[SNeCu]

Dear all,

I want to see the casing treatment effect on a rotor through numeca. The casing treatment method is showed in the attachment: casing (shroud) radius is enlarged and there is a circle block in the cavity. How to add this cavity and draw the mesh in numeca ?

[DarylMusashi]

Dear SNecU,

have you tried to do some tutorials, as the ZR-effect is described in detail in Advanced Tutorials, number 2 (Meridional Effect)?

However, I made some screenshots how to do it. I describe the method by drawing your solid lines of the casing treatment directly in AutoGrid. Another solution would be to draw your lines in a separate project with IGG (or any other CAD software), select "import and link CAD" in AutoGrid (left panel, middle) and link that loaded geometry to your meridional effect.

If you want to draw it directly in AutoGrid the procedure is as follows:
1. Add a zr-effect (picture 1, top)
2. right click it, edit
3. now you are in edit mode of the zr-effect. Draw the outer solid lines, which surround your casing treatment. (picture 2, top)
4. now you simply click through the left panel menu from top to bottom: define your domain (left click somewhere on the solid line, right click to accept and finish), hit automatic blocking, adjust your wall cell width (if needed), set some optimization steps.
5. hit "default mesh", optimize mesh
6. if you are satisfied with this close the edit mode and now you build your 3D mesh of the corresponding row at first
7. finally select your zr-effect in the rows tab (top left) and hit "generate 3d mesh" again.

It is important that you build the 3D mesh of the main channel first and then build your 3d mesh of the zr-effect, otherwise the channel connection of the zr-effect cannot be established.

Finally, in the 3D view it should look like in picture 3.

Kind regards,
Holger

[SNeCu]

Dear DarylMusashi,

Thank you very much for your kindly reply and it is a very helpful guidance for my case.

However, there is another problem when I take the first trial: the topology of added ZR-effect is not consistent with blade row flow field geometry after I import the cgns file into CFX... making it difficult to set boundary interface between main channel and casing treatment... Is it a normal mesh result from NUMECA or I did some mistakes? The mesh of main channel and ZR-effect seems to be consecutive.

[SNeCu]

Dear DarylMusashi,

Thank you very much for your kindly reply and it is a very helpful guidance for my case.

However, there is another problem when I take the first trial: the topology of added ZR-effect is not consistent with blade row flow field geometry after I import the cgns file into CFX... making it difficult to set boundary interface between main channel and casing treatment... Is it a normal mesh result from NUMECA or I did some mistakes? The mesh of main channel and ZR-effect seems to be consecutive.

Originally Posted by DarylMusashi

Dear SNecU,

have you tried to do some tutorials, as the ZR-effect is described in detail in Advanced Tutorials, number 2 (Meridional Effect)?

However, I made some screenshots how to do it. I describe the method by drawing your solid lines of the casing treatment directly in AutoGrid. Another solution would be to draw your lines in a separate project with IGG (or any other CAD software), select "import and link CAD" in AutoGrid (left panel, middle) and link that loaded geometry to your meridional effect.

If you want to draw it directly in AutoGrid the procedure is as follows:
1. Add a zr-effect (picture 1, top)
2. right click it, edit
3. now you are in edit mode of the zr-effect. Draw the outer solid lines, which surround your casing treatment. (picture 2, top)
4. now you simply click through the left panel menu from top to bottom: define your domain (left click somewhere on the solid line, right click to accept and finish), hit automatic blocking, adjust your wall cell width (if needed), set some optimization steps.
5. hit "default mesh", optimize mesh
6. if you are satisfied with this close the edit mode and now you build your 3D mesh of the corresponding row at first
7. finally select your zr-effect in the rows tab (top left) and hit "generate 3d mesh" again.

It is important that you build the 3D mesh of the main channel first and then build your 3d mesh of the zr-effect, otherwise the channel connection of the zr-effect cannot be established.

Finally, in the 3D view it should look like in picture 3.

Kind regards,
Holger

[DarylMusashi]

Dear SNeCu,
indeed it is normal that the zr-effect is shifted a few degrees in theta direction (around the axis of rotation). As both the channel as the zr-effect have periodic patches on each side is does not make any difference where the zr-effect is located. Secondly, AutoGrid automatically creates the interface to the main channel, as you have recognized already.

What you can do is to further work on your created AutoGrid mesh. Please open IGG and load the IGG file created by AutoGrid. With the "Transform Blocks" button (left panel, in the middle, two blocks with a "T") you can select your desired zr-effect blocks and rotate them so that they are aligned with the rest of the flow channel. Might that help?

[SNeCu]

Dear DarylMusashi,

Thank you for your advice. I am a beginner of NUMECA and not very familiar with its operations... I just followed your steps but the main problem is not the stagger but the difference of topology of interfaces between main channel and zr-effect, showed in the attachment figure. Therefore, it is very hard to set 'matching interfaces' in CFX. Moreover, I do not find any proper interfaces made automatically by Autogrid5 but there is also no error tips while 3D mesh is established in NUMECA... I feel very confuse now.

