Learning Forum

[KORAY2255]

Referring to page 713 of Fluent Theory Guide for 20.2 only vapor transport equation is introduced. To clarify, we must select the vapor phase as secondary phase since the continuity equation is solved for the secondary phase in VOF, is it? n

[Rob]

We solve for both phases, so we assign primary & secondary as desired. I'm not sure what section you're referring to as the documentation doesn't really have page numbers any more: can you post the link?n

[DrAmine]

I think you are referring to the fact that in Fluent for all multiphase models with one exception we just solve for N-1 phase transport equations of phase mass conservation equation + pressure based bulk conti equation.n

[KORAY2255]

The section I mentioned is attached. I am confused how to model evaporation & condensation (i.e liquid film and vapor bubbles) simultaneously. And I could not get an opinion from your answers.nn

[DrAmine]

The model will based on the cell temperature and the provided saturation temperature / curve /table either provide a mass transfer from liquid to vapor (evaporation) or from vapor to liquid (condensate).n

[KORAY2255]

I see, but how to assign primary & secondary phases. And how many mass transfer for both evaporation & condensation with Lee model?n

[Rob]

Primary and secondary phases are assigned as normal in the Multiphase panel, you then set the rest of the phase interactions, mass transfer etc in the tabs in that panel. Be aware that some models require the mass transfer to be from liquid to gas phase but this is covered in the relevant section of the User's Guide. n

[DrAmine]

Another question what do you want to do?n

[KORAY2255]

Thank you, I am trying all the cases..n