[fan01]

I want to model a two phase flow (vapor & liquid) with two components. Both components are miscible and at steady state the two fluid complete mix and becomes a single phase. The system is isothermal, so i am neglecting energy equation. The fluid flow is governed by continuity, momentum and species equation.

which of the two phase model can I use to solve this problem in Fluent or CFX? VOF method is not applicable to this problem since there is mixing and the interface vanishes after a while.

mechanism governing interfacial transfer between the phases include dissolution of the gas phase into the liquid phase and vaporization of the liquid phase into the gas phase.

[granzer]

Originally Posted by fan01

I want to model a two phase flow (vapor & liquid) with two components. Both components are miscible and at steady state the two fluid complete mix and becomes a single phase. The system is isothermal, so i am neglecting energy equation. The fluid flow is governed by continuity, momentum and species equation.

which of the two phase model can I use to solve this problem in Fluent or CFX? VOF method is not applicable to this problem since there is mixing and the interface vanishes after a while.

Mechanisms governing interfacial transfer between the phases include dissolution of the gas phase into the liquid phase and vaporization of the liquid phase into the gas phase.

I am new to this too. This sounds like a multiphase flow with species transport in Fluent So maybe you should try VOF with species transport since initially the problem requires interface tracking.

[fan01]

Originally Posted by granzer

I am new to this too. This sounds like a multiphase flow with species transport in Fluent So maybe you should try VOF with species transport since initially the problem requires interface tracking.

Thank you for suggestion.

[LoGaL]

The problem is exactly that at the beginning of your simulation you will need to use a VOF like technique, while later not. It’s very tricky simulation.

Perhaps mixture model can work. Also, if you expect at one point one of the fluids to be much more diluted than the other, could be worth looking also at VOF to DPM. Again, only if one is very diluted.

But again, this is tricky stuff I think

[fan01]

Originally Posted by LoGaL

The problem is exactly that at the beginning of your simulation you will need to use a VOF like technique, while later not. It’s very tricky simulation.

Perhaps mixture model can work. Also, if you expect at one point one of the fluids to be much more diluted than the other, could be worth looking also at VOF to DPM. Again, only if one is very diluted.

But again, this is tricky stuff I think

I expect that at a critical point, which is defined by the pressure and mass fraction of the mixture, the vapor phase becomes completely miscible with the liquid phase. And the gas phase vanishes away remaining just a single liquid phase containing both components.

[granzer]

Originally Posted by fan01

I expect that at a critical point, which is defined by the pressure and mass fraction of the mixture, the vapor phase becomes completely miscible with the liquid phase. And the gas phase vanishes away remaining just a single liquid phase containing both components.

You can try VOF model with phase interaction. Else try Eulerian model too if you have access to the computational power to run it..since Eulerian model is much more general and can work as both VOF and Mixture model.