cfx intro 14.5 ws13 turbo pre post

8/13/2019 CFX Intro 14.5 WS13 Turbo Pre Post

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2012 ANSYS, Inc. December 17, 2012 1 Release 14.5

14. 5 Release

Introduction to ANSYS CFX

Workshop 13Axial Fan simulation usingTurbo Pre and Post


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Introduction

A simple workshop follows todemonstrate how to use theTurbomachinery mode in CFX-Pre andCFD-Post.

This workshop models an Axial fan. Themodel consists of a single rotatingdomain for the fan blade with stationarydomains upstream and downstream ofthe blade.

The full axial fan contains ten blades.Due to rotational periodicity a singleblade passage will be modeled. FrozenRotor interfaces are used to connect therotating and stationary domains.


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Turbo-Pre

1. Open Workbench (Start > Programs > ANSYS 14.5 > ANSYSWorkbench)

2. Drag CFX into the project schematic

3. Start CFX-Pre by double clicking Setup

4. Select Tools > Turbo Mode


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Basic Settings

The Turbo mode uses a setup wizard to walk you throughCFX-Pre. The first step is the Basic Settings panel:

1. Set the Machine Type to Fan

2. Select Z as the Rotation Axis Notice that the rotational axis is displayed in the Viewer

3. Select Analysis Type as Steady State

4. Click Next >


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Component DefinitionThe Component Definition panel is used to import meshes, select the rotationspeed for each component and set the tip clearance (if any).

For this Axial Fan Tutorial there are 3 components to be defined

Start by defining the 1 st stationary component:

1. Right-click in the Component Definition white space, and select AddComponent

2. Select the Type as Stationary and set the Name to S1

3. Select the Mesh File as fan.gtm(workshop_input_files\WS_13_TurboPrePost)

4. Expand the Available Volumes frame and select the Volumes as INBlockMain

5. Expand the Region Information frame and compare with the picture onthe next page and make the necessary changes


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Component Definition

The mesh file contains all three components, but only one of thosecomponents is to be included in S1

Default values can be used for all other options Do Not click the Next Button

The Region Information is used by CFX-Pre to identify mesh regions of interest.CFX-Pre will try to automatically identifythese regions, but manual input may berequired depending on how the regionsare named in the mesh file.

CFX-Pre will automatically createboundary conditions and domaininterfaces using these regions, sochecking the Region Information at this

stage will save time later.


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Now define the 2 nd component which is rotating:

1. Right-click in the Component Definition white space, and selectNew Component

2. Select Rotating and set the Name as R1

3. Set the Rotating Value to 3000 [rev min^-1] The rotation direction is shown in the Viewer

4. Do not select a mesh file. The mesh has already been importedin the previous step.

Under Available Volumes select Passage 5. Expand the Wall Configuration frame. Set Tip Clearance at

Shroud to YES and Tip Clearance at Hub to NO This sets boundary conditions for a fan with a rotating hub and a counter-

rotating shroud surface


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Now define the 3 rd component which is stationary:

1. Create a new stationary component named S2

2. Under Available Volumes select OUTBlock Main

3. Expand the Passages and Alignment frame The number of Passages in 360 and the number of

Passages To Model is determined automatically You can change the automatic values or apply a Theta

Offset by clicking the Edit button, but this is notnecessary for this case, so click cancel

4. Expand the Region Information frame and compare withthe picture next page and make the necessary changes




5. Click Next > to proceed


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Physics Definition

All Physics settings, including Fluid Type, Inlet & Outletboundary conditions, Interface types, and Solver Parameters areset in one panel.

1. The default Fluid and Model Data are appropriate for thissimulation

2. Select Boundary Template as P-Total Inlet Mass Flow Outlet The Boundary Template provides quick setup of the most common turbomachinery

boundary combinations

3. Set P-Total to 0 [atm]

4. Set Flow Direction to Cylindrical Components with direction setto 1,0,0

5. Set Mass Flow to Per Component and then enter a Mass FlowRate of 0.04 [kg s^-1]


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Physics Definition Contd

6. Change the Interface Default Type to Frozen Rotor

7. Expand the Solver Parameters frame

8. Set the Convergence Control to Physical Timescale with avalue of 0.02 [s] (select the expression icon to allow this tobe entered)

This sets the timescale to roughly 6/ , where is themachine rotational speed in [rad/s]. Typically, thetimescale for rotating machinery is specified somewherebetween 0.1/ and 10/ .

9. Click Next > to proceed


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Boundary Definition

Boundary conditions are also automatically created using theRegion Information from the Component Definition panel andinformation from the Physics Definition panel.

