Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version 5.1

Transcription

1 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version 5.1 Flomerics, Inc. May 2005 Flomerics Inc. 4 Mount Royal Ave., Suite 450 Marlborough, MA USA Tel: (508) Fax: (508) Flomerics Limited 81 Bridge Road Hampton Court, Surrey, KT8 9HH United Kingdom Tel: +44 (0) Fax: +44 (0) 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.

2 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version 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: Software Version: FLOTHERM Version 5.1 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.

3 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Introduction Welcome to the FLOTHERM V5.1 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 V5.1. 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. In this tutorial you will use FLOTHERM V5.1 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.

4 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version 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 Pro/E, SolidWorks, IGES, SAT, STEP, STL and IDF files. You could use FLO/MCAD and ECAD import to enter the information directly into FLOTHERM. Modeling Steps & FLOTHERM V5.1 Application Window A. Project and File Management Project Manager B. 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

5 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Start Flotherm Designing a Telecommunications System Using FLOTHERM: Project and File Management [1] Select FLOTHERM 5.1 in the Start menu under Programs\Flomerics, or [2] Use the Desktop Icon: The Project Manager (PM) is now open. Load the template file DefaultSI [1] Select [Project/New] in the PM and [2] select the Templates 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.

6 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version 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 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 Simple telecom system. [4] Click on [Notes] and [5] click on [Date] and [Time] to add the date and the time at which you started the project. [6] 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 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 (PM) and Drawing Board (DB) windows to see them both displayed side by side.

7 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version 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. 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. [1] In the Project Manager (PM) node tree, [2] right mouse click on the System icon. [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].

8 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Definition of Overall Domain 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. [1] Type r on your keyboard to refit the overall solution domain in the Drawing Board. Define the default units and Drawing Board parameters In the Project Manager (PM), check that the length unit is set to inches. [1] Select Edit/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.

9 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Definition of Overall Domain In the Drawing Board, set the Snap Grid to 1 inch. [1] Select Edit/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] Right mouse click on the System icon in the Project Manager model tree and [2] select [Ambients]. [3] Click on the [New] button to bring up the Ambient Attribute box.

10 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Definition of Overall Domain [4] Enter the following information: Name System Ambient Gauge Pressure 0 Atm Temperature 35 C Radiant Temperature 35 C Heat Transfer Coefficient 6 W/(m 2 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 6 W/(m 2 K), we are ensuring that any solid surfaces that are in contact with the Overall Domain will have 6 W/(m 2 K) 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.

11 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Definition of Overall Domain In the Ambient dialog box, [1] select Default All in Attachment/Applied To. [2] Highlight System Ambient in the selection list. [3] Click the [Attach] button. This will attach the new ambient condition to all surfaces 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. [4] Press the save icon in either the Drawing Board (DB) or the Project Manager (PM), or Choose [Project/Save], to save the changes you ve made to the 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.

12 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Geometry Creation (Part 1) In this section (consisting of two parts) we will create combinations of FLOTHERM objects such as SmartParts to represent the physical geometry in our model. We will include the chassis (enclosure Smart part), the vents (perforated plate Smart Part), a rectangular fan (fan Smart Part) and boards (PCB Smart Part). 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 on the Overall Domain. [4] Highlight the Enclosure name (named Enclosure 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. [8] left click on the + sign to the left of Walls to expand the branch. 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.

13 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Geometry Creation (Part 1) [1] Highlight the Walls 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. [Apply] is useful when you will want to inspect changes before closing the dialog [7] Double check the entries before pressing [OK] to close the enclosure dialog window. To attach the material Mild Steel to the Walls, [1] Click on to open the Library Manager. [2] Expand the Libraries folder by clicking on the + sign. [3] Expand the Materials folder. [4] Expand the Alloys folder and left click to select Steel (Mild). To attach the material to the enclosure, [5] Drag and drop it on the Walls. [6] Save the project. To review the material properties of mild steel, [1] right click on the Walls and [2] select [Material]. [3] Click [Edit] to see the Material Property dialog. Once you have reviewed the properties, or made any necessary changes, [4] click [OK], then [dismiss].

