Surface Radiation Exchange Workflow

Using the surface radiation exchange models in Simcenter STAR-CCM+, Surface-to-Surface Radiation and Surface Photon Monte Carlo, you can analyze thermal radiative heat transfer between surfaces that form enclosed spaces. The medium that fills the space between the surfaces is non-participating. That is, it does not absorb, emit, or scatter radiation. Under these circumstances, the radiation properties and the thermal boundary conditions that are imposed on each surface uniquely define the amount of radiation that a surface receives and emits. The surface properties are quantified in terms of emissivity, reflectivity, transmissivity, and radiation temperature. These properties are not dependent on direction; however, they can be dependent on radiation wavelength with the Multiband Radiation model. At the boundaries, you can also specify external radiative energy sources, which can be diffusive (for example daylight) or directional (for example laser beams).

The surface radiation exchange models rely on the spatial discretization of the boundary surfaces into patches. Patches can be formed, for instance, from aggregating the boundary faces from the underlying mesh. Patches allow you to make trade-offs between accuracy and computational cost. The S2S model relies on the view factors that quantify the proportion of surface area in each patch that the other patches illuminate.

To model surface radiation exchange:
  1. For the physics continuum, select the following models:
    Group Box Model
    Space Three Dimensional
    Time Select one of:
    • Steady
    • Implicit Unsteady
    • Explicit Unsteady
    Material Any single- or multi-component material model within these limitations:
    • Surface Photon Monte Carlo is not compatible with Multi-Layer Solid. It is compatible with Multi-Part Solid but only when the Gray Thermal Radiation model is used.
    • Neither Surface-to-Surface nor Surface Photon Monte Carlo is compatible with the Multiphase model.
    Flow Coupled Flow or Segregated Flow (for fluids only)
    Optional Models For solids, select one of:
    • Segregated Solid Energy
    • Coupled Solid Energy
    For fluids with Segregated Flow, select one of:
    • Segregated Fluid Temperature
    • Segregated Fluid Isothermal
    • Segregated Fluid Enthalpy
    For fluids with Coupled Flow, select Coupled Energy.
    Equation of State Any
    Viscous Regime Any (for fluids only)
    Optional Models Radiation

    Surface Materials (selected automatically). See Surface Materials Model Reference.
    Radiation Select one of:
    Radiation Spectrum Select one:

    For the Multiband Thermal Radiation model, set up the Spectral Bands.

    Solar Radiation If you want to model solar radiation, select Solar Loads.
  2. Specify appropriate Radiation Transfer Options for the regions in your model:
    1. Select the Regions > [region] > Physics Conditions > Radiation Transfer Option node.
    2. For opaque regions, set Radiation Transfer to External. For regions with dual-sided boundaries, select Internal and External, which also permits objects to interact through meshless space. For regions where radiation transfer in not relevant, set Radiation Transfer to None.
  3. If two regions of same continuum are interfaced, place either a baffle or a porous baffle between them where both interface boundaries are actively participating in radiation. If the interface does not participate, use an internal interface.
  4. To produce a semi-transparent interface, make sure that the same spectral model is used on both sides—both Gray or both Multiband. An interface boundary automatically becomes opaque when any one side has no radiation model or has the Radiation Transfer Option set to None or External.
  5. Specify thermal radiation properties on boundaries and interfaces.
  6. To set the patch parameters on boundaries, select the Boundaries > [boundary] > Physics Conditions node and set the following conditions:
  7. Select the [region] > Physics Conditions node and set Patch Specification for the region, then set the corresponding Physics Values parameters. See Patching Parameters.
  8. If you want to include external radiative energy sources, identify the boundaries of your model where the external heat flux enters the domain. For each boundary, select the Physics Conditions > Radiative Flux node and set Radiation Flux Option to the following:
    Radiation Flux Option Steps
    Diffusive radiation flux—choose this option to model diffuse non-Planck radiation.

    For more information, see Diffuse Radiation Flux.
    • Select the Physics Values > Diffuse Radiation Flux node and specify the flux as a scalar profile.

      If you are using the Multiband Thermal model and the Diffuse Radiation Flux node has Method set to Composite, there is a node for each band under Diffuse Radiation Flux. Set the physics values for each band.
    Directional radiation flux—choose this option to model non-Planck radiation that is directed from the boundary into the computational domain.

    For more information, see Directional Radiation Flux.
    1. Select the Physics Values > Directional Flux Orientation node and set the Direction and Divergence Angle with respect to Coordinate System.
    2. Select the Physics Values > Directional Flux Power Distribution node and specify the heat flux distribution as a scalar profile.

      If you are using the Multiband Thermal model and the Directional Flux Power Distribution node has Method set to Composite, there is a node for each band under Directional Flux Power Distribution. Set the physics values for each band.
  9. Set Thermal Environment > Radiation Temperature to a single value for all continua.
  10. For the Surface Photon Monte Carlo model, set the properties of the Photon Monte Carlo solver:
    • Verbosity
    • Surface Ray Tracing Parameters
    • Environment Load Parameters
    • Statistical Sampling Factor
    • Update Frequency
  11. For an S2S radiation simulation, if you want to analyze view factor results, follow the steps in 可视化滤过入射和传出辐射.