Hi, I'm using NREL Phase VI turbine for my analysis.
I noticed that UAE has provided two torque values, one estimated torque (from pressure measurement along different sections) and another measured torque(low speed shaft torque). These values get closer at low wind speeds but at higher wind speed there is a big difference. Does any one knows reason behind it.
It looks like you need someone who knows the NREL Phase VI Turbine code intimately enough to know how the torque is computed. How is induction factor calculated? Are tip effects corrected for?
For the experimental data, were the tests full scale? If not what blockage corrections were performed? These tend to have their greatest effect on the extremes of the performance spectrum.
Independent of the software, I'm not sure there's a way to answer your question without knowing the Tip Speed Ratios (TSR's) associated with your high and low speed wind cases.
If the TSR's deviate by a large amount then I could see how the manner in which induction factor is calculated might change the calculated torques.
@Karthi bro, thanks. Even CFD computed torque is lower than the experimental torque. So only I got confused how CFD post computes torque. Is it from pressure values.
@Aaron thanks sir, But here nothing to do with BEM, experimental data is full scale. In NREL Phase VI report itself they have provided two torque values. Estimated torque from pressure measurements and lsst torque
Still no answer to the TSR question though?
Also, if someone is splining spanwise slices of chordwise pressure distributions to get to an integrated blade-wide solution for torque they would still presumably have to apply some form of 3-dimensional correction (since sectional characteristics alone cannot fully compensate for the three-dimensional induced wake effect). This correction would be larger when the blade is more heavily loaded and thus the deviation between measured shaft torque and torque from integrated pressure would also be larger, no?
yes sry
lamda= (omega*R)/wind speed =(7.54*5.029)/25= 1.52
Also I accept the fact that 3d corrections has to be included, I have included various corrections by Snel, Lidenburg etc. But my concern is about CFD and experimental analysis.
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