Exploration And Application Of PTC Ceramics In Airfoil Anti-/de-icing Structure

When flying in high attitude in the sky,a plane often travels through super-cooled cloud with high speed,which would easily make its windshield,airplane wings,tail wing,propeller blade and engine inlet on the plane get into icing condition,thereby severely threatening the safety.Thus,it is important and necessary to study on anti-/de-icing of these related components.Electric-thermal anti-/de-icing method is among the common ways,where traditional metal sheet loop structures are usually selected to work as the heating unit.However,the temperature of the metal sheet loop structures cannot be self-controlled when getting powered.Generally,the temperature is collected with the assistant of temperature sensor,and then adjusted by the control system,which would inevitably complicate the structure.In this thesis,we use PTC ceramics to work as heating unit on anti-/de-icing structure due to the characteristic of high heating efficiency,heating rapidly and self-protection in case of over-heated.We also make exploration on feasibility of the design,main works are as follows:(1)We proposed to select PTC ceramic to work as heating unit for anti-/de-icing structure due to their unique characteristics.According to the thermal-performance target,PTC ceramics were prepared to meet the performance requirements,and then the structure model for anti-/de-icing system was designed.(2)The harm of aircraft icing and related protective methods were systematically introduced,and the world-wide research progress about the method of anti-/de-icing was summarized.Compared with traditional heating units,the advantages of using PTC ceramics were listed,and then the working principle of the PTC ceramic heating unit was elucidated..(3)Based on the plate heating structure,the simulation mathematical model of plate heating structure is established,and the heating effect of PTC ceramics sheet was calculated by finite element analysis software,according to the heating characteristics of heating unit.At the same time,the physical model of plate heating structure is designed and fabricated.Further,the heating effect of physical model and simulation mathematical model is compared and analyzed to verify the feasibility of numerical simulation method.On the basis of this,the simulation mathematical model of airfoil structure was established by drawing software,.the feasibility of airfoil structure anti-/de-icing design was verified by the calculating results,according to the high altitude environment under forced convection conditions.(4)Based on the experimental conditions of wind tunnel in NUAA,airfoil anti-/de-icing experiment was successfully carried out by setting the flow temperature at-10 ??-2 ?,air velocity at 30 m/s?40 m/s?50 m/s and using the method of experiment on physical model of the characteristic temperature on the airfoil surface was collected and the results further confirmed feasibility of using the PTC ceramics working as heating unit for anti-/ de-icing system.