| In 2016,China put forward the "two reduction" requirement,which requires the need to improve the utilization of pesticides to ensure pest control effect.Electrostatic spraying technology can improve the utilization rate of pesticides and ensure the effectiveness of pest and disease prevention using a small amount of pesticides.In order to further improve the effect of aerial plant protection technology,this paper designed a set of electrostatic spraying system based on the characteristics of Y5-B fixed-wing agricultural aircraft used in the northeast reclamation area.The atomization and charge performance of the system were tested,and then aerial and non-static comparative tests were conducted in the field.The experimental results showed that the design can improve the effect of droplet deposition.(1)Based on the electrostatic atomization mechanism analysis,the electrostatic electrode has the limit voltage value,which is related to the charging method and the size of the electrode structure.Through the analysis of the droplet charge effect of the induction charging method,it can be seen that the structure of the sensing electrode is related to the liquid film structure of the aerial nozzle.The results of this analysis provided the theoretical and experimental basis for the design of the induction electrode of aviation electrostatic nozzle.(2)The charging method of induction charging was determined by electrostatic atomization mechanism analysis and according to the analysis of the induction charge electrical model,it can be seen that the droplet charge is related to the structure parameters of the sensing electrode and the air jet nozzle.Therefore,the high speed photography technique was used to determine the structure of the liquid film of the aerial spray nozzle,and the structure dimension of the induction electrode was determined to be conical ring,the cone angle 80 degrees,the length 17 mm.Finally,the atomization performance and charge performance test of the aerial electrostatic spray system were carried out in the room.When the maximum charge-mass ratio was 1.98 mC/kg,the electrostatic induction electrode reached the static voltage limit value of 9 kV in the case of the spray performance of the aviation nozzle,The correctness of the conclusion of electrostatic atomization is verified.Moreover,the droplet charge-mass ratio by the design of the electrostatic spray system can meet the requirements that the droplet charge-mass ratio of the aerial electrostatic spraying technology is greater than 0.8mC/kg.(3)In order to study the effect of lateral wind speed on the electrostatic spraying system design,and determine the critical wind speed of electrostatic spraying system suitable for working.The influence of the lateral wind speed and the electrostatic voltage on the electrostatic droplet drift was studied by using the indoor wind tunnel test bed.Finally,it is confirmed that the lateral wind speed is less than 3m/s and the maximum should not exceed 4.6m/s.(4)In order to study the effect of aerial electrostatic spraying technology,the experimental study on the effect of electrostatic spraying and non-static spraying was carried out in the field.The experimental results show that aerial electrostatic spraying can improve the deposition of droplets in the canopy below the canopy and the backside of the leaves,which increases the deposition density of the droplets below the canopy by 132.24% and increases the deposition density on the back of the crop leaves by 407.41%.It is proved that the aerial electrostatic spraying technology can improve the penetration of the droplets in the canopy of crops and the deposition effect on the back of the leaves.It is suitable for the prevention and control of rice diseases and insect pests. |
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