Experimental investigation on ice accretion on a rotating aero-engine spinner with hydrophobic coating

Abstract

Ice accretion on aero-engine inlets is a serious threat to the inflight safety. As an important part of the engine inlet components, the rotating spinner has special icing phenomena compared with the stationary ones. An experimental study is conducted to investigate the ice accretion on a rotating aero-engine spinner in the icing wind tunnel. A full-scale engine spinner model is used in the experiments operated under different conditions. The hydrophobic nanoparticle-polymer composite coating is applied to cover on the aluminum-based spinner and then to examine its anti-icing performance. The dynamic icing processes and the final ice shapes on the rotating spinner surface are captured. The experimental results reveal that the ice growth and ice shape are basically determined by the airflow temperature and slightly affected by the rotating speed when the airflow velocity and icing cloud parameters are constant. The ice fracture and shedding are greatly dependent on the rotating speed when the icicle length is large enough. The freezing delay on the hydrophobic coating is inconspicuous and there is even no effect on the ice growth. However, the ice shedding on the coating happens, especially in the mixed icing condition with a higher rotating speed, demonstrating its icephobicity. Meanwhile, the dynamic icing processes and the effects of the airflow velocity and rotating speed on the ice growth are analyzed based on the mechanism of the supercooled droplet impingement characteristics, heat and mass transfer, force analysis on the rotating surface. The surface wettability is introduced to evaluate the freezing delay and icephobicity on the hydrophobic coating.