Fluids

Fluids

ANSYS Fluent’s P-1 Radiation Model Equations

    • SK95
      Subscriber

      Hi everybody,


      I am currently implementing the P1 radiation model via UDF in Fluent and have therefore looked at the example "8.2.5.2. Implementing ANSYS Fluent's P-1 Radiation Model Using User-Defined Scalars" in the Ansys Fluent Customization Manual 18.2 (page 537). Can someone explain to me how to derive the formula 8.11?


       


      Ansys Fluent Customization Manual 18.2, page 537


       


      Many thanks in advance.


       

    • Rob
      Ansys Employee

      Check in the Theory Guide for the P1 model. Note, we may have taken models from external references so may state equations with a reference: you'll need to go and find those. 

    • SK95
      Subscriber

      Only the general equations of the P1 model are explained in the Theory Guide. I haven't found a hint in any of your guides/ manuals on how to get from eq. 8.8 and 8.9 to 8.11. Neither the Fluent Customization Manual nor the Theory Guide state any references which could hold further information.

    • DrAmine
      Ansys Employee

      I think you need to make a literature review about the P-n models for radiation. How equation is derived is mentioned in the theory guide but not all steps are included.

    • SK95
      Subscriber

      I already have done a literature review. Derivations of the equations of radiation in general as well as the PN and P1 - Model model are described in detail in standard works such as "Radiative Heat Transfer" by Modest and "Thermal Radiation Heat Transfer" by Howell et al. I know how to derive all the equations on that topic in the theory guide which includes equation 8.8 and 8.9. But I cannot find anything on the equations 8.10 and 8.11 which is why i assume that they were derived from ansys for the implementation in fluent.

    • DrAmine
      Ansys Employee

      Sorry but we won't get to the details about implementation on this open community.

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