A computationally efficient engineering aerodynamic model for swept wind turbine blades

Li, Ang; Pirrung, Georg Raimund; Gaunaa, Mac; Madsen, Helge Aagaard; Horcas, Sergio González

doi:10.5194/wes-7-129-2022

Cited by 15 publications

(21 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…One such approach is presented by Li et al 13 The employed model is based on the near wake model originally adapted for wind turbine applications by Madsen and Rasmussen 14 and further developed by Pirrung et al 15 It combines a lifting line representation of the near wake consisting of the first quarter revolution of the wake with a far wake BEM implementation. In their work, Li et al 13,16 extend this near wake model to be able to account for swept blade geometries. Contrary to BEM, the near wake model models the coupling of the solutions of multiple streamtubes.…”

Section: Introductionmentioning

confidence: 99%

An efficient blade sweep correction model for blade element momentum theory

2022

View full text Add to dashboard Cite

This article proposes an efficient correction model that enables the extension of the blade element momentum method (BEM) for swept blades. Standard BEM algorithms, assuming a straight blade in the rotor plane, cannot account for the changes in the induction system introduced by blade sweep. The proposed extension corrects the axial induction regarding two aspects: the azimuthal displacement of the trailed vorticity system and the induction of the curved bound vortex on itself. The extended algorithm requires little additional processing work and maintains BEM's streamtube independent approach. The proposed correction model is applied to simulations of swept blade geometries based on the IEA 15 MW reference wind turbine. Results show good agreement with lifting line simulations that inherently can account for the swept blade geometry. Blade sweep couples bending and torsion deformations by curving the blade axis in the inplane direction. As such, it can be used to passively alleviate loads and, thus, aeroelastically tailor wind turbine blades. The implementation of aeroelastic tailoring techniques, and the aeroelastic analysis in general, becomes increasingly significant with the size of wind turbine rotors continually rising. Due to its low computing complexity, BEM remains a crucial tool in the aerodynamic and aeroelastic analysis of wind turbine rotors. Thus, the proposed correction model contributes to a fast and accurate evaluation of swept blade designs.

show abstract

Section: Introductionmentioning

confidence: 99%

An efficient blade sweep correction model for blade element momentum theory

2022

View full text Add to dashboard Cite

show abstract

“…The model was first proposed by Beddoes [17] and later introduced in a wind turbine context by Madsen et al in [18]. Further modifications to the model have been made by Pirrung et al [19,20] and Li et al [9,21]. The wake is separated into two regions, the near-wake (quarter rotation of the blade) and the far-wake.…”

Section: Near-wakementioning

confidence: 99%

“…The sum of both contributions results in the total induction. The near-wake model was further enhanced by the capability to model swept blades by Li et al [9]. Therefore, the trailing functions described in [19,20] are extended by a geometrical parameter that allows an analytical treatment of the sweep.…”

Section: Near-wakementioning

confidence: 99%

Comparison of different fidelity aerodynamic solvers on the IEA 10 MW turbine including novel tip extension geometries

Luna

Marten

Barlas

et al. 2022

J. Phys.: Conf. Ser.

View full text Add to dashboard Cite

Lifting-line based solvers could supersede the blade element momentum (BEM) method as the industry standard in the near future as rotor sizes of modern wind turbines and computational resources continue to increase. A comparison study between both methods is presented where the IEA 10 MW wind turbine is evaluated in the aero-servo-elastic simulation tool QBlade, comparing the lifting-line free vortex wake method to an unsteady blade element momentum solver. Besides the baseline rotor of the IEA 10 MW turbine, the comparison includes several blade tip extensions, including a swept and a dihedral geometry, to further differentiate capabilities between both methods in aerodynamically complex flow fields. As a reference serve results from equivalent simulations performed with multiple fidelity solvers of the simulation tool HAWC2. Results of a rigid load case demonstrate considerable improvement regarding the aerodynamic accuracy of lifting-line based methods in below rated conditions over BEM codes. The aerodynamic loads on geometrically complex tip extensions in steady conditions prove good capabilities of lower fidelity codes to predict out-of-plane bend shapes but also clear limitations regarding loads on swept geometries. A quasi-steady aeroelastic load case further demonstrates the capability of both QBlade codes to produce comparable results to similar fidelity solvers of the HAWC2 tool on an integral level. A detailed comparison in the time domain shows a larger dependency of the results on the type of structural solver that is used in contrast to the fidelity level of the aerodynamic method.

