Experimental study on the pressure fluctuation characteristics of target spray system

Abstract: Precise target spraying can be widely used to detect the target information for the on-demand operation using sensors and variable actuators. An effective way can prevent the excessive spraying from the environmental pollution of food safety caused by the traditional continuous spraying, particularly for the high pesticide utilization. Nevertheless, there is the a serious fluctuation of pipeline pressure at present, due to the repeated opening and closing of different numbers of nozzles in the process of target spraying. A great threat has been posed to the droplet size, deposition distribution, and service life of the spraying system. In this study, a test platform was designed to investigate the influence of the reflux ratio on the pipeline pressure fluctuation in the target spraying system. A simulation model of target spraying pressure fluctuation was established using AMESim software. A test was also carried out to verify the model. The initial pressure of the system was set as 0.2-0.4 MPa, and the reflux ratio as 0-0.9 in the simulation. The number of closed nozzles was accounted for the a large proportion of 1/5-4/5, indicating the more serious fluctuation of pipeline pressure. The reflux ratio was 0 at the initial pressure of 0.2 MPa. Once the 4/5 proportion nozzles were closed, the pressure of the pipeline system rose from 0.2 to 5.15 MPa, indicating a 2 400% fluctuation rate. The more significant ratio was obtained in the number of closed nozzles to the pressure fluctuation at the large initial working pressure of the system. The return pipeline was effectively reduced the pressure fluctuation of the target spraying system. Specifically, the greater the return ratio was, the more significant the elimination effect was. The maximum pressure fluctuation rate was 64.53% caused by the closure of some nozzles, when the initial pressure of the system was 0.2 MPa and the return ratio reached 0.6. Therefore, the reflux ratio was recommended to be less than 0.6, in terms of the utilization rate of the pump. Once the initial pressure values of the system were 0.3 and 0.4 MPa, the reflux ratios were recommended to be less than 0.7, and 0.8, respectively. Finally, an optimal combination of target proportion and reflux ratio was achieved, according to the requirements for the tolerance of the pressure fluctuation in the target spraying system. When the initial pressure of the system was 0.2 MPa, the combination of the proportion of the target and the optimal reflux ratio were 1/5 and 0.5-0.6, 2/5 and 0.5-0.6, 3/5 and 0.2-0.3, or 4/5 and 0-0.1, respectively. When the initial pressure of the system was 0.3 MPa, the relationship groups between the proportion of the spraying target and the optimal reflux ratio were 1/5 and 0.6-0.7, 2/5 and 0.5-0.6, 3/5 and 0.2-0.4, or 4/5 and 0-0.1, respectively. When the initial pressure of the system was 0.4 MPa, the relationship groups between the proportion of the spraying target and the optimal reflux ratio interval were 1/5 and 0.7-0.8, 2/5 and 0.6-0.7, 3/5 and 0.4-0.5, or 4/5 and 0-0.3, respectively. This finding can provide a strong reference to optimize the precision target operation for the technical variables and working parameters in the plant protection spraying.