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

15 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Geometry Creation (Part 1) Use the Perforated Plate object to create a vent in the Drawing Board. The Drawing Board is divided into 4 views: 3 planar views along each axis and an isometric 3-D view. Each planar view is labeled according the axis normal to the view. + indicates that the positive axis direction is toward the user. Make sure you are in the DB, and [1] click on the Perforated Plate icon from the DB palette. [2] In View 3 (+X), which is outlined in red, start from the lower right corner (corner closest to the origin) and drag the mouse to create a perforated plate that is the full width in the Z-direction and approximately 6 in. in the Y-direction. [3] Rename the Perforated Plate to Vent 1. The size and location of selected objects is shown in the lower left corner of the Drawing Board window. Check the size of the Perforated Plate by [1] highlighting Vent 1 in the Project Manager and [2] right clicking on the name. [3] Select Construction from the pull-down menu. [4] Change the size values if necessary (Yo should be 6 in). Note that the plate thickness does not need to be modified since the plate is a 2 D object. This option is available in case the model is read into Flo/EMC in order to make an electro-magnetic compliance analysis (FLOTHERM and Flo/EMC share the same Graphical User Interface).

16 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Geometry Creation (Part 1) Change the units for Perforated Plate from in to mm. Define the perforated plate free area ratio by [1] selecting the Hole type to be Round, [2] entering the hole diameter to be 2 mm and [3] specifying the hole pitch in the X and Y direction to be 2.5 mm. Based on this information, FLOTHERM computes the free area ratio to be about 50%. The free area ratio helps set the loss coefficient for the vent so that the right pressure drop is being computed. Click [OK] to save the changes and exit the dialog window. To create a second vent, we can copy Vent 1 and relocate it. 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 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 (face farthest from the local coordinate origin and in the Y-Z plane). When dragging the vent to a new location, use the middle mouse button. Using the left mouse button may resize the vent if you select the resizing handles.

17 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Geometry Creation (Part 1) Define sub-assemblies and arrange the object hierarchy. In the Project Manager [1] select the Root Assembly and then select the sub-assembly icon from the palette (click on if the palette is not open). [2] Locate the new sub-assembly (at the bottom of the tree in the Project Manager) and [3] rename it Vents. [4] Select Vent 1:0 and [5] use the Ctrl key while selecting Vent1:1 to select the second vent as well. [6] 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. Remember to Save often while you are working on a model. 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.

18 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Geometry Creation (Part 2) 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 (remember to highlight the Root Assembly first) and [2] rename it Fan Tray. [3] Highlight the Fan Tray sub-assembly. In the Project Manager, [4] click on the Fan icon from the object palette. Edit the properties of the Fan In the Project Manager [1] click on Fan to select it. [2] Right click to access the Fan menu and [3] select Construction to bring up the fan construction dialog.

19 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Geometry Creation (Part 2) 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 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: X 0 =20 in and Y 0 =10 in. [4] Under Flow Specification, toggle Non-Linear Fan. [5] Set the Open Volume Flow-Rate to 1060 cfm and the Pressure at Stagnation to in H 2 O (Remember to change the units first and enter the values next). [6] [Apply] the changes. [1] Click on [Fan Curve]. In the Fan Curve dialog box, [2] toggle on Edit Mode. [3] Enter the following data points for the fan curve: Volumetric Flow rate (cfm) Pressure (in H 2 O) [4] Click [Dismiss] when all of the data points have been added. [5] Click [OK] to close the Fan curve edit dialog. [6] Click on [Fan Curve] again to check the curve. Note that Flotherm interpolated the fan curve so that for each pressure point corresponds a single volume flow point. [7] Click [OK] twice to close the fan curve and the fan windows.

