Experimental Research on Icing Surface Freezing Adhesive Characteristic
|School||Shanghai Jiaotong University|
|Course||Aerospace Propulsion Theory and Engineering|
|Keywords||icing freezing freezing intensity temperature surface roughness|
Icing of aircraft affects flight safety seriously. Heating the surface or breaking ice with machine are both kinds of anti-icing/de-cing technologies commonly used, which decrease adhesion between ice and surface so that the ice falls off under the function of the aerodynamicforce, centrifugalforce, vibration and so on. Adhesion between ice and material surface depends on the freezing environment. In order to understand the freezing mechanism better, grasp the adhesion movement rule and reduce adhesion,an experimental system is designed to study the influence of different factors to adhesion based on the analysis of the theory about icing and freezing. The main research contents and conclusions include:Analyse all kinds of freezing adhesive phenomenon and determine the object of this paper. Introduce the basic theory in connection with freezing and adhesion, including surface energy, interface energy and adhesion work. Analyse the effects of temperature and surface roughness to adhesion.Design an experimental system, process different material samples and carry out many experiments. Propose the concept of icing adhesion coefficient according to the characteristics of icing combination with theory. Study that how the surface roughness change influencing freezing intensity for different material in different freezing temperature.Checking samples’surface characteristics after the ice is pulled off, we find that freezing intensity is depended on the intensity of ice in the interface. Analysing the effect of temperature to freezing intensity, we find the change of interface is consistent with the flow solidifying liquid model, which means a transitive state existed between the solid ice and material surface, translating from liquid water to solid ice. Studying the relationship between the surface roughness and freezing intensity, we find there is a non-liner and nonmonotonic relationship between them. Processing reasonably proper surface roughness will be helpful to reduce the adhesion for. To the relationship about normal and tangential icing adhesion, and the influence of material thermal property to icing adhesion, further research are needed because we have not found a reasonable rule about them in this study.This study will help us to understand icing adhesion mechanism and utilize the property of freezing and material to solve the problem of icing and freezing.