Authors

Abstract

The utilization rate of pesticides in China is low, which causes much pesticide waste and serious pollution of the ecological environment. The main reason of this problem is that the deposition rate of spray is not fairly high and the most fundamental factors affecting droplet deposition are the speed of droplet movement and the size of droplet particles. This study establishes a PWM intermittent spray system under pressure regulation and flow control. Through CFD simulations, the atomization characteristics of the nozzle are analyzed. The results indicate that the system can generate finer droplet sizes and higher droplet velocities. By constructing a measurement platform for droplet experiments, tests are conducted on droplet sizes at different horizontal positions under four pressure levels: 0.3 MPa, 0.4 MPa, 0.5 MPa, and 0.6 MPa. The results indicate that as the spray pressure increases, the droplets exhibit a significant tendency to disperse toward both sides, and the droplet size decreases significantly. The field experiment is conducted with broad bean in flowering period. The results show that the average deposition rate increases by 9.9%, 26.4% and 22.9% when the spray pressure is 0.4MPa, 0.5MPa and 0.6MPa compared with 0.3MPa. This paper verifies the feasibility of the system in improving the spray pressure and quantitatively controlling the spray flow rate, and improving the deposition of droplets by obtaining finer particle size and higher spray velocity. In this sense, this paper has a certain reference significance for improving the effective utilization rate of pesticides and protecting the environment.

Abstract in Chinese

我国农药的利用率低，在造成农药大量浪费的同时严重污染了生态环境，其中主要原因就是喷雾沉积率不高导致的。雾滴运动速度和雾滴粒径大小是影响雾滴沉积的最根本因素。本文搭建了PWM间歇式调压控流喷雾控制系统，利用CFD仿真，对喷头的雾化特性进行了分析，结果表明系统能够产生出更细的雾滴粒径，更大的雾滴运动速度；通过搭建雾滴测量平台进行实验，对0.3MPa、0.4MPa、0.5MPa和0.6MPa四个压力下不同水平位置的雾滴粒径进行了测试，结果表明：随着喷雾压力的增大，雾滴向两侧分散的趋势显著，雾滴粒径减小明显。以开花期蚕豆为试验对象，进行了田间实验，结果表明：喷雾压力为0.4MPa 、0.5MPa和0.6MPa相比于0.3MPa，平均沉积率增加了9.9%、26.4%、22.9%。本文验证了系统在提高喷雾压力的同时定量控制喷雾流量，通过获得较细的雾滴粒径和更高的雾滴速度，来提高雾滴沉积的可行性，对提高农药的有效利用率，保护环境有一定的参考意义。