[amira]

hi everybody,
I am working on a simulation of an external airlift reactor, and to follow the bubble diameter distribution, I always find this expression: " The
bubble size distribution is predicted using a Population Balance (PB) model"
So, pls how to use a population balance model,? is there an algorithm?
does it mean an UDF??
thx for help

[Mostafa]

Hi amira;
I saw your message accidentally and I decided to answer your question despite it is too late for replying and probably you have found the answer. Anyway I hope it helps.
Population balance model in Fluent is a model for multiphase flows. By default this model is not visible in the drop down list of “Models” panel. You should activate it by typing this command “define models addon-module” in the Fluent and then choosing 5 to enable the population balance model.

The following link contains complete description of this model in Fluent.

http://hpce.iitm.ac.in/website/Manuals/Fluent_6.3/Fluent.Inc/fluent6.3/help/pdf/popbal/pdf.htm