Development of an Ice Shedding Model for Icing Simulation on Rotor Blades 2023-01-1453

Aircraft icing is the phenomenon that forms an ice layer on the solid surface by impingement of supercooled water droplets in the atmosphere. In icing on rotor blades, ice is shed from the blade surface by centrifugal force as the accumulated ice grows. The ice shedding on rotor blades is a dangerous phenomenon, but the physical mechanism and properties are unclear, and most simulations have not considered it. Therefore, it’s necessary to establish an ice shedding model for icing simulations. In this study, we proposed an ice shedding model in which the condition for ice shedding is that the centrifugal force exceeds both the adhesion and tensile forces. Centrifugal force exceeding adhesion force expresses adhesion failure, while centrifugal force exceeding tensile force expresses cohesion failure. We also proposed functions of temperature and medium volume diameter (MVD) as adhesion strength and tensile strength for ice shedding judgment. Numerical simulations were performed to validate the model, and the ice shedding conditions were investigated through comparison with the experimental results. The progress of icing on the rotor blade was simulated by UPACS, which is composed of the flow field and droplet trajectory computations and the extended Messinger model (Ozgen, S. and Canibek, M., 2009) to simulate the thermodynamics. In the icing process, we simulated the change of centrifugal, adhesion, and tensile force over time. The results showed that icing simulation using UPACS can reproduce the experimental ice shapes, and the present ice shedding model can predict both the shedding timing and location with reasonable accuracy.