Clarification on Flow Thermal simulation

Hi all,

I'm new to SW Flow Thermal simulation and I have a doubt on adiabatic wall condition (Internal flow) VS External Flow.

Boundary condition : A Hollow pipe of steel has to reach certain temperature on the external face at specific time by passing hot water inside. 

Analysis type : Transient thermal analysis 

Which wall condition is best to get right results and can I get some examples of Transient thermal analysis 

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