旋转式喷头空间流道设计及低压水力性能试验  

Space flow channel design of rotary sprinkler and hydraulic performance experiments at low pressure

作　　者：刘俊萍[1] 李红[1] 张前[1] 李一鸣[1] Liu Junping;Li Hong;Zhang Qian;Li Yiming(Research Center of Fluid Machinery Engineering and Technology,Jiangsu University,Zhenjiang 212013,China)

机构地区：[1]江苏大学流体机械工程技术研究中心,镇江212013

出　　处：《农业工程学报》2022年第5期65-71,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金项目(51939005);江苏省重点研发计划项目(BE2021341);镇江市重点研发计划项目(NY2020013)。

摘　　要：喷头在低压工况下存在均匀性较差、射程变短及工作不稳定等问题。为了扩宽喷头的工作压力范围,该研究设计了旋转式喷头空间流道结构。以空间流道仰角、中间截面偏置角、出口截面偏置角为因素,以喷头空间流道出口平均速度和旋转驱动力为指标,采用CFD数值模拟正交设计,分析了空间流道结构参数对喷头水力性能的影响,并对旋转式喷头与相同规格的NelsonR33喷头在不同压力工况下进行水力性能对比试验。结果表明:空间流道各参数对喷头出口平均速度影响顺序依次为:空间流道仰角、中间截面偏置角、出口截面偏置角;对喷头旋转驱动力的影响顺序依次为:中间截面偏置角、空间流道仰角、出口截面偏置角。空间流道结构最佳参数组合为:出口截面偏置角为3°、中间截面偏置角为3.5°和空间流道仰角为30°。在工作压力为150及200 kPa下,旋转式喷头的水量分布更为均匀,组合均匀性系数更高。为扩宽喷头工作压力范围以及提高喷头低压下水力性能提供依据。A rotary sprinkler has been commonly used in a wide spray pattern in various irrigation systems,depending on the nozzle type,flow rate,and water pressure.The broad working pressure range of the sprinkler can require uniform water distribution,increased wetted radius,and stable operation under low pressure.In this study,a novel spatial structure of the flow channel was designed in the rotary sprinkler suitable for low pressure.The structure was greatly contributed to the increased driving force of sprinkler rotation,whereas,the outlet structure of the spatial channel was to promote the wetted radius and spraying uniformity.A numerical simulation was conducted to widen the rated working pressure range of the sprinkler using a computational fluid dynamics(CFD)software,where the elevation angle of the space flow channel,the offset angles of the middle and outlet section were taken as the factors,while the average speed,and the rotation driving force of the outlet as the indexes.The hydraulic performance was then evaluated under the structural parameters of the space flow channel.A comparative experiment was performed on the hydraulic performance between the low-pressure rotary and Nelson sprinkler.The results show that the average velocity at the outlet of the nozzle in the spatial channel and the uniform velocity distribution were closely related to the wetted radius of the sprinkler.The larger average velocity at the outlet was a benefit to the wetted radius of the sprinkler.The uniform velocity distribution maintained the water jet near the jet core area in the air,further improving the wetted radius of the sprinkler.A stable working range was better under the stable operation of sprinkler,and the greater driving force at low pressure.There was a relatively uniform velocity distribution of the flow field in Schemes 1,5,7,and 9,where the variation range of velocity at the outlet section was less than 40%,indicating the large average velocity.Therefore,Schemes 1,5,7,and 9 were conducive to the water jet near the jet

关 键 词：旋转式喷头 数值模拟 水力性能 低压喷洒 空间流道 均匀性 

分 类 号：S277.94[农业科学—农业水土工程]