Analysis of the droplet size and distribution for micro-sprinkling hose based on the LPM

A micro-sprinkling hose is promising water-saving irrigation equipment due to its low cost and ease of installation and dismantlement during operation. The performance of the micro-sprinkling hose depends on the kinetic energy generated during field irrigation, which in turn is determined by the distribution of water droplets sprayed into the air. This paper aims to investigate the droplet diameter distribution provided by micro-sprinkling hoses by determining drop characteristics and assessing the impacts of the pressure and spraying angle on the droplet diameter distribution. Therefore, an indoor experiment was conducted to investigate the drop diameter distribution provided by micro-sprinkling hose under different pressures (20, 24, 28, and 32 kPa) and spraying angles (20 degrees, 30 degrees, 40 degrees, 50 degrees, 60 degrees, 70 degrees, and 80 degrees). Droplet characteristic parameters were measured and collected using a laser precipitation monitor (LPM). The results show that (1) the diameter of water droplets sprayed from a micro-sprinkling hose with a single-hole diameter increases with increasing pressure, resulting in an expanded distribution range. Moreover, the diameter of these droplets initially increases and then decreases with increasing spraying angle. The maximum droplet is observed at a spraying angle of 40 degrees. (2) The percentage of water droplets increases with increasing distance from the ground, with a diameter distribution range of 0-2.00 mm and an increase in the droplet diameter from 0.50 to 0.75-1.00 mm. The results reflect the characteristics of the droplet diameter distribution obtained with micro-sprinkling hoses under different pressures and spraying angles, providing guidance for the design of hose structures.