Extruded 2D Mesh

mayis

I'm using extruded 2d mesh in CFX. My volume (air) has totaly 2.1 mm thickness. In the middle, I have a 0.1 mm solid body. I splitted my volume to 3 part 1 mm -0.1 mm -1 mm (thicknesses) on z direction. I did it to have periodic pairs. Air is covering the solid and to use 2d extruded mesh ı have to have periodic pairs. But my problem is when ı finish the mesh, 0.1 mm solid is looking as it has 1 mm thickness and it is becoming apart from the air( I mean I'm having a meaningless blank in the volume). Can anyone explain me what can I do!? I need help...! ı can also use another methods in cfd which has the same effect.