NaCoolantChannelfvPatchScalarField

Description

Coolant subchannel module to provide thermal boundary condition for Na cooled fuel rods. The model solves the 1D energy equation in the coolant along the axial direction to calculate the coolant bulk temperature axial profile. The surface temperature on the cladding is computed through the heat transfer coefficient \(h\). To determine \(h\), different Nusselt correlations are implemented in the model.

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Options

The NaCoolantChannel fvPatchField can be selected in the patch subdictionary inside the boundaryField subdictionary of the temperature field.

Parameters in the patch subdictionary for NaCoolantChannel:

flowArea	Flow area in m\(^2\).
hydraulicDiameter	Hydraulic diameter in m.
massFlowRate	Mass flowrate in kg/s (time-dependent list is also possible).
inletTemperature	Coolant inlet temperature (K) (time-dependent list is also possible).
NusseltModel	Selected model for Nu computation.
conductivityModel	Selected model for \(k_{Na}\) computation.
viscosityModel	Selected model for \(\nu\) computation.
heatCapacityModel	Selected model for \(\C_p\) computation.

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Usage

In T boundary condition dictionary:

cladOuterSurface
{
    type                    NaCoolantChannel;

    // Flow area in m2
    flowArea                20e-6;

    // Hydraulic diameter in m
    hydraulicDiameter       4.0e-3;

    // Mass flowrate in kg/s (time-dependent list is also possible)
    massFlowRate            0.15;

    // Coolant inlet temperature (K) (time-dependent list is also possible)
    inletTemperature        565;

    // Under-relaxation factor for heat transfer coefficient
    relaxHTC                1.0;

    // Nusselt correlations (Default: Schad)
    NusseltModel            Schad;
    // NusseltModel            Lyon;
    // NusseltModel            SebanShimazaki;
    // NusseltModel            DittusBoelter;
    // NusseltModel            constant;

    // Only if NusseltModel Schad is selected
    pitchOverDiameter       1.2;

    // Sodium Conductivity Model (Default : FinkLeibowitz) 
    conductivityModel       FinkLeibowitz;

    // Sodium Heat Capacity Model (Default : Vargaftic) 
    heatCapacityModel       Vargaftic;

    // Sodium viscosity model (default : Shpilrain)
    viscosityModel          Shpilrain; 

    // Switch to write Tcoolant and enthalpy volFields
    writeCoolantT           true; 

    // Initialize cladding temperature
    value                   uniform 565;
}