There are three ways heat can transfer namely, conduction, convection and radiation.
Conduction is the transfer of energy where atoms take part and no movement of the particles is required. Heat transfer from one end of a solid to the other is an example of this type.
In Convection he particles need to be moved from a hotter place to a cooler place to transfer heat, this typically takes place in liquids and gases.
Radiation does not require any media to transfer heat from source to receiver.
So, in pro mechanica you will think of applying convection conditions when there are contacts between solids and fluids.
You can either go to insert > convection conditions or click on the related icon to open the convection condition dialogue box (refer to the attached picture). You have to specify the name and load set, as well as define the reference entities where you want to apply these thermal boundary conditions.
Then you have to specify the spatial variation, it may be:
Uniform — Use this option to apply a convection coefficient and bulk temperatures that are uniform over the entity.
Additionally, the following options are available for shell and solid surfaces in 3D models:
External Conv Coefficient — Imports a convection condition FNF file that contains an externally calculated or measured convection coefficient that can vary spatially over the selected surface(s).
External Bulk Temperature — Imports a convection condition FNF file that contains an externally calculated or measured bulk temperature that can vary spatially over the selected surface(s).
External Conv Coefficient & Bulk Temperature — Imports a convection condition FNF file that contains an externally calculated or measured convection coefficient and bulk temperature, both of which can vary spatially over the selected single or multiple surfaces.