卷盘式喷灌机移动喷洒均匀度是衡量灌溉质量的重要指标。现有卷盘式喷灌机组均匀度计算方法或过于繁琐，或显计算精度不足。该研究提出一种基于最小二乘法的移动喷洒均匀度计算模型，模型计算结果与实测结果偏差在6%以内。应用该模型对配备50PYC垂直摇臂式喷枪的卷盘式喷灌机进行模拟，结果表明：不同工作压力下的灌水深度呈梯形分布，移动喷洒均匀度随喷枪工作压力的升高略有提升。喷枪辐射角对机组的喷洒均匀度有较大影响，喷枪辐射角为180°、220°和270°时，移动喷洒均匀度系数分别为61.4%、69.9%和71.9%。喷枪辐射角的增大可有效提高喷洒域内各点的灌水历时，从而降低平均喷灌强度，减小地表径流的发生概率。移动喷洒均匀度系数随组合间距的增加先增高后降低，组合间距在1.5R~1.7R时的组合喷洒均匀度系数不低于85%。综合考虑喷枪辐射角和组合间距双因素对移动喷洒均匀度的影响，该工况下喷枪辐射角的适宜范围为240°～320°，组合间距的适宜范围为1.4 R～1.7 R。该研究结果可为卷盘式喷灌机组运行参数的优化配置提供参考。%Spray uniformity is an important index to evaluate the irrigation quality of hard hose traveler. The existed uniformity calculating methods are complicated or show poor calculation accuracy. In this study, a curve fitting based on least square method was used for the radial water application of large flow rate sprinkler gun and a corresponding simplified calculation model was built to attain the mobile spraying uniformity. The model was mainly composed of three parts: the curve fitting of radial water distribution, water overlapping in the moving direction and the calculation of combined spraying uniformity. A spraying experiment was designed to verify the accuracy of the model. A JP75-300 type hard hose traveler was adopted in the experiment, the walking speed of the moving cart was 30 m/h, and the working pressure of the spray gun was 0.2 MPa. In addition, the flow rate of the system was 11.22 m3/h and the sector angle was 180°. The deviation between calculated values and measured values were within 6%, which verified the accuracy of the model. The model was then used to calculate and analyze the relation between operating parameters and mobile spraying uniformity of a hard hose traveler equipped with a 50 PYC vertical impact arm sprinkler gun. The results show that: 1) The mobile spraying uniformity improves slightly with the increase of working pressure. The uniformity coefficient of 50 PYC vertical impact arm sprinkler gun under 0.1, 0.2, 0.3 and 0.4 Mpa are 64.9%, 71.9%, 73.8% and 74.7%, respectively. The application depth of water under each pressure presents a form of trapezoid distribution. The depth close to the cart pathway is relatively low. And this value increases to a stable value with the increase of distance to the pathway, nonetheless this value drop dramatically at the end of spray zone. 2) The radiation sector angle of the sprinkler gun shows a great influence on the spraying uniformity. The mobile spraying uniformity coefficients are 61.4%, 69.9% and 71.9% under a radiation sector angle of 180°, 220° and 270° on the setting conditions. The form of water application depth transform from triangle distribution to trapezoidal distribution with the increase of sector angel. The increase of sprinkler gun sector angle can stretch the length of irrigation duration time effectively, which is prone to a lower average application rate and a lower incidence probability of surface ponding and runoff. 3) The mobile spraying uniformity increases at first and then decreases with the increase of combination space. Under the setting conditions, the mobile spraying uniformity is higher than 85% with a combination space of 1.5 R-1.7 R. When considering the influence of both sprinkler gun sector angle and combination space on the uniformity, the recommended sector angle range is 240°-320° and the combination space between adjacent pathway is 1.4 R-1.7 R under the setting conditions. 4) The mobile spraying uniformity shows no difference under various gun rotation cycles without considering on the influence of water distribution profile caused by the rotation cycle. The spraying jet hydraulic characteristic of sprinkler gun was taken under condition of no wind or slight wind (wind speed<1.5 m/s), and the turbulence caused by wind was not yet considered in the model. The conclusions of this study can provide theoretical basis for the operation optimization of hard hose traveler.
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