Simulation Of Spray Flow Field Simulation And Distribution Of Droplets In Fixed-wing Aircraft

At present,the problem of forest pests and diseases in China is quite serious.The pesticides used in large quantities to solve the problem of pests and diseases have caused serious pollution.Aeronautical spray technology is more efficient and adaptable to a variety of emergencies than manual or mechanical spraying.In order to further improve the efficiency of the spray technology,it is necessary to simulate the influencing factors of the aviation spray operation,and obtain the law of droplet movement and sediment distribution under the influence of various influencing factors.The paper mainly uses CFD simulation and actual flight test to analyze the droplet movement and sediment distribution.The data obtained by actual flight test is compared with the data obtained by CFD software to test the accuracy of CFD simulation analysis.In the CFD simulation,the simulation of the airflow field and the spray field were carried out separately.Based on the simulation of the spray field,the parameters such as the altitude,the spray volume and the installation angle of the nozzle were changed to simulate the movement and deposition distribution of the droplets under different parameters.The results show:1)The higher the altitude,the longer the droplets fall,the more the droplets disappear due to the volatility of the air,the more droplets there are,the less the droplets are deposited.When the altitude is 4m,the droplets appear from the position 6 and the droplet concentration at the position 3 is 0.1kg/m3,then the droplet concentration gradually increases,and the densely distributed area is concentrated at the position 14 to 18 at the position.The peak appeared at 5.6 kg/m3 at 17 points,then gradually decreased to 0.2 kg/m3 at position 29,and there was no more fog after the position 30.When the altitude is 8m,the droplets appear from position 5,the droplet concentration is 0.2kg/m3,then the droplets begin to increase gradually,and the peak droplet concentration reaches 4.2kg/m3 at position 17,and then decreases.Increasingly,it gradually decreases to 0 kg/m3 at position 32 after reaching 3.1 kg/m3 at position 21.2)The larger the spray volume,the more the number of droplets,the larger the droplet deposition.When the spray volume is 4.63L/min,the distribution of the droplets is in the position 5 to the position 31,and the droplets start to appear at the position 5,the droplet concentration is 0.1kg/m3,and gradually increases to the maximum at the position 18.The droplet concentration is 4.5kg/m3,and then decreases.The droplet concentration is 0.1kg/m3 at position 31.When the spray volume is 8.02L/min,the droplet starts from position 4,and the droplet concentration is 0.2kg /m3,then gradually increase,the concentration of the droplet reaches a maximum of 5.8kg/m3 at the position 19,and finally the droplet concentration at the position 31 is as small as 0.1kg/m3.3)The larger the nozzle installation angle,the smaller the droplet is sheared,the larger the droplet size,and the larger the droplet deposition amount.When the nozzle installation angle is 90°,the droplets appear from the position 6,the droplet concentration at the position 6 is 0.1kg/m3,and then gradually increases,and the maximum droplet concentration at the position 19 is 4.3kg/m3.After the start of the reduction,the final reduction to 0.2kg/m3 at the position 31;and when the nozzle installation angle is 180°,the droplets start to appear at the position 5,the concentration is 0.2kg/m3,and then increase and then decrease Small increase,decrease to the maximum value of 5.8kg/m3 at position 19,and the concentration to 0.2kg/m3 at position 30,no fog drop from position 31.Comparing with the results of the experimental data,it is found that the results of the simulated data and the experimental data are very similar.The simulated data is more concentrated than the experimental data,and the deposition of the droplets is larger.Actual flight tests are affected by external factors.In general,the data results of CFD simulations are largely close to the results of the test data,which is persuasive and can be used as a basis for subsequent research.