modeling condensation in humid air...
I am working on a project in which I have to consider condensation in humid air.
it is a cross-flow condenser, which it's use is in air conditioning; in it's hot air inlet, the air is mixed with some water vapor, and the other side is cold air. in this process I have to capture the phase change from water-vapor, to water-liquid.
can anyone plz help me in this?! which multiphase model is proper for this simulation?! may I use the mixture model, or it won't include phase changes?! if I should use species to model this project, does anyone know the coefficients that I have to use for condensation (latent heat modelling) and properties that I should set?!
tnx in advance for your helps...
use either a two-fluid or even a mixture model - doesnt matter. You need to write appropriate mass transfer function. Not only volumetric condensation - you probably have to model wall condensation as well.
which code are you using to perform these calculations?
Hi CFDtoy; tnx for ur answer...
I'm using ANSYS 13.0 which seems that have the mass transfer functions embedded in its own models! but the problem is that when I use it, even for the most simple geometries, it won't converge!!! (the equation which this mass transfer function uses is "ranz-marshall")
I've tried it with several different models like, Eulerian and mixture and I've tried each one with different inlet types, different magnitudes for inlets and etc. I just don't know which option I'm using wrong that makes it diverge!!! :(
so I would be more thankful if you could help me out here...
I dont have the recent ANSYS 13 manual - so dont know what input is being specified from your end. Is it possible for you to upload / send ANSYS manual for this feature alone?
I think the settings in the model can clearly help you out here.
I have experience in boiling models both coding and usage (commercial) - convergence can purely be manipulated by the implemented model.
Hi again, and thank for your patience;
as this new version of ansys has a help in java format, I couldn't get a print out of it to send to you; but I got some screen pictures of the settings I set:
1. this picture shows my "Models" tab:
2. this pic is my settings on Eulerian mode:
3. these are my materials:
4. my phases definition:
5. "phase interaction" window:
6. settings on heat transfer method for this feature:
7. and finally the mass transfer model settings:
I hope that these pictures can help both of us!
thanks again; I'm waiting to hear from you...
I know this thread is a bit old, but did you try changing the "from" and "to" phases in your evaporation-condensation model settings? I am trying to model condensation in my own simulation, and the evaporation-condensation only works for me when it's going from liquid to gas (condensation would then be a negative mass transfer).
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