Fluids

Fluids

Multiphase in pipeline

    • Mohsenhiva
      Subscriber

      Dear friends,


       


      I have a simple problem that must be solved easily but I wasn't able to solve it! I have two separated phases of air and water in an air vessel. I want to create a flow in the main pipeline below the air vessel. The project is two=phase transient based. The inlet boundary is velocity inlet and the outlet is a pressure outlet. I don't want to enter air at the inlet. But when I simulate I see the air intrusion from inlet as you see in t=0.5 s in attached images. Can anyone help me to solve this? I tried several thing like punch and defining different zones, but didn't work. Any suggestion? I only want to have water in the pipeline.


      Thanks a lot. 



       


    • DrAmine
      Ansys Employee

      Creating a dedicated thread for your question.

    • DrAmine
      Ansys Employee

      So do you mean that air is entering from the "velocity-inlet" bottom-left but it should not?


      Can you insert screenshot of your phase definitions as well as the velocity inlet settings for liquid and air (multiphase tab in the boundary is important here)?

    • Mohsenhiva
      Subscriber

      Dear abenhadj,


       


      Yes exactly, air shouldn't enter from the velocity-inlet boundary. I don't know how to stop that. Here are the screenshot. Should I use water as the primary phase?!


       


      Thanks for your help.


       


    • DrAmine
      Ansys Employee

      So in your case you have water as secondary phase. Which value for volume fraction are you giving at the Velocity-Inlet? Please screenshot.

    • Mohsenhiva
      Subscriber

      Yes, you were right. My problem was the definition of volume fraction in the velocity-inlet boundary. I hadn't pay attention to that. I appreciate your help. Now, I have to deal with the dynamic mesh for my check valve! ;-)

    • Mohsenhiva
      Subscriber

      By the way, I appreciate if you review my settings for six dof dynamic mesh in the following screenshot and give me some comments. Thanks a lot.


       


    • DrAmine
      Ansys Employee

      Please create a new thread for dynamic mesh suggestions. But what I can say is that is okay (as I do not know the motivation). I guess you do not need to have deforming for the zone itself if you do not want to alter the global settings but it is not important. 

    • Mohsenhiva
      Subscriber

      Thanks a lot for your kind response and help.

    • Raef.Kobeissi
      Subscriber

      Interesting model, is it a pressure surge tank by any chance

    • Mohsenhiva
      Subscriber
      Yes it is. A new thread is opened for dynamic mesh discussion for check valve in this model. You may be interested to see:

      https://studentcommunity.ansys.com/thread/dynamic-mesh-for-simulation-of-a-check-valve-cone-type/

      Regards
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