Which macro must be used for getting the phase volume fraction in an Eulerian multiphase model?

- July 22, 2021 at 8:25 pm
  
  RRaghavendra
  Subscriber
  
  Hello,
  I am working on mass transfer in air-water bubble columns in ANSYS Fluent, using the Eulerian multiphase model. For computing the mass transfer coefficient, I am creating a UDF. In the UDF, I need to get the volume fraction of air in a cell, for computing the specific interfacial area. Which macro should I use for this? There are macros for getting the values of flow variables, but I don't know what it is for phase volume fraction. Please do help me with this.
  Thanking you in advance,
  Raghavendra.
- July 23, 2021 at 6:27 am
  
  Amine Ben Hadj Ali
  Ansys Employee
  
  All of these macros are standard cell data access macros and documented in the customization manual: 3.2.3.12. VOF Multiphase Model Macro.
- July 23, 2021 at 6:41 am
  
  RRaghavendra
  Subscriber
  
  I did find a macro called C_VOF in the section you mentioned. But it seems that C_VOF can be used only for the VOF multiphase model. I want to find the phase volume fraction in a cell for the Eulerian model. This is the reason I posted here earlier.
  Thanking You Raghavendra.
- July 23, 2021 at 10:51 am
  
  Amine Ben Hadj Ali
  Ansys Employee
  
  The same macro can be used for all Eulerian Based Multiphase Approaches in Fluent: So that is the right macro!
- July 23, 2021 at 10:53 am
  
  Rob
  Forum Moderator
  
  Doesn't look that way, https://ansyshelp.ansys.com/account/Secured?returnurl=/Views/Secured/corp/v212/en/flu_ug/flu_popbal_popbal_udf.html
- July 23, 2021 at 11:23 am
  
  RRaghavendra
  Subscriber
  
  I am being asked to login when I click on the link you sent. I don't have an account and when I try to create one, I am not able to, since I have the student version of ANSYS Fluent. Please provide the same information by some other means so that I can access it.
  Thanking You Raghavendra
- July 23, 2021 at 12:24 pm
  
  Rob
  Forum Moderator
  
  We can, /forum/categories/rules-guidelines
- July 23, 2021 at 1:02 pm
  
  RRaghavendra
  Subscriber
  
  Thank you for helping me with the link issue. In the link you provided, there is a macro for the volume fraction of the ith size bin, which is in context of population balance modelling. My query is related to the Eulerian model.
- July 23, 2021 at 1:26 pm
  
  Rob
  Forum Moderator
  
  Which model do we use for PBM work?
- July 23, 2021 at 3:26 pm
  
  RRaghavendra
  Subscriber
  
  I agree that Eulerian model is used with PBM, but I am working with just the Eulerian model, without PBM, assuming a constant bubble size. The solution previously suggested can be used when PBM is used with the Eulerian model....not for the case with just the Eulerian model.
- July 23, 2021 at 3:55 pm
  
  Rob
  Forum Moderator
  
  And it's used here https://ansyshelp.ansys.com/account/Secured?returnurl=/Views/Secured/corp/v212/en/flu_udf/flu_udf_sec_define_source.html%23flu_udf_udf_degas We're only able to guide using what's in the documentation where UDFs are concerned. Have a look at the multiphase specific macros and see how they're used as all then have examples.
- July 23, 2021 at 3:57 pm
  
  RRaghavendra
  Subscriber
  
  Thank You. I will look into it.