| The icing of wind turbine blades is complex and brings many adverse effects,so it is necessary to study the icing of wind turbine blades.In this paper,with the help of ANSYS fluent platform,a set of numerical prediction methods for icing of airfoil is established by embedding the water drop impact module and the ice growth module.Firstly,the flow field around the airfoil is calculated.Based on the Eulerian model of water drop impact,the water droplet impingement on the surface of the airfoil are solved by using the UDS framework built in fluent,and then based on the thermodynamic theoretical model,the ice is solved by using UDF program In the process of thermodynamic equilibrium,the angular bisector method and dynamic grid technology are used to simulate the ice growth.The accuracy of the ice prediction method established in this paper is verified by verifying the distribution of water droplet impingement and the calculation of ice type.Using this ice prediction method,the distribution of water droplet impingement and ice shape on the surface of NACA63418 under different conditions are analyzed and compared,and the research on water drop impact and ice shape prediction on the surface of naca63418 under freezing rain is extended.Finally,the aerodynamic analysis of two typical ice shapes is carried out.Research findings:1.The maximum droplet collection coefficient and the droplet impact range on the airfoil surface are positively related to the free flow wind speed and the droplet diameter,and the overall trend of the droplet collection coefficient distribution is not significant.The droplet impact range increases with the increase of the angle of attack.The impact limit of the pressure surface is larger than that of the suction surface;2.When the temperature is 253.15 k,the regular wedge ice is formed on the surface of airfoil.The amount of ice increases with the increase of water drop diameter,natural inflow velocity and liquid water content.The trend of surface has no obvious change.With the increase of angle of attack,the ice area moves to the pressure surface.The downward movement range of ice limit point decreases with the increase of angle of attack.The ice area increases but the maximum ice thickness changes Not obvious.3.When the temperature is 263.15 k,the airfoil surface forms irregular ice with edges and corners.The surface trend of open ice changes significantly with the increase of water drop diameter,natural inflow velocity and liquid water content,and the amount of ice also increases correspondingly.A large ice ridge is formed on both sides of the airfoil.With the increase of angle of attack,there are more bulges on the ice surface and more sharp ridges on both sides.4.Under the condition of SLD,the surface of the ice shape is irregular,and a large ice angle is formed on the upper and lower sides of the front edge of the ice shape,which shows that the wind turbine faces a very serious ice problem under the condition of SLD.5.The ice on the surface of the airfoil changes the geometry of the airfoil,resulting in severe pressure fluctuation at the leading edge,leading to the early separation of the flow,early stall of the airfoil,and reduction of aerodynamic performance. |
