Fluids

Fluids

Fluent Crash when using multiphase

    • HorstvanGrass
      Subscriber

      Hi,

      I'm trying my first multiphase simulation, where water from a reacting mixture condensates to liquid water droplets. However every time I'm starting the simulation fluent crash and closes.

    • Rob
      Ansys Employee
      Probably not a bug, but as the set up isn't always straight forward it's easy to miss something. Which models are you using? Any UDFs?n
    • HorstvanGrass
      Subscriber
      Ok it seems that is something related to the implicit formulation, with explicit formulation it diverges but fluent does not crashn
    • HorstvanGrass
      Subscriber
      Mixture model, no UDFs. Eddy Dissipation Modell for reaction where vapor water is produced, which then cools in the later combustion chamber and should condensate.n
    • HorstvanGrass
      Subscriber
      n
    • HorstvanGrass
      Subscriber
      Ah wait is it possible to have steady simulation for multiphase? Because implicit crashes when I let it to steady instead to transientnn
    • Rob
      Ansys Employee
      Possible yes, but highly unlikely as stuff always changes with time in multiphase. Depending on the initial conditions you may find there is a lot of condensation early on that then stabilises. n
    • HorstvanGrass
      Subscriber
      yeah makes sense! Thx for helping! Do you know if it is still possible to have relaxing to chemical equilibrium for multiphase?n
    • Rob
      Ansys Employee
      We can solve species on a per phase basis, and then worry about mass transfer. I'm not sure what you mean in the question. n
    • HorstvanGrass
      Subscriber
      For the eddy dissipation model, there is an option to relax to chemical equilibrium, but it disapear when choosing multiphase... I think this option is not avaible therenn
    • Rob
      Ansys Employee
      Possibly, I'm relatively competent with combustion chemistry but not so much combustion modelling. Check the model limitations for mixture and eddy dissipation. n
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