Visualizing Particle Movement In Flat Drip Irrigation Emitters With Digital Particle Image Velocimetry

A computer numerical control (CNC) engraving technology on a full-scale transparent model of a flat emitter is presented, combined with digital particle image velocimetry (DPIV) and planar laser-induced fluorescence (PLIF), to observe the movement characteristics of particles with different diameters in the prototype and transparent model of embedded flat emitters. The results show that the velocity, vorticity, the overall distribution of streamlines as well as the velocity distribution in the mainstream region of particles with diameters of 10, 50 and 100 µm in the structural units of the model and the prototype emitters, were obviously consistent. The differences among the particles’ maximum velocities reduced with increasing pressure. Both the particles with diameters of 50 and 100 µm in the model and the prototype emitters had a good following behaviour, but it showed the fine particles better than the coarse particles, and the particles of the near wall of flow path were shown better than in the central region. The particle deposition near the wall caused by the frequent starting of the irrigation system was one of the main reasons for formation of clogging substances in the emitters.