Radiative Heating

Create a Radiative Heating simulation object to define selected elements in your model as diffusely or collimated radiating heat sources and calculate their direct heat flux view factors to other elements. With Radiative Heating:

• The heat source can radiate either solar or infrared spectrum energy.

• You can define a spectral distribution of the energy by specifying the time varying temperature of the emitting surfaces or by specifying intensity, expressed as a fraction of the entire energy emitted, as a function of wavelength.

• Diffuse reflection and absorption of the incident radiative energy throughout the enclosure is automatically computed provided that you also create an Enclosure Radiation type of Radiation simulation object.

• Ray-tracing is used for specular or transmissive surfaces.

• Heat flux view factors are calculated from the radiative source elements to the elements of the illuminated objects. If any of the illuminated elements have specular or diffuse properties, rays will be traced from those elements. Diffuse reflections are also computed from the illuminated elements, provided that you also create an Enclosure Radiation type of Radiation simulation object.

You can also define the heat (Total Power, Power per Element, or Flux) emitted by the surfaces as varying in one, two, or three dimensions. For loads applied to 2D or 1D geometry, you can specify how the load varies spatially over the area of the 2D geometry or length of the 1D geometry.

Use Radiative Heating to model the radiative thermal effects of such heat sources as electrical heater elements, engine and exhaust systems, electrical arcs, lasers, or any object in the model that emits significant and known quantities of radiative energy.

Note:

Elements that you select as emitting should not be selected as illuminated.

Do not use a Radiative Heating simulation object to model the temperature of a radiative heat source. To accurately model the temperature of a radiative heat source, follow these recommendations:

• Make sure that the mesh of the heat source elements represents the geometry of the heat source accurately.

• If the heater is at a much higher temperature than other parts of the model, use non-gray thermo-optical properties for the heat source elements.

• Model loads using Thermal Loads or Joule Heating simulation objects.

• Calculate radiation using a Radiation simulation object.

Supported variables

The following table lists the independent variables for the Radiative Heating quantities that you can define using fields and expressions.

Quantity	Variables
Intensity vs Wavelength	Length
Power	Time
Power per Element****Flux	TimeSpatial variablesTime, spatial variables

In expressions, you can also use all built-in functions that are listed in Mathematical functions in expressions and Thermal-flow functions in expressions.

Where do I find it?

Application	Pre/Post
Command Finder	Radiative Heating
Simulation Navigator	Right-click the Simulation Objects node→New Simulation Object→Radiative Heating

How do I

Define Radiative Heating

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Inputs to expressions

Look up more details

Auto-generated expressions

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

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

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Radiative Heating, Simcenter 3D 2021.1 Series

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