摘要
为了研究低压喷头异形喷嘴水量分布的均匀性,依据面积相同原则,设计出圆形、三角形、正方形3种以及不同锥角形式的喷嘴,研究低压下异形喷嘴喷头对喷灌水量分布的影响.通过外特性试验测量了异形喷嘴喷头的流量、射程和水量分布,利用Matlab软件分析不同喷嘴喷头的喷洒均匀性,同时采用高速摄影技术观测不同喷嘴形式下喷头射流空间流态.结果表明:同一压力下,随着喷嘴锥角的增大,喷头流量逐渐减小,且正方形喷嘴喷头流量最大,三角形喷嘴喷头流量最小;喷头射程随着喷嘴锥角的增大呈先增大后减小变化趋势,且圆形喷嘴喷头射程最远,三角形喷嘴喷头射程最短.由高速摄影图像可以看出,三角形喷嘴喷头的射流破碎段最短,圆形喷嘴喷头的射流破碎段最长;随着喷嘴锥角的增大,3种喷嘴喷头的射流破碎长度段呈减小趋势;综合射程和雾化效果可知,锥角为45°时圆形喷嘴喷头为最优.同时,通过对圆形喷嘴和异形喷嘴的水量分布均匀性测量,发现异形喷嘴喷洒组合均匀性系数比圆形喷嘴明显要高.
According to the principle of equal nozzle cross-section area, a few nozzles with different shapes were designed to study their effect on the distribution of sprinkler irrigation at low pressure. The nozzle hydraulic performances were measured, the spraying uniformity of different nozzles were ana- lyzed by using Matlab software. Additionally, the spatial flow pattern with different nozzles were observed with high speed photographical technique. The results show that the flow rate decreases gradual- ly with increasing nozzle cone angle at the same pressure, the flow rate through the squared cross-section nozzle is the largest, that through the triangular cross-section nozzle is the smallest. The nozzle wetted radius firstly increases then decreases with increasing cone angle, and the circular and triangular cross-section nozzles are subject to the longest and shortest wetted radius, respectively. Based on high-speed photographical images, it can be seen that the jet breaking length issued from the triangular cross-section nozzle is the shortest, while the breaking length from the circular cross-section nozzle is the longest. With increasing nozzle cone angle, three nozzle jet breaking lengths show a decreasing trend. Composting the nozzle wetted radius and the atomization effect, it can be known that the circular cross-section nozzle with 45 degrees cone angle is the best. Moreover, it is found that the combined water distribution uniformity coefficient of the non-circular cross-section nozzles is evidently better than the circular nozzle based on measurements.
出处
《排灌机械工程学报》
EI
CSCD
北大核心
2017年第5期448-453,共6页
Journal of Drainage and Irrigation Machinery Engineering
基金
国家自然科学基金资助项目(51279068)
公益性行业(农业)科研专项资助项目(201503130)
国家863计划项目(2011AA100506)
关键词
异形喷嘴
摇臂式喷头
均匀度
低压
non-circular nozzle
impact sprinkler
uniformity
low pressure
