How to simulate hot air in pipe
 

Hi Everyone,
I want to do simulation with ansys fluent about finding temperature distribution in pipe where hot gas flowing in and out as describe in figure. The gas enter with velocity 1 m/s , temperatur 100 C . How to do this in fluent? what boundary condition I shall used? shall I consider heat transfer to atmosfer and how to accomplish it?

Thanks you for helping...

BR
Gus