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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,

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.

ghorrocks April 14, 2010 06:09


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.

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