Feather-Like Ice Growth on Aeroengine Spinner: An Experimental Study

Feather-like ice on the inlet spinner of an aeroengine endangers flight, yet its formation mechanism was unknown. This study systematically investigates the formation mechanism of ice accretion on a conical spinner using icing-wind-tunnel experiments and 3D scanning technologies. Experiments revealed two distinct ice morphologies on the spinner: forward-growing nail-like feathers and backward-growing needle-like feathers. The transition between these morphologies was found to depend critically on rotational speed, liquid water content (LWC), incoming flow velocity, and temperature. Specifically, higher rotational speeds, elevated LWC, increased flow velocities, and warmer temperatures promoted the shift from forward nail-like to backward needle-like ice structures. Three-dimensional characterization of ice profiles identified two key angles ([Formula: see text] and [Formula: see text]) governing growth directionality, with [Formula: see text] defining windward or leeward inclination and [Formula: see text] representing lateral broadening perpendicular to streamlines. Under rotation, centrifugal forces and shear stresses redistributed unfrozen water films on ice particles, driving leeward growth of needle-like feathers. When the spinner is stationary, the merging of adjacent ice elements along the [Formula: see text] direction generates broader structures, forming ice structures analogous to scallop ice on swept wings. These findings provide the first 3D experimental evidence of dynamic ice-feather evolution on rotating spinners, resolving longstanding gaps in understanding spinner-specific icing mechanics.