organization and Flomerics Limited. Users thereby agree not to disclose in full or in part the manual or the software or the intellectual content thereof to any other individual or organization without the prior written consent of Flomerics Limited.


Introduction Welcome to the FLOTHERM V3.2 tutorial “Designing a Telecommunications System Using FLOTHERM”. This tutorial is designed to provide you with a short introduction to the functions and features of FLOTHERM V3.2. Although it is not a replacement for the full introductory training classes, this exercise does provide you with a thorough, step-by-step guide to creating, solving and analyzing a simple telecommunications system.

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In this tutorial you will use FLOTHERM V3.2 to: • Define and set the solution domain size

and ambient conditions Create an enclosure, a PCB, vents and a fan Create a computational grid Obtain results for fan flow rates and velocity profiles and temperature distributions within the system Create parametric design changes and analyze the results

Hints, shortcuts and other modeling tips and tricks.

Helpful reminders and step-by-step instructions to complete common tasks

Try it out – Extra steps

Indicates a completed section – a good time to stop if you can’t work on the tutorial from start to finish.


Problem Description Model a standard telecommunications system chassis, containing: 2 Vents, 1 Fan and 14 Boards Assume that the details for the locations, materials and properties were provided in separate drawings and product specification materials.

• • •

Sometimes this information will be available as IGES, SAT, STEP, STL and IDF files. You could use FLO/MCAD, FLO/EDA and/or FLOGATE to enter the information directly into FLOTHERM.

Modeling Steps & FLOTHERM V3.2 Application Window

A. Project and File Management Project ManagerB. Set up overall domain for solution Project Manager C. Create geometry Drawing Board, Project Manager D. Add grid Project Manager, Drawing Board E. Solve Profiles Window F. Analyze results FLOMOTION, Tables Window G. Parametric design analysis Command Center

Objectives • Determine fan flow rate

Observe temperature distribution Observe flow velocity profiles Observe the effect of different venting configurations on maximum system temperature


Designing a Telecommunications System Using FLOTHERM: Project and File Management

Start Flotherm [1] Select FLOTHERM32 in the Start menu or Program list, or [2] Use the Desktop Icon: [3] Click on the Splash Screen. The Project Manager (PM) is now open.

Load the template file “DefaultSI” [1] Select [Project/New] in the PM and [2] select the “Applications Examples” tab; notice the different projects available as template files.

You can select any one of the other tabs and available project templates to download. When you are finished looking at the project file, you can select [Project/New] in the Project Manager and continue with the tutorial (step [4] below).

[3] Select [Project/New] in the PM and [4] select the “Defaults” tab. [5] Highlight the project file “DefaultSI” and [6] click OK. This will open a new project with the default units in SI, and will revert all other settings to the default values.


Designing a Telecommunications System Using FLOTHERM: Project and File Management Save the project file with a new name and description.

Always begin by saving your project with a file name and project description. You can also add notes with further details under the “Notes” section. Later we may want to save this project as a template file under the Tutorials category, along with the other FLOTHERM Tutorials.

To save the project file under a new name, [1] select [Project/Save As] in the Project Manager (PM). [2] Type in “Short Tutorial Model” under ‘Project Name’.

Under ‘Title’, [3] type “System level analysis of a simple telecommunications system”.

[4] Click [OK] to exit out of the dialog box and to save the project with its new name and title.

Open the Drawing Board

Launch the Drawing Board (DB) Application Window by [1] clicking on

the icon. The DB is a CAD-based environment where we can view our model as it is being created.

The DB opens with the Overall Domain selected. The selection mode menu in the lower right corner of the DB allows you to select particular types of objects, as they are created.

[2] Use the cursor to grab the frame and resize the Project Manager


Designing a Telecommunications System Using FLOTHERM: Project and File Management (PM) and Drawing Board (DB) windows to see them both displayed side by side.

Make sure the cursor position is visible at the bottom of the Drawing Board. If you click the mouse anywhere in the Drawing Board and move the cursor, you should see the cursor position change. If you do not see it in the bottom left corner of the Drawing Board, reposition and resize the Drawing Board.

