Journal cover Journal topic
Wind Energy Science The interactive open-access journal of the European Academy of Wind Energy
Journal topic
Discussion papers
https://doi.org/10.5194/wes-2020-43
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/wes-2020-43
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Submitted as: research article 12 Feb 2020

Submitted as: research article | 12 Feb 2020

Review status
This preprint is currently under review for the journal WES.

Accurate loads and velocities on low solidity wind turbines using an improved Blade Element Momentum model

Yassine Ouakki and Abdelaziz Arbaoui Yassine Ouakki and Abdelaziz Arbaoui
  • INSCM team, LM2I, National School of Arts and Crafts (ENSAM), Moulay Ismail University, BP 4024 Meknes, Morocco

Abstract. The accurate prediction of loadings and velocities on a wind turbine blades is essential for the design and optimization of wind turbines rotors. However, the classical BEM still suffer from an inaccurate prediction of induced velocities and loadings, even if the classical correction like stall delay effect and tip loss correction are used. For low solidity rotors, the loadings are generally over-predicted in the tip region, since the far wake expansion is not accurately accounted for in the one-dimensional (1D) momentum theory. The 1D dimensional momentum theory supposes that the far wake axial induction is equal to twice the axial induction in the rotor plane, which results in an under-estimation of the axial induction factor in the tip region. Considering the complex nature of the flow around a rotating blade, the accurate estimation of 3D effects is still challenging, since most stall delay models still often tend to under-predict or over-predict the loadings near the root region. As for the solution method for the classical BEM equation, the induced velocities are computed accounting for the drag force. However, according to the Kutta-Joukowski theorem, the induced velocities on a blade element are only created by lift force. Accounting for drag force when solving the BEM will result in an over-estimation of the axial induction factor, while the tangential induction factor is under-estimated. To improve the accuracy of the BEM method, in this paper, the 1D momentum theory is corrected using a new far wake expansion model to take into account the radial flow effect. The blade element theory is corrected for three-dimensional effects through an improved stall delay model. An improved solution method for the BEM equations respecting the Kutta-Joukowski theorem is proposed. The improved BEM model is used to estimate the aerodynamic loads and velocities on the National Renewable Energy Laboratory Phase VI rotor blades. The results of this study show that the proposed BEM model gives an accurate prediction of the loads and velocities compared to the classical BEM model.

Yassine Ouakki and Abdelaziz Arbaoui

Interactive discussion

Status: open (until 25 Mar 2020)
Status: open (until 25 Mar 2020)
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
[Subscribe to comment alert] Printer-friendly Version - Printer-friendly version Supplement - Supplement

Yassine Ouakki and Abdelaziz Arbaoui

Yassine Ouakki and Abdelaziz Arbaoui

Viewed

Total article views: 90 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
64 21 5 90 0 0
  • HTML: 64
  • PDF: 21
  • XML: 5
  • Total: 90
  • BibTeX: 0
  • EndNote: 0
Views and downloads (calculated since 12 Feb 2020)
Cumulative views and downloads (calculated since 12 Feb 2020)

Viewed (geographical distribution)

Total article views: 75 (including HTML, PDF, and XML) Thereof 75 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 

Cited

Saved

No saved metrics found.

Discussed

No discussed metrics found.
Latest update: 16 Feb 2020
Publications Copernicus
Download
Short summary
It is well known that the classical BEM model fails to accurately predict the loadings and velocities on a wind turbines blade. In this work, an improved BEM model for low solidity wind turbines is proposed by accounting for 3D stall delay and far wake expansion effects. Additionally, the improved BEM equations are solved without the drag force. The results show that the improved BEM model predicts accurately the loading and velocities on the NREL phase VI rotor compared to the classical BEM.
It is well known that the classical BEM model fails to accurately predict the loadings and...
Citation