Research On Icing Airworthiness Certification Methods And SLD Key Technology For Transport Category Airplanes

Civil aviation administrations and industrial departments have issued icing airworthiness regulations in order to ensure the safety of transport category aircraft under icing conditions,which is the basis for the design of the aircraft and the safety of the flight.Therefore,airworthiness certification and compliance of methods are needed study deeply.The main contents of this paper are as follows:(1)The standards,advisory circulars and other data related to the icing airworthiness certification of foreign countries were investigated.The certification requirements of flight performance and handling quality of aircraft and anti-icing systems were analyzed and summarized;The differences between the rules of the aircraft icing airworthiness of the United States and Europe were compared and analyzed.Moreover,the methods of compliance for icing aircraft was given.(2)In view of the multiple crash accidents caused by the supercooled large droplet(SLD)icing condition in recent years,the emphasis of the study was placed on the airworthiness contents and the meteorological parameters in the SLD icing conditions.According to aircraft icing,the development direction of the detection technology of SLD icing condition in the future was proposed.Also,the feasibility of the current engineering tools used in SLD compliance methods was assessed to carry out SLD airworthiness certification work for the follow-up.(3)Due to the limitations of the capacity and size of existing icing wind tunnels at home and abroad,it is not possible to conduct the compliance work for SLD icing conditions.Therefore,it's necessary to scale the parameters of SLD icing condition.Based on the aircraft icing process and mechanism,the similarities between icing model and reference model were analyzed,and a series of similar dimensionless parameters of SLD were obtained.The program was completed according to the SLD icing scaling law.(4)In order to verify the scaling law,the typical SLD icing condition test parameters were selected to calculate the scaled ice shape by using finite element method.The numerical calculation results of the ice shape were compared for the reliability analysis and found that the ice shapes were in good agreements with the reference ice.Finally,the effects of water droplet size and mass and temperature change on the scaling results were analyzed.It was found that the similarity error at low when the droplet size was small or the temperature was higher.In this paper,the latest airworthiness certification requirements and methods of compliance were studied,a set of completed icing airworthiness certification reference guide was formed.The icing wind tunnels scaling methods of SLD icing condition was researched to provide technical support for SLD airworthiness certification.