Revolve 3D geometry to display a 360-degree image.

Tutorial 24. Turbo Postprocessing Introduction This tutorial demonstrates the turbomachinery postprocessing capabilities of FLUENT. In this example, you will read the case and data files (without doing the calculation) and perform a number of turbomachinery-specific postprocessing operations. This tutorial demonstrates how to do the following: Define the topology of a turbomachinery model. Create surfaces for the display of 3D data. Revolve 3D geometry to display a 360-degree image. Report turbomachinery quantities. Display averaged contours for turbomachinery. Display 2D contours for turbomachinery. Display averaged XY plots for turbomachinery. Prerequisites This tutorial assumes that you are familiar with the menu structure in FLUENT and that you have completed Tutorial 1. Some steps in the setup and solution procedure will not be shown explicitly. c Fluent Inc. September 21, 2006 24-1

Problem Description The problem considered in this tutorial is a centrifugal compressor shown schematically in Figure 24.1. The model comprises a single 3D sector of the compressor to take advantage of the circumferential periodicity in the problem. The flow of air through the compressor is simulated and the postprocessing capabilities of FLUENT are used to display realistic, full 360-degree images of the solution obtained. inlet shroud side hub side outlet Figure 24.1: Problem Schematic 24-2 c Fluent Inc. September 21, 2006

Setup and Solution Preparation 1. Download turbo_postprocess.zip from the Fluent Inc. User Services Center or copy it from the FLUENT documentation CD to your working folder (as described in Tutorial 1). 2. Unzip turbo_postprocess.zip. turbo.cas and turbo.dat can be found in the turbo postprocess folder created after unzipping the file. 3. Start the 3D (3d) version of FLUENT. Step 1: Reading the Case and Data Files 1. Read the case and data files (turbo.cas and turbo.dat). File Read Case & Data... When you select turbo.cas, turbo.dat will be read automatically. Step 2: Grid Display 1. Display the grid (Figure 24.2). Display Grid... (a) Retain the default Edges option in the Options group box. c Fluent Inc. September 21, 2006 24-3

(b) Select Outline in the Edge Type list. (c) Deselect all the surfaces from the Surfaces selection list and click the Outline button (below the Surface Types list). (d) Click Display. (e) Rotate the view using the left mouse button and zoom in using the middle mouse button, to obtain an isometric display of the compressor duct. Y X Z Grid FLUENT 6.3 (3d, dbns imp, rke) Figure 24.2: Graphics Display of the Edges of the Compressor Mesh (f) Close the Grid Display panel. Extra: You can use the right mouse button to check which zone number corresponds to each boundary. If you click the right mouse button on one of the boundaries displayed in the graphics window, its zone number, name, and type will be printed in the console. This feature is especially useful when you have several zones of the same type and you want to distinguish between them quickly. 24-4 c Fluent Inc. September 21, 2006

Step 3: Defining the Turbomachinery Topology You will define the topology of the flow domain in order to establish a turbomachineryspecific coordinate system. This coordinate system is used in subsequent postprocessing functions. Specifically, you will select the boundary zones that comprise the hub, shroud, inlet, outlet, and periodics. The boundaries may consist of more than one zone. The topology setup that you define will be saved to the case file when you save the current model. Thus, if you read the saved case back into FLUENT, you do not need to set up the topology again. See Section 28.9.1 of the User s Guide for more information on defining turbomachinery topologies. Define Turbo Topology... 1. Specify the surfaces representing the hub. (a) Retain the default selection of Hub in the Boundaries list. (b) Select the surfaces that represent the hub (wall-diffuser-hub, wall-hub, and wall-inlet-hub) in the Surfaces selection list. Hint: Scroll down the Surfaces list to locate the surfaces representing the hub. 2. Specify the surfaces representing the casing. (a) Select Casing in the Boundaries list. c Fluent Inc. September 21, 2006 24-5

