Staff

When passenger aircraft fly through clouds comprising ice crystals, these ice crystals impact onto the aircraft structure and are ingested into their turbofan engines. Due to rising air temperatures inside the engine compressor, the ice particles start to melt and impact onto the inner engine surfaces. Therefore, melt water is generated which may form a liquid film on the stationary engine surfaces. The presence of a liquid film promotes sticking of impacting ice particles, which may lead to an ice accumulation. During melting, the ice particles are able to cool down the water film, finally resulting in solidification of the film and growth of hard ice accretions inside the warm engine core, despite ambient air temperatures above 0°C. This mechanism is called Ice Crystal Icing (ICI).

In the scope of the EU project MUSIC-haic, partners from academia and industry cooperate in order to investigate the complex phenomenon of ICI. The project ultimately aims to model the relevant physical phenomena of ICI and to deliver 3D multiphysics mature simulation tools able to simulate ICI in real conditions and to support design and certification of engines and aircraft.

The role of the institute Strömungslehre und Aerodynamik (SLA) in the project is to investigate the impact of single ice crystals onto different targets as well as the physics of ice accretions, which are relevant subprocesses of the ICI phenomenon. Two experimental setups for the investigation of ice particle impacts exist, where ice particles are shot onto a target using a pneumatic gun. Impact and fragmentation of the ice particle is recorded using high-speed cameras and analyzed via image processing. An improved particle tracking algorithm based on a Kalman filter routine is used to measure the fragment sizes and velocities.