Designing a Telecommunications System Using FLOTHERM: Definition of Overall Domain

In this section we will define the size of the solution or overall domain (the size of the computational space). We will also define the ambient conditions for the problem.

Examine the model parameters associated with the DefaultSI template.

In the Project Manager (PM), [1] click on the ‘+’ sign to the left of ‘Model’ to expand the branch. You will see 3 boxes appear: Modeling, Turbulence, and Gravity.

Expand these further by [2] clicking on the ‘+’ signs. The default settings for the modeling parameters are now visible: Heated Flow, 3-dimensional, Radiation off, Steady state, Solar off, Automatic Turbulence Model, Gravity, acting in the negative Y-direction.

To collapse the expanded branches, [3] click on the ‘-‘ signs.



Define the dimensions of the Overall Domain.

The solution domain represents the size of the computational domain. In this example, our solution domain will coincide with the size of the chassis, which has dimensions 24 in x 36 in x 12 in.

The size of the overall domain depends on the physics of the problem and your area of interest. The overall domain is not always the same size as the outer chassis for the system you are modeling.

To set the size of the solution domain, you need to go to the “Overall Solution Domain” dialog. In the Project Manager (PM), [1] go to the ‘System’ icon and [2] right mouse click on the box.

[3] Highlight [Location] and left click with the mouse button. The ‘Overall Solution Domain’ dialog box will appear. [4] First change the units to “in” and then [5] change the ‘Size’ of the ‘Overall Solution Domain’ to the following dimensions: X=24 in; Y=36 in; Z=12 in

Leave the ‘Position’ at (0,0,0) mm and [6] click [OK].



Examine the size of the Overall Domain in the Drawing Board.

The overall solution domain can also be re-sized in the drawing board by left mouse clicking on the grab handles and dragging the red highlighted box to the desired size.

The overall solution domain may also be repositioned anywhere within the Drawing Board (DB) by selecting the highlighted lines between the grab handles. Again, if the left mouse button is held down then the domain may be dragged to the new position.

Define the default units and Drawing Board parameters

In the Project Manager (PM), check that the length unit is set to “inches”. [1] Select “Option/Units” in the PM. [2] Scroll down to “Length” and select inches. [3] Press “Dismiss”.

Use the “Save” icon in any active window to save your project at any particular stage.



In the Drawing Board, set the “Snap Grid” to 1 inch. [1] Select “Option/Modify Picture” in the Drawing Board. Under “Snap Grid”, [2] change the units to “in” and [3] enter 1 as the size.

The snap grid is not related to the solution grid. The snap grid setting determines the gap between the snap grid lines used for aligning objects when dragging or drawing in the Drawing Board. The finer the detail required, the smaller the snap grid size. It will be easier to create new geometry if you set the snap grid first.

Define and attach the ambient conditions for the model.

To specify the ambient conditions for the model, open the Ambient Attribute dialog.

[1] Click the right mouse button on the ‘System’ tab in the Project Manager model tree and [2] select [Ambients]. [3] Click on the [New] button to bring up the ‘Ambient Attribute’ box.



[4] Enter the following information:

Name Top surface

Gauge Pressure 0 Atm

Temperature 35°C

Radiant Temperature 35°C

Heat Transfer Coefficient 8 W/(m2 K)

External Velocities 0

System Ambients are the boundary conditions that join the overall (or computational) domain with the “outside world.” By imposing a Heat Transfer Coefficient of 8 W/(m2K), we are ensuring that any solid surfaces that are in contact with the Overall Domain will have 8 W/(m2K) of heat removed from the system through the walls.

[5] Click [OK] to save the changes and exit the dialog window. You will now see “Top Surface” appear in the Selection list.



In the ‘Ambient’ dialog box, [1] select the Y0-High face under the ‘Attachment/Applied To’.

To attach an attribute, always select the face first, and then the attribute.

[2] Highlight “Top Surface” in the selection list. [3] Click the [Attach] button. This will attach the new ambient condition to the top surface of the solution domain.

