In-Flight Gas Turbine Engine Icing: Review

Inflight icing can occur on gas turbine engines for aircraft when there is significant atmospheric water content coupled with low temperatures. Supercooled droplet icing tends to occur at the front of the engine, and ice crystal icing tends to occur inside the engine (engine core region). The risk associated with engine icing to flight airworthiness and safety has been confirmed with several reported inflight incidents, especially for ice crystal icing. This includes ice accretion on critical components of an engine, followed in some instances by ingestion into the combustor, where engine icing can problematically cause flow blockage, surge/stall, or flameout. This comprehensive survey on engine icing provides a broad discussion of the environmental conditions that cause engine icing, including the atmospheric water phase (supercooled droplets vs ice crystals icing) and the aero-thermal-fluid physics that cause specific types of ice accretion (rime, glaze, etc.). The engine components that are most susceptible to each type of icing and the associated engine icing problems (mechanical, operational, etc.) are also identified, along with key recent developments in understanding the physics and characteristics of ice crystal icing.