双喷嘴负压反馈射流喷头水力性能研究

Hydraulic Performance of Negative Pressure Feedback Jet Sprinkler with Double Nozzles

为简化摇臂式喷头结构、提高其水力性能,通过负压反馈技术设计了一种双喷嘴射流喷头,包括射流元件、主副喷管、旋转密封机构等,其主副喷管长度分别为5.6 mm和4.8 mm、喷头仰角为30°,左右喷管里产生的间歇脉冲水流能够驱使喷头步进式全圆旋转。在0.20、0.25、0.30、0.35 MPa进口压力下,以射程、平均喷灌强度和喷灌均匀度为评价指标,通过加权评分法,对比了4种不同主副喷嘴直径组合(4 mm×3 mm、4 mm×4 mm、5 mm×4 mm和5 mm×5 mm)射流喷头与摇臂式喷头的水力性能。结果表明:在上述4种进口压力下,主副喷嘴直径分别为5 mm和4 mm时的射流喷头综合性能最好,其水量分布呈“三角形”,射程在13.2~13.7 m之间,平均喷灌强度在3.81~4.38 mm/h之间,喷灌均匀性系数在82.5%~86.0%之间。

In order to simplify the structure of rocker-arm sprinkler and improve its hydraulic performance,a jet sprinkler with double nozzles was designed by using negative pressure feedback technology,including jet elements,main and auxiliary nozzles and rotary sealing mechanism.The length of the main and auxiliary nozzles were 5.6 mm and 4.8 mm,respectively,and the elevation angle of the nozzle was 30°.The sprinkler was innovative in its mechanism and spraying method.The pulsed oscillating water flow can be formed between the main sprinkler and the auxiliary sprinkler by using the wall-attaching effect of the jet.The step-by-step rotating sprinkler can be realized by intermittent striking of the driving plate by the pulsed jet.The main nozzle of negative pressure feedback jet nozzle provided a long range jet,while the secondary nozzle jet struck the driving plate connected with it,breaking the whole continuous jet into small droplets,providing a jet with a relatively short range,and providing a rotating driving force for the nozzle,thus realizing full circle rotation.Under the inlet pressure of 0.20 MPa,0.25 MPa,0.30 MPa and 0.35 MPa,taking range,average sprinkler irrigation intensity and sprinkler irrigation uniformity as evaluation indexes,the hydraulic performances of six different diameter combinations of main and auxiliary nozzles(3 mm×3 mm,4 mm×3 mm,4 mm×4 mm,5 mm×3 mm,5 mm×4 mm and 5 mm×5 mm)were compared by weighted scoring method.The results showed that under the above four inlet pressures,the jet nozzles with diameters of 5 mm and 4 mm had the best comprehensive performance.The water distribution was“triangular”,the range was 13.2~13.7 m,the average intensity of sprinkler irrigation was 3.81~4.38 mm/h,and the uniformity of sprinkler irrigation was 82.5%~86.0%.The results provided certain theoretical value for studying the hydraulic characteristics of negative pressure feedback nozzle and optimizing the nozzle structure,and brought ideas and applications for the nozzle technical field.