Aircraft icing presents a serious threat to the aerodynamic performance and safety of aircraft. The numerical simulation method for the accurate prediction of icing shape is an important method to evaluate icing hazards and develop aircraft icing protection systems. Referring to the phase-field method, a new ice accretion mathematical model is developed to predict the ice shape. The mass fraction of ice in the mixture is selected as the phase parameter, and the phase equation is established with a freezing coefficient. Meanwhile, the mixture thickness and temperature are determined by combining mass conservation and energy balance. Ice accretions are simulated under typical ice conditions, including rime ice, glaze ice and mixed ice, and the ice shape and its characteristics are analyzed and compared with those provided by experiments and LEWICE. The results show that the phase-field ice accretion model can predict the ice shape under different icing conditions, especially reflecting some main characteristics of glaze ice.
Icing phenomenon is an important problem in helicopter rotor design. Conducting experiments in a cold chamber is one of the main methods used to study the law of rotor icing. The purpose of this paper was to analyze the influence of different parameters on the ice shapes of rotor blade and to obtain the relationship between the ice shapes and the input parameters. The icing experimental platform of rotation blade in a cold chamber was set up, and the rotor icing experiments under various conditions were carried out. The ice shapes on the blade were obtained, and the influence of different icing temperatures, rotation speeds, liquid water content, icing times, number of blades on the rotor, and blade materials on the ice shapes were analyzed. The results showed that the ice thickness on the leading edge increased with the increase of liquid water content, rotation speed, and icing time, and the number and material of blades had little effect on icing. The conclusions of this paper can provide a reference for the rotor numerical simulation and future experimental research.
Icing will occur when wind turbines are installed in cold and humid regions. Blade icing will reduce the efficiency of wind turbines. In this paper, a numerical simulation method is proposed for glaze, mixed, and rime ice accretion on three-dimensional wind turbine blades. The air flow field is calculated by the multiple reference frame model and droplet trajectories are obtained using the Eulerian two-phase flow method. In the ice accretion calculation, a three-dimensional icing calculation model is established and a new water flow distribution method based on shear force and centrifugal force is presented. The calculation results of ice shapes are compared with the experimental results and the good agreement proves the validity of the icing numerical simulation method. Based on the calculation results, the influence of centrifugal force on the ice shape is studied. Finally, the droplet impingement characteristics and ice shapes of the wind turbine blade are simulated. The results show that the in-cloud icing of wind turbine blades occurs mainly near the leading edge. The icing thickness is thicker and the icing range is wider with the increase of spanwise length.