Conducting and insulating domains

Vanellus uses a monolithic energy solve: fluid and conducting-solid temperatures are solved in one equation system, rather than in separate fluid and solid solves coupled through interface conditions.

Conducting domains

A conducting domain is either the fluid or a solid component that uses the conducting thermal model. The combination of all the conduction domains form the thermal domain, where temperature is solved.

• Fluid–conducting and conducting–conducting interfaces need no thermal boundary condition. Temperature and heat transfer across them are part of the solve.
• Each conducting component’s material properties determine its behavior within that shared domain.

A conducting component can also define power. This is its net thermal power in watts, distributed uniformly over the component’s meshed volume. Positive values add heat to the thermal domain; negative values remove it. The default is 0.0 W.

Insulating domains

Insulating domains are excluded from the temperature solve. They include:

• Insulating components: their interiors are excluded and their interfaces are adiabatic. Their cells in solid.vtu are set to the simulation’s reference temperature as a placeholder, not a predicted component temperature.
• Compact thermal models (CTMs): their interiors are also excluded, but the CTM supplies boundary conditions that represent heat paths through a resistor network. Vanellus calculates the junction temperature and writes that value into the component’s cells in solid.vtu when producing the result.

Only cuboid components support CTMs because the model depends on named, opposing faces. CAD components can be either insulating or conducting.

See also

• CAD voxelization explains how imported geometry defines the solid cells, for either thermal model.
• Material properties explains the properties used in conducting regions.
• Compact thermal models explains the resistor networks applied to CTM faces.
• VTU fields and domains explains conducting temperatures, insulating placeholders, and CTM junction values in downloaded results.