An aerodynamic study on flexed blades for VAWT applications

The Science of Making Torque from Wind 2012

Micallef, Daniel^1 ; Farrugia, Russell^1 ; Sant, Tonio^1 ; Mollicone, Pierluigi^1

University of Malta, Faculty of Engineering, Department of Mechanical Engineering, Msida

MSD2080, Malta^1

关键词: Blade performance;    Bound vorticities;    Collaboration with industries;    Induced velocity;    Level of detail;    Self-adjusting;    Straight-bladed;    Structural stress;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/555/1/012073/pdf
DOI  :  10.1088/1742-6596/555/1/012073

来源: IOP

【 摘 要 】

There is renewed interest in aerodynamics research of VAWT rotors. Lift type, Darrieus designs sometimes use flexed blades to have an 'egg-beater shape' with an optimum Troposkien geometry to minimize the structural stress on the blades. While straight bladed VAWTs have been investigated in depth through both measurements and numerical modelling, the aerodynamics of flexed blades has not been researched with the same level of detail. Two major effects may have a substantial impact on blade performance. First, flexing at the equator causes relatively strong trailing vorticity to be released. Secondly, the blade performance at each station along the blade is influenced by self-induced velocities due to bound vorticity. The latter is not present in a straight bladed configuration. The aim of this research is to investigate these effects in relation to an innovative 4kW wind turbine concept being developed in collaboration with industry known as a self-adjusting VAWT (or SATVAWT). The approach used in this study is based on experimental and numerical work. A lifting line free-wake vortex model was developed. Wind tunnel power and hot-wire velocity measurements were performed on a scaled down, 60cm high, three bladed model in a closed wind tunnel. Results show a substantial axial wake induction at the equator resulting in a lower power generation at this position. This induction increases with increasing degree of flexure. The self-induced velocities caused by blade bound vorticity at a particular station was found to be relatively small.