Micro-PIV analysis of flow fields in flow channel of emitter

For exploring the flowing rule and the clogging mechanism of the micro-irrigation emitter, Micro-PIV technology was adopted to detect and compare the inner flowing hydraulic movement of squared cross section of straight angled and round angled zigzag profile in the micro-scale channels when Re (reynolds number)was 200. Clear images of particles were obtained by combining 10x microscope, 14-digit grey scale PCO1600 camera, 3μm fluorescence tracer particles and light filtering lens allowing 610nm red light permeation. The flow field velocity vector patterns and streamlined diagrams of high resolution were obtained by using image processing techniques. Experiments exposed that the inner flow of tooth space in the micro-channels was proved to be cycled flow after fully development. For the more, low velocity vortex cavities existed in the vertex angle and inner side of bend angle of straight angle micro-channel, while back flow only appeared in the internal side of bend angle of round angle micro-channel. It’s easy to take place deposition in the low velocity vortex cavities, which is the main cause of blocking. The low velocity vortex cavities were expanded and the back-flowing tendency appeared in the turning point of vertex angle if the section was narrowed, which had a negative impact on anti-blocking.