1. Select each boundarycondition to verifythe settings areappropriate

2. Select Next > tocontinue


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Solver and CFD-Post

1. Switch to the Projects window

2. Select File > Save

3. Enter the File name asturbo_demo.wbpj and clickSave

4. Now double-click on Solution in the Project Schematic tostart the Solver Manager

5. When the Solver Manageropens, click Start Run


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Turbo-Post

In CFD-Post the following features will be demonstrated: Auto Initialize of Turbo Components Modifying Turbo regions

Displaying Hubs and Blades using the 3D view Create vector and contour plots using the Blade to Blade

View Create vector and contour plots using the Meridional View Use of Turbo Charts and Macros Table creation and viewing using the Table Viewer


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Turbo-Post GUI

1. Switch to the Projects window2. View the results in CFD-Post by double clicking Results in the

Project Schematic

3. In CFD-Post, click on the Turbo tab

4. Click Initialise All Components For each component CFD-Post detects which regions correspond to the

Hub, Shroud, Blade, Inlet, Outlet and Periodic regions. CFD-Post usesthis information to make turbo plots and charts. You can manuallyassign these regions, or check the auto-assigned regions by editing eachof the component object from the Turbo tree ( Component 1 (S1) ,Component 2 (R1) and Component 3 (S2) )

5. Select the Three Views toggle You can toggle between a Single View and Three Views . The three views

shown are a 3D view, a Blade to Blade View and a Meridional View


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3D View

6. Edit the 3D View object from the Turbo tree The Details of 3D View are shown

7. Select All Domains

8. Under Parts to Draw , select Hub and Blade

9. Toggle Show Faces on

10. Under Instancing , set Domain to R1, set # of Copies to 3 and then click Apply Now set Domain to S1, set # of Copies to 3 and click Apply Finally set Domain to S2, set # of Copies to 3 and click Apply

The 3D View now shows 3 copies of the Hub and Blade in each of the 3components


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Blade-to-Blade View

Now create a Blade to Blade Vector Plot:

1. Edit the Blade-to-Blade object from the Turbo tree

2. Change Plot Type to Vector3. Set Sampling to Equally Spaced and # of Points to 400

4. Click Apply A Vector Plot is shown in the Blade-to-Blade View

5. Change Sampling from Equally Spaced to Vertex and click Apply

The Vector Plot now shows vectors starting from eachmesh node


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Meridional View

1. Edit the Meridional object from the Turbo tree2. Generate a Contour plot of Pressure using a Local Range

A Contour plot is shown in the Meridional View

3. Now enable the Show Sample Mesh toggle (near thebottom of Details of Meridional Plot ) A mesh is now shown on the Contour plot This illustrates the resolution used in creating the

meridional data


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Turbo Charts & Macros

1. Double-click on the Inlet toOutlet object under Turbo

Charts in the Turbo tree2. Increase the number of

Samples/Comp. to 20

3. Examine some of the other

Turbo Charts

Turbo Charts and Macros are also available:


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TablesThe Table Viewer allows you to create a table that can be

exported in .html, .csv, or .txt formats. You can also save a statefile for a table for later use. Next you will create a table andexport it to an html file

1. Select the Table Viewer tab from the bottom of the Viewer

window2. Select the New Table icon from the Table Viewer toolbar

and accept the default name

3. In cell A1 type: Mass Averaged Inlet Total Pressure

4. In cell B1, type: =massFlowAve(Total Pressure)@S1 Inlet Alternatively you can use the Table Viewer toolbar to select Insert:

Function > CFD-Post > massFlowAve , then Insert: Variable > Total Pressure ,etc to build the expression


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Tables

5. In cell A2 type: Mass Averaged Outlet Total Pressure6. In cell B2, enter the equation:

=massFlowAve(Total Pressure )@S2 Outlet

7. In cell A3 type: Omega

8. In cell B3, select Insert: Expression > omega or type:

=omega


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Tables

9. In cell A4 type: Filename10. In cell B4, select Insert: Annotation > File Name > Name

11. Click the Save Table icon from the Table Viewer toolbar

12. Save the file as axial_table.html13. Open this file in a web browser


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Turbo Report

4. Switch to the ReportViewer , and Refresh thereport

The Refresh button is in

the Report Viewertoolbar The new comment will

appear at the end ofthe report


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Turbo Report

Now create a Velocity plotat 50% span:

1. Switch to Turbo tab

2. Double-click Blade-to-Bladefrom the Turbo tree

3. Set Span to 0.5

4. Set Plot Type to Vector and

Variable to Velocity5. Click Apply


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Turbo Report

Now add this plot to you report:

1. Click the Figure icon from the main toolbar or Right-Click in the viewer window and select Copy to NewFigure

2. Set the Name to Vector Midspan and click OK

3. Scroll to the bottom of the Outline tree

The Figure appears at the end of the Report4. Switch to the Report Viewer tab and Refresh the report to

see the changes


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Turbo Plot

Once the report is complete you can publish it to an html file

1. Click the Publish icon from the Report Viewer toolbar

2. Click OK to write the HTML file The file and figures can be distributed as necessary


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CFD-Post

You may want to try the following on your own, timepermitting

1. Create various figures, tables, comments and charts thatyou might typically want to see in your analysis

2. Try enabling the Generate CFX- Viewer Files toggle whenpublishing your report

Image in the report can then be rotated, zoomed andpanned. The CFX Viewer must be installed on themachine viewing the report; this is freely available fromthe Customer Portal and does not require a license (soyour customers can view your figures in 3D)

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