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-   -   Problem in free surface modeling of water-oil mixture (http://www.cfd-online.com/Forums/fluent/71682-problem-free-surface-modeling-water-oil-mixture.html)

scythe January 12, 2010 03:24

Problem in free surface modeling of water-oil mixture
 
I want to model a free surface flow of oil-water mixture in Fluent. I have used VOF model, but I cannot set volume fraction of oil in water when I enable open channel option.
Any help would be highly appreciated
Regards

CFDtoy January 12, 2010 10:18

Free surface flow
 
Hi ,
Do want to keep oil and water separate and simulate the interfacial dynamics? or you have a "mixture" of oil and water and you want to simulate the interface between oil-water mixture and some gas around?

For, initializing oil in water etc..you may want to use the "patch" option - select cells with water and patch vf of oil in those regions.

Thanks,

CFDtoy
visit http://cfdtoy.blogspot.com



Quote:

Originally Posted by scythe (Post 242259)
I want to model a free surface flow of oil-water mixture in Fluent. I have used VOF model, but I cannot set volume fraction of oil in water when I enable open channel option.
Any help would be highly appreciated
Regards


scythe January 12, 2010 10:53

Quote:

Originally Posted by CFDtoy (Post 242316)
Hi ,
Do want to keep oil and water separate and simulate the interfacial dynamics? or you have a "mixture" of oil and water and you want to simulate the interface between oil-water mixture and some gas around?

For, initializing oil in water etc..you may want to use the "patch" option - select cells with water and patch vf of oil in those regions.

Thanks,

CFDtoy
visit http://cfdtoy.blogspot.com

Thanks for the reply
The inlet boundary condition is an immiscible mixture of water and oil, for example an oil with 200 ppm water as the inlet flow enters the domain with velocity of 0.7 m/s, and as you know because of the difference between the densities of oil and water, the oil phase tends to move upward and this effects the velocity profile. All I want is to find the velocity profile at different sections.
I am looking forward to hearing from you soon
Thanks again

CFDtoy January 12, 2010 11:21

oil problem
 
Hi,
For this try eulerian-lagrangian type modeling with buoyancy effects. You are looking at more the averaged distribution of the fractions and their effect on velocity profile. Eulerian modeling will give you that - inclusive of velocity difference.

but again, if you think this is a dilute assumption: use Eulerian-lagrangian type modeling and treat the dispersed part (water droplets) as embedded in the continuous (oil) flow and track their behavior.

you dont need VOF to get the interface tracking or capture the droplets ..its may consume too much comp resources and time.

I have posted an entry on my blog concerning doing Eulerian-Lagrangian modelign and where it should be considered.


Thanks,

CFDtoy
Visit http://cfdtoy.blogspot.com


Quote:

Originally Posted by scythe (Post 242321)
Thanks for the reply
The inlet boundary condition is an immiscible mixture of water and oil, for example an oil with 200 ppm water as the inlet flow enters the domain with velocity of 0.7 m/s, and as you know because of the difference between the densities of oil and water, the oil phase tends to move upward and this effects the velocity profile. All I want is to find the velocity profile at different sections.
I am looking forward to hearing from you soon
Thanks again


Volumeoffluid November 12, 2013 12:47

Hi all,
the line between oil-water how did you define this??
as wall??as what and with what specifications?
Thank yoU!


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