摇臂式喷头组合喷洒均匀性的改进

该文针对摇臂式喷头副喷嘴为圆形，径向水量分布中部较高不利于组合的问题，根据水射流原理，设计出一种新型结构的副喷嘴，其上端设有盖板，起到阻挡水流的作用，使副喷嘴水流射出后主要分散在近处，从而有利于提高组合喷洒的均匀性。分别对15PY、20PY、30PY摇臂式喷头副喷嘴改进前后的水量分布进行了对比试验，同时，以正方形布置方式为例，计算出不同组合间距下的喷洒匀性系数。结果表明：副喷嘴的改进消除了改进前喷头中间部分水量，使径向水量分布呈“三角形”。改进副喷嘴后提高了均匀性系数，不同组合间距下的值均为80%以上，平均喷灌强度符合喷灌规范中的要求。最后，提出副喷嘴改进后15PY，20PY，30PY摇臂式喷头的最佳组合间距分别为1.2R，1.3R，1.1R，计算出组合均匀性系数值分别为85.6%，86.3%，85.3%。改进后的副喷嘴对喷洒均匀性有较好的改善作用。

Combination uniformity improvement of impact sprinkler

According to that the sub-nozzle of impact sprinkler is circle, and the middle of radial water distribution for combination is higher, a new structure of sub-nozzle was designed based on jet flow theory. A cover plate was fixed at the top of the nozzle so that the jet water was barrieried to drop near the sprinkler, with which the combination uniformity increased. The tests of water distribution of original and improved impact sprinklers were carried out for the types of 15PY, 20PY, 30PY respectively. At the same time, the combination uniformity coefficient in different distance was calculated for square arrangement mode. The results showed that the middle part of radial water distribution was decreased than before, and the shape distribution was triangle. After the improvement, the uniformity coefficient was increased, and the value of them was over 80%. The sprinkler irrigation intensity was accorded with sprinkler irrigation standard. Finally, the combination distances of the types of 15PY, 20PY, 30PY were 1.2R, 1.3R, 1.1R after improvement, and the combination uniformity coefficient values were 85.6%, 86.3%, 85.3% respectively. The new structure of sub nozzle improved the combination uniformity observably.