Hybrid Airfoil Design Procedure Validation for Full-Scale Ice Accretion Simulation

Abstract

This paper presents results of the ice accretion tests performed to validate the hybrid airfoil design method. The hybrid airfoil design method was developed to facilitate the design of hybrid airfoils with full-scale leading edges and redesigned aft sections that simulate full-scale ice accretion simulation for a given ® range. Icing tests in the NASA Lewis Icing Research Tunnel were conducted with test conditions representative of è ight. A two- dimensional half-scale hybrid airfoil was designed and built with a 20% plain è ap and a 5% upper and 20% lower full-scale leading-edge surface of a modern business jet wing section. This paper presents a comparison between the ice shapes accreted on the business jet and hybrid airfoil models during the tests. The test results show that ice accretion simulation could be predicted in terms of the droplet-impingement simulation alone and coné rm the assumption that the leading-edge ice accretion will be the same for the full-scale and hybrid airfoils if icing cloud properties, droplet impingement, local leading-edge è owé eld, model surface characteristics, and geometry are held constant. This assumption was found to be valid when tested under the most severe conditions of glaze ice accretion over a large time interval. A comparison between the actual ice shapes and those predicted by LEWICE 1.6 under similar conditions is also shown. The results suggest that the hybrid airfoil design method has signié cant application potential for tests where leading-edge ice accretion is desired because it provides an alternative to the myriad of issues related to ice accretion scaling.