Learning Forum

[mesakca]

I have a bubble column problem. A cylindrical column of 6 cm diameter and 1 m length, full of water. Ozone gas is introduced through the bottom of the column with a certain flow rate. The bottom, where gas is introduced has a certain porosity and pore size. 

My question is; 

Should the gas inlet be a porous material? If not, for the inlet velocity can i take it (flow rate/area x porosity) and introduce the bubble diameter as pore size of the bottom inlet? Would this be OK?

edit: I am using ANSYS Fluent R19.2 by the wat

 

 

 

[Karthik Remella]

Hello,

It depends on the purpose of your simulation. If you are looking at the individual bubble scale, then you might need to introduce the bubbles at the pore scale. If you are looking for more bulk phenomena and are not worried about the individual bubbles and their interaction, then you can use an effective area at the bottom as an inlet.

Thanks.

Best,
Karthik

[mesakca]

Thank you for your respond sir

My purpose is to simulate dissolved ozone concentration through the column, rather than the individual fate of bubbles. So i do not need to assign a porosity to my inlet, am i right?

[Amine Ben Hadj Ali]

you just need to account for the effective area. You can use mass flow rate at inlet and provide the porosity as volume fraction. Set the mass flow rate of the other phase at inlet to be zero.

[mesakca]

Thank you sir

[mesakca]

I have one more question sir

I have two phases. one is water + ozone and another is ozone + dummy ozone

if i provide porosity as volume fraction for secondary phase (ozone + dummy ozone) at mass flow inlet, wouldn't fluent consider the rest of the incoming flow to be primary phase (water+ozone)?

Thank you.

 

[Amine Ben Hadj Ali]

No because you will provide zero as mass flow.

[mesakca]

Thank you very much

[Amine Ben Hadj Ali]

Welcome!