| Drip irrigation technology is an advanced water saving method in water saving irrigation technology,which has the advantages of water saving,soil protection and high yield.The emitter is a key component of the drip irrigation system.The complex labyrinth channel in the emitter can dissipate the pressure water of the main pipe,and can deliver the pressure water to the root of the crop uniformly,slowly and stably.The hydraulic performance of the emitter determines the irrigation quality of the emitter,and the anti-clogging performance of the emitter determines the stability and durability of the irrigation system.In order to improve the energy dissipation efficiency and anti-clogging performance of the emitter,the water is uniformly and stably transported to the root of the crop.In this paper,a single inner tooth rectangular labyrinth channel emitter is designed.The right side of the vertical channel of the emitter is toothed,and the upper and lower sides of the lateral channel are toothed.The tooth position is the vortex-free zone of the channel.This paper mainly studies the influence of the change of tooth width and tooth height of the labyrinth emitter on the hydraulic performance and anti-clogging performance of the emitter.The single-phase flow and twophase flow models of numerical simulation are used to explore the influence of the change of tooth width and tooth height of the emitter on the flow velocity distribution,the size of the vortex and the trajectory of the sediment particles in the flow channel of the emitter.Finally,the influence of the change of tooth parameters on the hydraulic performance and anti-clogging performance of the emitter is analyzed through the pressure – flow curve,flow state index,vortex characteristics and the trajectory of the sediment particles in the flow channel.Through the above analysis,the following conclusions can be drawn :（1）The outlet flow of three types of emitters with tooth height of 0.3mm,0.5mm and0.7mm increases with the increase of inlet pressure,increases with the increase of tooth width,and decreases with the increase of tooth height.When the tooth width is 1.0 mm,the change of tooth height has no obvious effect on the flow pattern index of labyrinth channel emitter.The emitter with tooth height of 0.5 mm had good hydraulic performance;the flow pattern index of the emitter with tooth width of 0.8 mm and tooth height of 0.5 mm is the smallest,and its hydraulic performance is the best.（2）The change of tooth width has obvious influence on the distribution of low-speed region in the velocity field of emitter,and the change of tooth height has obvious influence on the maximum velocity in the mainstream channel.The emitters with a tooth width of 1.2 mm and a tooth height of 0.3 mm,the emitters with a tooth width of 1 mm and a tooth height of 0.5mm,and the emitters with a tooth height of 0.7 mm and a tooth width of 0.8 mm have small low-speed range,large flow velocity in the mainstream channel,and are not prone to clogging in the channel.（3）The influence of vortex distribution on particle motion is more obvious than that of velocity field,and the change of tooth height is more obvious than that of tooth width of emitter.The emitter with the tooth height of 0.7 mm generally has large vortex area,and the particles of the emitter with the tooth width of 0.6 mm are trapped,resulting in particle deposition and poor anti-clogging performance.The emitter particles with tooth height of 0.3 mm and tooth width of 1.2 mm have orderly motion trajectory and short residence time in the flow channel,good particle transport and good anti-clogging performance.Tooth height 0.3 mm,tooth width1 mm. |
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