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-   -   Marbles in the pipe like trumpet-shaped (http://www.cfd-online.com/Forums/floefd-floworks-flotherm/97443-marbles-pipe-like-trumpet-shaped.html)

JosephKim February 17, 2012 03:39

Marbles in the pipe like trumpet-shaped
 
Analysis Model shaped like trumpet.

Inlet is small circle, Outlet is big circle. Can you imagine that?
And so many Marbles are in the model randomly.
When air thruogh trumpet-shaped, how will flow shape changed?

The problem is this.
At a time like this, how can I modeling mables that in the trumpet-shaped.:confused:

Can I using patterns?
or Anyother easy solution?

Boris_M February 21, 2012 11:50

Hi Joseph,

I'm not sure I understand you correctly. You want to know how to model a marble (sphere) that is placed somewhere in your trumpet like model?

This is a CAD related task and very easy to do. Ideally you create a new part with just the sphere in the size you need and build this part as often into your trumpet assembly as you need. You can position it by using the "Move Component" feature and simply drag it to the location you want it to be.

Regards,
Boris

JosephKim February 21, 2012 21:26

Thank you for your conciderate reply.
You understand correctly. But the more I made spheres, the more computer slow performance. Because there are several thousand shperes. So.. I have to simplify the model.. And I got a result that is competent.

I have one more questions.
What is difference between 'Cells' and 'Fluid Cells' ?
Accroding to the result of property report,
Cells are 866568 and Fluid Cells are 615386.

Why different the number between Cells and Fluid Cells?
And What is Cells?

Boris_M February 22, 2012 03:34

Hi Joseph,

Ok, if there are several thousand spheres it explains the slowing down of the computer. What do you want to do with the spheres, what shall they represent and what is their diameter?

There are three cell types:
Solid Cells
Fluid Cells
Partial Cells

Depending on if you use heat conduction in solids, you will have solid cells or not. Fluid cells are the cells that are completely fluid and partial cells are the cells that intersect with the geometry, basically solid-fluid portions in the cell or in case you use different solid materials solid-solid portions with the different material properies.
"Cells" then are the over all count of cells so solid+fluid+partial cells. In your case you would have additional 251182 partial cells.

Is the model you try to create a muffler as they are used in pneumatics made from sintered metal spheres?

JosephKim February 22, 2012 10:17

Wow.. Thank you Boris. I understand perfectly.

Sphere is catalyst. It is actually not shpere perfectly. Almost like sphere.
Diameter is about 5 mm.

I want to know gas flow shape when the gas through the space(trumpet-shaped) that filled with small catalysts. Does the gas will evenly spread the whole of space? That is important. because the gas should spread evenly, respond with catalysts very well.
So I want to see the stream of gases.

Boris_M February 22, 2012 10:33

Ah, I understand. Of course then you cannot really use the porouse media approach. This would probably simplify it too much.
You can use porous media if it's just about the pressure loss and roughly about the distribution but for a detailed simulation on the gas flow between the spheres this would not be detailed enough.

Boris

JosephKim February 22, 2012 20:22

Ok. I will try use out a porouse media approach.
And I will try simplify a whole of model, too.

Conversation with you is a great help to me. Thank you. :)

Boris_M February 23, 2012 03:16

Yes, in case you use a porouse media you can get the pressure drop (if unknown) similar to the way I did but with your spheres:
http://go.mentor.com/21kh8

No problem,
Boris


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