# Thermal Properties for Composite Silicon Carbide

Computes thermal conductivity and specific heat of composite (CVI) SiC/SiC cladding.

## Description

The ThermalCompositeSiC model computes the thermal conductivity and specific heat capacity of composite silicon carbide using correlations from Snead et al. (2007) and Koyanagi et al. (2017).

### Thermal Conductivity

For unirradiated composite SiC the through thickness (of tube specimens) thermal conductivity correlation is calculated from the measured thermal diffusivity data through: (1) where is the thermal conductivity (W/m-K), is the thermal diffusivity, is the specific heat at constant pressure, and is the density of composite SiC. The density of composite SiC is taken as the average of the reported value by Koyanagi et al. (2017) ( = 2700 kg/m). The specific heat is calculated by Eq. 2. The range of thermal diffusivity measurements for full SiC/SiC composite as a function of temperature are shown in Table 1.

Table 1: Ranges of temperature dependent thermal diffusivity of Full SiC/SiC composite (Koyanagi et al., 2017)

Temperature (K)Thermal Diffusivity Range (mm/s)
298.02-7
573.151.25-4.5
1073.151-3.25

For the computation of the thermal conductivity, the thermal diffusivity is calculated from a piecewise linear function generated from the mean of the ranges given in Table 1. After converting to SI units for the thermal diffusivity (m/s) the tabulated values used in the piecewise linear function are shown in Table 2.

Table 2: Mean temperature dependent thermal diffusivity used in the Bison piecewise linear function.

Temperature (K)Thermal Diffusivity (m/s)
298.04.510
573.152.87510
1073.152.12510

### Specific Heat Capacity

The correlation for specific heat (J/kg-K) is the same as for monolithic SiC:

(2) where is the temperature in K.

## Example Input Syntax

[./thermalCompositeSiC]
type = ThermalCompositeSiC
temperature = temperature
[../]
(test/tests/thermalCompositeSiC/thermal.i)

## Input Parameters

• temperatureCoupled Temperature

C++ Type:std::vector

Description:Coupled Temperature

### Required Parameters

• boundaryThe list of boundary IDs from the mesh where this boundary condition applies

C++ Type:std::vector

Description:The list of boundary IDs from the mesh where this boundary condition applies

• computeTrueWhen false, MOOSE will not call compute methods on this material. The user must call computeProperties() after retrieving the Material via MaterialPropertyInterface::getMaterial(). Non-computed Materials are not sorted for dependencies.

Default:True

C++ Type:bool

Description:When false, MOOSE will not call compute methods on this material. The user must call computeProperties() after retrieving the Material via MaterialPropertyInterface::getMaterial(). Non-computed Materials are not sorted for dependencies.

• blockThe list of block ids (SubdomainID) that this object will be applied

C++ Type:std::vector

Description:The list of block ids (SubdomainID) that this object will be applied

### Optional Parameters

• enableTrueSet the enabled status of the MooseObject.

Default:True

C++ Type:bool

Description:Set the enabled status of the MooseObject.

• use_displaced_meshFalseWhether or not this object should use the displaced mesh for computation. Note that in the case this is true but no displacements are provided in the Mesh block the undisplaced mesh will still be used.

Default:False

C++ Type:bool

Description:Whether or not this object should use the displaced mesh for computation. Note that in the case this is true but no displacements are provided in the Mesh block the undisplaced mesh will still be used.

• control_tagsAdds user-defined labels for accessing object parameters via control logic.

C++ Type:std::vector

Description:Adds user-defined labels for accessing object parameters via control logic.

• seed0The seed for the master random number generator

Default:0

C++ Type:unsigned int

Description:The seed for the master random number generator

• implicitTrueDetermines whether this object is calculated using an implicit or explicit form

Default:True

C++ Type:bool

Description:Determines whether this object is calculated using an implicit or explicit form

• constant_onNONEWhen ELEMENT, MOOSE will only call computeQpProperties() for the 0th quadrature point, and then copy that value to the other qps.When SUBDOMAIN, MOOSE will only call computeSubdomainProperties() for the 0th quadrature point, and then copy that value to the other qps. Evaluations on element qps will be skipped

Default:NONE

C++ Type:MooseEnum

Description:When ELEMENT, MOOSE will only call computeQpProperties() for the 0th quadrature point, and then copy that value to the other qps.When SUBDOMAIN, MOOSE will only call computeSubdomainProperties() for the 0th quadrature point, and then copy that value to the other qps. Evaluations on element qps will be skipped

### Advanced Parameters

• output_propertiesList of material properties, from this material, to output (outputs must also be defined to an output type)

C++ Type:std::vector

Description:List of material properties, from this material, to output (outputs must also be defined to an output type)

• outputsnone Vector of output names were you would like to restrict the output of variables(s) associated with this object

Default:none

C++ Type:std::vector

Description:Vector of output names were you would like to restrict the output of variables(s) associated with this object

## References

1. T. Koyanagi, Y. Katoh, G. Singh, and M. Snead. SiC/SiC cladding materials properties handbook. Technical Report ORNL/TM-2017/385, Oak Ridge National Laboratory, 2017.[BibTeX]
2. L. L. Snead, T. Nozawa, Y. Katoh, T.-S. Byun, S. Kondo, and D. A. Petti. Handbook of sic properties for fuel performance modeling. Journal of Nuclear Materials, 371:329â€“377, 2007.[BibTeX]