Week 3 Challenge : CFD meshing on Turbocharger

Week 3 Challenge : CFD meshing on Turbocharger

AIM:

• To check for the geometrical errors to make appropriate volumes for the given model.
• To create and assign PIDs for the various components of the geometry.
• To perform surface mesh with the given target lengths as per PIDs.

1. Blade stage-1 = 1 mm
2. Blade stage-2 = 1 mm
3. Impeller = 2 mm
4. Shaft rotor = 1 mm
5. Turbo casing = 5 mm
6. Compressor casing = 5 mm
7. Inlet casing cover = 5 mm

• To perform Volumetric mesh for the required volumes.
• To write a detailed report on your surface meshing & Volume meshing process.

PROCEDURE:

1. Patch the missed surfaces:

• First we need to import the geometry model from the source folder.
• The geometry file contains lot of ir-regularities, discontnuities, so we need to patch all the missing and open surfaces in the geometry.
• This can be done by the following procedure;

TOPO → faces → new → here we can select any method → select the cons (this can be done by entity or PID method) → middle click or surface click.

2. Removing overlapped surfaces:

• At some areas of the geometry, we need to clear the overlapped surfaces.
• This can be done by following procedure;

TOPO → delete → select the surface to be deleted by using entity or PID mode.

• Sometimes we need to project the cons to make the single cons into triple cons.
• This can be done by the following procedure;

TOPO → cons → project → select the cons → middle click → select the face where the cons has to be projected → middle click.

3. PID assigning:

• Now we need to create PID (Property ID) for all the surfaces like inlet, outlet, spring, column, base and valve head.
• This can be done by the following procedure;

Properties → right click on the properties screen → new → PSHELL → PSHELL → box pops-up → name has to be given.

• Similarly we need to create as many as required.
• Now we need to assign the created PID 's to the respective surfaces required and we need to make sure that cross-hatches option is enabled.
• This can be done by the following procedure;

Properties → right click on the PID → apply → select the cross hatch present in the surface of the geometry → middle click on the mouse.

• Similarly we need to do for all the required surfaces.

4. Surface mesh process:

• Now we need to mesh the geometry.
• This can be done in two ways;

1. Meshing the whole geometry in one shot. (only with single element length can be done at a time)
2. Meshing the geometry part by part individually. (each part or component can be given different element length)

• The first method is employed in this challenge, however the second is highly beneficial when meshing distinct pieces with varying target lengths.
• Messhing can be done by following procedure;

MESH (right side on the screen) → perimeters → length → perimeters → give the target length → ok.

MESH (right side on the screen) → perimeters → length → macros → give the target length → ok.

Mesh parameters (Top of the screen) → give the target length, min and max length in that dialog box.

Quality criteria (Top of the screen) → give the target length, min and max length in that dialog box.

Mesh generation (right side on the screen) → spot mesh → select the geometry to be meshed.

5. Volume mesh process:

• Now we need to move to volume mesh.

Volume → define → work on → whole db.

• Now we need to drop volume mesh to the geometry.
• This can be done by following procedure:

Volume → list → here we need to select the component to do volume mesh → right click → remesh → fluent method.

Mesh pictures:

Surface mesh:

Volume mesh:

1st stage blades:

2nd stage blades:

Impeller:

Compressor casing:

Turbo casing:

Turbo inlet casing:

Compressor inlet:

Compressor outlet:

Turbo inlet:

Turbo outlet:

Shaft rotor:

Cut view of volume mesh:

Conclusion:

• The above figures are surface, volume mesh of all the components in the geometry.
• The last two pictures shows the cut section of the volume mesh.
• We may also deduce from the final two figure that the shaft, first and second stage blades have 1mm element sizes, while the compressor casing has a 5mm element size, resulting in a transition from 1m to 5mm, as shown in the diagram.

Meshed file link:

https://drive.google.com/file/d/1GCaqifnQTR0arCpEhHyP9mhSv16NUXqk/view?usp=sharing