# interFoam / bubbleFoam to simulate an aerated tank

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September 1, 2009, 09:22
interFoam / bubbleFoam to simulate an aerated tank
#1
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Baptiste Merat
Join Date: Aug 2009
Posts: 1
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Hello,

I am a student in applied mathematics and quite new to OpenFOAM. I have been using it for a few months and read part of Henrik Rusche's thesis but I am still facing some difficulties.

I would like to simulate a tank with a gas inlet at the bottom of the tank and an inlet of liquid on the left. The outlet of liquid is on the right side of the tank and in the final simulation that shall be a free overflow outlet.
To do so, I have already tried with both interFoam and bubbleFoam. The attached files show some results.

I want to compute for a balance of gas and liquid inside the tank to check that the Gauss' theorem is fulfilled. Yet, it seems to me that the VOF method used in interFoam is computing for only one velocity field for both phases. Only one vector U is written out.

My first question is therefore how one could then e.g. detect rising air in the liquid phase?

Is there a way to discern the velocities of the two phases?

Some other combined cases (free surface plus aeration) are also interesting me. For instance, taking into account the effect of a structure in an aerated tank such like a wall that may involve waves at the interface between air and water, (i. e. the water surface). The letter may be achieved by interFoam, whereas bubbleFoam seems more appropriated to model the aeration of the tank.

In a second example, if the aeration field is close to the outlet, both gas and liquid may go out of the tank by the outlet and the flow situation of the free overflow surface would be influenced by the bubble flow.

Is it possible to combine the two solvers in such a way that the two models are either solved together or interdependent with the disperse approach inside the liquid and the VOF for the free surface resp.? Is there perhaps already a tutorial/example available?

Best regards,

Baptiste
Attached Images
 interFoam.jpg (35.2 KB, 205 views) bubbleFoam.jpg (35.3 KB, 168 views)

June 8, 2011, 09:08
#2
New Member

Amine
Join Date: May 2011
Location: CAEN
Posts: 1
Rep Power: 0
Quote:
 Originally Posted by Meratb Hello, I am a student in applied mathematics and quite new to OpenFOAM. I have been using it for a few months and read part of Henrik Rusche's thesis but I am still facing some difficulties. I would like to simulate a tank with a gas inlet at the bottom of the tank and an inlet of liquid on the left. The outlet of liquid is on the right side of the tank and in the final simulation that shall be a free overflow outlet. To do so, I have already tried with both interFoam and bubbleFoam. The attached files show some results. I want to compute for a balance of gas and liquid inside the tank to check that the Gauss' theorem is fulfilled. Yet, it seems to me that the VOF method used in interFoam is computing for only one velocity field for both phases. Only one vector U is written out. My first question is therefore how one could then e.g. detect rising air in the liquid phase? Is there a way to discern the velocities of the two phases? Some other combined cases (free surface plus aeration) are also interesting me. For instance, taking into account the effect of a structure in an aerated tank such like a wall that may involve waves at the interface between air and water, (i. e. the water surface). The letter may be achieved by interFoam, whereas bubbleFoam seems more appropriated to model the aeration of the tank. In a second example, if the aeration field is close to the outlet, both gas and liquid may go out of the tank by the outlet and the flow situation of the free overflow surface would be influenced by the bubble flow. Is it possible to combine the two solvers in such a way that the two models are either solved together or interdependent with the disperse approach inside the liquid and the VOF for the free surface resp.? Is there perhaps already a tutorial/example available? Best regards, Baptiste
hi, i am new in OpenFoam, I would similate bubbleFoam with interFoam, ie: inlet is wave, outel is pressure but I can't introduce the air bubble at bottom....
how can I do this plz????

Nb: excuse me for my worst english!!

cordialement.

June 9, 2011, 07:35
#3
Senior Member

Santiago Marquez Damian
Join Date: Aug 2009
Location: Santa Fe, Santa Fe, Argentina
Posts: 452
Rep Power: 23
Quote:
 Originally Posted by Meratb [...] Some other combined cases (free surface plus aeration) are also interesting me. For instance, taking into account the effect of a structure in an aerated tank such like a wall that may involve waves at the interface between air and water, (i. e. the water surface). The letter may be achieved by interFoam, whereas bubbleFoam seems more appropriated to model the aeration of the tank. [...] Is it possible to combine the two solvers in such a way that the two models are either solved together or interdependent with the disperse approach inside the liquid and the VOF for the free surface resp.? Is there perhaps already a tutorial/example available? Best regards, Baptiste
Baptiste, there are some approaches to your topic:

http://www.sciencedirect.com/science...2199910196810X

http://onlinelibrary.wiley.com/doi/1....2978/abstract

this topic is quite novel and solutions are, a sometimes, a bit specific. There is another approach by Bohorquez using VOF+mixture, but between air-water-particles:

http://infoscience.epfl.ch/record/13...ezPatricio.pdf

I'm following this approach to solve cases like yours, i.e. aerated tanks, pipes with different size bubbles, etc. I'm working on the model combination right now, maybe we can share some experiences, papers, test-cases, experiments.

Regards.
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November 6, 2020, 11:45
#4
Senior Member

Join Date: Nov 2019
Posts: 205
Rep Power: 7
Dear Friends
I am simulating aerator in a large tank. Since I am simulating both aerator and large tank at the same time, I want to use the same mesh size all over the domain to avoid different timescales(eg if I use smaller mesh for aerator, my time step will be much smaller). To do so, I have used fvOptions to generate a source of momentum to push the water out of the channels and also suck the water to the aerator(You can see it as a red cylindrical momentum source).

I have done all aforementioned things using pimplefoam(I am just working with water instead of water and air mixture), but my simulation is instable. Now, I have two questions;
1- How can make it stable?

2- Is there any other way I can simulate the outlet of the channels without considering the aerator chamber? If so, what is happening to continuity equation? since mass increases inside the domain without any outlet.

3- Do you have any other suggestion for me?

Thanks,
Attached Images
 photo_2020-11-06_15-00-28.jpg (33.8 KB, 7 views)