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.
Figure 3-1: Internal and external films and the associated film coefficients (blue), and wall layers (dark and light gray).
Heat Transfer Model
Select an option from the External temperature list—User defined, or Temperature (ht/ht), the latter representing a temperature field calculated by a surrounding 3D solid physics. For User defined 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.