(b) Select wall-diffuser-shroud, wall-inlet-shroud, and wall-shroud in the Surfaces selection list. 3. Specify the surfaces representing the periodic boundaries. (a) Select Theta Periodic in the Boundaries list. (b) Select periodic.33, periodic.34, and periodic.35 in the Surfaces selection list. Note: While Theta Periodic represents periodic boundary zones on the circumferential boundaries of the flow passage, Theta Min and Theta Max are wall surfaces at the minimum and maximum θ position on a circumferential boundary. There are no such wall surfaces in this problem. 4. Specify the surface representing the Inlet (inlet). 5. Specify the surface representing the Outlet (outlet). 6. Specify the surface representing the Blade (wall-blade). 7. Retain the default name of new-topology-1 for the Turbo Topology Name. 8. Click Define to set all the turbomachinery boundaries. 9. Close the Turbo Topology panel. FLUENT will inform you that the turbomachinery postprocessing functions have been enabled, and the Turbo menu will appear in FLUENT menu bar at the top of the console. You can define any number of turbo topologies in the Turbo Topology panel. This is especially useful when you have a model comprising multiple blade rows and you need to define more than one blade row simultaneously. Each topology can be assigned a specific name and accessed using the drop-down list in the Turbo Topology panel. See Section 28.9.1 of the User s Guide for more information on defining turbomachinery topologies. Note: You can display the selected surfaces by clicking the Display button in the Turbo Topology panel. This is useful as a graphical check to ensure that all relevant surfaces have been selected. 24-6 c Fluent Inc. September 21, 2006

Step 4: Isosurface Creation To display results in a 3D model, you will need surfaces on which the data can be displayed. FLUENT creates surfaces for all boundary zones automatically. In a general application, you may want to define additional surfaces for viewing results. FLUENT s turbo postprocessing capabilities allow you to define more complex surfaces, specific to the application and the particular topology that you defined. In this step, you will create surfaces of iso-meridional (marching along the streamwise direction) and spanwise (distance between the hub and the shroud) coordinates in the compressor. 1. Create surfaces of constant meridional coordinate. Surface Iso-Surface... (a) Select Grid... and Meridional Coordinate from the Surface of Constant dropdown lists. (b) Enter 0.2 in the Iso-Values text field. (c) Enter meridional-0.2 for New Surface Name. (d) Click Create. Note: The isovalues you enter for these turbo-specific surfaces are expressed as a percentage of the entire domain (i.e., you just defined a surface of meridional coordinate equal to 20% of the path along the duct). (e) Similarly, define surfaces of meridional coordinates equal to 0.4, 0.6, and 0.8. c Fluent Inc. September 21, 2006 24-7

2. Create surfaces of constant spanwise coordinate. (a) Select Grid... and Spanwise Coordinate from the Surface of Constant drop-down lists. (b) Enter 0.25 in the Iso-Values text field. (c) Enter spanwise-0.25 for New Surface Name. (d) Click Create. (e) Similarly, define surfaces of spanwise coordinates equal to 0.5 and 0.75. 3. Close the Iso-Surface panel. 24-8 c Fluent Inc. September 21, 2006

Step 5: Contours 1. Display filled contours of pressure on the meridional isosurfaces (Figure 24.3). Display Contours... (a) Enable Filled in the Options group box. (b) Select Pressure... and Static Pressure from the Contours of drop-down lists. (c) Select inlet, meridional-0.2, meridional-0.4, meridional-0.6, meridional-0.8, and outlet from the Surfaces selection list. (d) Enable Draw Grid in the Options group box. The Grid Display panel will open. i. Retain the current settings and close the Grid Display panel. (e) Click Display. (f) Rotate and zoom the display using the left and middle mouse buttons, respectively, to obtain the view shown in Figure 24.3. In Figure 24.3, you can observe the buildup of static pressure along the duct. 2. Display filled contours of Mach number (Figure 24.4). (a) Select Velocity... and Mach Number from the Contours of drop-down lists. (b) Click Display. In Figure 24.4, you can observe locations at which the flow becomes slightly supersonic, about halfway through the duct. c Fluent Inc. September 21, 2006 24-9

