Fluids

Fluids

RPM calculation

    • Jansys
      Subscriber

      I'm trying to validate an experimental study by trying to obtain the same torque.

      the dimensions of the blades were given, so I modeled and ran simulations on CFD fluent

      TSR: 0.555

      wind speed: 7 m/s

      Used this formula to calculate rpm : rpm = 60 * V * TSR / ( Pi * D )

    • Rob
      Ansys Employee
      Assuming the blade shape is also defined I'd expect to get a similar result with a good mesh. With a poor mesh I'd expect to be closer than you're seeing above.
    • Jansys
      Subscriber
      The blade shapes are halve cylinders, here are my mesh settings as well. I'm not sure what would be considered as good mesh?
      Here is a link to the study I am trying to validate for as required by our thesis defense panel:
      https://reader.elsevier.com/reader/sd/pii/S1876610215005652?token=06F41B08CDE2292E2B4025CCE91C6A45B3144166B70DFF7FEEEAFA81455DDF1EEB8398AF983295C66EB2F957E4E90A2B&originRegion=us-east-1&originCreation=20220124144208
      Results after increasing domain size at 5 m/s: I was able to reach torque of around .06 still far from .03 as per graph above




    • Jansys
      Subscriber
      I did face sizing for the blades .005m

    • Rob
      Ansys Employee
      Please show a slice through the mesh on a z-plane and zoom in on the rotor. How many cell zones have you got?
    • Jansys
      Subscriber
      20842346 elements, element size at .04 for fluid and .004 for the blades


    • Rob
      Ansys Employee
      z-plane please - ie across the turbine unit. Contours of velocity will be useful too.
    • Jansys
      Subscriber
      Here are my recent results I was able to get .053 tq but I had reduced blade diameter by 20mm, our defense panel wants a validation with 5-10% error

    • Jansys
      Subscriber

    • DrAmine
      Ansys Employee
      How are you calculating the torque in Fluent?
    • Jansys
      Subscriber
      By using the report definitions for moment at the blades, is that correct?
    • Rob
      Ansys Employee
      Yes, what did you define as the axis?
    • Jansys
      Subscriber
      I used the z axis
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