Mid Plane Driven Flow in ANSYS Fluent. A Complete Solution Guide
This is the first of my article series on step by step Computational Fluid Dynamics (CFD) guides. Today, I will be showing how to perform a complete ANSYS Fluent simulation from geometry to results. The problem is to simulate flow and heat transfer in a lid driven flow in the mid-plane of an enclosure. The geometry of the problem is shown below:
Solution:
A. Create the project
3. Double click on Fluid Flow (Fluent) package inside the Analysis Systems window. After some seconds, the Analysis System’s Interface appears inside the Project Schematic window. Note that the title is highlighted in blue.
4. Type in any suitable title to replace the highlighted text and press the Enter key on the keyboard. In this case, ‘Mid-Plane Driven Flow’ was typed.
5. Save the project by clicking on the save icon . In the dialog window that comes up, choose the appropriate directory and use a descriptive file name. In this case, ‘Mid-Plane Driven Flow’ was used.
6. After saving the project, the title on the ANSYS Workbench window will be changed to that of the project name.5. Save the project by clicking on the save icon . In the dialog window that comes up, choose the appropriate directory and use a descriptive file name. In this case, ‘Mid-Plane Driven Flow’ was used.
A. Creating the geometry
1. Double click on the Geometry item listed in the Analysis System’s interface. After a while, Design Modeller launches.
2. Change the units to mm by using the following clicking sequence: Units > Millimeters
3. Create a new plane by first clicking a base plane in the Tree Outline window. For this problem, XYPlane, was chosen as the base plane. The second step is to click on the new plane icon and finally, clicking on the generate button. To see the new plane in planar mode, click on the Look At Face/Plane/Sketch icon on the tool bar.
4. To create a new sketch, click on the sketching tab.
5. The Sketching Toolboxes window is displayed. This window contains the following tabs: Draw, Modify, Dimensions, Constraints and Settings.
6. Click on the Settings tab and use the following configuration:
Grid: select Show in 2D, select Snap
Major Grid Spacing: 10 mm
Minor-Steps per Major: 5
Steps per Minor: 1
7. Click on the Draw tab, scroll down and select Rectangle from the list. In the Graphics window, click on points 1 and point 2 to create the rectangle. For this problem, the rectangle is 40 mm x 40 mm.
8 Draw a horizontal line through the middle of the rectangle or square by selecting the line tool from the Draw tab and clicking on points 1 and point 2.
9. It is time to create a body object out of the sketch. This body will represent the problem domain. This can be done by doing the following clicking sequence from the menu bar: Concepts > Surfaces from Sketches.
In the Tree Outline window, select Sketch1 and click on apply in the Details View window.
Click on the generate button . The body object is created.
10. The body object will be split into 2 by the dividing plane at the middle. To achieve this, select Tools from the menu bar and click on Face Split in the drop down.
In the Details View, for the target face, select the face to split with the mouse cursor. To select a face, the selection filter, must be toggled on.
For the tool geometry, select the line representing the mid-plane. To select a line or edge, the selection filter must be toggled on.
Click the generate button to complete the task. On selecting the faces of the domain, it can be confirmed that the domain has indeed been split into 2.
11. Create a Named Selection for each boundary and zone of the domain. A Named Selection can be created by selecting a feature, right clicking on it and selecting Named selection from the context menu. For example, to create a Named Selection for the upper zone, select it, right-click on it and select and click on Named Selection.
12. The Named Section objects created for this problem are listed below.
upper_zone
bottom_zone
left_wall
right_wall
top_wall
bottom_wall
12. Save the project and close Design Modeller.
C. Meshing
1. Double click on the Mesh item in the Analysis System in Workbench’s Project Schematic window.
After some seconds the meshing software user interface is displayed.
2. Click on Mesh in the Outline window
3. Under Details of Mesh, use the following settings:
4. Click on the update button to generate the mesh. To view the see the mesh
in planar mode, click on the navigator z-axis
5. Contact regions are needed between
i. the upper zone and the mid-plane
ii. the lower zone and the mid-plane
To create a contact region, we need the Connections object. To create a Connections object, right click on Model in the Outline window, click on Insert and select Connections. The Connections object appears in the Outline window.
5. To create a Contact Region, right-click on the Connections object, click on Insert and select Manual Contact Region.
7. In the details window, for contact, select the mid-plane line and Apply. For target, select the upper face and Apply.
8. Repeat steps 6 and 7 to create another Contact Region for the mid-plane and the lower face. Two Contact Region objects should appear under the Connection object in the Outline window.
