Hi Fatemeh

Did you try to construct a geometry which composes of three layers and then assign two sets of material, one for the outer layers and the second for the interior wall?

Hi

Thanks,I made two layers with two materials and I want, fluid transit from first layer to second layer. should I make one layer for interior wall? 

hi anyone

i try to put tow layer on each other and Flow and mass transfer from one to another. how can i do it?

Have you solved your problem, you can send in your file so that I can have  look.

Yes.

Thanks a lot.