1.84e+00 1.78e+00 1.73e+00 1.67e+00 1.62e+00 1.56e+00 1.50e+00 1.45e+00 1.39e+00 1.34e+00 1.28e+00 1.22e+00 1.17e+00 1.11e+00 1.06e+00 1.00e+00 9.44e-01 8.88e-01 8.32e-01 7.76e-01 7.20e-01 X Y Z Contours of Static Pressure (atm) FLUENT 6.3 (3d, dbns imp, rke) Figure 24.3: Filled Contours of Pressure on the Meridional Isosurfaces 1.04e+00 9.85e-01 9.35e-01 8.85e-01 8.35e-01 7.84e-01 7.34e-01 6.84e-01 6.34e-01 5.83e-01 5.33e-01 4.83e-01 4.33e-01 3.82e-01 3.32e-01 2.82e-01 2.32e-01 1.81e-01 1.31e-01 8.07e-02 3.05e-02 X Y Z Contours of Mach Number FLUENT 6.3 (3d, dbns imp, rke) Figure 24.4: Filled Contours of Mach Number on the Meridional Isosurfaces 24-10 c Fluent Inc. September 21, 2006

3. Display filled contours of Mach number on the spanwise isosurfaces (Figure 24.5). (a) Deselect all surfaces in the Surfaces selection list. (b) Select spanwise-0.25, spanwise-0.5, and spanwise-0.75 from the Surfaces selection list. (c) Click Display. 1.04e+00 9.85e-01 9.35e-01 8.85e-01 8.35e-01 7.84e-01 7.34e-01 6.84e-01 6.34e-01 5.83e-01 5.33e-01 4.83e-01 4.33e-01 3.82e-01 3.32e-01 2.82e-01 2.32e-01 1.81e-01 1.31e-01 8.07e-02 X 3.05e-02 Y Z Contours of Mach Number FLUENT 6.3 (3d, dbns imp, rke) Figure 24.5: Filled Contours of Mach Number on the Spanwise Isosurfaces The display in Figure 24.5 allows you to further study the variation of the Mach number inside the duct. You may want to explore using different combinations of surfaces to display the same or additional variables. 4. Display a 360-degree image of the Mach number contours on the 0.5 spanwise isosurface (Figure 24.6). (a) Deselect spanwise-0.25 and spanwise-0.75 from the Surfaces selection list. (b) Click Display. c Fluent Inc. September 21, 2006 24-11

(c) Display the full 360-degree geometry. Display Views... i. Click the Define... button to open the Graphics Periodicity panel. A. Select fluid in the Cell Zones list. This will select all the surfaces in the Associated Surfaces list. The default value for Number of Repeats is set to 20. The display is updated to give a full, 360 degree view. B. Click Set and close the Graphics Periodicity panel. The display will be updated to show the entire geometry (see Figure 24.6. 24-12 c Fluent Inc. September 21, 2006

Turbo Postprocessing 1.04e+00 9.85e-01 9.35e-01 8.85e-01 8.35e-01 7.84e-01 7.34e-01 6.84e-01 6.34e-01 5.83e-01 5.33e-01 4.83e-01 4.33e-01 3.82e-01 3.32e-01 2.82e-01 2.32e-01 1.81e-01 1.31e-01 8.07e-02 Y 3.05e-02 X Z Contours of Mach Number FLUENT 6.3 (3d, dbns imp, rke) Figure 24.6: Filled Contours of Mach Number on the 0.5 Spanwise Isosurface ii. Close the Views panel. 5. Close the Contours panel. Note: This step demonstrated a typical view-manipulation task. See Tutorial 23 for further examples of postprocessing features. c Fluent Inc. September 21, 2006 24-13

Step 6: Reporting Turbo Quantities The turbomachinery report provides some tabulated information specific to the application and the defined topology. See Section 28.9.2 of the User s Guide for details. Turbo Report... 1. Retain the default selection of Mass-Weighted in the Averages list. 2. Click Compute. 3. Close the Turbo Report panel. 24-14 c Fluent Inc. September 21, 2006