20 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Geometry Creation (Part 2) There are several axial fans available through the Flomerics Fan Library, including: Comair Rotron, Delta, ETRI, Micronel, NMB, Papst and Sanyo Denki. All the fan libraries as well as any other vendor library are located in the Library Manager. To review the fans in the fan library, [1] click on the Library Manager icon. [2] Expand the Libraries folder and browse to the Fans folder. [3] Expand the Papst folder (located under the Axial folder) and click on the Papst 3412N fan to select it. To load this fan into your project, [4] drag it and drop it in the Fan Tray sub-assembly. To view the Fan properties, [5] Select the newly loaded fan in the Project Manager and [6] right click to bring up the Fan Menu, then [7] select Construction. Review the entries, including the fan curve data. When you are finished, you can delete the newly loaded fan by hitting the Delete key and continue with the tutorial. Creating your own library works in the same way. In the Library Manager, [1] left click on the Libraries folder and [2] right click to access the Library Popup. [3] Select New Library and [4] name it Fan Tray. A new folder called Fan Tray should appear below the ATX Library. [5] Select the Rectangular Fan from the Project Manager and [6] drag it and drop it in the Fan Tray folder in the Library Manager. The Fan Tray library could then be used for any future FLOTHERM project. To close the Library Manager, click on.

21 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Geometry Creation (Part 2) The Rectangular Fan needs to be located correctly. The fan must be rotated and centered on the top (Y High) face of the enclosure. In the Drawing Board, [1] click on View 3. 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 0. [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.

22 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Geometry Creation (Part 2) At this point, we need to make sure that the fan is extracting air from the box and not blowing air inside. In the Drawing Board, [1] go to [Edit/Modify Picture] or click on to open the Drawing Board Picture window. [2] Toggle on the Flow/Source Direction and [3] click on [Apply]. [4] Go to [View/Refit] to refit the Drawing Board window (or use the Hot Key r ). You should see the flow direction of the fan pointing up, meaning that flow will exit through the top of the chassis. [5] Untoggle the Flow/Source Direction and [6] click on [OK] to close the Drawing Board Picture Window.

23 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Geometry Creation (Part 2) Create a conducting PCB with smeared heat on the board. In the Drawing Board, [1] Select View 3 and [2] click the PCB icon on the palette. [3] Drag the cursor from the bottom right corner to the top left corner to create a board approximately 12 in. by 8 in. located above the vent. In View 2, [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. [5] Right click on the PCB in the Drawing Board to access the PCB menu and [6] click on Location. [7] Set the position of the PCB to be 7 in. in the Y direction (7 in. from the Y-Low face of the Walls ). The exact location of the PCB in the X and Z direction is not too important at this point. When we are finished creating all of the boards, we will align the entire assembly in a later step.

24 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Geometry Creation (Part 2) [1] Select the PCB in either the Project Manager or Drawing Board, and [2] right click to bring up the PCB menu. [3] In Construction, Check that the PCB size is 8 in. in Length and 12 in. in Width. [4] Choose Conducting for the modeling level and set the % Conductor by volume to 10. [5] Click on [Material] under Dielectric. This brings the Material window up. [6] Click on [Library] and browse the Library Manager down to FR4 (located in Laminates). [7] Select FR4 and [8] click on [Load]. Since we will also need Copper, [9] browse to Copper (Pure) (located under Metals ) and load it. [10] [Dismiss] the Material Libraries window. In the Material window, [11] select FR4 and [12] click on [Attach]. You should see that FR4 has become Currently Attached. [13] [Dismiss] the Material window. To make Copper the Conductor Material, [14] click on [Material] in the PCB menu and repeat steps [11] to [13].

25 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Geometry Creation (Part 2) In the PCB menu, [15] click on [Apply] then [16] click on Summary to see the board summary. At the bottom of the summary, the equivalent thermal conductivity of the board is computed in plane and through plane. The rest of the settings are zero since no component has been defined yet on the board. Close the PCB menu by [15] clicking on [OK]. Remember to Save often while you are working on a model.

