Laminar flow in a circular duct with a constant heat flux
 

Dear friends

I am trying to simulate a circular duct with a constant heat flux using Fluent. I have modelled my case in a 2D case. I have computed the results but I am not able to obtain changes of temperature in all the domain. I just obtain temperature changes in the zone close to the walls (I enclose an image as example).

I am not sure which is the problem because I believe I should obtain different temperature in my domain

Thank you