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-   -   friction & windage (http://www.cfd-online.com/Forums/cfx/22940-friction-windage.html)

alex August 11, 2006 03:48

friction & windage
 
hi, I am modelling a rotating machinery by using the MFR CFX option. I have to compute the friction and windage of this machine. The rotation axis is z. To determine the friction and windage ( ie torque * rotating velocity), i have to find, in the CFX post, the torque_z()@"rotating part". Rotating wall's torque are negative value. if i compute the static wall's torque, some value are >0 and some other value are <0. It's very strange!! How can i find the friction and windage by using CFX post? I don't know if i have to consider the torque on stator. I don t understand the positive torque on some stator's wall?

best regards

Alex

Turbine August 14, 2006 06:21

Re: friction & windage
 
Alex

Did you have a look at the rotation direction? Is this the cause for +ve and -ve torgues ?

GT

alex August 16, 2006 03:00

friction & windage - how to determine it with post
 
i understand that torques could be positive or negative values for the rotor (sign depends on the rotation direction). But, for the stator, some value are positive and some others, are negative. That is very strange. Also, i don't know how can i evaluate the friction and windage using cfx post.


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