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-   -   boundary conditions for cyclone separator (http://www.cfd-online.com/Forums/cfx/77042-boundary-conditions-cyclone-separator.html)

siddhukb June 11, 2010 02:27

boundary conditions for cyclone separator
 
4 Attachment(s)
i am doing a gas-solid simulation of cyclone separator. In the solution i get the mass is not balanced.
i have attached pics of the domain settings.
can someone help me in showing where i went wrong or what is the correct settings?

i have given a velocity inlet with both air and aluminium having 10m/s and air is 0.9 and aluminium is 0.1 volume fraction
both overflow and underflow i have given pressure outlet with pressure of 0atm
Attachment 3725

Attachment 3726

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Attachment 3728

ghorrocks June 14, 2010 18:20

Please show your convergence results, and maybe post the CCL file.

siddhukb June 15, 2010 03:07

1 Attachment(s)
i have attached the ccl file

Thanks in advance
siddharth

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Attachment 3771

ghorrocks June 15, 2010 06:53

You are using a Reynolds Stress turbulence model. If you go to SST or some other more stable turbulence scheme it will be much more stable.

siddhukb June 15, 2010 07:11

but most of the journal i had studied suggested that Reynolds stress turbulence model is most suitable for cyclone separator


Thanks
siddharth

ghorrocks June 15, 2010 07:18

It is, but it will make convergence extremely difficult.

Get the basic model working with SST. Once everything is working with SST then switch back to RSM.

Also keep in mind that multiphase modelling introduces large simplifications. These simplifications can swamp the extra accuracy gained by RSM models. So if you have a have heavy multiphase interaction then I probably would not bother with RSM at all.

siddhukb June 15, 2010 07:53

will look into it.
I have one more doubt.
In the basic settings of the Domain -- Air is the continuous fluid. what should i define aluminium? cause i am confused in giving it as continuous fluid or dispersed solid or particle transport solid.

Thanks
siddharth

ghorrocks June 15, 2010 08:01

For a full answer to that question do a multiphase modelling course.

The quick answer is - light particle loadings - use particle tracking, heavy particle loadings use a Eularian approach.


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