What is default material of boundary walls if heat transfer takes place

[majidkhalil]

Dear Developer!

1. What is the default material of the boundary walls in the heat transfer case?
2. Where I can change the properties of boundary walls (material type, thermal conductivity, other coefficients, etc)?

[cgw]

There is no “default material” for the walls. Instead, the boundaries are described by certain differential equations, with coefficients you can specify:

You can set these per-phase - use the Fluid and Solids subtabs to set the properties for each phase.