Importing thermo-physical properties

Thermal Desktop does not have a concept equivalent to the mesh collector in Simcenter 3D. The thermo-physical properties, which you specify on a mesh collector, are directly assigned to elements or nodes in Thermal Desktop.

The following section details the material, physical and optical properties are supported by the Thermal Model Exchanger.

Importing material properties

Thermal Model Exchanger only supports importing isotropic and orthotropic Simcenter 3D materials. An orthotropic material in Simcenter 3D is imported as an anisotropic material in Thermal Desktop.

When importing a material, Thermal Model Exchanger only transfers mass density, specific heat, and thermal conductivity.

For the remaining material properties, Thermal Desktop uses the default values.

Mass density

Thermal Model Exchanger only supports constant mass density. When the value is defined as a table in Simcenter 3D, the value is imported as a constant using the first value of the table. The application shows a warning in the import summary.

Specific heat

Thermal Model Exchanger supports constant and temperature-dependent specific heat. For other dependencies, the value is imported as a constant using the first value of the table. The application shows a warning in the import summary.

Thermal conductivity

Thermal Model Exchanger supports constant and temperature dependent thermal conductivities. If the Simcenter 3D material conductivity is temperature dependent, the table values is transferred as is. For other dependencies, such as time-dependent thermal conductivity, the thermal conductivity will be imported as a constant using the first value of the table. Thermal Model Exchanger shows a warning in the import summary.

For isotropic materials, Thermal Model Exchanger transfers a single value. For orthotropic materials, it transfers the K, K2 and K3 values of the thermal conductivity and assigns it to the three components of the anisotropic material in Thermal Desktop.

Importing physical properties

The concept of physical properties does not exist in Thermal Desktop. Thin Shell, Null Shell, Multi-layer Shell Uniform and Multi-layer Shell Non-Uniform physical properties are not imported as Thermal Desktop entities.

For the Thin Shell physical property, Thermal Model Exchanger converts the thin shell thickness, as a thickness property for the mesh elements in Thermal Desktop.

For the Null shell property, since Thermal Desktop does not support elements with a thickness value of 0, Thermal Model Exchanger creates elements with the following properties:

Thickness = 0.001 m
Specific heat = 0 J/kg/K
Density = 1E-10 kg/m^3

Thermal Model Exchanger does not import Multi-layer Shell Uniform and Multi-layer Shell Non-Uniform physical properties.

Importing thermo-optical properties

Thermal Model Exchanger supports all types of basic and advanced thermo-optical property modeling objects defined in Simcenter 3D, which are converted to the Thermal Desktop Optical Property entity assigned to each element during the import.

Thermal Model Exchanger supports constant and table field values for the Gray and Non Gray – Wavelength Dependent types of advanced property modeling objects. The following table shows the types of thermo-optical property values supported by the Thermal Model Exchanger application.


	Simcenter 3D thermo-optical properties	Simcenter 3D value	Thermal Desktop value
Gray	Solar Absorptivity Infrared Emissivity	Constant	Constant
		Temperature-dependent	Vs. Temperature
		Angle-dependent	Vs. Angle
	Solar Specular Reflectivity Solar Transmissivity Infrared Specular Reflectivity Infrared Transmissivity	Constant	Constant
		Angle-Angle	Constant*
Non Gray – Wavelength Dependent	Emissivity	Constant	Constant
	Emissivity	Length-dependent	Length-dependent
	Specular Reflectivity Transmissivity	Constant	Constant
		Length	Length
		Angle-Angle	Constant*

*When the value is defined as a table field in Simcenter 3D, it is imported to Thermal Desktop as a constant using the first value of the table field. The application shows a warning in the import summary.

Basic thermo-optical properties

The Thermo-Optical Properties modeling object in Simcenter 3D contains only the emissivity value while you can specify other entities in the Optical Property dialog box in Thermal Desktop. Thermal Model Exchanger assigns the Simcenter 3D emissivity value to the Infrared Emissivity in Thermal Desktop and assigns the remaining thermo-optical properties default values.

Advanced thermo-optical properties

The Thermo-Optical Properties - Advanced modeling object in Simcenter 3D differs from the Optical Property entity in Thermal Desktop.

For Gray Solar Properties in Simcenter 3D, the absorptivity, transmissivity and specular reflectivity are all imported directly to the corresponding Thermal Desktop properties. Thermal Model Exchanger assigns default value to the solar transmissive specularity in Thermal Desktop because this property does not exist in Simcenter 3D.

For Gray Infrared Properties in Simcenter 3D, the emissivity, transmissivity and specular reflectivity are all imported directly to the corresponding Thermal Desktop properties. Thermal Model Exchanger assigns default value to the infrared transmissive specularity in Thermal Desktop because this property does not exist in Simcenter 3D.

The Specular Reflectivity property in Simcenter 3D is named Specularity in Thermal Desktop.

In Thermal Desktop the Specularity is expressed as a percentage of the total reflectivity, whereas Simcenter 3D requires the absolute value of the Specular Reflectivity. Thermal Model Exchanger applies the following conversion formulas during the import process:


Property	Conversion formula
Solar Specular Reflectivity	STD = SSC3D / (1 - A - T)
Infrared Specular Reflectivity	STD = SSC3D / (1 - E - T)

Where:

STD is the Thermal Desktop specularity,
SSC3D is the Simcenter 3D specular reflectivity,
A is the absorptivity,
T is the transmissivity,
E is the emissivity.

Thermal Model Exchanger sets the Thermal Desktop solar and infrared Refractive Indices Ratio values equal to the Simcenter 3D Index of Refraction value. Note that only one index of refraction exists in Simcenter 3D.

Thermal Model Exchanger does not support the Simcenter 3D BRDF method, the emissivity or absorptivity value is imported to Thermal Desktop as a constant using the first value of the table field. The application displays a warning in the import summary.

For the Simcenter 3D Non Gray – Wavelength Dependent properties, the emissivity, specular reflectivity, transmissivity and index of refraction are all imported directly to the corresponding Thermal Desktop properties. Thermal Model Exchanger assigns default value to the Transmissive Specularity property because it does not exist in Simcenter 3D.