The CFX tutorials are designed to introduce general techniques used in CFX and to provide tips on advanced modeling.
The initial tutorials introduce general principles used in CFX, including setting up the physical models, running CFX-Solver and visualizing the results in CFD-Post; the later tutorials highlight specialized features of CFX.
This manual contains the following tutorials:
Simulating Flow in a Static Mixer Using CFX in Stand-alone Mode simulates a static mixer consisting of two inlet pipes delivering water into a mixing vessel; the water exits through an outlet pipe. A general workflow is established for analyzing the flow of fluid into and out of a mixer.
Simulating Flow in a Static Mixer Using Workbench simulates the previous tutorial using Ansys Workbench.
Flow in a Static Mixer (Refined Mesh) uses a refined mesh to obtain a better solution to the Static Mixer problem created in the first tutorial.
Optimizing Flow in a Static Mixer shows how to use Design Points and DesignXplorer to optimize the static mixer first shown in Simulating Flow in a Static Mixer Using CFX in Stand-alone Mode.
Flow in a Process Injection Mixing Pipe describes the general approach taken when working with an existing mesh.
Flow from a Circular Vent simulates a chimney stack releasing smoke that is dispersed into the atmosphere with an oncoming side wind.
Flow Around a Blunt Body models the behavior of fluid flow around a generic vehicle body.
Free Surface Flow Over a Bump demonstrates the simulation of a free surface flow in which the bottom of the channel is interrupted by a semicircular bump.
Supersonic Flow Over a Wing simulates supersonic flow over a symmetric NACA0012 airfoil at an angle of attack of 0°.
Flow Through a Butterfly Valve investigates the detailed flow pattern around a valve to better understand why flow losses occur.
Flow in a Catalytic Converter models a catalytic converter in order to determine the pressure drop and heat transfer through it.
Non-Newtonian Fluid Flow in an Annulus simulates a shear-thickening liquid rotating in a 2D eccentric annular pipe gap.
Flow in an Axial Turbine Stage sets up a transient calculation of an axial turbine stage.
Reacting Flow in a Mixing Tube models basic reacting flows using a multicomponent fluid and CEL expressions.
Heat Transfer from a Heating Coil models the transfer of thermal energy from an electrically-heated solid copper coil to the water flowing around it.
Multiphase Flow in a Mixing Vessel simulates the mixing of water and air in a mixing vessel.
Gas-Liquid Flow in an Airlift Reactordemonstrates the Eulerian-Eulerian multiphase model by simulating an airlift reactor (a tall, gas-liquid contacting vessel used in processes where gas absorption is important).
Air Conditioning Simulation simulates a room with a thermostat-controlled air conditioner.
Combustion and Radiation in a Can Combustor gives a qualitative impression of the flow and temperature distributions inside a can combustor that burns methane in air.
Cavitation Around a Hydrofoil demonstrates cavitation in the flow of water around a hydrofoil by modeling a thin slice of the hydrofoil and using two symmetry boundary conditions.
Modeling a Ball Check Valve using Mesh Deformation and the CFX Rigid Body Solver uses an example of a ball check valve to demonstrate both two-way Fluid-Structure Interaction (FSI) between a ball and a fluid, as well as the mesh-deformation capabilities of Ansys CFX.
Aerodynamic and Structural Performance of a Centrifugal Compressor simulates the aerodynamic and structural performance of a centrifugal compressor.
Axial Turbine Equilibrium and Non-Equilibrium Steam Predictions uses an axial turbine to demonstrate setting up and executing equilibrium and non-equilibrium steam calculations using the IAPWS water database for properties.
Modeling a Gear Pump using an Immersed Solid simulates a gear pump that drives a flow of water.
Drop Curve for Cavitating Flow in a Pump uses a simple pump to illustrate the basic concepts of setting up, running, and postprocessing a cavitation problem.
Spray Dryer models the way in which water drops are evaporated by a hot air flow.
Coal Combustion models coal combustion and radiation in a furnace.
Steam Jet simulates a high-speed wet steam jet into air.
Modeling a Buoy using the CFX Rigid Body Solver models the interaction between a rigid body (represented by a buoy) and two fluids (air and water).
Time Transformation Method for an Inlet Disturbance Case sets up a transient blade row calculation to model an inlet disturbance (frozen gust) in an axial turbine using the Time Transformation model.
Fourier Transformation Method for an Inlet Disturbance Case sets up a transient blade row calculation to model an inlet disturbance (frozen gust) in an axial turbine using the Fourier Transformation model.
Time Transformation Method for a Transient Rotor-stator Case sets up a transient blade row calculation using the Time Transformation model.
Time Transformation Method for a Transient Rotor-stator Case with Conjugate Heat Transfer sets up a transient blade row calculation with conjugate heat transfer using the Time Transformation model.
Fourier Transformation Method for a Transient Rotor-stator Case sets up a transient blade row calculation using the Fourier Transformation model.
Fourier Transformation Method for a Blade Flutter Case sets up a transient blade row simulation using the Fourier Transformation model as part of blade flutter modeling. The tutorial demonstrates two approaches: Time Integration Solution Method and Harmonic Balance Solution Method.
Time Transformation Method for a 1.5-stage Transient Rotor-stator Case sets up a transient blade row calculation with a multistage machine using the Time Transformation model.
Film Cooling in a Turbine defines injection regions on a turbine and shows the injection positions in CFX-Pre and CFD-Post.
Operating Map for a Centrifugal Compressor sets up an operating point case and displays the results using operating maps.
Flow in an Intake Manifold using GT-SUITE Coupling sets up a case that is coupled with GT-SUITE.
