Wall Heat Transfer
Use the Wall Heat Transfer node to set up heat exchange across the pipe wall. Define the external temperature and the nature of the heat transfer. The Internal Film Resistance, Wall Layer, and External Film Resistance subnodes are available from the context menu (right-click the parent node) or from the Physics toolbar, Attributes menu. These compute heat transfer coefficients based on the section Theory for the Heat Transfer in Pipes Interface.
You must add at least an Internal Film Resistance subnode. This corresponds to a drilled channel in a solid. If a pipe wall exists, (pipe embedded in a solid), add also Wall Layer. If the pipe wall has more than one layer, add more Wall Layer features. If the pipe exchanges heat to a surrounding fluid by forced or natural convection, add also External Film Resistance.
Figure 3-1: Internal and external films and the associated film coefficients (blue), and wall layers (dark and light gray).
Heat Transfer Model
Enter a value for the External Temperature Text (SI unit: K). If an expression is used for Text that is a locally defined variable on the edge, the check box Take average in adjacent domain should be cleared.
Use the Pipe Wall Heat Transfer multiphysics coupling if the temperature in surrounding 3D solid physics is calculated using Heat Transfer interface.