26 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Geometry Creation (Part 2) Add components to the board. From the Project Manager, [1] highlight the PCB and [2] create a component by clicking on the icon in the palette. [3] Select the component and [4] right click to access the component menu. [5] Click on Construction and [6] rename the component All Components, to create an artificial component to represent all the components located 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. Components can also be built, modified and moved from the Drawing Board. The artificial component is located over the entire board, with a height of 0.5 in. chosen to represent the average height of all the components on the board. The overall power dissipation is 20 W. In the PCB Component dialog, [1] set the power to 20 W and [2] set the size to (8, 12, 0.5) inches (Note that the default size of the component is 1/10 th of the overall board size). [3] Toggle on Solid Component so that the component is made a full 3 dimensional geometry (the Discrete modeling option represents the 2-D footprint of the component only). Since the component is a solid dissipating 20 W of heat, a material needs to be defined and attached to the component so that the heat can be dissipated correctly. In the PCB Component window, [4] click on [Material]. This action brings up the Material window. [5] Click on [New] to create a new Material.

27 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Geometry Creation (Part 2) In the Material Property window, [6] type Lump component for the material name and [7] set the thermal conductivity to 10 W/m.K. [8] Click [OK] to close the Material Property window. In the Material Window, [9] click on [Attach] to attach the Lump component material to All Components. Make sure that the Material is attached by checking the Currently Attached status. [10] Click on [Dismiss] to close the Material window. A lump thermal conductivity of 10 W/m.K for components is a good representation to get accurate air temperature around the components. To get accurate component temperatures (junction or case), a detailed or a compact model of the component should be used. This could be done later once problem areas are identified. In the PCB Component window, leave all of the other values as defaults, and [11] select [OK]. [12] Select [OK] to close the PCB component construction window. 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!

28 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version 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 drag and drop the PCB into the subassembly. Remember to Save often while you are working on a model. In the Project Manager, [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.

29 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Geometry Creation (Part 2) 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 chassis. Collapse the PCB assembly by [1] clicking on the - sign next to the PCB Racks subassembly in the Project Manager. [2] Select View 0 in the Drawing Board. Follow the same procedure as before to align objects in the Drawing Board; remember to first select the chassis (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.

30 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version 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 (virtual probe) to the components. In the Project Manager, [1] multiple-select PCB 3, 7, 10 and 13 (hold down the Ctrl key while selecting each PCB). In the Palette, [2] select a monitor point. This will automatically add 4 monitor points to the bottom of the PCB Rack sub-assembly in the Project Manager. Each Monitor point is by default located at the center of each PCB 3, 7, 10 and 13 and is named accordingly. [3] Highlight the monitor points in the Project Manager and [4] check their location in the Drawing Board. This is the end of the sections on Geometry Creation. The next section addresses gridding.

31 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version 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, press g to toggle on the grid display. The grid that appears in the Drawing Board comes from the objects that we built (fan, vents and boards) and can be considered as a base grid. Additional grid cells need to be added in order to capture accurate flow and heat transfer in the chassis.

32 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Add Grid Add grid around the boards and localize it. In the Project Manager, [1] select the PCB Rack sub-assembly and [2] right click to access the Grid Constraints menu. [3] Click on [New] to create a new grid constraint. [4] Name it Grid_Rack x. [5] Toggle on Maximum size and set 0.8 in. to be the maximum grid cell size. [6] Click on [OK] to close the Grid Constraint Modeling window. In the Grid Constraint window, [7] select Grid_Rack x and [8] [Attach] it to the Xo-direction. [9] Click on [Copy] to create a copy of the Grid_boardx constraint. [10] [Edit] the copied constraint and [11] rename it Grid_Rack yz. [12] Set a Maximum size of 2 in and [13] click on [OK]. [14] [Attach] Grid_Rack yz to the Yo and Zo-direction. [15] [Dismiss] the Grid Constraint window. In the Project Manager, [16] type the hot key L to localize the grid around the board and [17] click on the Inflate icon to inflate the grid around the board. In the Drawing Board, [18] check the grid and see how the grid is refined around the boards.

