Fluids

Fluids

Calculating swirl angular velocity for combustion

    • cehangir
      Subscriber
      Hi,


       


      I am using ANSYS Fluent for combustion problem with swirl in 2D.


       


      At the moment, I know the air going in the system is 15 m/s and the diameter of the duct is 0.3 m with 45 degree fins to generate swirls.


       


      Can someone help me finding the swirl angular velocity (rad/s) that I should input in Fluent. If not, can someone tell me how swirl angular velocity is calculated in rad/s, and what information is generally need.


       


      Thanks
    • Karthik R
      Administrator

      Hello,


      Could you please elaborate a little more about your problem? Can you not specify normal velocity and the 45 degree fins will deflect the flow internally when Fluent solves your model? What I don't understand is, I guess, your geometry? Could you please help us understand your problem better?


      Thank you.


      Best Regards,


      Karthik

    • klu
      Ansys Employee

      Hi,


      How about switching to magnitude and direction settings? I would think to put 15 m/s as the magnitude. Assume no radial component thus axial and swirl components are equal since the fins turn 45 degrees.

    • DrAmine
      Ansys Employee

      If you do not know anything about inflow then just stick to what klu said and assume normal inflow direction.

    • cehangir
      Subscriber

      I can use normal flow. Unfortunately, my geometry is 2D. Therefore I dont have physical 45 degree fins in the inlet. 


       


      That is why I want to include the expected swirl in the inlet. 

    • cehangir
      Subscriber

      Hi,  


      Can you elaborate how I can do that by switching to direction and magnitude setting. 


      Considering I have velocity as 15m/s, what will be the direction components for the axial and swirl component for 45 degree? 


      I have an additional information that the swirl No. is 0.79. Can I use it in some way to give direction ?

    • DrAmine
      Ansys Employee

      Swirl number is the ratio of flow rate of angular momentum to flow rate of axial momentum. 


      Velocity in cylindrical coordinate is V= r*e_r+(r*tehta)*e_theta+axial*e_axial with e_r, e_theta and e_axial the main cylindrical direction.


      Moreover radial velocity=u cos (theta) + v sin(theta), tangential velocity = -u sin(theta) + v cos(theta) und axial velocity is the velocity into the rotational axis.

    • SaiKiran
      Subscriber

      Hi,


      Can you please elaborate u and v components in the radial and tangential velocity. i am also working on the similar problem


      thanks & regards,


      saikiran

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