Mechanism Analysis of the Influence of Structural Parameters on the Hydraulic Performance of the Novel Y-Shaped Emitter

Abstract

As a key component of a drip irrigation system, the performance of drip irrigation emitters is determined by the flow channel structures and parameters. In this paper, a novel Y-shaped labyrinth-channel emitter was proposed, and the influence of the hydraulic performance was researched under different waist-arc angles (α) and ratios of crown height to chord length (a:b). The flow characteristics and energy dissipation mechanisms of water in the emitter were analyzed by using fluid dynamics software. The analysis showed that, keeping the ratio of crown height to chord length unchanged and with an increase in the waist-arc angle from 90° to 180°, the pressure-drop ratio before and after the water flow through the vortex area increased, and the hydraulic performance of the emitter was improved, specifically: the design flow could be reduced by 6.02–26.7%, and the slope of the curve could be reduced by 9.83–28.1%. The smaller the ratio of crown height to chord length, the weaker the influence of waist-arc angle was on the design flow and hydraulic performance. Keeping the waist-arc angle unchanged, there was a decrease in the ratio of crown height to chord length from 6:30 to 1:30, the vortex strength inside the emitter channel increased, and the hydraulic performance was improved: the design flow could be reduced by 7.56–23.5%, and the slope of the curve could be reduced by 5.43–20.5%. The bigger the waist-arc angle, the weaker the influence of the ratio of crown height to chord length was on the design flow and the hydraulic performance, even to the point of having no effect. When the Y-shaped emitter was close to the pressure-flow curve slope of the commonly-used triangular-channel emitter, the hydraulic performance of the two was similar, and the former could increase the channel width by 25%, as compared to the latter, or shorten the channel length by 44.3%. The results showed that the Y-shaped emitter had better hydraulic performance compared with the triangular-flow-channel emitter commonly used today. Therefore, the Y-shaped emitter has broad application prospects in water-saving irrigation.

Hydraulic Performance and Energy Dissipation Mechanism Analysis of the Tesla-Shaped Emitter

“…In this paper, we used FLUENT 19.2 software [30][31][32][33][34] to simulate the water flow inside the tesla-shaped emitter channel, without considering the compressibility, mass force, and temperature variation of the water flow. The governing equations included the continuity equation and Navier-Stokes [35]:…”

“…ICEM CFD 19.2 software [35] was used to mesh division the calculation model. In the labyrinth emitter channel set boundary layer to encrypt the mesh, the first layer of the boundary layer was set to 0.01 mm, and the other layers in 1.5 proportional increments for a total of six layers, with a total thickness of 0.21 mm.…”