Comparison of Water Distribution Characteristics for Two Kinds of Sprinklers Used for Center Pivot Irrigation Systems

Abstract

Abstract:Sprinkler selection influences the water distribution uniformity of center pivot irrigation systems. The sprinkling uniformity of the center pivot is crucial for the yield and quality of crops on a large scale. Rotating and fixed spray plate sprinklers (RSPSs and FSPSs) are the two most popular types. However, sprinkler selection is mainly based on price, not on differences in performance between them. Under low-wind field conditions, the water distributions of individual RSPSs and FSPSs with different nozzles (2.78, 4.76, and 6.75 mm in diameter) were measured using a catch can method. Cubic spline interpolation was used for data conversion for FSPS measurements; the nozzle configuration model was used to simulate the water distribution of the same-nozzle-sprinkler pipe section and full circular irrigated areas in a simulated center pivot under three sprinkler intervals of 1.5, 3.0, and 4.5 m respectively. Results showed that (1) individual RSPSs distributed the most water around the sprinkler, whereas individual FSPSs distributed the most water over a ring-shaped region at the periphery of the sprinkler, and the wetted radii for RSPSs and FSPSs ranged from 4.88 to 7.05 m and from 5.02 to 6.85 m, respectively; (2) same-nozzle-sprinkler pipe sections of RSPSs distributed the most water around the central axes of the pipe sections, and their sprinkling uniformities were 44.7%-51.0%, whereas FSPSs distributed the most water over both sides of the axes symmetrically, and less water around the axes, with sprinkling uniformities of 40.3%-58.0%; and (3) the sprinkling uniformities of the full circular irrigated areas were 85.8%-91.7% and 85.8%-86.2% when using RSPSs and FSPSs, respectively, under different sprinkler intervals, and the uniformities were 3.1% and 6.2% higher using RSPSs than FSPSs with sprinkler intervals of 3.0 and 4.5 m, respectively. RSPS accommodated larger sprinkler intervals (>3.0 m) and maintained superior sprinkling performance when compared with FSPS.

Development of sprinkler with adjustable orifice using iris-type mechanism for variable rate irrigation

“…In contrast, the RSPSs presented two peaks of water application, one near to the sprinkler outlet and the other at up to 75% of the effective wetted radius. These RSPS distribution profiles were different from those obtained by , Sourell et al (2003), Playán et al (2004) and Jiao et al (2017) when evaluating RSPSs from another manufacturer and at different installation heights.…”

“…with the reduction of the step angle. The FSPSs showed peaks of water application clearly visible near the borders of the wetted area, corroborating the results obtained by and Jiao et al (2017) when evaluating FSPSs in outdoor conditions and by Sayyadi et al (2014) when evaluating the same deflector plates indoors. In contrast, the RSPSs presented two peaks of water application, one near to the sprinkler outlet and the other at up to 75% of the effective wetted radius.…”

“…For the 6.94-mm orifice diameter, when the effective wetted area increased, the CUC values were not particularly sensitive to the increase in the sprinkler spacing, decreasing on average by 19.7% and 6.7% for FSPSs and RSPSs, respectively (Table 3.4). Jiao et al (2017) also observed reductions in CUC values with an increase in sprinkler spacing; moreover, with an increase in the discharge section, CUC values tended to decrease slowly relative to increases in sprinkler spacing for FSPSs and RSPSs. Playán et al (2004) obtained superior CUC values for two RSPSs evaluated in relation to FSPSs, employing the same overlap spacing but increasing the discharge sections and generating an average CUC increase of 22%.…”

“…According to Sourell et al (2003), the characteristics of spray plate sprinklers, sprinkler spacing and machine speed will define irrigation performance in all self-propelled sprinkler irrigation systems. rotating spray plate sprinklers (RSPSs), which produce very different droplet size distributions and water application patterns DeBoer, 2002;Sourell et al, 2003;Sayyadi et al, 2014;Jiao et al, 2017). FSPSs are based on the impact of a water jet on a fixed grooved plate, comprising various numbers or sizes of grooves to break up the water jet into discrete water droplets.…”

Temperature Fields of the Droplets and Gases Mixture

“…In some cases, there is a demand for higher convective heat exchange (contact heat exchangers) and, in others, for higher vaporization (thermal water-treatment chambers and gas-vapor heat medium generators). In addition to the aforementioned practical industrial applications, the study of liquid spraying [7,8] in a high-temperature environment is important for the design of efficient firefighting techniques [6,[9][10][11].…”