Characterization of aerodynamic performance of vertical axis wind turbines: Impact of operational parameters

Abdolrahim Rezaeiha*, Hamid Montazeri, Bert Blocken

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

167 Citations (Scopus)

Abstract

Vertical axis wind turbines (VAWTs) have received growing interest for off-shore application and in the urban environments mainly due to their omni-directional capability, scalability, robustness, low noise and costs. However, their aerodynamic performance is still not comparable with their horizontal axis counterparts. To enhance their performance, the impact of operational parameters such as tip speed ratio (λ), Reynolds number (Rec) and turbulence intensity (TI) on their power performance and aerodynamics needs to be deeply understood. The current study, therefore, intends to systematically investigate the effect of these parameters in order to provide a deeper insight into their impact on the aerodynamic performance of VAWTs. For this investigation, a Darrieus H-type VAWT has been employed. A wide range of the parameters is considered: λ = 1.2-6.0, Rec = 0.3 × 105-4.2 × 105 and TI = 0%-30% to analyze the turbine performance, turbine wake and dynamic loads on blades. High-fidelity computational fluid dynamics (CFD), extensively validated with experimental data, are employed. The results show that (i) variable-speed operation maintaining the optimal λ at different wind speeds improves the turbine power coefficient, e.g. up to 168% at 4 m/s, while keeping an almost constant thrust coefficient, (ii) the turbine performance and wake are Re-dependent up to the highest Rec studied, (iii) large TI (> 5%) improves the turbine performance in dynamic stall by promoting the laminar-to-turbulent transition and delaying stall on blades, however it deteriorates the optimal performance by introducing extra skin friction drag. The findings of the current study can support more accurate performance prediction of VAWTs for various operating conditions and can help the improvement of the aerodynamic performance of VAWTs.

Original languageEnglish
Pages (from-to)45-77
Number of pages33
JournalEnergy Conversion and Management
Volume169
DOIs
Publication statusPublished - 1 Aug 2018

Keywords

  • Darrieus H-type VAWT
  • Dynamic loads
  • Reynolds number
  • Tip speed ratio
  • Turbine wake
  • Turbulence intensity

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Nuclear Energy and Engineering
  • Fuel Technology
  • Energy Engineering and Power Technology

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