CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   CFX (http://www.cfd-online.com/Forums/cfx/)
-   -   Multiphase analysis (http://www.cfd-online.com/Forums/cfx/74897-multiphase-analysis.html)

dev325 April 11, 2010 09:42

Multiphase analysis
 
I am trying to learn the CFX capability for performing multiphase (air + water) analysis. When I get results, I get two heat transfer coefficients viz "Air. Heat Transfer Coefficient" and "Water. Heat Transfer Coefficient". How do I interpret the results to find the effective heat transfer coefficient?

ghorrocks April 11, 2010 20:23

This is all discussed in the documentation, see under solver modelling/multiphase/boundary conditions/wall boundaries

dev325 April 12, 2010 11:59

Dear Mr. Horrocks,

Thanks a lot. I could get the documentation. When I run some of the cases (flow inside the pipe) I get the following message. Can you indicate the type and extent of inaccuracy in analysis due to the same?

****** Notice ******
A wall has been placed at portion(s) of an OUTLET
boundary condition (at 1.4% of the faces, 2.4% of the area)
to prevent fluid from flowing into the domain.
The boundary condition name is: Outlet.
The fluid name is: Air at 25 C.
If this situation persists, consider switching
to an Opening type boundary condition instead.

With best regards,
Dev325

ghorrocks April 12, 2010 18:27

This question has been asked thousands of times. Do a search on the forum for comments on this issue.

AliTr April 13, 2010 19:33

Change your Outlet BC into an Open BC and use hydrostatic pressure through CEL.

dev325 April 13, 2010 22:17

I would go through the posts more carefully and thoroughly.
Thanks.

ghorrocks April 14, 2010 06:09

Quote:

Change your Outlet BC into an Open BC and use hydrostatic pressure through CEL.
This is one approach and there are many others. Sometimes this approach is not a good choice - but again this issue has been discussed thousands of times so search the forum for a complete discussion.


All times are GMT -4. The time now is 18:20.