Study Of Icing Mechanism On The Rotating Cone Surface

Ice accretions may occur when the subcooled water droplets impact on the airplane surfaces such as wing and spinner and so on when the airplane flies under icing conditions.Ice accretions may affect the aerodynamic characteristics of the flight.In order to prevent icing on spinner,we need to do some experiments on icing of spinner and study the mechanism of icing on spinner.A small ice wind tunnel was built,and the ice accretion tests on sub-scale rotating spinner model were conducted in detail with visualization experiments in icing wind tunnel and the ice shapes were got under different conditions.The law of icing shapes were obtained by image analysis method.A simplified model was built to analyze the movement and heat transfer of water droplets.The two-phases model combined with the wall impacting model were used to simulate.The mechanism of water droplets freezing was gained by experiment and simulation study,and some experiences were got on the icing.The ice shapes in different temperatures,liquid water contents and rotating speeds were revealed by visualization experiments.There were three ice shapes,they were rime ice,glaze ice and spiny ice.The influence of conditions on the processes of rime ice and glaze ice were knew by using image analysis method.The results showed that ice grow rate was increased with the decrease of temperature and rotating speed and the increase of liquid water content.The axial growth rate was much larger than the radial.Spiny ice was different from the rime ice,the area and length of spiny ice were analyzed,the results showed that the spiny ice was appeared near the bottom first,and then to the cone tip.The area and length were increased with the increase of liquid water content and rotating speed,and the liquid water content effect was obvious.A simplified model was built to explain the icing on spinner.The ice surfaces were built by using image analysis method,and then simulate the phenomenon of water droplets movement by using two-phases model combined with wall impacting model.The local water collect coefficient were obtained and compared with experimental results,and matched very well,then the influences of rotating speed,median volume diameter,rotating speed and two types of surfaces on local water collect coefficient were analyzed.The results showed that the local water collect coefficients were increase with the decrease of rotating speed and the increase of median volume diameter and rotating speed.The local water collect coefficient between the smooth surfaces and ice surfaces was different.