Research Of A New-type Contact Electrostatic Spray Device Based On Cone Electrode

Control of crop diseases,insect pests and weeds is an indispensable link in agricultural production.Operating tools,pesticide preparations and application technology have important effects on pesticide utilization rate and pest control effect.At present,the technology level of plant protection machinery in China is relatively low,the level of applicator and technology is seriously lagging behind.In the process of pesticide control,not only the utilization rate of pesticides is low and the effect of pesticide application is poor,but also a series of problems such as pesticide residues in agricultural products exceeding the standard,environmental pollution,crop pesticide damage and operator poisoning.Therefore,increasing the research and development of new plant protection machinery,reducing the consumption of pesticides per unit area and improving the utilization rate of pesticides per unit area have become the core requirement of the"double reduction"strategy in China,and also an important strategic direction in the field of agricultural plant protection facing the new situation.Based on the research status of pesticide electrostatic spray device at domestic and abroad,combined with the basic mathematical theory of electrodynamics,the electrostatic field analysis technology of Maxwell 3D electromagnetic field software is used to analyze the electrostatic field of the contact electrostatic spray device.The influence of space electrostatic field on the performance of the contact electrostatic spray device is explored,and a new contact electrostatic spray device is developed.The experiments of charge-mass ratio determination,droplet group diameter determination and leaf back deposition optimization were carried out.The main contents and conclusions are as follows:（1）Based on the principle of electro-hydrodynamics,the concept of main charging chamber is put forward,and the method of increasing static electric field intensity by loading conical electrodes inside it is put forward.From the point of view of electro-hydrodynamic theory,the advantages of tip discharge are analyzed and demonstrated.The optimization idea of loading the cone electrode inside the main charging chamber and using the advantage of its tip discharge to improve the distribution of electrostatic field intensity in the main charging chamber is put forward,which lays a theoretical foundation for the development of the contact electrostatic spray device.（2）Maxwell 3D electromagnetic field software was used to analyze the static electric field intensity in the main charging room with different conical electrodes,and the distribution law of the static electric field intensity was obtained.Maxwell 3D electromagnetic field software was used to analyze the static electric field intensity in the main charging room.According to the results of simulation analysis,the relationship between the number of conical electrodes and the distribution of electrostatic field intensity in the main charging room is analyzed from the angles of mid-section field intensity distribution nephogram and mid-section field intensity distribution vector nephogram.The results show that the conical electrodes have a significant effect on the increase of electrostatic field intensity in the main charging room.In addition,the Fluent software was used to analyze the flow field in the main charging chamber.It was proved that the cone electrode had no obvious effect on the internal flow field in the main charging chamber of the electrostatic spray device.It was proved that the electrostatic field intensity distribution in the main charging chamber analyzed in this paper is the only factor affecting the contact electrostatic spray device.（3）The charge-mass ratio and the diameter of droplet population were measured.The results show that the charge-mass ratio of the five-cone electrode scheme is the highest,and the diameter of the droplet population decreases.The charge to mass ratio and droplet mass volume diameter measurement of electrostatic spray device with different cone electrodes in main charging chamber were obtained.The mass ratio of one cone,three cone,five cone,seven cone and nine cone experiment group were obtained,with the value of 0.4325、0.445、0.46、0.3825and0.36m C/kg.Among them,the charge-mass ratio of the five-cone experimental group is 0.46 m C/kg,which is the best scheme in this paper.At the same time,the experiment of measuring the diameter of droplets in the five-cone experimental group was carried out.With D50 as the evaluation index,the diameter of droplets was 104.18 micron in the absence of electrostatic input.With electrostatic input,the diameter of droplets was 102.53 micron,and the diameter of droplets decreased slightly.（4）The electrostatic spray performance test of the five cone electrode scheme was carried out.The test showed that the electrostatic spray performance increased two times more than that of the three layers on the same target.In order to verify the electrostatic spray performance of the five cone electrode scheme,experiments were carried out on the back of the leaves under the same target.Using the dragon’s grass as the target,the amount of the back deposition in the middle and lower three layers of the target was measured under the condition of static electricity and no static electricity,and the droplet mass diameter of the droplets in each layer of the five cone electrode scheme was tested.The effect of volume increase is obvious.The upper layer of the deposit reaches 90μg·cm^-2,the middle part is 40μg·cm^-2,the lower part is 20μg·cm^-2,the increase is two times,indicating that the five cone electrode electrostatic spray device developed in this paper has good control effect and effect.