Step 7: Averaged Contours Turbo averaged contours are generated as projections of the values of a variable averaged in the circumferential direction and visualized on an r- z plane. 1. Disable the periodic repeats. Display Views... (a) Click the Define... button to open the Graphics Periodicity panel. i. Click Reset. ii. Close the Graphics Periodicity panel. (b) Close the Views panel. 2. Display filled contours of averaged static pressure (Figure 24.7). Turbo Averaged Contours... (a) Select Pressure... and Static Pressure from the Contours of drop-down lists. (b) Click Display. (c) Close the Turbo Averaged Contours panel. c Fluent Inc. September 21, 2006 24-15

1.80e+00 1.76e+00 1.72e+00 1.67e+00 1.63e+00 1.58e+00 1.54e+00 1.50e+00 1.45e+00 1.41e+00 1.36e+00 1.32e+00 1.28e+00 1.23e+00 1.19e+00 1.14e+00 1.10e+00 1.06e+00 1.01e+00 9.68e-01 9.24e-01 Y Z X Averaged Turbo Contour - pressure (atm) (atm) FLUENT 6.3 (3d, dbns imp, rke) Figure 24.7: Filled Contours of Averaged Static Pressure Step 8: 2D Contours In postprocessing a turbomachinery solution, it is often preferable to display contours on constant spanwise coordinates and then, project these contours onto a plane. This permits easier evaluation of the contours, especially for surfaces that are highly threedimensional. FLUENT allows you to display contours in this manner using the Turbo 2D Contours panel. 1. Display 2D contours of Mach number (Figure 24.8). Turbo 2D Contours... 24-16 c Fluent Inc. September 21, 2006

(a) Select Velocity... and Mach Number from the Contours of drop-down lists. (b) Enter 0.5 for Normalised Spanwise Coordinates. Note: For highly curved edges, if a surface is created very close to the curved edge the resulting surface may have some void spaces in it. (c) Click Display. (d) Use the mouse to obtain the view shown in Figure 24.8. 9.12e-01 8.69e-01 8.26e-01 7.83e-01 7.40e-01 6.96e-01 6.53e-01 6.10e-01 5.67e-01 5.24e-01 4.81e-01 4.37e-01 3.94e-01 3.51e-01 3.08e-01 2.65e-01 2.22e-01 1.79e-01 1.35e-01 9.22e-02 4.91e-02 Z Y X 2D Turbo Contour - mach-number FLUENT 6.3 (3d, dbns imp, rke) Figure 24.8: 2D Contours of Mach Number on Surface of Spanwise Value 0.5 (e) Close the Turbo 2D Contours panel. c Fluent Inc. September 21, 2006 24-17

Step 9: Averaged XY Plots In addition to displaying data on different combinations of complex 3D and flattened surfaces, FLUENT s turbo postprocessing capabilities allow you to display XY plots of averaged variables, relevant to the specific topology of a turbomachinery problem. In particular, you will be able to plot circumferentially-averaged values of variables as a function of either the spanwise coordinate or the meridional coordinate. 1. Plot temperature as a function of the meridional coordinate (Figure 24.9). Turbo Averaged XY Plot... (a) Select Temperature... and Static Temperature from the Y Axis Function dropdown lists. (b) Select Meridional Distance from the X Axis Function drop-down list. (c) Enter 0.9 for the Fractional Distance. (d) Click Plot. (e) Close the Turbo Averaged XY Plot panel. 24-18 c Fluent Inc. September 21, 2006

3.50e+02 3.40e+02 3.30e+02 Static Temperature (k) 3.20e+02 3.10e+02 3.00e+02 2.90e+02 2.80e+02 0.000 0.100 0.200 0.300 0.400 0.500 0.600 0.700 0.800 0.900 1.000 X Meridional Distance Z Y Averaged XY - temperature FLUENT 6.3 (3d, dbns imp, rke) Figure 24.9: Averaged XY Plot of Static Temperature on Spanwise Surface of 0.9 Isovalue Summary This tutorial demonstrated the use of some of the turbomachinery-specific postprocessing features of FLUENT. These features can be accessed once you define the topology of the problem. More extensive general-purpose postprocessing features are demonstrated in Tutorial 23. Also, see Chapter 28 and Chapter 29 of the User s Guide for additional information. c Fluent Inc. September 21, 2006 24-19

24-20 c Fluent Inc. September 21, 2006