Research On Mixing Degree Of Direct Injection System For Pesticide Sprayer

Nowadays the plant diseases and insect pests are threatening the agricultural and forestry production in China and the pesticide application is inefficient as the main prevention and control means. It was less than 35% of total pesticide that can take effect because of the low-efficient application, the traditional plant protection machineries, and the poor application technology (especially the mixing of pesticide and water), which brought about the pesticide waste, environment pollution, pesticide residue and pesticide resistance, but also the life safety threatening of people and animals. Therefore, it is important to study the precision pesticide application technology based on the direct injection system for pesticide sprayer, which can decrease the pesticide cost of plant diseases and insect prevention and control, improve the efficiency of pesticide application, and protect ecological environment and the life safety and health of pesticide application operators.Firstly, the measurement system and image-collecting system of direct injection system was improved for pesticide sprayer. The experimental system included three sub-systems: the liquid–providing system, the mixer and detection system, the image acquiring and processing system. At present, the studies on mixers both in China and abroad mostly focused on numerical simulation. But the high-speed camera and the digital image processing technology were firstly applied to study the mixing effect of the mixer. The polystyrene was chosen as the tracing particle to follow the flow of the liquid pesticide, and the mixing images were acquired as the work conditions of the pump were changed. And a method for rectifying bad degree of uniformity of background was brought forward to solve the bad condition of the particle image. The bubbles and the tracing particles were successfully separated through the method of Mathematical Morphology, and then the centroid coordinate of particles was obtained. At last, the results of the mixing performance were analyzed and calculated, and it was found that not only the different work conditions of the pump had different effects on the mixing performance, but the distribution of the particles had the effects on the mixing performance of the mixer. The velocity field of the mixer's exit was simulated, and the relationship between velocity field and effect of mixing was further studied.In order to extend the application of the digital image processing in effect of mixers, the mixing image processing software for the mixers based on MATLAB7.1 was designed. It laid the foundation for more precise mixing performance of mixers.