Design And Performance Research Of The Subsurface Bubbler Emitter

Performance of the micro-irrigation emitters is one of the factors influencing cost of micro-irrigation system and uniformity. This paper designed a large size of helical labyrinth channel based on CFD, which simulated labyrinth channels of different structural parameters, and analysis the hydraulic performance of flow paths with different cross-sectional areas and shapes. RP and plastic material products that processed based on Rapid Prototyping Technology and steel mold, are carried out verification tests of hydraulic and anti-clogging performance. Through research and analysis, some basic conclusions drawn are as follows:(1) Aimed at the economic forest characteristics and requirements of irrigation, this paper designed a transnormal size of helical labyrinth channel invested two types of subsurface bubbler emitter. It is a novelty back-flushing emitter which can significantly improve performance of anti-clogging emitters and greatly extend the use of the product of the time.(2) Changes of emitter flow path sectional area and shape have a great effect on emitter discharge coefficient, but less impact the flow index. The impact on the flow coefficient order of hydraulic radius, cross-sectional area, breadth depth ratio and wetted perimeter; hydraulic radius is the most important factor affecting flow index, followed by breadth depth ratio, cross-sectional area and wetted perimeter. Channel of large flow rate can be designed by enlarging cross-sectional area, while pay attention to the selection of the shape of the channel.(3) Energy dissipation function and velocity distribution of flow pass has a close relationship. The maximum flow velocity is in the cross-section center of straight labyrinth. However, the maximum flow velocity is at the midpoint of the lateral wall of helical labyrinth channel, then U-decreasing to the inside and around. With the cross-sectional area smaller, Low-speed part increase in the total flow cross-sectional area. Both two types flow pass comply this rule that with the cross-sectional area smaller, Low-speed part increase in the total flow cross-sectional area. The helical flow in areas outside the mainstream, appearing the vortex corresponding to the mainstream. Because of the centrifugal force, high speed flow washes the lateral wall. All these cause the consumption of energy.(4) Flow index of the helical labyrinth channel is 0.4984 and flow index of the large labyrinth channel is 0.5201, both of the two flow regimes are turbulence. Flow rate of subsurface bubbler emitter under the working pressure meet the requirements. Manufacture deviation is 3.7%, which accord with excellent grade. Through the anti-clogging test, it is proved that subsurface bubbler emitter has better anti-clogging performance.