# MultiFluid Vof Model

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 November 22, 2014, 14:34 MultiFluid Vof Model #1 New Member   yusuke uchihashi Join Date: Jan 2014 Posts: 19 Rep Power: 3 Hello! I'm so happy if you give me some advice. I want to use multi fluid vof model to study single bubble behavior. Questions 1.Can I use the model to study it? 2.What is the Diameter in the secondary phase dialog box? Is it the bubble diameter I want to study? Thank you!

November 22, 2014, 17:29
#2
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Lucky Tran
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Quote:
 Originally Posted by japanese student Hello! I'm so happy if you give me some advice. I want to use multi fluid vof model to study single bubble behavior. Questions 1.Can I use the model to study it? 2.What is the Diameter in the secondary phase dialog box? Is it the bubble diameter I want to study? Thank you!
1. Probably. The multifluid vof model is highly appropriate for bubbly flows in a liquid (dispersed bubbles in a flowing fluid). Is this what you have?
2. It's better described as an average particle size of the dispersed phase and typically the Sauter mean diameter is used. But it's basically going to become your bubble diameter. See section 17.5.5 in Fluent Manual for more details.

http://en.wikipedia.org/wiki/Sauter_mean_diameter

November 23, 2014, 11:14
#3
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yusuke uchihashi
Join Date: Jan 2014
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I study single bubble(diameter=3mm) behavior using VOF(1 fluid model).
So, I don't focus on bubbly flow.

I focus on the mass transfer from the gas to the liquid.
But I can't study the momentum transfer between the gas and the liquid using VOF(1 fluid model) (section 17.7.1).
I want to study it by two fluid model, because I can study the momentum transfer.

Question.
1.If I can study single bubble behavior using multi fluid vof, is the diameter 3mm in the dialog box (fig.1)?

Thank you!
Attached Images
 phase.jpg (28.0 KB, 6 views)

November 24, 2014, 16:33
#4
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Hello, I think VOF is not appropriate for bubbly flow, VOF is availabe when your phases have distinct layer, for example Slug.
for Bubbuly (velocity of 1st and 2nd phases are different according to their density) so Eulerian might be good choice as I know
This is what I know :-)

Quote:
 Originally Posted by japanese student Thank you very much for your reply! I study single bubble(diameter=3mm) behavior using VOF(1 fluid model). So, I don't focus on bubbly flow. I focus on the mass transfer from the gas to the liquid. But I can't study the momentum transfer between the gas and the liquid using VOF(1 fluid model) (section 17.7.1). I want to study it by two fluid model, because I can study the momentum transfer. Question. 1.If I can study single bubble behavior using multi fluid vof, is the diameter 3mm in the dialog box (fig.1)? Thank you!

November 24, 2014, 19:22
#5
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Lucky Tran
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Quote:
 Originally Posted by famon Hello, I think VOF is not appropriate for bubbly flow, VOF is availabe when your phases have distinct layer, for example Slug. for Bubbuly (velocity of 1st and 2nd phases are different according to their density) so Eulerian might be good choice as I know This is what I know :-)
Multi fluid VOF is an Eulerian model. Multi Fluid VOF is different than Volume of Fluid model.

 November 24, 2014, 23:51 #6 New Member   yusuke uchihashi Join Date: Jan 2014 Posts: 19 Rep Power: 3 I understand the difference between VOF and multi fluid VOF. I'll do my best for my reseach. Thank you for your reply!

 November 25, 2014, 00:05 #7 New Member   yusuke uchihashi Join Date: Jan 2014 Posts: 19 Rep Power: 3 If anyone has some ideas for my reseach, please tell me. My reseach: mass transfer from the gas(single bubble) phase to the liquid phase. Thank you!

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