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-   -   The Definition of the Flow Angle (http://www.cfd-online.com/Forums/numeca/83246-definition-flow-angle.html)

yangdick001 December 21, 2010 02:28

The Definition of the Flow Angle
 
In the document of the .mf, what is the definition of the Meridional_flow_angle, Blade-to-blade_absolute_flow_angle and Blade-to-blade_relative_flow_angle?
I read the User_Manual_cfView, find the flow angle= arctan(Vt/Vm),this definition is which one above.
Thanks

sanboju January 25, 2011 12:39

Quote:

Originally Posted by yangdick001 (Post 287960)
In the document of the .mf, what is the definition of the Meridional_flow_angle, Blade-to-blade_absolute_flow_angle and Blade-to-blade_relative_flow_angle?
I read the User_Manual_cfView, find the flow angle= arctan(Vt/Vm),this definition is which one above.
Thanks

Hi yangdick,

I have been seen the results of the .mf document in my study case. First of all, the blade-to-blade_relative_flow angle doesn't appear.

I'm doing an unsteady simulation with a Vx flow. In all steps of the "*.mf" document appears -90 degrees for the meridional_flow_angle. I understand that angle is the angle between X axis and the normal flow axis, in my case 90. The negative symbol I think would be a sign criteria.

The flow angle you mentions (angle= arctang(Vt/Vm) in aeronautics is known as angle of attack and is the angle between the chord of the profile and the relative flow velocity (sum of upstream velocity and rotationary velocity).

In my document only appears with the merdional_flow_angle, the blade_absolute_flow_angle, so I'm not sure that would be the angle of attack because I've seen other parameters of the document and It only mentions 1 blade and I'm working with more blades. Another parameters that appear are in geometrical data (Hub_radius, Shroud_radius, ...) and the values are the domain I defined on IGG. So I'm not sure where calculate the values corresponding to the velocity, angles, etc. because I don't know the initial point of the reference axis systems, I supose It would be anti-clockwise. On the other hand, the solid is inside the rotor and I don't think that file will solve you the question of the instantaneus angle for each position.

Cheers

sanboju January 25, 2011 12:49

mf document
 
Hi again, as you see is GLOBAL RESULTS AT ROTOR/STATOR INTERFACE and not for inside blades. It means it's the transition from the rotor/stator

yangdick001 February 23, 2011 21:58

Quote:

Originally Posted by sanboju (Post 292122)
Hi again, as you see is GLOBAL RESULTS AT ROTOR/STATOR INTERFACE and not for inside blades. It means it's the transition from the rotor/stator

Thank you very much!
My study case is a radial inflow turbine and I working with 1 blade.I want to analyse the loss of the turbine inlet attack angle so I must konw the definition of the flow angle clearly especially the flow angle of the turbine inlet


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