Abstract: Presently design of anti-icing systems for aircraft engines is generally made for small droplet icing conditions. However, recent research shows that icing accretion due to supercooled large droplet (SLD) may result in extremely severe aircraft or engine performance degradation. With reference to the impact behavior of SLD on an aero-engine strut surface, a numerical method is presented in this paper to model some important phenomena and effects for the SLD, including deforming, breakup, splashing, rebounding, etc. Some semi-empirical computational models drawn from the literature are incorporated into the Eulerian droplet field equations. Comparisons are then made between the impingement characteristics on struts surface in two different regulated angles with an icing cloud median volumetric dimeter (MVD) of 120 μm. Results show that, when the regulated angle is 0°, some smaller droplets are formed because of the breakup effect. Also, due to the splashing and rebounding influence the droplet collection efficiency and impingement limit decrease by 11.8% and 35.7%, respectively. In contrast, no breakup phenomenon is observed when the regulated angle is 30°, and all the impacting mass rebounds away from the regulated surface.

Key words: aircraft engine, anti-icing system, aero-engine strut, supercooled large droplet, impact behavior, numerical simulation