Assessment of Blade Element Momentum Theory-based engineering models for wind turbine rotors under uniform steady inflow

Assessment of Blade Element Momentum Theory-based engineering models for wind turbine rotors under uniform steady inflow

Boatto, Umberto (Siemens PLM Software; Student TU Delft)
Bonnet, Paul A. (Siemens PLM Software)
Avallone, F. (TU Delft Flow Physics and Technology; TU Delft Wind Energy)
Ragni, D. (TU Delft Flow Physics and Technology; TU Delft Wind Energy)

Flow Physics and Technology

2023

Blade Element Momentum Theory (BEMT) -based approaches provide 15%–20% inaccurate load predictions under uniform steady inflow. Inaccuracies were related to unclear aerodynamic mechanisms causing the Prandtl Tip-Root Loss (TRL) correction to fail at high Tip-Speed Ratio (TSR) and the ambiguous drag coefficient treatment under Stall Delay (SD). With this study, we provide an in-depth flow analysis to explain what physical mechanisms are poorly captured in TRL and SD corrections and offer a potential solution for the improvement of the Prandtl model. Corrections are assessed by comparison with RANS CFD simulations of the NREL 5MW rotor at its design TSR, TSR 4, and TSR 10. The Prandtl tip-loss correction provides 5%–15% higher loading than CFD at TSR 10. The reason is a lower (0.5°) downwash angle of attack, providing a 5%–10% lift coefficient overestimation. We recommend employing the tip-loss correction of Zhong, as it considers the lift coefficient reduction due to the tip-vortex downwash. The investigated Eggers SD correction predicts an incorrect drag coefficient at TSR 4, while a better agreement is found for the lift coefficient. We conclude that only the latter requires a correction for SD in the inboard blade.

Aerodynamics
Blade Element Momentum Theory
Computational fluid dynamics
Stall delay
Tip loss
Wind turbine

http://resolver.tudelft.nl/uuid:bb873983-4952-4021-b61d-378670ed141e

https://doi.org/10.1016/j.renene.2023.04.050

2023-10-23

0960-1481

Renewable Energy, 214, 307-317

Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

Institutional Repository

journal article

© 2023 Umberto Boatto, Paul A. Bonnet, F. Avallone, D. Ragni