Nikhil Narale
Ansys Employee

'I don't think I'm able to use shell conduction as there's an already assigned thickness to the walls from the mesh.'

If you are explicitly meshing and solving for the solid pipe domain, you don't need to use shell conduction. 

 

Can you post a screenshot of the temperature contour?
Make sure you assign appropriate thermal boundary condition on the outer pipe wall as well. 

 

Nikhil