Engine Anti-Ice System

Abstract

When an aircraft flies through air with a high humidity and a temperature around the freezing point, moisture accumulates on the surfaces of the aircraft as ice. At the air inlet of a turbofan engine there are two areas where ice can accumulate on the surfaces. These are the inlet lip of the air inlet and the fan rotor. On the fan rotor the ice can accumulate on the fan blades and on the surface of the spinner. The ice on a surface of the inlet or the engine parts disturbs the airflow and generates vortices. In front of the compressor inlet, these vortices can lead to an unstable compressor operation. They facilitate stall and surge. Ice on the fan blades additionally produces imbalance, which leads to vibration. Detached ice pieces from the inlet structure create a risk for foreign object damage when they hit the fan rotor and the components behind the fan.