CFD Online Logo CFD Online URL
Home > Forums > Software User Forums > ANSYS > FLUENT > Fluent Multiphase

Mixture model + VOF?

Register Blogs Members List Search Today's Posts Mark Forums Read

Like Tree2Likes
  • 1 Post By Zaktatir
  • 1 Post By mostafa_zeynalabedini

LinkBack Thread Tools Search this Thread Display Modes
Old   November 27, 2013, 17:11
Default Mixture model + VOF?
New Member
Join Date: Feb 2012
Posts: 13
Rep Power: 14
blacksoil2012 is on a distinguished road
I noticed that in Fluent, you have to first choose which multiphase model you want to use: VOF, Eulerian, or mixture. Once selected, the remaining settings will be under that specified multiphase framework.

However, I'm wondering about the possibility of doing having more than one multiphase method in one simulation. For example, for an open-channel slurry flow, where I have air-water free surface, which is natural to use VOF; On the other hand, in slurry I have solid particles that tend to settle down. For the particle-water system, I would like to use mixture model.

What do I do?

Right now, I see I may just choose the mixture model, by specifying water as the primary phase, and air and solid particles as secondary phase, with the secondary phases all having a "diameter". Of course, for air this diameter value will be artificial. I haven't started the simulation so am not sure whether it works (mainly whether this all mixture multiphase approach will work to resolve the water-air free surface).

On the other hand, in CFX, it seems like that the mixture model can be used together with other multiphase models, since there the mixture model uses only one phase("variable composition mixture"), which comprises of several components. Corresponding to my case, the components there will be my particles of different size. And I can have another phase air, and the interaction between the air phase and this "variable composition mixture" phase can have the free surface model, while inside the variable composition mixture phase I can select the algebraic slip model. So in summary, CFX seems to be natural to combine the algebraic slip mixture model with any other multiphase model; WHILE in Fluent it seems that I cannot do that.

Anybody familiar with this can give some comments? I think my case is somewhat related with open-channel hydraulics and sedimentation.

Thank you very much and have a nice Thanksgiving!
blacksoil2012 is offline   Reply With Quote

Old   November 30, 2013, 07:51
Senior Member
Join Date: Jan 2010
Location: Germany
Posts: 268
Rep Power: 17
Zaktatir is on a distinguished road

that's a very interesting simulation you are now struggling with.

VOF mixutre are one fluid formulation and that's why not appropriate for flows where phases separates and interpentrate each other.

For your Case: The Full eulerian approach with zonal discretisation: there you select the order of your volume discretisation: 0- For slurry regions till 2 for free surfaces. There you may use the multi-Fluid-VOf approach

Look into zonal handling in the documentation: there you find a discreption..
caunima likes this.
Zaktatir is offline   Reply With Quote

Old   February 8, 2014, 23:59
Default Vof+mixture
New Member
Join Date: Jun 2013
Posts: 22
Rep Power: 13
mostafa_zeynalabedini is on a distinguished road
hello all
I want to use two multiphase model in one simulation. I mean VOF for gas and mixture fluid to find the interface and mixture model for the mixture fluid. Is there any option in FLUENT or CFX to do that using the FLUENT own models?
I think also about using VOF as a Platform in solving and use UDS to model the mixture phase. But in this way I should develop a UDS for mixture model that could not be as good as FLUENT own model!
Far likes this.
mostafa_zeynalabedini is offline   Reply With Quote


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
Superlinear speedup in OpenFOAM 13 msrinath80 OpenFOAM Running, Solving & CFD 18 March 3, 2015 05:36
Modelling Sand erosion using Mixture model and DPM karlchapman FLUENT 3 July 5, 2012 08:55
plz rply urgent regrding vof model for my system garima chaudhary FLUENT 1 July 20, 2007 08:37
urgent query regarding vof model plz rply Garima Chaudhary FLUENT 0 July 13, 2007 02:20
evaporation multiphase model ( vof? mixture ? ) emanuele FLUENT 0 March 2, 2007 11:44

All times are GMT -4. The time now is 04:38.