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双壁双腔型低压灌水器结构设计与性能优化

Structural Design and Performance Optimization of Double-Wall Dual-Chamber Low-Pressure Emitters

  • 摘要: 针对传统滴灌灌水器在5 m压力水头以下的低压工况下流量偏差大、抗堵塞性能差以及毛管铺设长度受限等问题,该研究提出双壁双腔型低压灌水器结构。首先通过内外腔分级联合消能、外腔变齿数主动补偿、内腔大尺寸流道与外腔沉沙槽协同抗堵的集成设计方案,实现了灌水器在低压工况下的均匀出流与高效抗堵。进一步地结合数值模拟与试验验证,优化灌水器关键结构参数,并揭示了流道内泥沙颗粒的运动机理。结果表明:该灌水器流态指数低至0.436,130 m长毛管铺设下的流量偏差率为7.43%,抗堵性能较贴片式灌水器提升16.7%~50%;经内腔流道直角转角圆弧化和内外腔对向布局优化后,大粒径沙粒进入漩涡区概率较流道转角和布局优化前降低50%~71.4%。本研究可为低压滴灌技术应用提供技术与装备支撑。

     

    Abstract: To address the problems of large flow deviation, poor anti-clogging performance, and limited lateral length in drip irrigation systems operating under low pressure (≤5 m), a novel double-wall dual-chamber emitter was developed. The emitter employs an inner and an outer labyrinth channel for graded energy dissipation: the inner chamber, with large channel dimensions (width ≥1.0 mm, depth ≥1.0 mm), dissipates 30~40% of the total energy to prevent clogging, while the outer chamber dissipates the remainder and utilizes a variable tooth-count design (20 teeth for Class I, 16 teeth for Class II) to actively compensate for frictional pressure loss along the lateral. An annular settling groove in the outer chamber traps large sediment particles, and the outer chamber is detachable for easy flushing. Orthogonal experiments and numerical simulations (standard k-ε model, validated with 3D-printed prototypes, nRMSE = 4.04%) were used to screen key structural parameters and to optimize the inner and outer channel geometries. The inner channel was set to width 1.2 mm, depth 1.0 mm, tooth height 1.5 mm, tooth width 1.4 mm, and 20 teeth, achieving 36% energy dissipation. The outer channel was optimized to width 0.8 mm, depth 0.8 mm, tooth height 0.9 mm, tooth width 1.0 mm, with tooth numbers of 20 (Class I) and 16 (Class II) to meet the target flow of 1.5±0.1 L/h and to provide effective compensation. Short-term anti-clogging tests with six sand size fractions (0.031~0.15 mm) at a concentration of 3 g/L and two-phase flow simulations (Eulerian–Lagrangian framework with bidirectional coupling) were performed to investigate sediment transport and deposition. Based on the observed sediment distribution, the right-angle corners of the inner channel were rounded to a radius of 1.0 mm, and the inner and outer chambers were rearranged in opposite orientation to enhance particle settling in the groove. The results showed that the emitter achieved a low flow index of 0.436 (before corner rounding) and maintained a value around 0.44 after optimization, indicating weak sensitivity to pressure changes. Under a 130 m lateral length with combined Class I and II emitters, the flow deviation rate was only 7.43%, far below the standard 20% limit. The active compensation gave a flow increase of 9.7% at 4 m head. In long-lateral tests at 3~4 m inlet pressure, the uniformity coefficient Cu exceeded 93% and the flow coefficient of variation Cv remained below 0.055. Anti-clogging tests revealed that, compared with a conventional patch-type emitter, the dual-chamber emitter required 16.7%~50% more irrigation cycles before reaching 75% relative flow, with the benefit being more pronounced for particles larger than 0.045 mm. After the structural optimization, the turbulent kinetic energy in the inner channel increased by 13.6%~30.6%, and the probability of large particles (0.10~0.15 mm) entering vortex zones dropped by 50%~71.4%. The transport path lengths for 0.05, 0.10, and 0.15 mm sand particles decreased by 13.6%, 21.3%, and 30.6%, respectively, and the residence times were shortened accordingly. Furthermore, the inner chamber energy dissipation remained within the design target (30% and 37% for the two stages), validating the dual-chamber synergy. The design approach successfully reconciles energy dissipation and anti-clogging requirements under low pressure, providing a practical solution and theoretical guidance for low-pressure drip irrigation equipment, and holds promise for reducing system energy consumption and investment while maintaining high irrigation uniformity.

     

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