Learning Center

Simulating Radiation in Semitransparent Media

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You can simulate radiation in semitransparent media using COMSOL Multiphysics^® with the Heat Transfer Module, an add-on product that expands the functionality and capabilities for modeling heat transfer. This is relevant for applications such as blast furnaces, gases in combustion chambers, glass at high temperatures, and laser absorption. In this webinar recording, we address core concepts relevant to modeling such applications. For example: What is radiation? What is a participating medium? We also discuss different types of radiation, such as scattered and emitted radiation.

The software has a range of numerical methods that can be used to simulate semitransparent media. These include:

• Discrete ordinates method (DOM)
• P1 approximation
• Rosseland approximation
• Beer–Lambert law

Each of these methods are discussed in great detail. We then take time to talk about the wavelength dependence of material properties. We also show the different options for defining the wavelength dependence of surface properties, which include constant, solar and ambient, and multiple spectral bands.

Next, we shift our focus to coupling radiation in participating media with heat transfer. Predefined coupling features for all types of cases are highlighted, including:

• Radiation
  • Heat Transfer with Surface-to-Surface Radiation interface
  • Heat Transfer with Radiation in Participating Media interface
  • Heat Transfer with Radiation in Absorbing-Scattering Media interface
  • Heat Transfer with Radiative Beam in Absorbing Media interface
• Heat transfer in solids
  • Optically Thick Participating Medium attribute node

The webinar concludes with a live demonstration of building a model of the radiative cooling of a glass plate. The model is a transient simulation that solves for radiation and temperature and compares the results obtained, showcasing some of the different methods listed earlier.

This webinar is relevant to recently released versions of COMSOL Multiphysics^®. You may notice small differences between versions. You can learn more about the features and capabilities in the Heat Transfer Module for modeling radiation in participating media by checking out this page.