Numerical and Experimental Investigation of Ice Accretion on Rotorcraft Engine Air Intake

Abstract

Ice accretion on the surface of an electrothermal anti-icing system around a rotorcraft engine air intake was investigated on the basis of computational and experimental methods. A compressible Navier-Stokes-Fourier computational fluid dynamics code was used to determine the fully three-dimensional flowfield around the inlet of the engine and the environment control system. Three-dimensional droplet trajectory and ice accretion codes based on the Eulerian approach, DROP3D and ICE3D modules of FENSAP-ICE, were used to calculate the collection efficiency and ice shape on the surface of an engine air intake. Furthermore, an experimental study using an icing wind tunnel was conducted to validate the computational predictions of ice accretion on the surface of the electrothermal anti-icing system in heat-off and heat-on modes. It is shown that the general shape and range of ice accretion obtained by numerical calculations are in close agreement with experimental observation. In particular, two features of glaze ice formation identified from computational results, the upper parts of the intake with the largest ice accretion and the narrow region between these parts showing relatively small ice accumulation, were confirmed in the experimental study.