How to verify the solution has converged when source terms are applied at liquid vapor interface?

- July 3, 2019 at 11:54 am
  
  vidyadhar.kpm
  Subscriber
  
  Hello,
  
  I am applying certain negative mass source terms on liquid phase and equivalent positive mass source terms on vapor phase at the liquid vapor interface in a VOF simulation. The mass source terms mimic evaporation from liquid phase to vapor phase. Similarly, I am applying an energy source term at the interface to account for heat loss by evaporation. All the source terms are applied by way of UDFs at the liquid-vapor interface.
  
  I am observing monitors such that they do not change with flow time to check convergence of my simulation.
  
  My query is that which of the following is correct and sufficient?
  
  1) Volume Integral of the mass source terms over the entire FLUID
  
  2) Surface Integral of the mass source terms over the INTERFACE(0
  
  3) Average Temperature on the iso-surface VOF=0.5
  
  4) DEFAULT Scaled Residuals
  
  I request to let me know should I monitor any other parameter?
  
  Thanks & Regards,
  
  Vidyadhar
- July 3, 2019 at 12:13 pm
  
  DrAmine
  Ansys Employee
  
  Mass of each phase within the time step. The mass transfer from one phase to be as positive accumulation in the other phase.
  
  All other stuff is okay.
  
  Why aren't you using the DEFINE_LINEARIZED_MASS_TRANSFER UDF?
- July 4, 2019 at 10:58 am
  
  vidyadhar.kpm
  Subscriber
  
  Hello Amine,
  
  May I know if it is better to use DEFINE_LINEARIZED_MASS_TRANSFER UDF instead of DEFINE_SOURCE for simulating evaporation? Can you please let me know what are the merits of it.
  
  Thanks & Regards,
  
  Vidyadhar
- July 4, 2019 at 2:16 pm
  
  DrAmine
  Ansys Employee
  
  More comfortable to use DEFINE_LINEARIZED_MASS_TRANSFER as secondary fluxes are automatically taken into account.

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