[ICEM] problem with pre-mesh preview

amin.nbkh · July 3, 2015, 08:56

hello experts,

I am working on a high twisted blade and I tend to generate a structured mesh on it. after blocking, when I turned the pre-mesh on, I couldn't see any elements. I have two questions:

1- what do you think about blocks in this model? does it work or I should block it once again from the beginning?

2- how can I view generated grid while I have about 18000 elements?

the attachments are some pictures that may help.

Blocking.PNG

Bocking2.PNG

curves.PNG

FJSJ · July 6, 2015, 05:44

Hi Amir,

I am not sure about your problem when you are trying to visualize your cfd-mesh but, have you set the number of elments that you want in the different edges inside "Pre-mesh param"? The number of element by defoult is 2 per edge.

For other hand, you can find different threads about blade meshing. Here an example

:

[ICEM] High Stagger Rotor Blade Meshing

amin.nbkh · July 16, 2015, 07:33

Hi fjsj,

thank you for your reply,
yes, I have already set the No. of nodes on each edge in edge-params

I don't know if there is something to do with edge associations. further recommendations on this topic would be more appreciated.

hefy · July 17, 2015, 07:19

Hi amin,

First I'd like to give a comment on the blade form. Blade is less or more twisted in the span-wise direction - from hub to the top/shroud. For that matter, your blade is an unsophisticated example.

About the blocking:
Special blocks close to the shroud are unnecessary. Condensing of the grid at the top can be achieved by appropriate selection of the edge parameters in span wise direction. A larger number of blocks along the centreline of the blade is not required. See comment and suggestion of FJSJ.
The origin of the main problem is uncontrolled association of the blocks edges. In Blocking > Edges turn on: <Show Association> and <Projected Edge Shape> as well as correct the association of individual edges. When the edges of the blocks are identical with the geometry curves, this is an indicator of the correct Pre-Mesh.

Regards

amin.nbkh · July 17, 2015, 07:50

Hi hefy,

what is your special suggestion about this case? you mean I should merge all the blocks between shroud and tip of the blade?

hefy · July 17, 2015, 15:19

Hi amin,
Yes, where you have now 23 pairs of blocks in spanwise, these merge into 23 blocks of blade computational domain. Then you can 18 blocks around the blade reduce as well by merging into 9 blocks. Meanwhile, do not overlook the circular periodicity of vertices.

July 3, 2015, 08:56	problem with pre-mesh preview	#1
amin.nbkh New Member amin Join Date: Jun 2015 Posts: 5 Rep Power: 10	hello experts, I am working on a high twisted blade and I tend to generate a structured mesh on it. after blocking, when I turned the pre-mesh on, I couldn't see any elements. I have two questions: 1- what do you think about blocks in this model? does it work or I should block it once again from the beginning? 2- how can I view generated grid while I have about 18000 elements? the attachments are some pictures that may help. Blocking.PNG Bocking2.PNG curves.PNG

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July 6, 2015, 05:44		#2
FJSJ Senior Member Javi Join Date: Jan 2013 Posts: 276 Rep Power: 16	Hi Amir, I am not sure about your problem when you are trying to visualize your cfd-mesh but, have you set the number of elments that you want in the different edges inside "Pre-mesh param"? The number of element by defoult is 2 per edge. For other hand, you can find different threads about blade meshing. Here an example : [ICEM] High Stagger Rotor Blade Meshing

July 16, 2015, 07:33		#3
amin.nbkh New Member amin Join Date: Jun 2015 Posts: 5 Rep Power: 10	Hi fjsj, thank you for your reply, yes, I have already set the No. of nodes on each edge in edge-params I don't know if there is something to do with edge associations. further recommendations on this topic would be more appreciated.

July 17, 2015, 07:19		#4
hefy New Member Eduardo Hoefler Join Date: Jun 2015 Posts: 8 Rep Power: 10	Hi amin, First I'd like to give a comment on the blade form. Blade is less or more twisted in the span-wise direction - from hub to the top/shroud. For that matter, your blade is an unsophisticated example. About the blocking: Special blocks close to the shroud are unnecessary. Condensing of the grid at the top can be achieved by appropriate selection of the edge parameters in span wise direction. A larger number of blocks along the centreline of the blade is not required. See comment and suggestion of FJSJ. The origin of the main problem is uncontrolled association of the blocks edges. In Blocking > Edges turn on: <Show Association> and <Projected Edge Shape> as well as correct the association of individual edges. When the edges of the blocks are identical with the geometry curves, this is an indicator of the correct Pre-Mesh. Regards

July 17, 2015, 07:50		#5
amin.nbkh New Member amin Join Date: Jun 2015 Posts: 5 Rep Power: 10	Hi hefy, what is your special suggestion about this case? you mean I should merge all the blocks between shroud and tip of the blade?

July 17, 2015, 15:19		#6
hefy New Member Eduardo Hoefler Join Date: Jun 2015 Posts: 8 Rep Power: 10	Hi amin, Yes, where you have now 23 pairs of blocks in spanwise, these merge into 23 blocks of blade computational domain. Then you can 18 blocks around the blade reduce as well by merging into 9 blocks. Meanwhile, do not overlook the circular periodicity of vertices.