Meshing a cylinder like geometry
 

I'm trying to mesh the cylinder like geometry shown in the images attached below. I've highlighted the areas where Wall spacing (Prism/hex layers) is required and also where mesh isn't required. I tried meshing it by creating a 2D swept block and then converting it to a 3D block. The 3D block was created around and above the inlet (in a straight line) only. Hence I was only able to create a surface mesh. The volume mesh was created only in the middle region, above the inlet, where the 3D block is present. How do I create a 3D block in the whole volume so that I can get a volume mesh? Or is it possible to create an unstructured mesh with prism elements at critical areas? Please help!