2 Replies Latest reply on Jul 16, 2014 6:12 AM by AJAY SELVAM

    Exit Behavior CD Nozzle

    Michael Knight
    Michael Knight Jul 9, 2014 11:05 AM

      I'm trying to determine the exit behavior of a converging-diverging supersonic nozzle. To do this I want to set up a simulation so that the exit boundary condition is standard atmospheric conditions. I then want to view the particle trajectories passing throught the exit to see if they are over or under expanding as they exit. Unfortunatly, the streamlines all seem to stop at the exit where I set up my boundary condition, is there any way around this?

       

      Thanks

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        • Re: Exit Behavior CD Nozzle
          Jared Conway
          Jared Conway Jul 10, 2014 12:16 PM (in response to Michael Knight)

          1. extend your exit area

          2. use an internal/external analysis where your nozzle is in an external analysis and then you put a volume flow rate at the inlet to it and it expands outwards.

           

          unless you use these methods, your flow trajectories stop at the outlet because that is the end of your computational domain

          • Re: Exit Behavior CD Nozzle
            AJAY SELVAM
            AJAY SELVAM Jul 16, 2014 6:12 AM (in response to Michael Knight)

            Dear Micheal,

             

            I hope you are trying to capture the flow behaviour when flow exits the C-D Nozzle and enters atmosphere.

            Mostly flow tends to attain high velocity at exit of C-D Nozzle, Mach, 1.3>M<5 (in case of Supersonic flow). 

            As Conway suggested,

                 The exit area to be increased - To capture flow behaviour at atmosphere, also

                 The CV (Control Volume/ Control Domain) has to be extended in exit region of  Nozzle

                 The Mesh settings has to be of very high refinement, inorder to capture High speed flows (like Mach > 1)