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  • Posted by T R Abhishek on November 15, 2023 at 1:33 am

    Hi,

    How does Velocity inlet & pressure outlet boundary condition compare to Pressure inlet and mass flow rate outlet boundary condition for a centrifugal pump? Which one should we prefer (if it matters) ?

    Are there any other combinations of BC that are commonly used?

    Rahul replied 5 months ago 2 Members · 3 Replies
  • 3 Replies
  • Rahul

    Member
    November 16, 2023 at 10:05 am

    Hi Abhishek,
    Velocity boundary conditions are not generally used for boundary conditions in turbomachinery applications. Mass flow rate should be used instead.
    For pumps/compressors, a pressure inlet and mass flow outlet boundary condition can be used to determine pump performance.
    Best regards
    Rahul
    Flowthermolab support

    • T R Abhishek

      Member
      November 17, 2023 at 12:50 am

      So for example,

      If an aircraft is moving at x speed, wont we give velocity inlet to its compressor?

      • Rahul

        Member
        November 17, 2023 at 5:58 am

        If you are modelling the external flow domain for the aircraft as well, then you can use velocity inlet for that domain. If you are modelling only the gas turbine compressor, which is usually done, you should use a mass flow inlet as it can also handle compressibility effects. In both cases, the objective of the simulation will be different.
        Also, when we try to model compressors, they will be specified based on their mass flow rates and pressure and not on the basis of velocity. So it may not be possible to specify based conditions using velocity boundary.
        Regards
        Rahul

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