Mass transfer
 

Hello
my project is:
The bubble column modeled in the simulation is semi-batch where air flows continuously through a batch layer of water-oil
The distributor inlet at the bottom of the vessel has only air flowing through it (air volume fraction =1).
,is the mass transfer really needed to completely simulate the flotation of oil?
if it needed,any model of mass transfer must i used, i mean Specified Mass Transfer or phase change or Cavitation?
Second question:
in fluid pair models just the two pairs
air-water
kerosene-water
appears in the tab, why the pair (air-kerosene) does not appear?
Thank you for help.

Why do you do CFD? What do you want to predict?
In other words: which question are you trying to answer with your CFD-calculations?

I want to simulation the flotation process (flotation of emulsion), three phase process (air-kerosene-water), as I mentioned in my question, is the mass transfer really needed to completely simulate the flotation of oil?

That did not answer my question. As an example:
- If I simulate a car, I want to know the Cw.
- If I simulatie a pump, I would like to know if it cavitates at a certain operation point, or the efficiency at a certain rpm.
- If I simulate a DAF-process (Dissolved Air Flotation), I want to know if the air bubbles distributie homogeneously over the incoming water, if they all leave the water with the emulsified solids at the top and do not end up in the clear water stream (carry-over).

So: what question are you trying to answer using CFD?
And what mass-transfer do you think you need? From where to where? Do you have dissolved air and want to include the mass transfer to air bubbles? Or something else? Please be as specific as you can be. Don't let us guess.

Regs, Gert-Jan

YES, i want to simulate DAF-process(Dissolved Air Flotation), The question is, do you expect mass transfer between air, oil or water?

It depends on how you setup your model and what question you are trying to answer. Do you work with Population Balances? Then there is mass transfer between the populations. But maybe you don't need it and are not interested in this. I don't know.

Also there is mass transfer from air in dissolved state to gas state. But, that is very difficult to model. Try to avoid that. But maybe you have to include it. I don't know.

I can't give advice if you don't want to tell what question you are trying to answer. Please be specific (last time).


Did you read this post: https://www.cfd-online.com/Forums/cfx/66198-before-you-post-question-please-read.html

jalalkheadr@gmail.com
please contact to me, in order to send the detail of the project