December 1, 2022 at 5:38 pma.ortolaniSubscriber
I am using the flamelet generated manifold (FGM) model in Ansys Fluent and I am implementing a UDF using the macro "DEFINE_PDF_TABLE".
I am solving scalar transport equations for a couple of species in the mixture and in the UDF I can easily access their source terms (Get_Pdf_Tss_FwdRates(c, t, i)). I can also access the tabulated mass and mole fractions of all species (Get_Pdf_Xi(c,t,i)).
What I can't do is to access the information about the mass (or mole) fraction of the transported species, i.e. the values computed in the CFD simulation. I couldn't find anything in the Customization manual.
Can anyone help me?
December 6, 2022 at 2:39 pmRobAnsys Employee
Does C_YI(c,t,i) return what you're after? I've turned on the Partially Premixed Model and have a PDF table and species reporting options.
December 9, 2022 at 3:43 pma.ortolaniSubscriber
thank you for your answer.
Unfortunatelly the C_YI(c,t,i) macro does not work with the partially premixed models. I need to use the Get_Pdf_Yi(c,t,i) macro which returns the value of the tabulated mass fraction, and not the one computed with the FGM scalar transport equation.
I can easily get the information in post processing, but I would like to access it also in my UDF
December 9, 2022 at 4:34 pmRobAnsys Employee
The post processing value is also taken from the pdf table: I think you've got the correct macro with Get_Pdf_Yi(c,t,i) , it's covered in the UDF manual (apparently - a colleague is the expert).
December 9, 2022 at 6:49 pma.ortolaniSubscriber
As you say, in post processing I can access all the species concentration taken from the PDF table (Species.. > Mass fraction of ***). Those are the quantities that I can access in the UDF with Get_Pdf_Yi(c,t,i).
What I would like to access in the UDF and I can't get is different. In post processing I find it in "Premixed Combustion... > Scalar Mass Fraction of ***"
December 13, 2022 at 12:00 pmRobAnsys Employee
Which may be calculated from the table. If it's not in the documentation I can't do much other than suggest checking the header files and retain all data (Section 18.104.22.168 https://ansyshelp.ansys.com/account/Secured?returnurl=/Views/Secured/corp/v222/en/flu_udf/flu_udf_DataAccessMacros.html )
December 21, 2022 at 12:37 pma.ortolaniSubscriber
I didn't find any macro that suits my problem. To be clear, I am trying to acces the value of a scalar for which it is solved a transport equation. In particular I want the value of phi in equation 8-119 of the theory guide, which is found in section 22.214.171.124.1 "Scalar Transport with FGM closure" (https://ansyshelp.ansys.com/account/secured?returnurl=/Views/Secured/corp/v212/en/flu_th/flu_th_sec_par_premix_theory.html)
January 3, 2023 at 2:45 pmRobAnsys Employee
Then it may be stored under a different value, as I can't share anything that's no in the documentation I'm a bit stuck.
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