Temperature Boundary Conditions

This section lists the main thermal boundary conditions currently available in OFFBEAT. Many other boundary conditions (including standard fixedValue and fixedGradient) are available in OpenFOAM and are not treated here. We refer to the OpenFOAM documentation for more information.

Fixed temperature (Dirichlet) boundary conditions

The fixedTemperature boundary condition base class is similar to fixedValue in OpenFOAM, with the added capability of incorporating resistance for the oxide layer (when used for the outer cladding). The derived classes provide additional flexibility by enabling radial or axial time-dependent temperature profiles.

Available coupled boundary conditions include:

• fixedTemperature
• timeDependentTemperature
• axialProfileT
• timeDependentAxialProfileT
• xzTemperatureProfile

Coupled Boundary Conditions

These boundary conditions are designed to handle heat exchange between two bodies, whether in direct contact or separated by a small gap. They are particularly suited for scenarios involving fuel and cladding heat exchange.

Available coupled boundary conditions include:

• temperatureCoupled
• resistiveGap
• fuelRodGap
• trisoGap

Convective Boundary Conditions

These boundary conditions simulate convective heat exchange mechanism between a solid and a fluid. They are mostly used in OFFBEAT for cladding outer surface.

Available options include:

• convectiveHTC
• timeDependentAxialProfileHTC

Radiative-Convective Sink Boundary Conditions

These boundary conditions simulate convective heat exchange mechanism between a solid and an environment via radiation and convection.

Available options include:

• radiativeConvectiveSink

Coolant channel boundary conditions

These boundary conditions simulate convective heat exchange between a solid and a coolant flowing on its surface.

Available options include:

• coolantChannelfvPatchScalarField
• NaCoolantChannelfvPatchScalarField