低压喷头喷嘴优化设计及内部流场数值模拟  

Optimization design of nozzle and numerical simulation of internal flow field in low-pressure sprinkler

作　　者：张前[1] 袁寿其[1] 刘俊萍[1] 鲍亚[1] 

机构地区：[1]江苏大学国家水泵及系统工程技术研究中心,江苏镇江212013

出　　处：《排灌机械工程学报》2016年第5期449-454,共6页Journal of Drainage and Irrigation Machinery Engineering

基　　金：国家自然科学基金资助项目(51309117);国家863计划项目(2011AA100506);江苏高校优势学科建设工程项目

摘　　要：针对目前喷头在低压工况下喷洒均匀性较差、射程变短等问题,依据面积相同原则设计多种形状的异形喷嘴,运用ANASY软件对其内流场进行三维仿真模拟,模拟结果表明:倒U形喷嘴出口断面的速度分布高速区域所占面积最大,整个出口的速度一致性较好,有利于提高喷头射程,改善喷灌均匀性.通过测量低压喷头的性能参数,包括射程、水量分布和末端水滴直径,来验证数值模拟的准确性.试验结果表明:倒U形喷嘴的射程约为圆形喷嘴的1.110倍,稍低于数值模拟的计算结果,基本在2%左右;工作压力为300 k Pa时,喷头的末端水滴直径以倒U形喷嘴最小为4.21 mm,说明倒U形喷嘴的雾化性能最好;倒U形喷嘴的水量分布近似呈三角形,其组合均匀性系数均在82%以上,圆形和圆角矩形喷嘴的水量随喷头距离的变大先增大后减小,均低于倒U形喷嘴的组合均匀性系数.数值模拟和试验结果表明,倒U形喷嘴的水力性能优于其他3种喷嘴,在提高喷灌均匀性的基础上,还增大了射程.In view of poor sprayiag uniformity and short range in low-pressure sprinklers,various special-shaped nozzles are designed based on the principle of identical cross-sectional area. ANASY CFX is applied to simulate three-dimensional internal flow field in these sprinklers. The numerical simulation results are validated by using the measured performance parameters of low-pressure sprinklers,including range,water distribution and drop diameter. The simulated results show that the region occupied by high velocity at the outlet of inverted U shaped nozzle is the largest and the velocity profile keeps consistent with the increasing working pressure,showing a good advantage in extending the range and improving the spraying uniformity. The experimental results show that the range of inverted U shaped nozzle is about 1. 110 times than that of the circular nozzle,which is basically around2% lower than the prediction. At a 300 k Pa working pressure,the drop diameter generated by the in-verted U shaped nozzle is 4. 21 mm as the minimum,showing the best atomization performance. The water distribution in that nozzle is approximately triangular,all the uniformity coefficients are more than82%. With increasing distance,the water through the circular and rounded rectangular nozzles rises first,and then decreases,and all the uniformity coefficients are lower than that of the inverted U shaped nozzle. In conclusion,the hydraulic performance of the inverted U shaped nozzle is much better in comparison with the others,particularly,the range is increased on the basis of uniformity improved.

关 键 词：低压喷头 异形喷嘴 优化设计 数值模拟 水力性能 

分 类 号：S277.9[农业科学—农业水土工程]