Experimental and numerical characterization of the vortex zones along a labyrinth milli-channel used in drip irrigation

Abstract

The labyrinth-channel is largely used in dripper systems. The baffles play an important role to generate the head losses and induce the flow regulation on the drip irrigation network. But they also develop vorticity regions where the velocity is low or zero. These vorticity regions promote the deposition of particles or other biochemical development causing dripper clogging. The flow in the dripper labyrinth-channel must be described to analyze dripper clogging sensibility which drastically reduces its performance. This characterization is performed experimentally using the micro-particle-image-velocimetry (Micro-PIV) method, and numerically using the RSM Simulation. In this study, Micro-PIV experiments allow to analyze the flow in ten-pattern repeating baffles which reproduce the micro-irrigation dripper. The cross section is equal to 1 mm 2 and the inlet Reynolds number varies from 345 to 690. The present study first introduces a global analysis of the flow through the mean velocity modulus, the Reynolds stresses u 02 , v 02 and u 0 v 0 and the turbulence Reynolds number. Then, results for the mean strain rate and the mean spanwise vorticity are presented and discussed. Next, advanced methods of vortex detection are introduced and analyzed to better distinguish the vortex zones and to determine the vortex sizes. Furthermore, the numerical model is used to validate and analyze in a more detailed way the experimental results obtained by Micro-PIV.

Simulation of the flow characteristics of a labyrinth milli-channel used in drip irrigation

“…In order to improve anti-clogging ability and to ensure high irrigation uniformity at a low discharge rate, current commercial emitters usually adopt a milli-labyrinth channel approach with discharge areas in the order of 1 mm 2 . This induces the development of a turbulent flow regime inside the channel but also creates some stagnant zones and zones with vorticity (Al-Muhammad et al, 2019).…”

Motion Characteristics of Gas–Liquid Two-Phase Flow of Microbubbles in a Labyrinth Channel Used for Aerated Drip Irrigation

“…At present, research into ADI is mainly focused on the positive effects it has on soil physical structure, soil chemical composition, soil microbial activities and crop growth, as well as its influences upon the utilization efficiency of water, nutrients, and greenhouse gas emissions [9][10][11][12][13][14][15][16]. There have also been many studies concerning the transport process of water-gas two-phase flow in pipeline systems.…”

Structure design and hydraulic performance analysis of drip emitters based on vortex energy dissipation

“…Feng et al (2016) proposed that the energy dissipation effect of the emitter could be improved by installing cylindrical blocking elements in the low-velocity region of the flow channel to enhance the eddy current effect and turbulence intensity. Nevertheless, impurities in water are easily deposited in the low-speed or zero-velocity zone in the vortex central region and cause the narrow channel to be blocked (Al-Muhammad et al, 2019;Liu et al, 2016;Wei et al, 2009Wei et al, , 2012. For emitters, anticlogging performance also needs to be considered, which is even more important than hydraulic performance to a certain extent.…”