show abstract

“…The resulting aeroelastically optimized tip maximizing power performance within load constraints, utilizing sweep (Fig. 1), achieved a 19.58 % increase in power with the baseline ultimate flapwise bending moment at the boom root and tip connection, when evaluated at an extreme turbulence case (class III-C) at 6 m s −1 in the aeroelastic code HAWC2 (Larsen and Hansen, 2007) using the near wake (NW) model (Madsen and Rasmussen, 2004;Pirrung et al, 2016Pirrung et al, , 2017aLi et al, 2022). Since the RTR is a powered setup, the local power changes cannot be translated to any meaningful full-scale turbine application, but are simply used in the design optimization herein.…”

Section: Tip Model Designmentioning

confidence: 99%

“…The coupling factor is calculated so that the rotor thrust is comparable to that computed with the BEM method (Andersen et al, 2010;Pirrung et al, 2016). The near-wake model was recently modified to model the blade sweep effects (Li et al, 2022), which also accounted for the curved bound vortex influence (Li et al, 2020). As for the BEM method, the unsteady airfoil aerodynamic model (Hansen et al, 2004;Pirrung and Gaunaa, 2018) is included for all load cases.…”

Section: Near-wake Aerodynamic Modelmentioning

confidence: 99%

Atmospheric rotating rig testing of a swept blade tip and comparison with multi-fidelity aeroelastic simulations

et al. 2022

Self Cite

View full text Add to dashboard Cite

Abstract. One promising design solution for increasing the energy production of modern horizontal axis wind turbines is the installation of curved tip extensions. However, since the aeroelastic response of such geometrical add-ons has not been characterized yet, there are currently uncertainties in the application of traditional aerodynamic numerical models. The objective of the present work is twofold. On the one hand, it represents the first effort in the experimental characterization of curved tip extensions in atmospheric flow. On the other hand, it includes a comprehensive validation exercise, accounting for different numerical models for aerodynamic load prediction. The experiments consist of controlled field tests at the outdoor rotating rig at the Risø campus of the Technical University of Denmark (DTU), and consider a swept tip shape. This geometry is the result of an optimized design, focusing on locally maximizing power performance within load constraints compared to an optimal straight tip. The tip model is instrumented with spanwise bands of pressure sensors and is tested in atmospheric inflow conditions. A range of fidelities of aerodynamic models are then used to aeroelastically simulate the test cases and to compare with the measurement data. These aerodynamic codes include a blade element momentum (BEM) method, a vortex-based method coupling a near-wake model with a far-wake model (NW), a lifting-line hybrid wake model (LL), and fully resolved Navier–Stokes computational fluid dynamics (CFD) simulations. Results show that the measured mean normal loading can be captured well with the vortex-based codes and the CFD solver. The observed trends in mean loading are in good agreement with previous wind tunnel tests of a scaled and stiff model of the tip extension. The CFD solution shows a highly three-dimensional flow at the very outboard part of the curved tip that leads to large changes of the angle of the resultant force with respect to the chord. Turbulent simulations using the BEM code and the vortex codes resulted in a good match with the measured standard deviation of the normal force, with some deviations of the BEM results due to the missing root vortex effect.

show abstract

A computationally efficient engineering aerodynamic model for swept wind turbine blades

Cited by 15 publications

References 27 publications

An efficient blade sweep correction model for blade element momentum theory

An efficient blade sweep correction model for blade element momentum theory

Comparison of different fidelity aerodynamic solvers on the IEA 10 MW turbine including novel tip extension geometries

Atmospheric rotating rig testing of a swept blade tip and comparison with multi-fidelity aeroelastic simulations

Contact Info

Product

Resources

About