Research On The Aircraft Icing Features Based On The Microscopic Physical Phenomena

When flying in the icing weather, the aircraft could be iced and its shape will be changed. This will damage the aerodynamic characteristics, maneuverability, stability of the aircraft and cause a lot of potential risk. The actual icing is a multidisciplinary integrated complex physical process so that a good model is essential in order to get precise simulated results. Nowadays most of the domestic and foreign scholars are using the numerical models that based on the Messinger thoughts, but since the model is continuous,the simulated ice shape surface is very smooth, and it can't simulate the microscopic physical phenomena well. So here a new model which based on the Szilder thoughts to simulate the movement of the single droplet is established.The main work of this paper is as follow:(1)The efficient CFD software Fluent is used to simulate the external flow field of the wing, and the pressure coefficient of the wing is calculated out to compare with the experiment data to figure out that whether the method is valid.(2)In order to find out whether the simulated ice is valid in the research of the aerodynamic characteristics on the iced wing, the structed mesh of ice shapes which based on the experiment and numerical simulation of Messinger model is got from ICEM, and the Fluent is used to calculate for the lift coefficient and drag coefficient of these two ice shapes in different angle of attack. The results shows that the simulated ice shape is not accurate in the calculation of the aerodynamic characteristics on the iced wing because that its characteristics of rough surface is not obvious.(3)The Euler's method is used to establish the control equations of the water droplet movement, and then some droplet impingement property calculation has been done in different diameters. The droplet collection coefficient on the icing surface of the wing is got to provide the initial conditions for icing prediction.(4)A new icing model which based on the new thoughts that contain random-emission model, random-walk model and the freezing probability model is established. The ice simulation program is wrote and used to do some numericial simulation of icing in different atmosphere conditon. Finally the simulated data is compared with the expermental data and the simulated data by CIRAMIL which based on the Messinger model. The advantages and disadvantages of the random-icing model is evaluated with the results.