• français
    • English
    français
  • Login
Help
View Item 
  •   Home
  • Laboratoire Ingénierie des fluides Systèmes énergétiques (LIFSE)
  • View Item
  • Home
  • Laboratoire Ingénierie des fluides Systèmes énergétiques (LIFSE)
  • View Item
JavaScript is disabled for your browser. Some features of this site may not work without it.

Experimental investigation of the effect of blade solidity on micro-scale and low tip-speed ratio wind turbines

Article dans une revue avec comité de lecture
Author
BOURHIS, M.
1003528 Laboratoire d'Ingénierie des Fluides et des Systèmes Énergétiques [LIFSE]
PEREIRA, M.
1003528 Laboratoire d'Ingénierie des Fluides et des Systèmes Énergétiques [LIFSE]
RAVELET, Florent
1003528 Laboratoire d'Ingénierie des Fluides et des Systèmes Énergétiques [LIFSE]

URI
http://hdl.handle.net/10985/22476
DOI
10.1016/j.expthermflusci.2022.110745
Date
2023-01
Journal
Experimental Thermal and Fluid Science

Abstract

It is well-established that micro-scale wind turbines require high blade solidity in order to overtake friction torque of all mechanical parts and starts operating. Therefore, multi-bladed micro-scale rotors with a low design tip-speed ratio λ are advocated. However, no consensual blade solidity is admitted by the scientific community at low Reynolds number and low tip-speed ratio because the reliability of the airfoil data, used in the blade element momentum theory, is questionable. The vast majority of the open literature has focused on the number of blades rather than varying blade chord length to increase the solidity. This experimental study carried out in a wind tunnel serves two purposes: to examine blade solidity effect on the power C p and torque coefficients C τ vs. tip-speed ratio curves at a fixed number of blades and to investigate its effects on the velocity distributions using stereoscopic particle image velocimetry (SPIV) for three tip-speed ratio λ = 0.5, λ = 1 and λ = 1.4. Six 200 mm diameter runners with 8 blades and various blade solidity from σ = 1.5 to σ = 0.5 were designed at λ = 1 without using airfoil data. The results emphasise that the maximum power coefficient increases with blade solidity up to a maximum value C p,max = 0.29 reached for σ = 1.25. High-solidity rotors have a very low cut-in wind speed V 0 = 3.8 m s −1 and their torque coefficient C τ decreases drastically and linearly while increasing the tip-speed ratio λ. These specificities could be of particular interest for energy harvesting of low speed air flow in order to power low-energy appliances. However, for low-solidity rotors, the C τ vs. λ curves present a similar trend than the lift coefficient vs. angle of attack polar plots of isolated airfoil which is characterised by a significant drop in C τ illustrating stall effect. An increase in blade solidity postpones and attenuates the stall effects due to greater mutual blade interactions. The SPIV recordings reveal that for high-solidity rotors the magnitude and radial profiles of axial and tangential induction factors and the flow deflection were close to the design settings. Moreover, the analysis exhibits that an increase in the blade solidity and tip-speed ratio leads to higher axial and tangential induction factors. The investigation of the wake highlights that the aerodynamic torque generated by a wind turbine is not produced in a same way as changing the blade solidity or the tip-speed ratio. To conclude, the best compromise between the maximum power coefficient, the cut-in wind speed, the mass of filament and the stability of the wake is achieved for the rotor with a blade solidity of σ = 1.25.

Files in this item

Name:
LIFSE_ETFS_2023_RAVELET.pdf
Size:
1.040Mb
Format:
PDF
Embargoed until:
2023-07-01
View/Open

Collections

  • Laboratoire Ingénierie des fluides Systèmes énergétiques (LIFSE)

Related items

Showing items related by title, author, creator and subject.

  • Innovative design method and experimental investigation of a small-scale and very low tip-speed ratio wind turbine 
    Article dans une revue avec comité de lecture
    BOURHIS, Martin; PEREIRA, Michael; RAVELET, Florent; DOBREV, Ivan (Elsevier BV, 2021)
    Small horizontal axis wind turbines operating at low wind speeds face the issue of low performance compared to large wind turbines. A high amount of torque is required to start producing power at low wind speed to overtake ...
  • Numerical Assesment of a Small-Scale and Very Low Tip Speed Ratio Wind Turbine 
    Article dans une revue avec comité de lecture
    BOURHIS, Martin; PEREIRA, Michaël; RAVELET, Florent; DOBREV, Ivan (EDP Sciences, 2021)
    The aim of this paper is to study by CFD the performance and to characterize the velocity fields in the wake of an horizontal axis wind turbine. The design of this wind turbine is far from classical as it has been designed ...
  • Experimental investigation of the effect of the Reynolds number on the performance of a micro-scale and low tip-speed ratio wind turbine 
    Communication avec acte
    BOURHIS, Martin; PEREIRA, Michaël; RAVELET, Florent (2022)
    Micro-scale wind turbines are of great interest to supply rechargeable batteries of autonomous sensors in the field of the Internet Of Things (IOT). However, they face the issue of lower dimensionless performance than ...
  • Improved Aerodynamics of a Hollow-Blade Axial Flow Fan by Controlling the Leakage Flow Rate by Air Injection at the Rotating Shroud 
    Article dans une revue avec comité de lecture
    PEREIRA, Michaël; RAVELET, Florent; AZZOUZ, Kamel; AZZAM, Tarik; OUALLI, Hamid; KOUIDRI, Smaïne; BAKIR, Farid (MDPI AG, 2021)
    Axial flow fans are used in many fields in order to ensure the mass and heat transfer from air, chiefly in the heating, ventilation and air conditioning industry (HVAC). A more proper understanding of the airflow behavior ...
  • Numerical Study on the Effect of an Off-Surface Micro-Rod Vortex Generator Placed Upstream NACA0012 Aerofoil 
    Article dans une revue avec comité de lecture
    LARABI, Abderrahim; PEREIRA, Michael; RAVELET, Florent; AZZAM, Tarik; OUALLI, Hamid; MENFOUKH, Laiche; BAKIR, Farid (EDP Sciences, 2021)
    In this paper, 3D numerical simulations have been carried out to enhance the understanding of a flow over a passive control device composed of micro cylinder with, d/c = 1.34% placed in the vicinity of NACA0012 aerofoil ...

Browse

All SAMCommunities & CollectionsAuthorsIssue DateCenter / InstitutionThis CollectionAuthorsIssue DateCenter / Institution

Newsletter

Latest newsletterPrevious newsletters

Statistics

Most Popular ItemsStatistics by CountryMost Popular Authors

ÉCOLE NATIONALE SUPERIEURE D'ARTS ET METIERS

  • Contact
  • Mentions légales

ÉCOLE NATIONALE SUPERIEURE D'ARTS ET METIERS

  • Contact
  • Mentions légales