Use the Wall Heat Transfer, Inner node to set up heat exchange across the pipe wall. This feature is only applicable if Annular is selected as Pipe Shape in the Pipe Properties node. Define the core temperature Tcore and the nature of the heat transfer. The Internal Film Resistance and Wall Layer subnodes are available from the context menu (right-click the parent node) or from the Physics toolbar’s Attributes menu. These compute heat transfer coefficients based on the section Theory for the Heat Transfer in Pipes Interface.