精确灌溉喷头变量调节器结构参数设计

Structural parameter design for variable regulators in precision irrigation sprinklers

为使喷头能根据灌溉面积形状变化的要求实现喷洒域和喷洒量同步可控,提出一种精确灌溉喷头变量喷洒调节器的设计.该变量调节器采用上阻水片和下阻水片式结构,上下阻水片由中央通孔和扇形通孔及扇形阻水片组成.喷头转动时上阻水片和下阻水片发生相对转动,导通时过水面积增大,射程增加,封闭时过水面积减小,射程降低.设计了使喷头能量损失达到最小的扇形通孔中心角及中央通孔等的结构参数.采用水流运动的局部阻力理论设计了变量调节器的上下阻水片中央通孔的直径.结果表明:研究的变量调节器过水通孔的结构和参数可以保证过水断面阻力损失最小,通过射程及水量分布试验,发现其射程周线由圆形变为近似方形,射程最大时基本能达到原喷头射程,水量分布较为均匀,能够满足喷头流量和射程的变化规律按需求控制,实现喷头的变量喷洒精确灌溉.

In order to simultaneously control the spray field and volume of sprinklers in accordance with various shapes of irrigation area,a variable regulator design for precision irrigation sprinklers is proposed.The variable regulator was constructed with upper and lower water-blocking pieces,each of which comprises a central through-hole as well as fan-shaped through-holes and fan-shaped water-blo-cking pieces.As the sprinkler rotates,the upper and lower water-blocking pieces rotate in opposite directions.In conducting,both the water-carrying area and spray range increase;when it is closed,both the water-carrying area and spray range decrease.In this study,the structural parameters,including the central angle of the fan-shaped and central through-holes for minimizing the sprinkler energy loss,were designed;based on the local resistance theory of water movement,the central through-hole dia-meters for the upper and lower water-blocking pieces were also designed.The results show that the va-riable regulator designed in this study can guarantee the minimal resistance loss at water-carrying cross section;through spray range and water-carrying area testing,it is found that the contours of sprayed areas has transformed from circles to approximately squares,with the largest range approaching closely the original nozzle range and the water distribution being even,which can meet the demand of controlling spray flow and spray range as they vary and realize variable-rate precision irrigation.