You can attach different ambient conditions to each of the six sides of the domain. Alternatively, if the ambients are all the same, then select Default All in the attachment list to attach a single attribute to all surfaces in just one step.

[1] Create two additional ambient conditions:

Name Side surface Bottom surface

Gauge Pressure 0 Atm 0 Atm

Temperature 35°C 35°C

Radiant Temperature 35°C 35°C

Heat Transfer Coefficient 6 W/(m2 K) 4 W/(m2 K)

External Velocities 0 0

[2] Attach “Side Surfaces” to the X0-low, X0-high, Z0-low and Z0-high faces. [3] Attach the “Bottom Surface” to Y0-low. [4] Dismiss the dialog box.


Designing a Telecommunications System Using FLOTHERM: Definition of Overall Domain box.

If you attach “Side Surfaces” to Default All first and then attach the “Bottom Surface” to the Y0-low face, you will save steps and have the same result.

[1] Press the save icon in either the Drawing Board (DB) or the Project Manager (PM), or [2] Choose [Project/Save], to save the changes you’ve made to the model.

To check which attribute has been assigned to a particular side of the solution domain, select the face under “Applied To”. The ambient condition for that face will appear under the “Currently Attached” section.

Remember to “Save” often while you are working on a model.

This is the end of the sections on “Project and File Management” and “Definition of the Overall Domain”. The next sections deal with “Geometry Creation”.

Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version 3.2

Designing a Telecommunications System Using FLOTHERM: Geometry Creation (Part 1)

In this section (consisting of two parts) we will create combinations of FLOTHERM objects and SmartParts to represent the physical geometry in our model. We will include the chassis (an enclosure), the vents (resistance objects), a rectangular fan (fan Smart Parts) and boards (PCB Smart Parts).

Create a mild steel enclosure named “Walls”.

[1] In the Project Manager press F7 to bring up the Geometry Palette.

You can also click on the Palette icon in the Project Manager to open the Geometry Palette.

[2] Highlight the ‘Root Assembly’, and, [3] in the PM, click on the

enclosure icon, . This will co-locate the enclosure the Overall Domain.

[4] Highlight the enclosure name (named Enclosure 1 by default) and [5]left click over the name. [6] Rename the enclosure to “Walls” . To exit the “edit name” function, [7] right click the mouse anywhere in the Project Manager.

Highlight the name of any object or assembly and left click over the name to replace the default name of any assembly or object with a new 32 character name.

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[1] Highlight the enclosure name in the Project Manager and [2] right click to bring up the Enclosure menu. [3] Select Construction and check the dialog entries. The dimensions should be (24x36x12) in. [4] Make sure that the modeling level selected is “Thin” and [5] change the “Thickness” (wall thickness) to 2 mm. [6] Press [Apply].

Pressing on [Apply] will apply the changes, but not exit the form. By pressing on [OK], you are applying the changes and exiting the form. There are times when you will want to visually inspect changes before closing the dialog; [Apply] is useful in these situations.

[7] Double check the entries before pressing [OK] to close the enclosure dialog window.

To attach the material Mild Steel to the enclosure, [1] Highlight the enclosure name in the Project Manager, and [2] right mouse click on the highlighted enclosure. [3] Select [Material] and [4] click on [Library]. [5] Select ‘Steel (Mild)’ under ‘Property’, and [6] press [Load]. [7] Press [Dismiss] to close the “Select Material” dialog window.

To review the material properties of mild steel, you can [1] Highlight ‘Steel (Mild)’ in the ‘Selection’ window and [2] Click [Edit] to see the “Material Property” dialog. Once you have reviewed the properties, or made any necessary changes, [3] Click [OK].

To attach the material to the enclosure, [8] Highlight the material “Steel (Mild)” and [9] Press [Attach]. [10] Press [Dismiss] to close the material dialog window. [11] Save the project.


Designing a Telecommunications System Using FLOTHERM: Geometry Creation (Part 1) With the enclosure “Walls” still selected in the Project Manager (PM), [1] click on the ‘Display Object Information’ icon . This will bring up the Summary dialog to display information regarding the objects selected in the Project Manager (PM). In the dialog box all of the attributes will be displayed in tabular form. [2] Press “Close” to close the Summary dialog window.