33 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Add grid at the System level. Designing a Telecommunications System Using FLOTHERM: Add Grid In the Project Manager or in the Drawing Board, [1] click on the System grid icon. 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. [2] Toggle on the Dynamic Update and [3] click on [Medium] to define a Medium System grid. [4] Select [Yes] to reset the manual settings. [5] [Dismiss] the System Grid window. Please note that it is possible to have numbers slightly different than those shown here, depending on the model construction. Check the grid in the Drawing Board. This is the end of the sections on Grid. The next section deals with solving the model.

34 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Solve In this section we will start the solver and solve the model. Perform a Sanity Check to identify possible problems with the model before the solver is activated. In the Project Manager, under the pulldown menu, [1] select Solve/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. For the model, the 2 messages that appear in the Message Window are of informational nature and therefore are not a concern. 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.

35 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Solve 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.

36 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version 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 with the Z-High face in view. FLOMOTION can be used in Selection mode to select specific items in the window, or in Manipulation mode to pan, zoom, and rotate the entire system assembly. Pan by holding down the middle mouse button and dragging the mouse. Zoom by holding down the left and middle mouse buttons and dragging. Rotate by holding down the left mouse button and dragging the mouse. [1] Use the pan, zoom, and rotate functions to inspect the model. Note the different colors used for the Rectangular Fan on the Y-high face and the Vents on the X-high and X-low faces. [2] In Selection mode, click on the High-Z enclosure wall; it is then highlighted in red in FLOMOTION. Note that it is also highlighted in the Project Manager node tree. Use F9 or Esc to toggle between Selection and Manipulation modes.

37 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Analyze Results Press F12 to hide the high-lighted Z-high wall. Press Z to automatically rotate the assembly back to the +Z view. Click on the Home icon to return the assembly to its original position in the window. To find out more about the features and icons in FLOMOTION, use the on-line help.

38 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Analyze Results Create a particle animation to visualize flow through the bottom vent. [1] Select Vent1:0 (left side of enclosure). The particle source will automatically snap to this vent. [2] Edit the Source Editor by clicking on. In the Source Editor, [3] select [Create] to create Source1, [4] change the number of Streamlines to 65 and [5] select Area for the Source Type. [6] Under Fields/Scalar Fields, select Speed instead of Pressure. [7] Click on the On box to turn on the particle generator. Note: the particle generator will not work unless it is inside the solution domain. [1] In the top tool bar, press to activate the animation of the particles. [2] Press to stop the particle animation. In the Source editor dialog window, [3] click on the On box again to turn off the particle generator. [4] Delete Source1 to remove the source frame from Vent1:0. [4] Close the Source editor dialog.

39 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Analyze Results Create a temperature profiles plot. [1] Click on the Create Show Plane icon. This action creates a Temperature visualization plane located in the Y direction and at the center of the chassis. In Manipulation mode, [2] rotate the geometry. [3] Type w to turn the geometry from Solid to Wireframe. [4] Switch from a Y plane to a Z plane by clicking on. Notice that the boards located close to the sides of the chassis are the hottest. As the source of particules showed, most of the air flow is towards the center of the chassis and not to the sides. [5] In the Viewing pull-down menu, select Show All Objects. This will unhide the Walls. Exit from FLOMOTION by [6] selecting File/Exit from the top-level pull-down menu. When prompted, [7] choose [Yes] to save the view and the properties of the FLOMOTION window.

40 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Analyze Results Use the Tables Window to analyze the results. From the Project Manager or from the Drawing Board, [1] select the Tables Window icon (located on the left hand side, below the FLOMOTION icon). [2] Click on the Select Table icon. [3] Select Fans from the Table Selections chart. Select particular tables, to organize and view specific information in a table format. [4] Click [OK] to close the selection dialog.

