Learning Forum

[vinitraj3]

Hi everyone,

Requesting help from all the experts out here. I need to model evaporation of a water droplet from a heated surface into air. Sort of a drying phenomena. I need to analyse the effect of contact angle on the droplet evaporation lifetime. This evaporation will happen well below the boiling temperature. Image of the domain is attached

I need to track the interface of the droplet as it evaporates. From the internet, discussion forums as well as ansys student community discussion here I understand I will need to write a UDF based on Schrage's and Hertz-Knudsen equation. The Lee Evaporation condensation model won't work.

I need to kickstart on writing the UDF. Can anybody guide me in writing the UDF. Any previously written code snippet of UDF for evaporation will help me.

Thanks in advance

Regards

Rajeev

[DrAmine]

Check the customization manual at first stage. Make a literature review. You require at least two UDF's for VOF to do that.

As ANSYS Staff I won't share any snippet here.

[vinitraj3]

Hi Amine,

 

Thanks for your reply. I have been going through the customization manual as well as going through literature as well. I can understand that you won't be able to share UDF in student community as Ansys Staff. But what about customers (My customer id is 431952, based in India).

I have few questions though.

1. What did you exactly mean when you said that two UDF's may be required. 

2. What is the best way. Write a UDF for species mass transfer and hook it up in the phase interaction panel or write a UDF for source terms in the VOF model.

3. Can Lee's evaporation condensation model be used for temperature below 100 C. If not then why?

4. In the best practices for Lee's model it states that the enthalpy should be now given at saturation temperature. Earlier it was at reference temperature of 298.15. Any reasons. Is there a change in way that the enthalpy of vapor is now calculated.

Answers to this may help me in clearing my doubts.

 

Regards

Rajeev Kumar Singh

mail: singhrajeev@sail-rdcis.com

 

[DrAmine]

Are you channel partner?

 

[vinitraj3]

No we are industry based client associated with Ansys since 2001

[DrAmine]

Local support will get in touch with you.