Investigation of airfoil profiles for use in self-starting, small-scale, low reynolds number vertical axis wind turbines

The selection of an appropriate airfoil profile is one of the most important considerations in order to improve the aerodynamic performance of a fixed-pitch straight-bladed vertical axis wind turbine (SB-VAWT). The aim of this paper is to investigate the aerodynamic performance of different airfoil profiles that have the potential to improve the self-starting performance of a small-scale fixed-pitch SB-VAWT. Using experimental data sets of low Reynolds number, a preliminary assessment of different airfoil profiles were examined. Seven potential airfoils were identified and compared with the most widely used conversional symmetric airfoil based on a potential flow model theory. The results indicate that the conventional symmetrical airfoil is unsuitable for self-starting of small-scale SB-VAWT. Further, the study found that no particular asymmetrical airfoil has all the desirable characteristics for self-starting. However, two asymmetrical airfoils, namely DU-06-W-200 and S 1210, showed exceptional aerodynamic performance and were further analysed to determine their torque output for a typical wind speed of 5m/s. The results show that the DU06-W-200 possesses a high starting torque and could be an ideal airfoil to eliminate the problem of self-starting for small-scale SB-VAWT.