Conjugate heat transfer problem
 

Hi,

I'm a beginner to CFD and trying to do a problem that involves a duct of size 160mm outside dia, 158.7mm inside dia. Air travelling through at a speed of 4m/s and a temperature of 293.75K. I need to find the heat transferred to the duct. I have the geometry and mesh fine. I think there is something wrong in the conditions I am setting as the solution keeps diverging. I set the energy equation to on, and put flow is laminar. I then set the speed and temperature of the velocity inlet, and the back flow temperature of the pressure outlet. Change the walls to 'convection' for thermal with the heat transfer coefficient for the metal that is being used and the wall thickness as 1.3mm. Using green-gauss node based and 200 iterations and ANSYS does the rest... But something's not right.

Any help would be appreciated.
Thanks.