Effect of atmospheric temperature and droplet size variation on ice accretion of wind turbine blades

A numerical study of ice accretion and the resultant flow field characteristics of a 5 MW pitch controlled wind turbine blade profile (NACA 64618) have been carried out to understand the effects that atmospheric temperature and droplet size variations have on the rate and shape of ice growth. Resultant aerodynamic characteristics of the blade profile were analysed at different angles of attack ranging from −10° to +20°. Results show an increase in the ice growth with the increase of droplet size; whereas change in atmospheric temperature significantly affects the shape of accreted ice. Streamlined ice shapes were observed for low temperatures, whereas horn shape ice accretion was found at higher temperatures. Results show that for the iced blade profiles, changes in the aerodynamic characteristics are least prominent for the case of rime ice as compared to glaze ice.