Numerical Study on the Change of Aerodynamic Characteristics of Rotors Due to Ice Accretion Depending on the Sectional Shapes

Abstract

Aircraft are frequently exposed to various atmospheric conditions during ascent, where they encounter supercooled droplets within clouds. These droplets can freeze upon contact with the aircraft surface, leading to ice accretion at temperatures below the freezing point. This ice formation alters the aircraft's shape, adversely affecting its aerodynamic properties, flight efficiency, and stability. This study investigates the effects of icing on airfoil geometries, focusing on the aerodynamic characteristics and robustness of rotor blades in icing conditions through two-dimensional simulations and the Blade Element Momentum (BEM) method. Our findings indicate that an increase in the thickness ratio within the same camber series leads to reduced maximum droplet collection efficiency and broadens the range of the impingement limit for supercooled droplets. This effect is pronounced as thicker airfoils show lesser ice accumulation, enhancing aerodynamic stability under icing conditions. Conversely, airfoils with a lower camber ratio exhibit decreased maximum collection efficiency and a milder slope of droplet collection efficiency, resulting in reduced thrust loss. This suggests that selecting airfoil profiles with a lower camber ratio and greater thickness can significantly improve the robustness against icing conditions.