You should review the following topics before attempting to start a tutorial for the first time:
Before you start CFX-Pre, CFX-Solver Manager, or CFD-Post, set the working directory. The procedure for setting the working directory and starting Ansys CFX in stand-alone is listed below:
Start the Ansys CFX Launcher.
You can start the launcher in any of the following ways:
On Windows:
From the Start menu, select All Programs > ANSYS 2024 R2 > Fluid Dynamics > CFX 2024 R2.
In a Command Prompt that has its path set up correctly to run CFX, enter
cfx5(otherwise, you will need to type the full pathname of thecfx5command).
On Linux, enter
cfx5in a terminal window that has its path set up to run CFX.
Specify the Working Directory in the launcher window.
Click the CFX-Pre 2024 R2 button.
If you were directed here at some point during a tutorial, return to that location.
Note: All tutorials assume that the CFX run history and multi-configuration options, under the Load Results File dialog box in CFD-Post, is set to Load only the last results.
Most Ansys CFX tutorials are written to work in stand-alone mode. This section includes the steps required to run these tutorials in Ansys Workbench:
Tip: You may find it useful to open the Ansys CFX help from the Ansys CFX Launcher (which does not take up a license).
Start Ansys Workbench.
To launch Ansys Workbench on Windows, click the Start menu, then select All Programs > Ansys 2024 R2 > Workbench 2024 R2.
To launch Ansys Workbench on Linux, open a command line interface, type the path to
runwb2(for example,~/ansys_inc/v242/Framework/bin/Linux64/runwb2), then press Enter.
From the main menu, select File > Save As.
In the Save As dialog box, browse to a working directory and specify a filename for the project.
Click .
In the Toolbox pane, open Component Systems and double-click CFX. A CFX system opens in the Project Schematic.
Note: You use a CFX component system because you are starting with a mesh. If you want to create the geometry and mesh, you will start with a Fluid Flow (CFX) system.
Type in the new name, such as
System 1, to replace the highlighted text below the system.Alternatively, you can right-click the first cell in the system and select Rename. The name will be highlighted. Now you can change the highlighted text by typing in the new name.
In the Project Schematic, right-click the Setup cell and select Edit to launch CFX-Pre.
Continue from the section of the tutorial that provides instructions for defining the case using CFX-Pre. The section is typically named Defining the Case Using CFX-Pre.
When running Ansys CFX within Ansys Workbench, no action is required for this section of the tutorial. The required files are automatically transferred between the cells within the CFX component system. Continue from Obtaining the Solution Using CFX-Solver Manager.
Once the simulation setup is complete, the Solution cell prompts you to refresh it. To refresh that cell:
Right-click the Solution cell and select Refresh.
Note: If the Solution cell displays a prompt to perform an update, ignore it and proceed to the next step.
To obtain a solution, you need to launch the CFX-Solver Manager and subsequently use it to start the solver:
Right-click the Solution cell and select Edit.
The CFX-Solver Manager appears with the Define Run dialog box displayed.
Continue from the Obtaining a Solution Using CFX-Solver Manager section of the tutorial.
When CFX-Solver has finished, a completion message appears in a dialog box. Click .
Alternatively, a message saying This run of the Ansys CFX-Solver has
finished is displayed in the final line of the CFX-Solver Output
file in the CFX-Solver Manager.
Once CFX-Solver has finished, you can use CFD-Post to review the finished results. At this point, the Results cell in Ansys Workbench prompts you to refresh:
Right-click the Results cell and select Refresh.
When the refresh is complete, right-click the Results cell and select Edit to open CFD-Post.
Continue from the Viewing the Results in CFD-Post section of the tutorial.
If this is the final section of your tutorial, continue from Closing the Applications. If you are running Ansys CFX tutorials with a sequence of multiple simulations, continue from Creating CFX Component Systems for Multiple Simulations.
Now that you have set the physics in the initial state, you will duplicate the CFX component system created earlier and edit the physics in the new system. To duplicate the existing CFX component system:
In the Ansys Workbench Project Schematic, right-click the first cell in
System 1and select Duplicate.A new system named
Copy of System 1will appear in the Project Schematic.Type in the new name
System 2to replace the highlighted text below the system.Click the Solution cell of
System 1and drag it to the Solution cell ofSystem 2.You will now see a line, indicating a transfer connection, going from Solution cell of
System 1to the Solution cell ofSystem 2.Once you have set up the new CFX component system, continue from Step 5 of Setting Up the Project.
Note: In the tutorial, ignore the steps that tell you to set the initial values file in the Define Run dialog box for CFX-Solver Manager. Dragging the solution cell between systems automatically sets the initialization options in CFX-Solver Manager.
If viewing objects in Ansys CFX becomes difficult due to contrast with the background, you can change the colors for improved viewing. The color options are set in different places, depending on how you run CFX:
Select Edit > Options.
The Options dialog box appears.
Adjust the color settings under
CFX-Pre>Graphics Style(for CFX-Pre) orCFD-Post>Viewer(for CFD-Post).Click .
If you were directed here at some point during a tutorial, return to that location.
The Ansys CFX interface uses editors to enter the data required to set up and post-process a simulation. The editors have standard buttons, which are described next:
Apply applies the information contained within all the tabs of an editor.
is the same as , except that the editor automatically closes.
Cancel and Close both close the editor without applying or saving any changes.
Reset returns the settings for the object to those stored in the database for all the tabs. The settings are stored in the database each time the Apply button is clicked.
Defaults restores the system default settings for all the tabs of the edited object.
To open the ANSYS Help, select Help > Contents.
Context-sensitive help is provided for many of the details views and other parts of the interface. To invoke the context-sensitive help for a particular details view or other feature, ensure that the window is active, place the mouse pointer over the feature, and press F1. Not every area of the interface supports context-sensitive help.