Use the hot key “i" in the Project Manager to open the summary dialog window.

If you select multiple objects before opening the “Summary” dialog window, the table will include data for all of the highlighted objects.

Add vents to the enclosure. Make the Drawing Board (DB) the active window by [1] clicking anywhere in the DB window. [2] Use the F7 hotkey to open up the Geometry Palette in the DB.

Before creating the vents, you should make sure that the “Snap Mode” is set to “Snap to Object”.

Click on the “Snap Mode” icon

It should look like the “Snap to Object” icon


Designing a Telecommunications System Using FLOTHERM: Geometry Creation (Part 1) Use the resistance object to create a vent in the Drawing Board. Make sure you are in the DB, and [1] select the collapsed resistance

icon from the DB palette. [2] In View 1, start from the lower right corner and drag the mouse to create a resistance that is the full width in the z-direction and approximately 6 in. in the y-direction.

The size and location of selected objects is shown in the lower left corner of the Drawing Board window.

Rename the resistance by [3] highlighting the name in the Project Manager and [4] left clicking on the name. [5] Type in the name “Vent 1” and [6] right click the mouse in the Project Manager to close the edit name option.

Check the size of the resistance manually by [1] highlighting Vent 1 in the Project Manager and [2] right clicking on the name. [3] Select Location from the pull-down menu. [4] Change the size values if necessary and [5] press OK to close the dialog window.


Designing a Telecommunications System Using FLOTHERM: Geometry Creation (Part 1) A resistance attribute (defining loss coefficients) can be added to the resistance (Vent 1) to specify the characteristics of the vent. [1] Highlight the resistance named Vent 1 and [2] right click to bring up the Resistance Menu. [3] Select the “Resistance” option to bring up the “Resistance” attribute menu. By default, no resistance attribute is attached to the resistance Vent 1. The Flomerics Resistance Library contains several loss coefficients for common planar resistances. In the Resistance dialog, [4] select Library.

The “Select Resistance” library dialog should appear. [1] Select “Grid (planar) 70% open” from the Flomerics Resistance Library. [2] Load the resistance attribute and [3] Dismiss the dialog

To review the loss coefficients and definitions of other resistances in the Flomerics Resistance Library, [1] Load other resistances into the project and [2] Select edit from the resistance dialog to review the loss coefficient definitions.


Designing a Telecommunications System Using FLOTHERM: Geometry Creation (Part 1) The appropriate resistance attribute needs to be attached to Vent 1. In the “Resistance” dialog, [1] select “Grid (planar) 70% open” and [2] select “Attach”. [3] Press “Dismiss” to close the dialog.

To create a second vent, we can copy Vent 1 and move it to the correct location.

Copying Vent 1 ensures that the second resistance has the same attributes as Vent 1

[1] Activate View 0 in the Drawing Board by clicking the mouse in that window. [2] Select Vent 1 in the Project Manager and [3] Press Ctrl-C to copy Vent 1. [4] Highlight the Root Assembly and [5] press Ctrl V to past the copy. [6] Select the second resistance (named Vent 1:1). In the Drawing Board, [7] drag the new vent to the X high face (x=24 in).

When dragging the vent to a new location, be careful to select the vent without selecting the resizing handles. Use the Edit/Undo option in the Drawing Board to go back one move. Use the manipulation (hand-mode) for the cursor to zoom in on the vent when selecting, and use the shift key to constrain the move when relocating the copied vent.


Designing a Telecommunications System Using FLOTHERM: Geometry Creation (Part 1) Define sub-assemblies and arrange the object hierarchy. Define sub-assemblies to arrange the object hierarchy in the Project Manager. In the Project Manager [1] select the Root Assembly and then select the sub-assembly icon from the palette. [2] Locate the new sub-assembly (at the bottom of the tree in the Project Manger) and [3] highlight the name. [4] Left click on the name and [5] edit the name and change it to “Vents”. [6] Right click elsewhere in the Project Manager to close the edit dialog. [7] Select Vent 1:0, and [8] use the Ctrl key while selecting Vent1:1 to select the second vent as well. [9] Place the cursor over the icons and drag the two selected resistances into the new assembly to rearrange them in the Project Manager model tree.


