0
research-article

A critical analysis on low-order simulation models for Darrieus VAWTs: how much do they pertain to the real flow?

[+] Author and Article Information
Alessandro Bianchini

Department of Industrial Engineering, University of Florence, Via di Santa Marta 3, 50139, Firenze, Italy
alessandro.bianchini@unifi.it

Francesco Balduzzi

Department of Industrial Engineering, University of Florence, Via di Santa Marta 3, 50139, Firenze, Italy
francesco.balduzzi@unifi.it

Giovanni Ferrara

Department of Industrial Engineering, University of Florence, Via di Santa Marta 3, 50139, Firenze, Italy
giovanni.ferrara@unifi.it

Giacomo Persico

Dipartimento di Energia, Politecnico di Milano, Via Lambruschini 4, 20156, Milano, Italy
giacomo.persico@polimi.it

Vincenzo Dossena

Dipartimento di Energia, Politecnico di Milano, Via Lambruschini 4, 20156, Milano, Italy
vincenzo.dossena@polimi.it

Lorenzo Ferrari

Department of Energy, Systems, Territory and Construction Engineering, University of Pisa, Largo Lucio Lazzarino, 56122, Pisa, Italy
lorenzo.ferrari@unipi.it

1Corresponding author.

ASME doi:10.1115/1.4040851 History: Received June 26, 2018; Revised July 03, 2018

Abstract

To improve the efficiency of Darrieus wind turbines, CFD techniques are now extensively applied by researchers. Their computational cost makes them however prohibitive for routine industrial applications, which still make use of low-fidelity simulation models like the Blade Element Momentum (BEM) theory. These models have been shown to provide relatively accurate estimations of the overall turbine performance, but a quite poor description of the actual flow physics. In the present study, the effectiveness of the BEM approach was critically benchmarked against a comprehensive description of the flow past the rotating blades coming from the combination of a 2D unsteady CFD model and experimental wind tunnel tests; for both data sets, the overall performance and the wake characteristics of a small H-Darrieus turbine were available. Upon examination of the flow field, the validity of the ubiquitous use of induction factors is discussed, together with the resulting velocity profiles upstream and downstream the rotor. Particular attention is paid on the actual flow conditions experienced by the airfoils in motion at different azimuthal angles, for which a new procedure for the post-processing of CFD data is proposed. The actual lift and drag coefficients produced by the airfoils in motion are analyzed and discussed, with particular focus on dynamic stall. The analysis highlights the main critical issues and flaws of the low-order BEM approach, but also sheds new light on the physical reasons why the overall performance prediction of these models is often acceptable for a first-design analysis.

Copyright (c) 2018 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In