| In flight, when supercooled water droplets in air hit the surface of the wings and ice up, the wing's aerodynamic shape would be changed. It would cause resistance increased, lift droped, critical angle of attack reduced and so on. Or it would take more serious accidents such as occurred in the crash. This showed that the researches of the freezing process and the impacts of the shap changes in ice surface on the aerodynamic characteristics of the wings were very important. To study the impacts of the shap changes on the aerodynamic characteristics of the wings, first of all the size of the region on which the water droplets hitted should be syudyed, as well as the mechanism and the process of freezing on the wing surface, that is, the size of the freezing area, the growth of the ice and the ice shape after a certain period of time.Studies included: Using self-designed small-scale icing wind tunnel to simulate the different atmospheric conditions (The main parameters include temperature, wind speed, liquid water content, droplet diameter and so on), and then to research icing test of NACA0012. The effefts of temperature and liquid water content on icing limited and the effects of liquid water content on the growth of the ice shape were explored; A rational model of icing was built and then the numerical simulation of icing was carried on. Results of the numerical simulation and the experimental were compared; Finally, the impact of wing icing on the aircraft aerodynamic performance was discussed. And the impact of three typical ice-shapes on the aircraft aerodynamic performance was obtained. In addition, icing situation which is the most disadvantaged for the aircraft aerodynamic performance was gained.Three three typical ice shapes and the freezing weather conditions of the three typical ice shapes through the experiments were gained. And the results showed that temperature and liquid water content had no effects on the icing limited and the droplets hitting limited; Droplet diameter and wind speed had a significant impact on the droplets hitting limited; Liquid water content had no effect on the growth of the ice shape. Ice thickness and liquid water content had simultaneous increase; Ice on the aircraft surface can worsen aircraft flight performance severely. |
