model condensation?

[pei-ying.hsieh]

Dear Autodesk Simulation CFD experts,

I am wondering if Simulation CFD can model condensation.  I have a refriguration unit. Inside the refriguration unit, the temperature is at 4 degree C.  Ambient temperature is at 35 degree C.  Depending on the insulation material and the thickness of the insulation material, the outside wall of the insulation may be at low temperature not too much higher than 4 degree C.  In this case, the temperature on the outside may be lower than dew point, hence condensation occurs.  Is there any easy way to show whether condensation will occur on the outside wall?

Thanks!

Pei-Ying

[Jon.Wilde]

Hi Pei-Ying,

How about just modelling it as normal and observing if/when the temp is lower than the dew point. If you only need to know if condensation will occur or not, this is probably the quickest way.

Kind regards,

Jon

[pei-ying.hsieh]

Hi, Jon,

Yes, that is the approach I am using now.  I am trying to see if there is an easier way.

Pei-Ying

[RAALVM]

you can split the process into two or more simulations, 

first to see if the condensation occurs and where is the location of the begining of condensation, afterwards you can model an other simulation and use insead of cp defined in fluid properties the specific latent heat (the temperature will remain constant and yes I know that it doesn't take into account the superficial tension which is important in condensation) see where your condensation process will end by calculating the total mass which condensed, and finally you can do an other simulation with the liquid properties as liquid.

(in the mix region you can use a medium properties.

[RAALVM]

using the humidity can also be an option, but you have to deep deper to see.