This is the end of the first half of the section on “Geometry Creation” The next section is the second half of the “Geometry Creation”.



In this section we will continue to define the geometry.

Create a rectangular fan to represent the fan tray

In the Project Manager, [1] create a new sub-assembly and [2]rename it “Fan Tray”. [3] Highlight the Fan Tray sub-assembly in the Project Manager. In the Project Manager, [4] select the Fan icon from the object palette.

Edit the properties of the Fan

[1] Find the fan in the Project Manager (named Fan 1) and [2] highlight the fan. [3] Right click the mouse and [4] select construction to bring up the fan construction dialog.



In this tutorial we are using a Rectangular Fan to simulate the effects of several individual axial fans normally found in a fan tray. Instead of modeling all of the fans individually, a rectangular fan is used.

In the fan construction dialog, [1] Change the name to “Rectangular Fan”. [2] Select the “Rectangular Fan” option, and [3] change the dimensions to: X0=20 in and Y0=10 in. [4] Under ‘Flow Specification,’ toggle ‘Non-Linear Fan.’ [5] Set the ‘Open Volume Flow-Rate’ to 0.5 m3/s, and the ‘Pressure at Stagnation’ to 140 Pa. [6] [Apply] the changes

[1] select [Fan Curve]. In the Fan Curve dialog box, [2]toggle on ‘Edit Mode.’ [3] Enter the following data points for the fan curve:

Volumetric Flowrate (m3/s)

Pressure (Pa) Volumetric Flowrate (m3/s)

Pressure (Pa)

0.1175 100 0.3 470.1625 80 0.3375 490.205 60 0.35 480.235 50 0.375 450.25 48 0.4 38

0.275 46 0.45 20

[4] Click Dismiss when all of the data points have been added. [5] Click OK to close the Fan curve edit dialog. [6] Click OK again, to close the fan construction dialog box as well.



There are several axial fans available through the Flomerics Fan Library, including: Comair Rotron, Delta, ETRI, Micronel, NMB, Papst and Sanyo Denki. To gain access to the fan library and review these fans, you need to either create a dummy fan in the project first or use the existing fan.

To review the fans in the fan library, [1] highlight the rectangular fan we already created and [2] right click to bring up the Fan Menu, and [3] select Location. In the Edit SmartPart dialog, [4] select Library to review the types of fans available in the library. [5] Select a fan manufacturer and [6] select a particular type of fan. [7] Load the fan into the project and [8] dismiss the dialog. [9] Click OK to close the Edit SmartPart dialog. [10] Select the newly loaded fan in the Project Manager and [11] right click to bring up the Fan Menu and [12] select Construction. Review the entries, including the fan curve data for the particular fan. When you are finished, you can delete the newly loaded fans and continue with the tutorial.



The newly created rectangular fan “Rectangular Fan” needs to be located correctly in the Drawing Board. The fan must be rotated and centered on the top (Y High) face of the enclosure.

In the Drawing Board, [1] Select View 1. In the Project Manager, [2] select the “Rectangular Fan”. You will see the fan highlighted in the Drawing Board as well. [3] Click on the clockwise rotation icon in the Drawing Board to rotate the fan clockwise.

When using the rotate function, remember that the object will be rotated about the axis in the active view. For example, if the +X view is active, the object will be rotated about the +X axis.

[1] Drag the fan so that it is located on the Y-High face of the enclosure. To center the fan on the top face of the enclosure, in the Drawing Board, [2] highlight View 2. [3] Select the enclosure “Walls” in the Project Manager. To multiple select objects, you need to press the Ctrl key during selection. [4] Press the Ctrl key and [5] select the Rectangular Fan as well. [6] Select the “Align” icon in the Drawing Board, and [7] center the fan vertically and horizontally (the action will happen dynamically on the Drawing Board). [8] Dismiss the align dialog.

