Icing physics

This chapter discusses the fundamental physics in ice accretion over wind turbine surfaces under various icing conditions. The key parameters influencing the impact icing process on wind turbines are described in great detail. The two stages of ice accretion on a wind turbine are illustrated, that is, (i) the dynamic water droplets impinging process as the airborne droplets are intercepted by the rotating turbine blades and (ii) the solidification (i.e., freezing) process of the collected water mass on the blade surfaces. The different approaches of evaluating the droplet trajectory, water collection efficiency, heat transfer, and surface water transport in wind turbine icing phenomena are presented. In addition, the formation mechanisms of the different ice structures/types that may accrete on a wind turbine are elucidated in detail. The major icing test facilities and their key features are also introduced, along with illustrating the key scaling parameters in the similarity analysis of wind turbine icing experiments.