Learning Forum

[SR786]

Hi,

I want to implement a population balance model in fluent via solving for species transport and user defined scalars (where scalar quantity will be moments). My framework is homogeneous VOF with two phases, gas and liquid. Both species and UDS will be solved for liquid phase only. From my understanding of the manual, Fluent solves the conservative form of the transport equations as defined in https://www.afs.enea.it/project/neptunius/docs/fluent/html/th/node14.htm and https://www.afs.enea.it/project/neptunius/docs/fluent/html/th/node345.htm. For species transport I will be solving the following

My source term will therefore be:

Which has units consistent with the LHS of the equation.

For the UDS, the transport equation is 

  

Where source term will be 

With units consistent with LHS

My question is that when it comes to implementing this in UDF file do I need to multiply by alpha (volume fraction) or is this automatically handled in Fluent.

i.e.

For Species:

S = alpha*S_c

For UDS:

S = alpha*rho_liquid*S_mj