Condensation modelling of humid air

Hello!!

I am trying to simulate condensation of humid air as it passes over a set of cooling coils. I have modelled the fluid as a mixture of air and water vapour and given the corresponding mass fractions (which accounts for the rh). But I am not sure how to proceed with the simulation of the condensation phenomenon.

Can someone suggest a methodology of how to set up this phenomenon using ANSYS FLUENT ?

Comments

  • RobRob UKPosts: 9,749Forum Coordinator

    Have a look at the multiphase models and wall films.

  • saisantoshsaisantosh Posts: 5Member

    Yes, I am aware that I will have to use the multiphase models (mixture model) and subsequently enable phase interactions (evaporation-condensation). But the option here suggests to enter the condensation frequency and saturation temperature. Is there an option to enter the dew point temperature.

    When I try the above methodology, the rh at outlet is always increasing, but this is not true if condensation occurs.

    I guess I am going wrong with specifying the proper temperatures (saturation, dew point) and am not sure how to translate these into FLUENT.

    Please guide me in this aspect.

  • RobRob UKPosts: 9,749Forum Coordinator

    It depends on the model, hence reading through the options. The time factors are part of the Lee model, and there should be a saturation temperature in the settings. In some of the models this is in the material properties.

  • saisantoshsaisantosh Posts: 5Member

    Kindly let me know the other options/models available for modelling condensation phenomenon (other than Lee).

    Yes, there is an option available to set a "reference temperature" in material property, but not sure how it ties into the simulation. Kindly share your insights on this regard too.

    Is there any example (document or video) available for this particular phenomenon?

  • RobRob UKPosts: 9,749Forum Coordinator

    I don't think we've got a tutorial at present. Opening the manual and/or multiphase panels will show what's available: you can then decide what's most suitable for your system. We can guide you in that respect, but you need to work out the engineering. What drives the condensation, is it coil surface or free stream, where does the condensate go?

  • saisantoshsaisantosh Posts: 5Member

    Hello Rob, Sorry for the delayed response.

    We worked out the phenomenon of condensation, it is the coil surface that drives the condensation.

    The condensate is collected and removed after a few days of operation and we are interested in finding the amount of condensate formed when steady state reaches.

    Please guide us on how to set up the case for this condition.

  • RobRob UKPosts: 9,749Forum Coordinator

    OK, read the wall film models then, I'd suggest Eulerian Wall Film and you need mass transfer. Note, you may need to revise the model run duration as we typically solve at the flow timescale which is usually in the order of parts of seconds, so a few days might take a while.

Sign In or Register to comment.