Spray Characteristics and Parameter Optimization of Orifice Arrangement for Micro-Sprinkling Hoses

Abstract

The spraying width and uniformity coefficient are important for the design of a micro-sprinkling hose. In this study, experiments were conducted on the water application intensity distribution for an individual orifice and multiple groups of orifices under three different working pressures (41, 69 and 103 kPa). In the test of an individual orifice, the spraying angles varied from 40° to 90°. The results showed that the water application intensity distributions of an individual orifice were well fitted by a two-dimensional Gaussian distribution. Further study indicated that the bimodal Gaussian distribution model performed well on tracking the two-dimensional features of the water application intensity distribution, with the determination coefficient R2 > 0.90 and the standard root mean square error NRMSE < 30%. It was revealed that the fitting parameters of the two-dimensional Gaussian distribution model had physical meaning and were directly related to the strength and location of the water application intensity distributions. Based on the analysis of these fitting parameters, it was found that the water application intensity distribution of an individual orifice was affected by the pressure, spraying angle and orifice area, among which the spraying angle was the most sensitive factor. By establishing a linear relationship between the fitting parameters and the spraying angles, the water application intensity distribution of an individual orifice for any spraying angle could be predicted by the Gaussian model. Therefore, the water application intensity distribution of multiple groups of orifices could be calculated by overlapping the water application intensity distributions of the individual orifices. The Monte Carlo method was used in this study to determine the maximum spraying width and uniformity coefficient by generating different groups of orifice arrangement for micro-sprinkling hoses. Eventually, the optimized orifice arrangement was recommended for the better design of micro-sprinkling hoses.