Learning Forum

[smostafayi]

Hello everyone

I am trying to model CO2 dissolving from the gas phase to the liquid phase (water). In the manual for species mass transfer in the phase interaction, it is noted that : the gas phase must be selected as "to-phase". How should I consider the transfer of CO2 from the gas phase to the liquid phase (using Henry Law and two ressitance model"? Should I select the gas phase as "to-phase" ??! 

[Rob]

Yes. Fluent doesn't know what a gas or liquid is, so for phase change the "from" and "to" phases are important. The enthalpy is then used to work out the energy balance. Note, the disolution energy is different from the latent heat so you may need to check the material properties. 

[smostafayi]

Thank you for your response.

So, you mean whenever we want to have a mass transfer from the gas mixture to the liquid mixture, or vice versa, we should consider the gas phase as the "to-phase"?  

[Rob]

If that's the order in the manual, yes (I always have to check!). If the phase change is to the liquid Fluent will return a negative transfer coefficient, ie move the mass to the "from" phase. 

[smostafayi]

Thanks for answering. 

I am trying this model, but I have serious problems with the energy. The model gives very high temperature values for both phase, and I can not understand what can be the reason for this? Do you have any suggestion? What should I check?

[Rob]

If temperatures are very high check the boundary conditions and whether you've accidentally got an extra few 00s in the formation enthalpy of one phase or the other.