Micro-PIV characterization of the flow in a milli-labyrinth-channel used in drip irrigation

The baffle-fitted labyrinth-channel is largely used in drip irrigation systems. The existing baffles, which play an important role for generating head losses and ensure the flow regulation on the irrigation network, produce vorticity regions where the velocity is low or equal to zero. These vortices are likely to favor the deposition of particles or biochemical development causing dripper clogging which drastically reduces its performance. Flow topology in the dripper labyrinth-channel must be described to analyze dripper clogging sensibility and the effect on irrigation efficiency. Also, a question remains about the regime of this low Reynolds number flow. In the present study, the flow is characterized experimentally by micro-particle image velocimetry (micro-PIV) technique on ten-pattern repeating baffles used in drip irrigation dripper. Square cross-section is of about 1.4 mm2. Studied inlet Reynolds number varies from 345 to 690, which is equivalent to 1.4-2.8 l h-1. The mean velocity distribution and turbulence quantities within the labyrinth-channel flow are presented and discussed in this paper. The results underline that flow regime is turbulent and non-isotropic.Graphical abstract [GRAPHICS] .