Week 2 Challenge : Surface meshing on a Pressure valve

Aim: Surface meshing on a Pressure valve

Objectives:

1. To generate the surfaces at missing places.
2. To Check for geometrical errors and perform Topology and clean-up.
3. To create the mesh with different target lengths (1mm, 3 mm and 5 mm) with tria element

Procedure

Step 1. Import the geometry and create the new faces

TOPO- faces-new face option or Fill hole depend on the type of surface

Step 2. Check the mesh

Checks Manager- Geometry check (we observed geometrical and intersection errors).

To remove the geometrical error, we have to follow the following steps

Step 3. Assign the PID by generating new PID and renaming them component-wise

PIDs are inlet, outlet, body, spring, column, and column head

Step 4: As spring is the isolated part attached to the column.

!not region- PIG Region- Select Spring

Step 5: Remove the intersection

TOPO- faces- intersect- Select First (Column)- Select second (spring)- delete the intersecting section

Step 6: Select compress to delete the Shell_property PID

Step 7: Close the opening to generate the control volume

TOPO-faces-Planner (Triple cons can be avoided)

Meshing

Step 8: Click the quality criteria and click on Min and max length

Step 9: Mesh parameters- minimum target length and maximum target length

Step 10: Mesh- Spacing – Auto CFD for parameters and Macros

Step 11: Mesh generation- CFD-Visible

Learning Outcomes

1. For new face creation- PLANNER does not work on curve surfaces
2. Able to give the PID to the various parts
3. Can able to find the errors, both geometrical and intersecting errors, and able to remove those errors.
4. Able to use select the isolated region by applying !not resign, and PID region
5. Able to remove/ delete the intersecting part
6. Able to generate the mesh of defined target length

Result:

Fig. 1 meshing of valve body and spring at target length of 5mm

Fig. 2 meshing of valve body and spring at target length of 3mm

Fig.3 meshing of valve body and spring at target length of 1mm

From the above Figs. 1 and 2, it is observed that with the target length of 5mm and 3 mm, meshing quality is very poor on the spring, which is not suitable for the CFD analysis. Total mesh element for 5 mm and 3 mm was observed to be 9991 and 19320, respectively. However, from Fig. 3, with a target length of 1mm, it is observed that the quality of mesh in the complete valve and spring is very good compared with 5 mm and 3 mm target lengths. A total 85541 elements are available in the mesh with a target length of 1 mm.

From the simulation point of view, a mesh with a target length of 5 mm will take less time because of fewer elements, while a mesh with a target length of 1 mm will take more time because of more elements. While a target length of 1mm will give more accurate results when compared with other target lengths.

Conclusion

All geometrical and interface errors must be removed before surface mesh generation.

It is suggested to generate surface mesh before volume mesh

From the results, it can be concluded that the quality of the mesh with a target length of 1mm having 85541 mesh elements is excellent that will give more accurate results than the mesh with a target length of 5 mm and 3 mm.