Hello everybody ,
Firstly I would like to thank Jason for accepting me to this forum.
For my undergraduate thesis I’m designing a hydraulic pitch system for a 5MW wind turbine and for the the preliminary dimensioning of the hydraulic cylinder used I assume I need to know the maximum values for the blade pitching moment at the root , as in RootMzb1 in OpenFAST output.
My question is how would I go about simulating a turbine startup , going from feathered position to an optimal pitching angle for the wind speed input (I’m using a steady wind speed).
Or , in the case of an emergency , going from a initial pitching angle to a feathered position.
Should the blade pitching moment at the root be higher in a turbine startup or at a constant rotor speed rpm ?
For reference , I’m using the 5MW_Land_DLL_WTurb model.
Dear @Octav.Casian,
You can use the simple override pitch maneuver inputs available in ServoDyn to prescribe simple pitch ramps from the current angle ramping up to a final pitch angle which is held constant after the ramp–available via inputs TPitManS(1-3), PitManRat(1-3), and BlPitchF(1-3).
According to the loads analysis performed on the land-based version of the NREL 5-MW baseline wind turbine, the extreme pitching moments came from IEC design load cases 1.3 (extreme turbulence) and 1.4 (extreme coherent gust with direction change)–as seen from Appendix F.1 of my PhD-thesis turned NREL report: http://www.nrel.gov/docs/fy08osti/41958.pdf.
Best regards,