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Boundary conditions

Boundary conditions (BC) are physical definitions on domain boundary surfaces for thermal conditions and electromagnetism. Here are listed all boundary conditions used in CENOS, as well as the most common usage for each BC.

Thermal BC

Thermal BC's are boundary conditions through which the heat exchange between domains is defined.

Fixed temperature

Fixed temperature boundary condition defines a fixed temperature on the boundary surface.

Fixed temperature

usage

When Motion is used on infinite billet, the surface through which the billet enters the computational domain can be defined with Fixed Temperature.

Heat flux

Heat flux boundary condition defines a constant heat flux density on the boundary surface.

Heat flux

usage

Can be used if the heat flux going through a specific area is known

Heat flow

Heat flow boundary condition defines a constant heat flow (in watts) on the boundary surface.

Heat flow

usage

Can be used if the heat flow going through a specific area is known

Convection

Convection boundary condition defines the heat flux as dependent from the ambient temperature and heat transfer coefficient. Convection is defined as:

q=h(Tโˆ’Tamb)q=h(T-T_{amb})

Convection

usage

Convection is used on workpiece-air interface to define heat exchange when temperature is low. Usually used together with Radiation.

To learn more about Convection definition, click here.

Radiation

Radiation boundary condition defines the thermal radiation to infinity on the boundary surface, where the heat flux is defined as:

q=ฯƒSBฯต(T4โˆ’Tamb4)q=\sigma_{SB}\epsilon(T^4-T_{amb}^4)

Radiation

usage

Radiation is used on workpiece-air interface to define heat exchange when temperature is high. Usually used together with Convection.

To learn more about Radiation definition, click here.

Combined

Combined boundary condition allows to combine multiple BC such as Convection, Radiation, Heat Flux and Heat Flow on a single domain surface.

Combined

usage

Combined is used on workpiece-air interface to define both Convection and Radiation for a complete heat trasfer definition over wide temperature range.

Adiabatic

Adiabatic boundary condition defines 0 heat flux on the surface.

Adiabatic

usage

Adiabatic is used on symmetry surfaces for domains with thermal analysis.

Interface

Interface boundary condition defines boundary surface as the internal surface between two domains.

Interface

usage

Used to define interface between two domains who both have thermal analysis definition.

Thermal Contact Resistance

Thermal Contact Resistance boundary condition defines thermal resistance between two domains.

TCR

usage

Used to define interface between two domains who both have thermal analysis definition.

Electromagnetics

Electromagnetic BC's are boundary conditions through which the magnetic flux is defined.

Infinity

Infinity boundary condition defines a zero vector potential on the boundary surface.

Infinity

usage

Infinity is used to define outer surface of the air box.

Flux parallel

Flux parallel boundary condition defines the magnetic field lines as parallel to the boundary surface.

Flux parallel

usage

Flux parallel is used to define symmetry boundary conditions on the sides of slices and sectors.

To learn more about Flux parallel definition, click here.

Flux normal

Flux normal boundary condition defines the magnetic field lines as normal to the boundary surface.

Flux normal

usage

Flux normal is used to define symmetry boundary conditions on top and bottom of slices and sectors.

To learn more about Flux normal definition, click here.

Interface

Interface boundary condition defines boundary surface as the internal surface between two domains.

Interface

usage

Used to define interface between two domains from which only one has thermal analysis definition.

Surface Impedance

Surface Impedance boundary condition can be accessed only through the Surface Impedance domain. It defines the boundary surface as an infinitely thin layer for VH frequency skin layer resolution.

Surface Impedance

usage

Surface Impedance is used to replace manual skin layer resolution through mesh at very high frequency setup.

Symmetry axis

Symmetry axis is a 2D-axial-symmetric specific boundary condition which defines 0 vector potential on the symmetry axis.

Symmetry axis

usage

Symmetry axis is used in every 2D axial-symmetric case to define rotational axis.

Current source

Current BC's are accessed only under the Current source domain and through which the current or voltage flowing through the conductor is defined.

Voltage

Voltage boundary condition defines the voltage on the boundary surface.

Voltage

usage

Voltage is used to define voltage on one of inductor terminals. For the other terminal use Ground.

Current

Current boundary condition defines a positive current supply to the boundary surface and the value of current.

Current

usage

Current is used to define current on one of inductor terminals. For the other terminal use Ground.

Ground

Ground boundary condition defines a negative current supply to the boundary surface.

Ground

usage

Ground is used to define one of inductor terminals. For the other terminal use Voltage or Current.