3D Evaporation modeling from porous media
 

Hi,
I am trying to model evaporation of water from a porous media created with 3-layers of similar size spheres (2.2 mm) in a 10-mm-height, 5-mm-dia beaker. I am also applying a heat flux of 500 W/m2 on top by a lamp.
What multiphase model should I use to model it in 3D? I do have the CAD file of the porous structure? Can I use it? Or can I have one of the similar examples?