Originally Posted by DarylMusashi

Dear SNeCu,
indeed it is normal that the zr-effect is shifted a few degrees in theta direction (around the axis of rotation). As both the channel as the zr-effect have periodic patches on each side is does not make any difference where the zr-effect is located. Secondly, AutoGrid automatically creates the interface to the main channel, as you have recognized already.

What you can do is to further work on your created AutoGrid mesh. Please open IGG and load the IGG file created by AutoGrid. With the "Transform Blocks" button (left panel, in the middle, two blocks with a "T") you can select your desired zr-effect blocks and rotate them so that they are aligned with the rest of the flow channel. Might that help?

[SNeCu]

I found a paper which did a similar work :https://hal.archives-ouvertes.fr/hal-01517315/document

Originally Posted by DarylMusashi

Dear SNeCu,
indeed it is normal that the zr-effect is shifted a few degrees in theta direction (around the axis of rotation). As both the channel as the zr-effect have periodic patches on each side is does not make any difference where the zr-effect is located. Secondly, AutoGrid automatically creates the interface to the main channel, as you have recognized already.

What you can do is to further work on your created AutoGrid mesh. Please open IGG and load the IGG file created by AutoGrid. With the "Transform Blocks" button (left panel, in the middle, two blocks with a "T") you can select your desired zr-effect blocks and rotate them so that they are aligned with the rest of the flow channel. Might that help?

[DarylMusashi]

Dear SNeCu,
a channel matching connection might be a solution, which can be established by hitting "add matching z const lines" in the zr-effect edit mode (figure 1). Please leave the edit mode, in the meridional view you see three new z-const lines (from hub to shroud, figure 2). After creating the 3D mesh of the main channel and the 3D mesh of the zr-effect the result is shown in figure 3.

However, this works only if the zr-effect is upstream of the leading edge or downstream of the trailing edge. Maybe there is a solution directly in AutoGrid, but until now I did not manage to find it.

But maybe you wan to to further adjust the created zr-effect-blocks in IGG as you need it? You would need to extend the zr-effect-blocks downstream (in z-direction) and project the edges onto the edges of the main channel. In IGG geometric curves can be created from block edges, right-click an edge -> edge -> create geometry. Straight edges can be mapped onto geometric curves by hitting "i" (control point), which are dragged onto your desired curve then. As the shape of the zr-effect is constant in spanwise direction you may copy the created support curves of the main channel and translate its copies in positive spanwise direction (normally x).

[SNeCu]

It still a hard work to a rotor since the cross-section is different with different radius... Now I struggle with other software to do the job... The Numeca is really difficult... Anyway, thank you so much.

Originally Posted by DarylMusashi

Dear SNeCu,
a channel matching connection might be a solution, which can be established by hitting "add matching z const lines" in the zr-effect edit mode (figure 1). Please leave the edit mode, in the meridional view you see three new z-const lines (from hub to shroud, figure 2). After creating the 3D mesh of the main channel and the 3D mesh of the zr-effect the result is shown in figure 3.

However, this works only if the zr-effect is upstream of the leading edge or downstream of the trailing edge. Maybe there is a solution directly in AutoGrid, but until now I did not manage to find it.

But maybe you wan to to further adjust the created zr-effect-blocks in IGG as you need it? You would need to extend the zr-effect-blocks downstream (in z-direction) and project the edges onto the edges of the main channel. In IGG geometric curves can be created from block edges, right-click an edge -> edge -> create geometry. Straight edges can be mapped onto geometric curves by hitting "i" (control point), which are dragged onto your desired curve then. As the shape of the zr-effect is constant in spanwise direction you may copy the created support curves of the main channel and translate its copies in positive spanwise direction (normally x).

[SNeCu]

Dear DarylMusashi,

Recently I have tried to expand the casing radius in IGG, followed your guidance. I build a new block in IGG and one of its surface is mapped on the original channel shroud face. Two zr-effects before and after blade is drawn firstly in Autogrid and they both offer the new igg block two surfaces (front and back surfaces in axial direction).

The final results are shown in the attachments and it seems good at present. Thank you very much . Further modification will be conducted on the configuration of the block.

Originally Posted by DarylMusashi

Dear SNeCu,
a channel matching connection might be a solution, which can be established by hitting "add matching z const lines" in the zr-effect edit mode (figure 1). Please leave the edit mode, in the meridional view you see three new z-const lines (from hub to shroud, figure 2). After creating the 3D mesh of the main channel and the 3D mesh of the zr-effect the result is shown in figure 3.

However, this works only if the zr-effect is upstream of the leading edge or downstream of the trailing edge. Maybe there is a solution directly in AutoGrid, but until now I did not manage to find it.

But maybe you wan to to further adjust the created zr-effect-blocks in IGG as you need it? You would need to extend the zr-effect-blocks downstream (in z-direction) and project the edges onto the edges of the main channel. In IGG geometric curves can be created from block edges, right-click an edge -> edge -> create geometry. Straight edges can be mapped onto geometric curves by hitting "i" (control point), which are dragged onto your desired curve then. As the shape of the zr-effect is constant in spanwise direction you may copy the created support curves of the main channel and translate its copies in positive spanwise direction (normally x).