When aligning two objects, the first object selected remains fixed. The objects are aligned with respect to the active view in the Drawing Board.



Create a non-conducting PCB with smeared heat on the board.

In the Drawing Board, [1] Select View 1 and [2] click the PCB icon on the palette. [3] Drag and drop the cursor to create a board approximately 12 in. by 8 in. located above the vent. In View 0, [4] drag the board and locate it approximately 4 in. from the wall of the enclosure in the x direction.

Drawing Board Tips: Hold SHIFT while moving to restrict the move to a single direction. Use TAB to move between views in the Drawing Board without losing a selected object.

Using the Drawing Board alignment feature and the PCB Location dialog, [5] center the PCB in the z-direction with respect to the enclosure “Walls” and [6] locate the PCB 4 in. from the X-Low face of the “Walls” and 7 in. from the Y-Low face of the “Walls”.

The exact location of the PCB is not important at this point. When we are finished creating all of the boards, we will align the entire assembly in a later step.



[1] Select the PCB in either the Project Manager or Drawing Board, and [2] right click to bring up the PCB menu. [3] Select the construction menu to bring up the PCB dialog box. [4] Choose non-conducting for the modeling level and set the “Heat Dissipated Directly to Air” ratio to 70%.

Non-conducting boards do not need to have material properties attached to the board. All the heat dissipated by components on the board will be dissipated directly to the air, with the percentage specified indicating the split between the top and bottom surfaces of the board.

To create a conducting board, [1] choose conducting for the modeling level. [2] Set the % conductor by volume level and [3] attach the correct material properties for the dielectric and the conductor on the board. If you keep the settings for the conducting board, remember that your results will be different from the results described in the tutorial.




Create a component called “All Components”, to create an artificial component to represent all of the components on the board.

Within the PCB smart part, particular components can be constructed and located on the board. Each component is assigned its own properties.

In the PCB dialog box, in the component section, [1] click on New to open the Edit PCB Component dialog. The artificial component is located over the entire board, with a height of 0.5 chosen to represent the average height of all the components on the board. The overall power dissipation is 20 W. In the Edit PCB Component dialog, [1] Rename the component “All Components”. [2] Set the power to 20 W and [3] set the size to (8,10,0.5) inches. Leave all of the other values as defaults, and [4] select OK.

Remember to check the Drawing Board and Project Manager frequently to review your model. A visual check can reveal construction mistakes early in the modeling process. Also, remember to save often!

[5] Select OK to close the PCB construction dialog window.


Designing a Telecommunications System Using FLOTHERM: Geometry Creation (Part 2) Create a pattern of boards in the enclosure. Following the same procedure as before, create a sub-assembly named “PCB Rack” and place the PCB (PCB 1) into the sub-assembly.


In the Drawing Board, [1] Select the PCB. In the pull down menu, [2] select Edit/Pattern to open the Pattern creation dialog. [3] Set the “First Direction” to 7 in the +X direction and [4] set the “Second Direction” to 2 in the +Y direction. [5] Set the pitch dimensions to inches.

Remember to change the pitch dimensions before editing the pitch number. Always change the units first, before editing the number!

[6] Change the pitch to 3 inches in the First Direction and 14 inches in the Second Direction. [7] Press OK to create the pattern of boards.



Remember to check the Drawing Board and Project Manager frequently to review your model. If you have made an error patterning the boards, select all copies of the original board, delete them and repeat the steps to create the pattern correctly.

The PCB assembly needs to be moved so that it is centered in the Z and X directions with respect to the fan. Collapse the PCB assembly by [1] clicking on the “-” sign next to the PCB sub-assembly in the Project Manager. [2] Select View 2 in the Drawing Board. Follow the same procedure as before to align objects in the Drawing Board; remember to first select the rectangular fan (in the Project Manager) and to select the PCB Rack assembly second.

Use the undo function, under Edit/Undo to go back one step if you have made a mistake during the alignment process.

