UDF for evaporation rate and mass fraction
 

Hi,

I am a beginner in Ansys and C programming and working on water droplet evaporation in the air with the VOF model. I am kind of stuck writing the UDF at the interface for evaporation rate and mass/mole fraction of vapor.

It would be a great help if anyone helps me with this. Any suggestion/reference would be highly appreciated on how I can develop my knowledge on droplet evaporation.

# I went through the UDF manual several times but could not find any proper guidelines on how to write the functions.

# Is there any default model for evaporation rate and mass/mole fraction in UDF?

Thanks in advance.

Regards,
Faravi

Evaporation of Droplet
 

You don't need a UDF. Fluent has in-built models for this. You can either use Lee or Thermal Phase Change Model. With VOF, only Lee is available.

Thank you so much for your reply.

#I have another question regarding mass fraction and mole fraction at the interface. Do I have to use UDF for it or Ansys VOF model will automatically use this?

Regards,
Faravi

Hi Vinerm,

Thanks for your reply.

I was wondering do I have to use UDF for mass fraction or mole fraction at the interface or Ansys Vof model will implement this automatically?

Regards,
Faravi

Mass Transfer
 

No UDF is needed. Inbuilt model will suffice. Enable mass transfer and select Evaporation-Condensation model.

Thanks again Vinerm for your reply.