Hi everyone!


So I am looking to simulate the buoyancy-induced convection of a lower density fluid underlying a fluid of higher density. While this simulation seems straight forward, I'm struggling to get a species transport phenomena included in this. 

1. Phase 2 (lower density) is at the bottom section of the pipe while phase 1 (higher density) lies above it. 

2. Phase 2 is of lower density due to the presence of a gas (either CO2 or CH4) dissolved in it, I need this to be dissolved and not a mixture wherein the gas and phase -2 exist as two different phases in the bottom section. To keep it simple, phase 1 and phase 2 are just pure water to start with.

3. How do I activate the mass transport of the dissolved gas from phase-2 to phase-1 as phase-2 moves upwards due to buoyancy-induced convection?

4. How do I ensure that the gas in phase-2 exists as dissolved gas when I initialize rather than a separate phase?

5. I want to add 0.5 moles of CO2 in phase-2 at the first time step as it is the amount of gas that can be dissolved in water at 400 psi - the corresponding density should be lower than 998 kg/m3 which is that of pure water.

6. Should I use the Eulerian mutiphase model and also which would be the right model to use under phase interactions?

I have attached a file which would better help explain the separation of fluids in the pipe. Final output required is the concentration of the gas transferred from phase-2 to phase-1 after a specified interval of time.