Numerical Simulation Of Droplet Impact Characteristic About Aircraft Icing And Study On Icing Scaling Law

Icing is one of the most serious hazards for aircraft. Icing comes from the freezing of cloud droplets, or supercooled droplets which remain in liquid state even at temperatures far below freezing, when they are stuck by the aircraft during the flight. Development of icing research makes people know the reason of icing, get the law how icing affects the aircraft security, and provide designs of anti-icing system and criterions of flying operation under icing conditions. This paper does some works on aircraft icing by theory analysis, numerical simulation, and wind tunnel experiment, and it also expatiates on the law of icing scaling.This paper gives the introduction and danger of icing. It describes the status and characters of supercooled droplet in the cloud, and presents the process of freezing when supercooled droplets strike the aircraft. The factors which affect amount and shape of icing are discussed. The methods of icing research are also presented at last.The flowfield of two-dimension cylinder and aerofoil NACA0012 was calculated by using CFD software CFD-ACE. The paper presents the droplet trajectory and impact characteristic, the equation of droplet trajectory is found from Lagrange method, a code is developed to calculate the droplet trajectory and the impact points, then the local collection efficiency is solved.The icing scaling method research is expatiated in the paper, and presents the icing scaling equations about geometric similarity, flowfield similarity, drop trajectories similarity, the total water catch similarity, energy balance similarity, and, probably, surface-water dynamics similarity. The icing scaling method is validated by numerical simulation.Two-dimension cylinder icing wind tunnel experiments was partially finished. The effects of air velocity and atmosphere temperature to amount and shape of icing was obtained by comparing the experiment results; Author points out the problems and equipment localization that existed in the experiment, and then gives some suggestion about future icing wind tunnel experiment technology.