Close Fluent Meshing and save the project in workbench.
9. In the workbench window, under the Project Schematic window, right click on Mesh and the click on update.
D. Simulation Setup
1. Double click on Setup in workbench to open ANSYS Fluent.
In Fluent launcher, accept the default settings by clicking OK. After some seconds, Fluent is displayed and it loads all the mesh and all its modules.
2. Here are the settings for general
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3. Click on Units, change temperature to Celsius and close.
4. Here are the settings for Models:
5. Here are the settings for Materials:
6. Under Cell Zone Conditions, we have two zone objects:
i. bottom_zone-bounded
ii. upper_zone-bounded
We will use the same settings for both zones. To modify their settings, double-click on a zone object.
Beside Material Name click the Edit button.
In the Edit Material window, under ‘Properties of air’ for Density, change from constant to boussinesq and specify a value. For Thermal Expansion Coefficient, specify a value. The following values were used:
Density: 1.225 kg/m3
Thermal Expansion Coefficient: 0.0034/K
Click on the Change button and close the window. Click OK to close the Open Fluid window. These settings must be done for both zone objects.
7. Specify operating conditions by clicking on the Operating Conditions button . Here are the settings:
Click OK to close and save settings.
8. Boundary Conditions
left_wall-upper-zone-bounded: Stationary, No-slip, Heat flux = 0
left_wall-bottom-zone-bounded: Stationary, No-slip, Heat flux = 0
right_wall-upper-zone-bounded: Stationary, No-slip, Heat flux = 0
right_wall-bottom-zone-bounded: Stationary, No-slip, Heat flux = 0
Bottom_wall: Stationary, No-slip, Temperature = 20 °C
top_wall: Stationary, No-slip, Temperature = 20 °C
bonded_-_surface_body_to_surface_body-src:
· Change Type to wall
· Moving wall, speed (m/s) = 1, No-Slip
· Direction, X = 1, Y = 0
· Temperature = 100
bonded_-_surface_body_to_surface_body-src-shadow:
· Change Type to wall
· Moving wall, speed (m/s) = 1, No-Slip
· Direction, X = 1, Y = 0
· Temperature = 100
9. Solution Method settings
10. Leave the rest as default. Under Initialization Methods, use Hybrid to initialize.
11. In the Run Calculation settings, specify any reasonable number of iterations. If it is not sufficient, the simulation can continue from the last iteration by clicking on the Calculate button. Click on Calculate to run the simulation.
12. After convergence, we can view the results by clicking on the Graphics option under Results. Then we can double click on Contours.
Any variable of interest can be selected by selecting it in the Contours window:
1. Results in Fluent:
Velocity Magnitude:
Stream Function:
Close Fluent after extracting results.
E. Viewing result in CFD-Post
1. In workbench, double-click on Results in the Analysis System Schematic
After a while, CFD-Post’s User Interface shows up with the geometry pre-loaded.
2. Select the domain of interest. We will select both upper and bottom zone that have names ending with ‘symmetry 1’ from Cases > Mid Plane Driven Flow > … in the outline window. The domain becomes selected in View 1 window.
Click on the z-axis in the ISO navigator to see the domain in planar mode. You should have the view below
3. To display the contour of any variable, follow the following steps:
i. Click on the contour icon .
ii. Give the contour a preferred name and click OK.
iii. At the bottom left hand corner of the window, we can modify the domain details. Under geometry, do the following:
o Domains: change to domain
o Locations: Click the location editor button
o Resize the Location Selection window to have a clearer view.
o Holding the keyboard’s Crtl key, select all locations ending with symmetry 1 and click OK.
o Variable: change to desired variable (e.g Velocity)
o Range: leave default
o Click on the apply button to view the result
o Change the number of contours as desired
ii. Streamlines and legends can be created in a similar way
4. Repeat the steps on the previous instructions to create contour views of any other variable.
5. The contour views for the results of this assignment are presented below:
· Velocity Maginude:
· Velocity Streamlines
· Temperature Distribution
Thats the end. Close all open windows.
If you are interested in getting the full PDF and ANSYS Fluent file, reach me on my email: lekansbox1@gmail.com
Cheers!!!
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1yVery useful CFD simulation. Thank you.
Maintenance Coordinator at Nestle Nigeria PLC
3yThis is nice. You are indeed impactful. God bless you for all you do.
Project Manager | Operational Excellence Leader | Lean Six Sigma Black Belt | Enabling Cross-Functional Teams to Deliver Exceptional Results
3yGreat Job Dr Lekan