Geometry - Lesson 3

This page goes through the geometry steps for the Compressible Flow in a Nozzle in the SpaceClaim geometry engine included with Ansys Workbench.

You will need the Equation option for the below steps. In order to enable the Equation button to appear in the Create tab while sketching, the user must disable constraint based sketching. This can be done by opening SpaceClaim > Selecting File> SpaceClaim Options > Advanced > Uncheck 'Enable constraint based checking' > Restarting SpaceClaim.

We will use the axisymmetric option in Ansys Fluent. This solves the governing equations in the cylindrical coordinate system with no dependence on the circumferential coordinate. So pressure, velocity etc. will depend only on the axial (x in Ansys Fluent) and radial (y in Ansys Fluent) coordinates.

Summary of the above video:

1. Drag Fluid Flow (Ansys Fluent) to the Project Schematic
   1. Rename it Compressible Nozzle Flow (Note: Later videos might show a different name here.)
2. Right-click on Geometry → Properties
   1. Analysis Type → 2D
3. Right-click on Geometry and select New SpaceClaim Geometry
4. Go to File → SpaceClaim Options → Units
   1. For Length, select Meters
   2. Set Minor grid spacing to 0.1 m
   3. Click OK
5. Select New Sketch, choose XY plane, then click Plan View
   1. Under the Sketch tab, select Equation
   2. Curve Type = Custom
   3. Set limits of (t) from -0.5 to 0.5
   4. Change Scale to 1000. (NOTE: Some versions of Ansys may not require the use of a scaling factor of 1000 if units were changed in SpaceClaim. In this case, a scaling of 1 is sufficient.)
6. Click the button next to the definition of Y
   1. Enter the following equation: Sqrt (([ t ]*[ t ] + 0.1)/3.1416)
   2. Close the little equation box
   3. Click the green check mark
   4. Escape, Escape
   5. Rename as nozzle_wall
7. Select Line tool in Sketch tab
   1. Ensure you get "Snapping to Curve" when selecting one of the ends
   2. Complete the domain according to the problem specification
8. Enter 3D mode
9. Exit SpaceClaim and Save