Research Of Water Film Ice Accretion Model On Aircraft Icing

Aircraft icing affect the flight safety seriously. The ice accretion model which based on thethought of Messinger can’t descript microscopic phenomenon observed by tests. Predicting icingshapes of glaze ice and mixed ice of this model are not the same as measured icing shapes in somedegrees. In order to ensure the safety of flight, reduce resource consumption of the test, lay a goodfoundation for the design of anti-icing and de-icing ice system, the model of ice accretion needs to beimproved.This paper mainly studied ice accretion problem of aircraft. A brief introduction about aircrafticing and research status of ice accretion numerical simulation was given. A ice accretion model basedon the thought of Messinger was established on2D airfoils. Computational code for determining icewas programmed and numbers of typical ice accretion on2D airfoil were simulated, which indicatethat the predicted icing shapes of glaze ice are not the same as measured icing shapes in some degrees.Based on an analysis of basic modeling theory and rupture theory of water film, a ice accretion modelincluding different states of liquid water on surface, such as continuous film, rivulets and beads, wasestablished on2D airfoils. Computational code for ice accretion simulating was programmed andnumbers of typical ice accretion on2D airfoil were simulated, which show that the predicted icingshapes of glaze ice are agree better with these obtained in wind tunnel experiments than the results ofthe ice accretion model based on the thought of Messinger. The2D water film icing model wasextended to3D based on a series of simplifying assumptions. A numerical method of this model wasdeveloped and a corresponding computer code was accomplished. Ice accretion on a real aircraft withengine nacelle was simulated in order to test the capability of this model. A multi-zone roughnessmodel based on liquid water state on surface was established and the equivalent sand grain roughnessmodel was introduced. The surface roughness distribution on different temperature were calculated on2D airfoil and the isothermal surface boundary layer integral model for convection heat transfercoefficient calculating on rough surface was discussed.The water film model established in this paper may descript the distribution state of liquid wateron ice in detail, have a guiding significance for the researching of surface hydrophobic material andliquid deicing mechanism, lay the foundation for further study of some microscopic phenomena, suchas super-cooled large water droplets icing and surface roughness forming.