Degradation of Power Generation Performance due to Effects of Various Ice Shapes and Accretions on Wind Turbine Blades

Abstract

In today’s world, green energy has become a key initiative as an alternative energy resource. Wind turbines are widely used to harvest wind energy in seasonal and cold environments. Although efficient, cold weather conditions negatively affects wind turbine operations due to ice formation. Damage from icing is seen on blade-tips when super-cooled water droplets that form in colder environments rapidly freeze and accumulate. Different forms of ice structures are formed along the leading edge to the trailing edge of the turbine blade and are classified into horn, rime and glaze ice. These various ice structures can cause power losses, mechanical and electrical failures and pose serious safety hazards (e.g., ice throwing). Ongoing efforts have been in place to develop anti-icing and de-icing strategies, but only a few are available on the market. In this computational study using ANSYS 14, a variable pitched National Renewable Energy Laboratory (NREL) and National Advisory Committee for Aeronautics (NACA) airfoils are used to determine the effects of various ice formations along the cord of turbine blade. Ice accretions on turbine blade can cause significant performance issues such as decreased lift and increased drag leading to performance and energy losses. Understanding the flow behavior of iced airfoil is critical in determining what geometric features of ice contributes to the performance degradation and aerodynamic failures in wind turbines. This study may help optimize future designs and implementation of ice mitigations systems to maximize turbine power output.