Study On Water-Sediment Two Phase Flow In Labyrinth Emitter Channel

The clogging of drip irrigation emitter is a bottleneck problem that drip irrigation system faced with currently. In this paper, we carried out experiments to investigate the clogging features inside the labyrinth emitter, meanwhile, two-phase flow theories were applied to study the state of flow and particle motion within it.In the experiments, we first tested the muddy water charge process and clogging properties in signal-side packed labyrinth trip tape produced by XINJIANG TIANYE group. How the sediment particle diameter, muddy water concentration and inlet pressure influence the clogging proprieties of labyrinth emitter was analyzed. It is show that the sediment particle diameter is the primary factor and plays a definitive role in the clogging of the emitter. The inlet pressure also has some effect on the clogging. However, the muddy water concentrations affect only the clogging speed after the emitter is clogged. Then, to understand the phenomenon, position, process and amount of sediment deposition in labyrinth emitter, the experiment was conducted in a model emitter made of transparent material for the convenience of observations. We found that although the initial sedimentation cell is irregular, the sedimentation more likely take place at inlet and outlet sections, with a probability about 82%. The sedimentation phenomenon in labyrinth emitter tape and straight- pipeline are quite different, sine flow within former can keep turbulent state even at lower velocity, simultaneous sedimentation along the distance, which is common in straight- pipeline, did not observed here.We also performed numerical simulations to investigate the flow field and particle motion inside the channel of labyrinth emitter. It revealed that the original design of both inlet and outlet is unreasonable, where low velocity regions exist and sedimentation happens easily. Furthermore there exists dead angle region in the body of labyrinth channel, where the debris in water might stay instead of being carried away. This is also a potential factor leading to clogging. Base on these facts, we put forward an optimized configuration to eliminate low velocity regions and dead angle areas. Two-phase flow calculations indicate that the new design can effectively avoid the collision among particles, allow the particle pass through smoothly, therefore its ani-clogging property improves. Our last work in this paper is to determine the influence of particle diameter, inlet pressure and collision condition between particle and channel wall on the movement of particles.