To reduce clutter in the drawing board window, remove the directional arrows on the fans and boards. [1] Select Option/Modify Picture in the Drawing Board pull-down menu. [2] Toggle off the “Flow/Source Direction” display option.


Designing a Telecommunications System Using FLOTHERM: Geometry Creation (Part 2) Inspect the geometry in the Drawing Board and ensure that all objects have been created and located correctly. Use F6 to expand the collapsed sub-assemblies. Inspect the object hierarchy in the Project Manager.

The order in which objects appear in the project manager determines the object’s level in the hierarchy. In most situations, objects lower in the hierarchy override objects that appear higher in the hierarchy.

Add a monitor point to the model. In the Project Manager, [1] select the enclosure “Walls”. [2] Select a monitor point from the palette in the project manager. This will automatically add a monitor point to the bottom of the model tree in the Project Manager. [3] Highlight monitor point in the Project Manager, [4] right click, and [5] select Location. [6] Change the location to (12,20,6) to reposition the monitor point.

This is the end of the sections on “Geometry Creation”. The next section addresses gridding.


Designing a Telecommunications System Using FLOTHERM: Add Grid

In this section we will view the default grid, add grid constraints and review the grid.

View the grid.

In the Drawing Board, [1] press ‘g’ to toggle on the grid display. In the Project Manager, [2] select “System” and [3] right click to bring up the Overall Menu. [4] Select the system grid option.

The system grid dialog sets system level grid constraints that apply to the entire solution or computational domain. The grid constraints option sets specific parameters on the maximum and minimum size of the grid.

Grid definitions specific to particular objects or assemblies can be set under the “Grid Constraints” option for the specific object or sub-assembly.


Designing a Telecommunications System Using FLOTHERM: Add Grid

In the System Grid dialog, [1] toggle on the “Dynamic Update” function. [2] Select “Fine” for grid density. [3] Select Yes to reset the manual settings.

Please note that it is possible to have numbers slightly different than those shown here, depending on the model construction.


This is the end of the sections on “Grid”. The next section deals with solving the model.


Designing a Telecommunications System Using FLOTHERM: Solve

In this section we will start the solver and solve the model.

In the Project Manager, expand the Control icon by [1] clicking on the plus sign. [2] Right click on “Overall” and [3] select input from the Overall Menu. [4] Select “Multigrid” from the solver options.

Perform a sanity check to identify possible problems with the model before the solver is activated. In the Project Manager, under the pull-down menu, [1] select Project/Sanity Check. [2] Review the message window output and [3] Click Dismiss to close the Message Window.

It is a good idea to make sure you understand all of the messages in the Message Window, whether they are Errors, Warnings or Informational messages.


Designing a Telecommunications System Using FLOTHERM: Solve

To start the solver, [1] Press the GO button in any one of the open windows.

When the solver is active, the GO button becomes a STOP sign . The solver can be interrupted at any time by pressing the STOP button.

Once the solver has been activated, the message window reappears. [2] Click Dismiss to close the Message Window.

The Profiles Window should open when the solver is activated. This window will display the monitor point data as well.

If the Profiles window does not appear when you start the solver, you can open it manually in any of the active windows by clicking on the Profiles icon in the lower left margin.

When the solver is finished, the Message Window will reappear, with a CPU time summary, and a message indicating that the model has solved successfully.

Congratulations! The project is solved and you are now ready to view the results and


Designing a Telecommunications System Using FLOTHERM: Analyze Results

In this section we will review the results using FLOMOTION.

[1] Select the FLOMOTION visualization tool from any active window.

Initially the FLOMOTION window displays the model as a solid object. [1] Use the pan/zoom/rotate function to inspect the model.

To find out more about the features and icons in

FLOMOTION, use the on-line help .

[2] Select the enclosure “Walls” in the Project Manager; it will be highlighted in red in FLOMOTION.

Activate the FLOMOTION window by [3] clicking on the top bar of the FLOMOTION window.



[1] Press F12 to hide the enclosure.

Make sure that FLOMOTION is the active window when you press F12. Otherwise, the enclosure “Walls” will be hidden in the Project Manager and the Drawing Board, but not in FLOMOTION.

