Fluids

Fluids

Nuclei Number density and soot volume fraction in Moss Brookes model

    • me20s045
      Subscriber

      Sir, 

      I am trying to write the UDF for nucleation and coagualation in Moss Brooks model. In that how they have expressed number density in terms of mass fraction is unclear to me . I am currently trying to decode the expression that ansys has used in its udf(https://ansyshelp.ansys.com/account/Secured?returnurl=/Views/Secured/corp/v221/en/flu_udf/flu_udf_sec_define_soot_mass.html). The theory guide is inadequate to decode the expression. So I am requesting you to please help me undertand the mathematical steps or the final expression used for number density and soot volume fraction in therms of their mass fraction.

       

    • Rob
      Ansys Employee

      The best way is to use the example in the manual, then compare data in the model with the maths in the UDF. Setting some of the returned values to constants may help. 

    • me20s045
      Subscriber

      no I understand that . I am asking what is the mathematical expression used for N or the number density in this case. I need to know the mathematical expression for N only .

    • Rob
      Ansys Employee

      Check the other DEFINE_SOOT macros, they look to be linked. Otherwise, there is a section in the Theory Guide  https://ansyshelp.ansys.com/account/Secured?returnurl=/Views/Secured/corp/v222/en/flu_th/flu_th_sec_soot.html

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