Melting And Icing Mechanism Of Ice Crystal Ingested Into Turbofan Engine

Ice crystal in turbofan engine will accrete on internal blade surface when airplane flies in high altitude clouds.After ice crystal is ingested into high bypass ratio turbofan engine,it travels with air flow in fan and compressor.With the increase of static temperature of air flow in fan and compressor,ingested ice crystal will be heated by air flow and melt.It sticks to the stator surface of low pressure compressor,blocks flow passage,damages engine performance,leads to thrust loss even engine shut down in the air.To study the icing mechanism of ice crystal ingested into turbofan engine,this research proposes a numerical simulation method for one-dimensional and two-dimensional ice crystal melting.The thermodynamic process of ice crystals ingested into compressor of turbofan engine is divided into two states,which are supercooled ice crystal and ice water mixture.The simulation consists of two parts.One part is the simulation of heat and mass transfer of supercooled ice crystal.Sublimation of ice crystal is simulated by mass transfer.The other is the simulation of heat and mass transfer of ice water mixture.Melting of ice crystal and evaporation of liquid water on the surface of the ice crystal are considered.Newton's law is applied to calculate the trajectory and velocity of ice crystal along the straight line.Through analysis of parameters of air flow,by discretization of the motion equation and heat and mass transfer equation of ice crystal,ice crystal radius,temperature,velocity,liquid water content of ice water mixture,heat transfer coefficient and mass transfer coefficient between ice crystal surface and air flow in compressor along axial position of compressor are calculated.The trajectory of ice crystal in compressor and collision characteristics between ice crystal and blades are obtained.This research deepens the understanding of icing mechanism of ice crystal ingested into turbofan engine and provides a basis for forecasting and analyzing ice formation induced by ice crystals in turbofan engine.