Week 2 Challenge : Surface meshing on a Pressure valve

Challenge 2

Surface Meshing on a Pressure Valve

Aim

To mesh the given pressure valve with different target lengths 5mm, 3mm and 1mm as separate cases. And to observe which target length better discretize the geometry.

Procedure

1.Geometry Clean Up

1. The given pressure valve model is downloaded and checked for any geometrical errors.

Check Manager > Geometry > All entities

2. The errors are shown with white marks

Select the errors > use show/show only option

3. Use Topo mode (Topology) for geometry clean up, under the module

Face > new > Coons

CONS > Fill hole

2.PID: Properties

1. This option can be seen in the tool bar> It is used to assign the boundary conditions. In this workshop, the boundaries are assigned with names and colours only.
2. To create a new PID

Right-click > give name > (given names: inlet, outlet, valve head, column, casing, spring, base)

Right click > on the created name > assign the boundaries > select using PID option or PID region option > click Apply

Note: One can split or divide a PID region by hiding the connecting surface.

3. Double click on the colour box in the PID name list to assign individual colours for each PID.

3.Mesh Generation

1. Assign Length and Macros

Perimeter > Length > box select entire geometry > give perimeter length value as 5mm, 3mm, 1mm for each case.

Perimeter > Macros > box select > entire geometry > Macro length as 5mm, 3mm, 1mm for each case.

2. Set Mesh Parameters

Under basic tab

Select: CFD Mesh

Element type: Tria

Element order: 1^st order

Target Length: 5, 3, 1 mm for separate cases

Min Length: 4, 2, 0.5 for corresponding cases

Max Length: 6, 4, 1.5 for corresponding cases

3. Mesh Quality

Enable and set min length: 4, 2, 0.5

Enable and set max length: 6, 4, 1.5

4. Under Mesh Generation module

Use Spot Mesh > select PID region one by one to mesh (if you want to mesh separately)

Target Length (mm)	Total Mesh Elements
5	8362
3	24769
1	213210

Learning Outcome

Target Length (mm)	Mesh of Geometric Features (Spring)
5	Coarse (highly skewed)
3	Medium (not captured enough geometric features)
1	Fine (resolve the geometric feature properly)

Result

For capturing complex geometric features use a small target length, here a target length of 1mm capture the spring geometry very well.

Conclusion

For regular shape geometry or large geometry use a higher target length for complex or odd-shaped geometric features use a smaller target length.