[Bobby Charlton]

Hello guys,

I am trying to study the cooling of air that is flowing inside a steel pipe that sits in ambient air.

I have modeled the 3 different domains (air-environment domain, steel pipe domain, air flowing domain) and have created a part of all three domains.
I have a great structured mesh.

I have set the temperature of the air-environment at 273 K through the Fixed Values option in the Domains tab. The air is still and not moving so I have not defined any inlets/outlets.
I have set the steel pipe domain as a solid.
I have defined a velocity inlet (2 m/s and 320 K) and pressure outlet (0 pascals, 300 K backflow temperature) for the domain of the air flowing inside the pipe

I get a wall and shadow wall for the outer surface of the pipe, which is set as Coupled. I have the same for the inner surface of the pipe.

I am running the simulation and I am getting a result but when I get a temperature contour of a cross-section of the whole pipe, I get a specific temperature at the normal direction of the heat flow, instead of a classic conduction profile inside the pipe. There is no gradient of the temperature inside the steel pipe. I only get a temperature drop in the direction of the flow (axial direction) but not in the radial direction. Note that I get an expected gradient for the ambient air and the air inside the pipe.

Does anybody know what's up with this? I am trying to get the temperature profile of the steel pipe without doing an FSI with Fluent and Static Thermal.

I even tested a regular wall with two air domains on each side, one hot and one cold, and I still don't get a conduction profile, just a specific value of the temperature (a specific color in the contour). I have created and meshed the solid geometry of the wall.

Thanks!