Characteristics of ice accretions on blade of the straight-bladed vertical axis wind turbine rotating at low tip speed ratio

Icing on blade surface of wind turbine greatly affects the performance of wind turbine which becomes a very serious problem for the wind turbine installed in cold and wet regions both for larger-scale wind turbine and small-scale ones. The Straight-bladed Vertical Axis Wind Turbine (SB-VAWT) is a kind of lift-type VAWT which is widely used for small-scale wind power generation. Icing on blade of SB-VAWT will also affect both the starting performance and out power performance. To verify the icing characteristics of blade rotating at low tip speed ratio of the SB-VAWT during its starting stage, wind tunnel icing experiments have been carried out on a rotor with blade airfoil of NACA0018 in a wind tunnel icing experimental system by using natural low temperature in winter proposed in this study. The icing distributions were recorded by a high speed camera at different tip speed ratios from 0 to 1. The weight of icing on blade was also measured. Furthermore, the icing area ratio and icing rate were calculated and analyzed. The main results show that the ice accretion on a rotating blade of SB-VAWT at low tip speed ratio is quite different from the blade in static condition. The icing distributed on the whole surface of blade and the icing area increases along blade airfoil outline with the increasing of icing time and rotational speed. The whole weight of icing on all blades of wind turbine increased with the increasing of blade number.