VOF and species transport
 

I'm trying to use the VOF model in conjunction with species transport. The system in question is an air bubble rising in a water filled column.

My question is as follows: If I assume the air bubble to be fully composed of oxygen and I wish to account for oxygen transfer from the bubble to the water surrounding it, what species would I include for the mixture-material that is defined. Also, if the entire system is assumed to be isothermal, can I turn off the energy equation in the Solve-> Controls Solutio panel?