Fluids

Fluids

Define a particle mixture for simulation of a suspension drying process

    • lizardxy
      Subscriber

      Dear all,

      in my case, a suspension consisting of zeolite and liquid water should be dried by hot air in a spray dryer. Now I get some difficulties in defining the materials and hope you could help me.

      So far as I unterstand, DPM injection of type "particle mixture" should be used, so I have defined a solid type and a fluid type of "zeolite" and added the fluid one into "mixture". Now I am trying to add the solid type into "particle mixture" in the following way:

      • In "Create/Editing materials", select Material Type as "particle-mixture"
      • Click Edit in "Mixture Species"

      However the expected solid zeolite doesn't appear in the "Available Materials" and I can't go further. How should I add it into the "particle mixture"? Is it necessary to add a fluid zeolite into "mixture"?

      I am looking forward to your answers.


      Best,

      lizardxy

    • DrAmine
      Ansys Employee
      You create two types of droplet particles and you add them to the mixture. Alternative is to use a droplet particle with volatile fraction and adjust the density.
    • lizardxy
      Subscriber
      Thank you for the reply and it works However I am now facing another problem: the type "Droplet Particle" must be in liquid form, but I actually have a solid material and I am not sure how to define its "latent heat". I see there are 3 types of latent heat: latent heat of fusion/sublimation/vaporization. Which one should I choose?
      In my case there is no phase change of zeolite and I would treat it as very stable. May I just assume a very high value like 1e7 J/kg?
    • Rob
      Ansys Employee
      DPM doesn't really distinguish between bubbles, droplets and particles and the material is set in the Discrete Phase part of the materials panel. If you're wanting to dry particles then have a look at the wet combustion option, you don't burn anything but it does give you the volatile fraction to "dry" and the non-volatile that's left afterwards.
    • lizardxy
      Subscriber
      Thank you for the suggestion and I am now giving a try. What I model is a zeolite-water suspension with 70% water.
      After setting the option "Combusting" as the particle type, I defined the zeolite as shown in the 1st screenshot. Is the volatile component fraction of zero a right definition?
      In the 2nd screenshot, I am not sure if I've defined the right materials in the red frames. Besides I turn on the "Wet Combustion" option and set the water as 70% liquid fraction.
      Could you please have a look and check if I set everything right here?


    • Rob
      Ansys Employee
      I think so, it's been a while since I last abused the model in that way: I was modelling inhalers with the drug being carried in a carrier fluid of some sort. Try it and see what happens.
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