Thermo-optical properties

Use thermo-optical property modeling objects to define emissivity and other thermo-optical properties necessary for modeling radiation. The emissivity is required for all radiation modeling.

A part made of the same material may have different surface finishes, hence the thermo-optical properties are not available as a material property. Instead, you assign the thermo-optical properties modeling object to the appropriate mesh collector.

The following thermo-optical property modeling objects are available:

Thermo-Optical Properties

Defines emissivity which may vary with temperature.

Thermo-Optical Properties - Advanced

Defines the infrared and solar thermo-optical properties for modeling gray radiation when Type is set to Gray or wavelength-dependent thermo-optical properties for modeling non-gray radiation when Type is set to Non Gray - Wavelength Dependent.Gray — Defines infrared emissivity and solar absorptivity either as a constant, a bi-directional reflectance function (BRDF), or a table. When you define them as a table, the emissivity and absorptivity can vary either with temperature or with angle. You can also define specular reflectivity and transmissivity as functions of direction of incidence and angle of incidence.Non Gray - Wavelength Dependent — Defines a wavelength varying values of non-gray emissivity, specular reflectivity, and transmissivity. You can also define specular reflectivity and transmissivity as functions of direction of incidence and angle of incidence instead of function of wavelength.

Thermo-Optical Properties - State

Defines up to five thermo-optical property states. Each state references one Thermo-Optical Properties or Thermo-Optical Properties - Advanced modeling object. You specify which state you want to use in each solution.Use Thermo-Optical Properties - State to model optical property degradation where optical properties of the surface are different at the beginning of life to the ones at the end of life.

When you define thermo-optical properties for 2D meshes, you should always check the element normals to determine which is the top side of the mesh and which is the bottom side. For more information, see Checking and orienting the normals of 2D elements.

Note:

When you specify different transmissivity values for their respective top and bottom thermo-optical modeling objects of the same mesh collector, only the transmissivity value of the top side modeling object is used. This is because the transmissivity is a property of the material, not a property of the surface, as for example, emissivity.

You can use the referenced thermo-optical property modeling objects to define element emissivity for radiation modeling when you create either the Simple Radiation to Environment constraint or the Thermal Coupling — Radiation simulation object.

Where do I find it?

Application	Pre/Post
Prerequisite	Supported solver and analysis type
Command Finder	Modeling Objects
Simulation Navigator	Right-click the Modeling Objects node→Modeling Objects
Location in dialog box	Type = Thermo-Optical Properties, Thermo-Optical Properties - Advanced, or Thermo-Optical Properties - State→Create

How do I

Define thermo-optical properties

Model optical property degradation

Export thermo-optical properties

Import thermo-optical properties

Learn more

Managing thermo-optical properties

Inspecting thermo-optical properties

Modeling phase change

Simple Radiation to Environment

Thermal Coupling — Radiation

Checking and orienting the normals of 2D elements

Monte Carlo Settings

Understanding the Monte Carlo calculation method

Look up more details

Thermal material properties

Orthotropic and anisotropic thermal conductivity

Understanding bidirectional reflectance angles

Bidirectional reflectance distribution functions (BRDF)

Inspect Thermo-Optical Properties dialog box

Quick links

Simcenter 3D Thermal/Flow, Electronic Systems Cooling, and Space Systems Thermal boundary conditions

Thermal/Flow, Electronic Systems Cooling, and Space Systems Thermal

Command reference

Pre/Post video examples

Bulk Entry Descriptions

Simcenter 3D tutorials

Browse Simcenter 3D help by product area

Thermo-optical properties, Simcenter 3D 2021.1 Series

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