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Meshing in the space between two spheres

Posted Mar 24, 2011, 2:26 a.m. EDT Geometry, Mesh Version 4.0 6 Replies

Pardha Saradhi
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Hii

I have got a packed bed of catalyst particles(spheres). I am working in 3D using 4.0 version. I am unable to mesh in the space between three spheres.Also, the space between the reactor wall and spheres is not meshed. I am using free tetrahedral mesh. I tried by meshing in the remaining geometry, also using all domains options but the free space between reactor wall and the spheres is not meshed. Please help me in this aspect.
6 Replies Last Post Mar 28, 2011, 1:56 a.m. EDT
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Mar 24, 2011, 5:07 a.m. EDT
Hi

is it really not meshed, or is it that you do not see the mesh ?

If you get a meshing error its often related to the mesh size, particularly if you have silver faces and tangent intersection with multiple loops, then often it helps to subdivide the volume slightly by internal cuts

--
Good luck
Ivar
Hi is it really not meshed, or is it that you do not see the mesh ? If you get a meshing error its often related to the mesh size, particularly if you have silver faces and tangent intersection with multiple loops, then often it helps to subdivide the volume slightly by internal cuts -- Good luck Ivar
Pardha Saradhi
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Posted: 1 decade ago Mar 25, 2011, 2:06 a.m. EDT
Hii

Thanks a lot for the reply.

Its really not meshed. In 2D I can find an option to select the domain other than the spheres. But in 3D although there is domain selection option, I am not able to find out the free space between the spheres as a domain to mesh. I have attached two image files, one showing the geometry and the other clearly showing that the space between spheres is not meshed although I have done meshing in all the domains. This is because there is no such domain to select. How do I get the space between the spheres as a domain to mesh?

Thanks in advance.
Hii Thanks a lot for the reply. Its really not meshed. In 2D I can find an option to select the domain other than the spheres. But in 3D although there is domain selection option, I am not able to find out the free space between the spheres as a domain to mesh. I have attached two image files, one showing the geometry and the other clearly showing that the space between spheres is not meshed although I have done meshing in all the domains. This is because there is no such domain to select. How do I get the space between the spheres as a domain to mesh? Thanks in advance.

Attachments:

Edgar Kaiser
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Posted: 1 decade ago Mar 25, 2011, 4:03 a.m. EDT
Hi,

it appears like you simply don't have a domain between your spheres. I think you must create a 'container' for your spheres assembly. Can be a big spere or a cube or a cylinder around your assembly.

You will need to suppress the visualization of the outer boundaries to see the meshing inside and you will need to define crosssections to see the meshing between the spheres.

Best regards
Edgar
Hi, it appears like you simply don't have a domain between your spheres. I think you must create a 'container' for your spheres assembly. Can be a big spere or a cube or a cylinder around your assembly. You will need to suppress the visualization of the outer boundaries to see the meshing inside and you will need to define crosssections to see the meshing between the spheres. Best regards Edgar
Pardha Saradhi
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Posted: 1 decade ago Mar 25, 2011, 7:30 a.m. EDT
Hiii

Thanks for the reply

The geometry contains a cylinder around the packed bed of spheres. In order to show you the meshing between the spheres the container was kept hidden. Even the space between the container wall and packed bed was not meshed. Why am I not able to get the space as a domain in 3D where as in 2D I can easily select the space between the spheres as a domain. Please find the attached files which illustrates this.

Thank you in adv..awaiting your reply
Hiii Thanks for the reply The geometry contains a cylinder around the packed bed of spheres. In order to show you the meshing between the spheres the container was kept hidden. Even the space between the container wall and packed bed was not meshed. Why am I not able to get the space as a domain in 3D where as in 2D I can easily select the space between the spheres as a domain. Please find the attached files which illustrates this. Thank you in adv..awaiting your reply
Edgar Kaiser
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Posted: 1 decade ago Mar 25, 2011, 8:49 a.m. EDT
Hi,

try to visualize the mesh on a slice that intersects the whole assemly through the origin. If you have this cylinder in your geometry then there must be a domain.
It is just not straightforward to visualize a mesh in 3D space. You need a surface to do that. Like the surfaces of the spheres.
In space you need some kind of auxiliary surface and this can be achieved by a slice in post processing. I would really be surprised if this didn't show you the mesh.

Regards
Edgar
Hi, try to visualize the mesh on a slice that intersects the whole assemly through the origin. If you have this cylinder in your geometry then there must be a domain. It is just not straightforward to visualize a mesh in 3D space. You need a surface to do that. Like the surfaces of the spheres. In space you need some kind of auxiliary surface and this can be achieved by a slice in post processing. I would really be surprised if this didn't show you the mesh. Regards Edgar
Pardha Saradhi
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Posted: 1 decade ago Mar 28, 2011, 1:56 a.m. EDT
Thank you. I will check it out.

Thank you. I will check it out.

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