Research And Development Of Recycling Dry Powder Jet Cleaning System For Airport Navigation Lights

The efficient cleaning of airport navigation lights plays a very important role in the safety of aircraft take-off and landing.The existing cleaning methods have the disadvantages of low efficiency,high cost,long time and so on.The research of this thesis mainly involves the development of an efficient and environmentally friendly recycling dry powder jet cleaning system.For the cleaning system,the numerical simulation of the nozzle structure,nozzle geometry parameters,cleaning process parameters and the structure of the recovery hood were carried out,and the whole system was verified by experiments.The specific research contents and achievements are as follows:Firstly,the recycling dry powder jet cleaning system is designed.This thesis analyzes the main components of the mirror dirt of airport navigation lights,and determines the cleaning object and cleaning medium according to the formation mechanism of the mirror dirt.Using the characteristics of jet,the basic section and the diffusion section of the jet are used to clean the airport navigation lights.The overall design of the recycling dry powder jet cleaning system,introduces the composition and selection of cleaning equipment,select the mobile air compressor to provide power,select the feeding tank as the dry powder storage container,select the manual operation as the spray mode,select the industrial vacuum cleaner to recycle dry powder,select the mobile type for vehicle.The working process of the recycling dry powder cleaning equipment is explained.Secondly,three different nozzle structures are analyzed and compared.The results show that there is no obvious difference in the jet velocity of the three nozzles at the outlet axis,and the cleaning area of the three nozzles is as follows: flat nozzle > Laval nozzle > cone straight nozzle.The total pressure of the jet along the jet axis decreases gradually,but the pressure at the outlet is higher than the atmospheric pressure,which can form a stable jet.The results show that the wear of the three types of nozzles is similar,the wear is more concentrated in the contraction section and less at the nozzle outlet.Thirdly,the geometric parameters of the nozzle were optimized and the cleaning process parameters were analyzed.Based on the orthogonal test method,the influence of different geometric parameters on the mirror cleaning effect was analyzed,and the optimized horizontal parameter combination was determined: the flat width was 4mm,the flat height was 24.5mm,and the flat length was 55 mm.The process parameters of the whole cleaning system are analyzed,and the results show that the particle velocity increases with the increase of jet pressure,and the abrasive distribution increases with the increase of abrasive flow.Then,the structure of recovery hood for recovery is optimized.By using the optimized geometric parameters of the cleaning nozzle,the gas-solid flow field of the nozzle inside the air collection and dust collection recovery cover was analyzed.It was found that the velocity of the jet inside the three kinds of recovery cover changed similarly,and the velocity decreased after the energy exchange with the internal air.The energy exchange between the jet and the air in the straight cylinder and hemispherical recovery cover is less,the jet is dispersed and the jet area is large.In the recovery hoods with three different structures,the particles of the straight cylinder structure are the most widely distributed and exist the most,while the particles of the hemispherical structure are the least.At the same time,the recovery cover with the bottom diameter of 450 mm is optimized.Finally,the recycling dry powder jet cleaning system is verified.According to the overall design,the assembly of the whole machine is completed.According to the actual airport navigation light mirror,the orthogonal cleaning experiment of recycled dry powder jet is carried out.After cleaning,the mirror cleanliness is detected by using the visual inspection device.The results show that: the jet pressure has a great influence on the mirror cleanliness of airport navigation lights,the abrasive flow rate has a little influence on the mirror cleanliness of airport navigation lights,and the jet target distance has the least influence on the mirror cleanliness of airport navigation lights;the optimal jet cleaning parameters of this system are as follows: jet pressure is 0.5MPa,abrasive flow rate is 0.004kg/s,jet target distance is 50 mm,and the cleaning effect is the best.Dry powder particles can effectively clean the surface dirt,and no damage is found.