Activate the snap target using the pull down menu.

[1] Use the pull down menu to choose Selection/Activate Snap Target.



Locate the snap target in the FLOMOTION window. [1] Move the snap target arrow to one of the bottom vents.

Remember that when the cursor is in “Manipulator” mode

it looks like a hand . When the cursor is in “Selection”

mode, it looks like an arrow . Use F9 to toggle between the two modes.

Create a particle animation to visualize the flow through the bottom vent.

[1] Select the Particle Property Editor under Editors/Particle Property Editor…

In the Particles Editor, [2] select Create to create a source and [3] Turn the source on.

[4] Select translate for the Manipulator type and [5] select Area source.

[6] Change the number of particles to 70 and [7] select Snap to snap the source to the snap target.

[8] Select Reset to adjust the particle properties.



[1] Under Selection/Activate Snap Target, toggle off the snap target.

Minimize or move the Particle Editor window to see the images in FLOMOTION clearly.

[2] Select the translation handles to drag the source through the solution domain.

You can adjust the settings for each of the “Global Particle Properties” and observe the effects. For example, setting the “Pulse Rate” to “1” gives streamlines instead of individual particles.

animation of the particles. [2] Press Stop to stop the particle animation.

source and [4] close the particles editor dialog.

.

[2] Select the Visualization Editor under Editors.

In the top level menu of FLOMOTION, [1] press Play to activate the

In the Particle Property editor dialog window, [3] delete the particle

Create a temperature profiles plot in FLOMOTION.

[1] Select the create visualization plane icon



[1] HIghlight the newly created plane “Plane 1” and [2] use the slider bar to move the visualization plane through the solution domain. [3] Under “Clip/Wireframe Geometry” set “Above” to “Wireframe”.

Change the orientation of the visualization plane, the variable displayed and the plot type in the visualization editor.

Exit from FLOMOTION by [1] selecting File/Exit from the top-level pull-down menu.

When prompted, [2] choose yes to save the view and the properties of the FLOMOTION window.



Use the Tables Window to analyze the results.

From any active window, [1] select the Tables Window icon .

[2] Select the Tables Display Mode Menu and [3] choose Select.



[1] Select Fans from the Table Selections chart.

Select particular tables, to organize and view specific information in a table format.

[2] Click OK to close the selection dialog.

[3] Click OK to close the Display Mode dialog.

[1] Click the Next icon in the Tables Window to inspect the working conditions for the fans.

[2] Close or minimize the Tables Window before continuing.

This is the end of the section on “Analyzing Results””. The next section deals with “Parametric Design Analysis”.


Designing a Telecommunications System Using FLOTHERM: Parametric Design Analysis

In this section we create a series of parametric changes for the design. In this set of parametric changes, we will decrease the open area for Vent 1.

Launch the Command Center by [1] selecting the Command Center icon from any active window.

[1] Expand the Root Assembly, the Vents sub-assembly and Vent 1:0.

[2] Double left click the Resistance item under Vent 1.

[3] Expand the Flomerics Resistance Library and double left click the 30% resistance.



[1] Select the “Output Variables” tab and [2] expand the Field Summary and Temperature items.

[3] Double left click the Maximum Temperature, to select this as an output variable.

Select the “Scenario Table” tab to view the scenario table.



Check the solver configuration under Edit/Solver Configuration.

[1] Highlight the “Store Results?” row, [2] right click and select “History Only”

Select GO to solve the project scenario, Scenario 1.

Select the Solution Monitoring tab and highlight a scenario to view the profiles window residual plot while the project is solving.



Once the project has finished solving, review the scenario table and note the effect on the “Maximum Temperature”.

To see the effect of the parametric change on the airflow paths, save Scenario 1 as a separate project and use FLOMOTION to observe the change resulting from the obstruction of the vent.

When you are finished, close all of the FLOTHERM windows, and save the information when prompted. If you close the Project Manager first, all of the related FLOTHERM windows will close as well.

Congratulations! You have now successfully completed the tutorial exercise.

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