[oliveira1820]

I´m simulating the phase change between water liquid and water vapour and I want to define a cylindrical heat (energy) source in my fluid domain constant in time.

When I had only one fluid in my domain I defined a CEL source inside the subdomain that corresponded to the domain itself.

Now I only got the bulk source option ( which varies with the volume fraction and I want the source to be cosntant with time) and fluid source defined for each fluid independently.

How can I define a constant heat (energy) source with a especific geometry in my fluid domain like it was only one fluid?

First Image - One fluid Source
Second Image - Two fluid Source

[Gert-Jan]

I guess you use H2Ovl and want to add heat to liquid, not? (or cool the vapour for condensation). If you were able to do that, then with H2Ovl the heat would be converted instantly into vapour, since the model assumes equilibirum(!).
So, if you add or remove energy, the equilibrium will shift immediately. In other words, mass and heat transfer are assumed to be infinitely fast. Therefore it does not matter whether if you modify the vapour or the liquid using a specific source: you see a "Total Source".

If you want to add heat to the liquid solely, then the liquid and vapour are not in equilibrium anymore. For that, you should separate the two phases and define your own liquid and vapour, and create your own heat and mass transfer rates. So you will create your non-equilibrium model. That is doable, but not easy and it is a lot of work.