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Julian121 May 20, 2018 12:00

How to merge meshed parts?
 
1 Attachment(s)
I am trying to merge two meshed parts, upstream part of rotor and the rotor itself.
The reason why I divided the rotor domain into two parts is because a type of vane-recessed casing treatment is placed on the top and upstream of the rotor.
The lower part of casing treatment is one millimetre shorter than the shroud so the casing treatment domain must go inside the rotor domain.
I used bladegen to create the rotor domain and used Solidworks to create the upstream domain.
When I import both meshes they are not placed near each other in ICEM even though I used correct dimensions.
I do not need an interface between them too.
Any suggestion would be welcome!

Far May 20, 2018 14:32

Do you have blocking for both?

Julian121 May 21, 2018 03:52

No, I used Turbogrid to generate mesh for the rotor and exported it to ICEM.
For the upstream part of the rotor I used ANSYS meshing.
Can these two meshes be merged in some way in ICEM without a need to use blocking?
Is there any alternative way of creating the upstream part and the rotor in one step? Bladegen does change the shroud curve even piecewise linear is selected for the shroud curve.

Far May 21, 2018 10:45

You can merge them.

johny0688 May 24, 2018 04:04

Quote:

Originally Posted by Julian121 (Post 693013)
Bladegen does change the shroud curve even piecewise linear is selected for the shroud curve.

I can hardly believe that, but anyway.

Turbogrid stick only to radial and axial dimension so the circumferential position of inlet and outlet is random. I think that the best method is to check coordinates of corner nodes at inlet to rotor domain and based on that create your upstream part in Solidworks. Then generate upstream mesh in Mesher.

But still it is very hard to merge two meshes in 1:1 because you need the same spacing on both surfaces. Why you don't want interface? For me it won't influence significantly.

Julian121 May 26, 2018 09:08

2 Attachment(s)
Quote:

Originally Posted by johny0688 (Post 693411)
I can hardly believe that, but anyway.

Turbogrid stick only to radial and axial dimension so the circumferential position of inlet and outlet is random. I think that the best method is to check coordinates of corner nodes at inlet to rotor domain and based on that create your upstream part in Solidworks. Then generate upstream mesh in Mesher.

But still it is very hard to merge two meshes in 1:1 because you need the same spacing on both surfaces. Why you don't want interface? For me it won't influence significantly.

Is there an easier way to draw the rotor and the upstream of the rotor (the upstream part is shorter because of the casing treatment) in one geometry instead of separating them?
I tried to do so in bladegen, but as I said when the geometry is imported in Turbogrid or ICEM, the right corner angle changes.

Ludvik May 28, 2018 02:49

An another possible way:
1. Create a mesh in TG just for rotor itself.
2. Create a geometry for upstream part.
3. Load mesh from TG into ICEM CFD and extract mesh on a interface.
4. Create a block(s) for extention.
5. Convert the block(s) to Sweept with main Source Face on the interface.
6. Use command Associate Face-> Surface/Reference mesh.
7. Create Premesh/Mesh. Merge both parts. ...

Julian121 June 2, 2018 02:36

1 Attachment(s)
Quote:

Originally Posted by Ludvik (Post 693740)
An another possible way:
1. Create a mesh in TG just for rotor itself.
2. Create a geometry for upstream part.
3. Load mesh from TG into ICEM CFD and extract mesh on a interface.
4. Create a block(s) for extention.
5. Convert the block(s) to Sweept with main Source Face on the interface.
6. Use command Associate Face-> Surface/Reference mesh.
7. Create Premesh/Mesh. Merge both parts. ...

Thank you for the answer.
I have followed your instructions but when I convert the block into sweept with main source face on the interface, the face cannot be selected to associate with rotor mesh. Please see the screenshot.

Far June 2, 2018 13:00

Use ICEM CFD for this purpose. Or create interface but that should be upstream or downstream of casing recess.

Julian121 June 3, 2018 01:52

Quote:

Originally Posted by Far (Post 694387)
Use ICEM CFD for this purpose. Or create interface but that should be upstream or downstream of casing recess.

Dear Far
Thank you for the answer.
Since the height of the upstream domain is shorter than the height of the rotor, the interface between the two domains should be applied based on the upstream height right? If so, how the inlet face of the rotor should be divided? I have not used blocking in ICEM so I cannot create two parts based on the blocking. I have imported the mesh from TG.

Far June 3, 2018 05:29

see this reference...

https://www.researchgate.net/publica...ed_Endwall_NGV


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