Influence of Emitter Structure on Its Hydraulic Performance Based on the Vortex

Cuncai Wang,Zhiqin Li,Juanjuan Ma

doi:10.3390/agriculture11060508

Abstract

The rectangular labyrinth emitter is taken as the study object in this article, as we added internal teeth to vortex-free and vortex areas in its lateral channel or lengthened the vertical channel, to change the channel structure. Using the computational fluid dynamics (CFD) method simulates the water flow field, to get the relationship between flow rate and pressure, and the vortexes distribution in channel. The aim of this study is to explore the reasons for the influence of structural change on hydraulic performance of the emitter through the analysis of vortex intensity and its distribution from the perspective of the vortex. The results show that the relative error of simulated results and experimental data was 1.02–2.11%. Adding internal teeth to vortex-free areas in lateral channel can improve hydraulic performance of the emitter; adding them to vortex areas can reduce it. The increase in vortex number and intensity in flow field is the internal reason for the improvement of the emitter’s hydraulic performance. The channel structure changes promote the formation of a larger velocity gradient, and the increase in the velocity gradient in flow field exacerbates vortex formation. Changing channel structure to improve the emitter’s hydraulic performance can promote an increase in the number and intensity of vortexes in the channel.

Highlights

Emitters are key components of drip irrigation systems; their hydraulic performance directly determines the working performance of drip irrigation systems [1,2,3]
Yu et al [6] studied the relationship among five key structural parameters and the flow index and flow coefficient through the orthogonal experimental design method, and gave the regression equations regressed by the linear multivariable regression method regarding the relationship between the flow coefficient and flow index and the structural parameters
Xie et al [7] analyzed the influence of the tooth angle and pitch on the flow coefficient and flow index, indicating that the tooth angle, tooth pitch, and flow coefficient are positively correlated, and the flow coefficient increased with the increase in the tooth angle and pitch

Summary

Introduction

Emitters are key components of drip irrigation systems; their hydraulic performance directly determines the working performance of drip irrigation systems [1,2,3]. An emitter with superior hydraulic performance has low flow rate sensitivity to inlet pressure and can better ensure the irrigation uniformity of drip irrigation systems. Studies have shown that emitters of the labyrinth channel have superior hydraulic performance when compared with other types of emitters. For this reason, in recent years, many authors have conducted considerable amounts of research on the relationship between channel structural parameters and the flow index and flow coefficient, especially the flow index, striving to reduce it by changing the channel structure of the emitter in order to improve its hydraulic performance. Tian et al [9] selected nine major structural parameters, using multivariable regression methods, to establish the regression equations regarding the relationship between the flow index and flow coefficient with the nine structural parameters, in the process of their research

Objectives

Methods

Findings

Conclusion