41 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Analyze Results [1] Click the Next icon in the Tables Window twice to see the working conditions for the fans. [2] Go to Edit/Units and browse to VOLRATE. [3] Select VOLRATE and [4] change the unit from m 3 /s to cfm. [5] [Dismiss] the Global Units window. [6] Write down the volume flow rate shown in the Fans table. cfm [6] Close or minimize the Tables Window. This is the end of the section on Analyzing Results. The next section deals with Parametric Design Analysis.

42 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Parametric Design Analysis In this section we will learn how to implement design optimization using Command Center. Analyzing the results showed that the boards that are the closest to the chassis walls do not receive enough air to get cooled as much as the boards located towards the center. A change in the design is therefore necessary. One thing that could help get lower temperature would be to set a baffle at the inlet so that air is directed to the hotter boards. Questions about the baffle design, such as at what angle should the baffle be and/or at what location, may then rise. This section will guide you through creating the baffles using the sloping block SmartPart and re-running the base case to see the impact of these baffles on the temperature distribution. Finally, it will show you how to do a parametric study on the baffle angle and location in order to find the optimum baffle design. Add the baffles to the model In the Drawing Board, [1] highlight View 2 (+Z) and [2] change to a single view mode by clicking on. In the Project Manager, [3] select the Vents sub-assembly. [4] Go back to the Drawing Board, [5] check that the Snap to Object option is on ( ). [6] Open the Palette ( ) and [7] select the Sloping Block SmartPart. You will draw a Sloping Block starting approximately at the center of the left vent and angled towards the top of the chassis so that more air is redirected towards the external boards. [1] Left click at the center of the left vent and [2] drag and drop the mouse towards the bottom of the boards. A window referring to the fact that the Grid has changed will pop up. [3] Click on [Yes] and [4] Save the project as Short Tutorial Baffle. 1 2

43 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Parametric Design Analysis From the Drawing Board or the Project Manager, [1] select the baffle and [2] right click to open the Construction menu. [3] Set the width to 12 in., the Length to 3 in. and the Angle to 45 degrees. There is no need to specify a thickness for the Sloping Block since it is used to direct the flow and not to conduct heat. [4] Click [OK] to apply the settings and close the Sloping Block Construction menu. [5] Right click on the baffle to access the Location menu. [6] Change the Y Position to 3 inches so that the baffle is located exactly at the center of the Vent. [7] Set X and Z position to be 0 if it is not the case.

44 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Parametric Design Analysis The next step is to attach grid constraints to the baffle. From the Project Manager or the Drawing Board, [1] right click on the copied baffle and [2] click on the Grid Constraints. [3] Click on [New] to create a new grid constraint called Plate with a Maximum Grid Cell size of 10 mm. [4] Click on [OK] to close the Plate grid constraint, [5] select the Yo direction and [6] [Attach] the grid constraint. [7] [Attach] the Plate grid constraint to the Zo direction as well. [8] [Dismiss In the Project Manager, [9] highlight the first baffle and [2] hit the L key to localize the grid.] the Grid Constraint menu. Create a mirror copy of the baffle [1] Hit Ctrl C to copy the baffle. [2] In the Project Manager, highlight the Vents sub-assembly and [3] hit Ctrl V to paste the copied baffle. In the Drawing Board, [4] rotate the baffle by clicking on and [5] translate the rotated baffle to the middle of the right vent. Make sure that you hold down the Shift key while dragging the baffle so that it is moved in the X direction only.

45 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Parametric Design Analysis Check the grid In the Drawing Board, check the grid by [4] hitting g on the keyboard. Solve the case [1] Save the case and [2] hit the Go icon to solve it. Results are interpolated on the new grid and the solver starts from the previous results. Note that adding the baffles increased the board temperature slightly, which tells us that the baffle angle as well as the baffle location needs to be investigated.

