Analyzing Static Spray Characteristics of Variable Spray System of Centrifugal Nozzle

Abstract

【Objective】 This paper is to investigate experimentally the static spray characteristics of variable spray systems of centrifugal nozzles. 【Method】 A centrifugal nozzle variable spray test system was constructed by using a diaphragm pump, a high-precision turbine flowmeter, a solenoid valve and a centrifugal nozzle. Its static spray characteristics were studied for the nozzle flow rate in the range from 1.5 L/min to 13 000 r/min. For each nozzle flow rate, we measured the water droplet sizes and deposition distribution of the droplets using water-sensitive paper and droplet collection devices, respectively. 【Result】 With the increase in centrifugal nozzle flow rate, the size of droplets decreased. The deposition amount of fog droplets in the 0.5 m proximal to nozzle decreased first and then increased showing a double-peak patten, with the deposition amount increased in the second peak more than in the first peak. With the increase in the centrifugal nozzle flow rate, the peak value on the left side of the distribution center of the droplet deposition decreased, and the peak value on the left side skewed towards the droplet distribution center. The peak value on the right side remained unchanged, while the peak value on the right side moves away from the droplet distribution center. 【Conclusion】 The rotating speed of the centrifugal nozzle has a significant influence on sizes and deposition distribution of the water droplets. Reasonably controlling the droplet size to improve the uniformity of the droplet deposition distribution is a key to improving pesticide utilization and reducing its leaching to the environment.

Keywords

• centrifugal nozzle
• variable rate application
• pulse width modulation