Flowsimulation how to split box in to 2 fluid subdomains?

Dear readers,

I'am currently working on a tile witch contains air and water and needs to absorb and conduct heat.
I had made a lid in the box to divide the water and air from each other, but flowsimulation sees the lid as a barrier between them.
There is no heatconduction between them!

How can i properly setup the model so it does ?


Thanks in advance


Greetings
Koen
The Netherlands

SolidworksFlow Simulation