46 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Parametric Design Analysis Implement automated design changes on the baffles The two parameters we will change on the plates are the Y location of the plate along the vent and the plate angle. We will define design constraints for each parameter and set the highest board temperature to be the variable that needs to be minimized. Based on these settings, Command Center will try to find the optimum plate design. From the Project Manager or the Drawing Board, [1] click on the Command Center icon. In the Input Variables window, [2] Expand the Root Assembly tree and [2] browse down to Sloping Block:0. [3] Expand the Sloping Block:0 sub-assembly to access the Absolute Location subassembly. [4] Expand the Absolute Location sub-assembly and [5] double click to select the Y location of the Sloping Block. [6] Check that the actual Y position of the plate is 3 in. [7] Toggle on Design Parameter and [8] enter a Minimum Value of 1 in and a Maximum Value of 5 in. [9] Click on [Apply Variation] to save the settings. In the Sloping Block:0 sub-assembly, [1] Expand the Parametric Data sub-assembly and [2] double click to select the Block Angle of the Sloping Block. [3] Check that the actual angle is 45 degrees. [7] Toggle on Design Parameter and [8] enter a Minimum Value of 45 and a Maximum Value of 70. [9] Click on [Apply Variation] to save the settings.

47 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Parametric Design Analysis The second plate design needs to vary in the same way as the first plate. To do so, we will make the second plate Y location and angle a linear function of the first plate Y location and angle. [1] Expand the Sloping Block:1 sub-assembly and [2] expand the Absolute Location sub-assembly. [3] Double click on the Y Location to select it. [4] Toggle on Linear Function and [5] click on [Add Term]. [6] Select Sloping Block:0 Y location as the added variable. [7] Click on [Apply Variation]. Both plate Y locations are now linked accordingly. Under the Sloping Block:1 sub-assembly, [1] expand the Parametric Data sub-assembly. [2] Double click on the Block Angle to select it. [4] Toggle on Linear Function and [5] click on [Add Term]. [6] Select Sloping Block:0 Block Angle as the added variable. [7] Enter -1 as the coefficient in front of the Sloping Block:0 Block Angle and [8] enter 90 as the added value. [9] Click on [Apply Variation]. Both plate angles are now linked accordingly.

48 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Parametric Design Analysis Select the board temperature as the variable to minimize At the bottom of the Command Center window, [1] click on the Output Variable Tab. [2] Expand the Root Assembly and [3] Expand the PCB Rack subassembly. [4] Double click on the Monitor Point ( ) PCB 7 to expand it. [5] Double click on Temperature. On the right hand side of the window, [6] toggle on Include in Cost Function. Run the design optimization At the bottom of the Command Center window, [1] click on the Scenario Table Tab. [2] Check the Input Variables and the Output Variables. Results displayed are the results from the base project with the baffles. Command Center can be used to easily extract results from your analysis.

49 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Parametric Design Analysis [1] Click on the Optimization icon. [2] Check that the 2 variables selected (Y location and Block Angle) vary in the correct Design Limits. [3] Toggle on Design Experiments Before Optimization. Running a Design of Experiments upfront can help the optimizer find the lowest cost function (and therefore the optimum design) faster. [4] Click on [Optimize]. 10 Design of Experiments (DOEs) are created in the design limits specified and run one after the other on a local computer. Note that jobs could be farmed out to other computers if available. Once the 10 Design of Experiments are run, the optimizer kicks in and starts from the best of the 10 DOEs (the one with the lowest cost function, in this case the lowest board temperature). The optimizer runs until it finds the lowest cost function and then stops, assuming that it found the optimum.

50 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Parametric Design Analysis Once the optimizer stops, [1] browse the Scenario Table to the Optimum design. [2] Check the PCB temperature as well as how the Y location and the plate angle changes. [3] Note that the results can also be checked from the 2 graphs that are automatically created by Command Center.

51 Designing a Telecommunications System Using FLOTHERM: A Short Introduction to Version Designing a Telecommunications System Using FLOTHERM: Parametric Design Analysis In order to check graphically the optimum design, [1] click on the Graphical Input Tab and [2] highlight the Optimum design. Note that if the geometry is collapsed, you can hit F6 to expand it. Congratulations! You have now successfully completed the tutorial.