全射流喷头压力调节装置损失系数分析及试验

针对变量喷洒全射流喷头工作中压力调节装置压力损失研究不足的情况，根据喷头工作中系统特性发生变化的特点，应用伯努力方程对系统压力变化规律进行了分析。提出压力损失系数为压力调节装置动静片的截面积变化系数及形状系数之和并减去轴向间隙系数，通过计算得到压力损失系数最大值为0.7414，最小值为0.0204。采用虚拟仪器LabVIEW软件测量调节装置前后压力与时间、工作状态之间的关系。结果表明：随着流量的减小，调节装置上游压力增大，下游压力减小，下游压力变化幅度较大。测量得到装置压力损失系数的变化规律，随着流量的减小而增大，最大值为0.582，最小值为0.265。对全射流喷头压力调节装置的设计及改进提供了理论依据。

Experiments on loss coefficient of complete fluidic sprinkler pressure regulation device

According to the shortage of resoarch work on pressure loss in pressure regulation device of complete fluidic sprinkler for variable irrigation, the pressure variation of system was analyzed by Bernoulli equation. Based on definition system characteristics the sprinkler changed when working. The loss pressure coefficient was put forward with the value that, plus of section area variable coefficient and shape coefficient and then minus axial clearance influence coefficient of the moving chips in relative motion. For the calculation, the maximum loss pressure coefficient value was 0.7414, the minimum value was 0.0204. Virtual instrument and LabVIEW software were adopt to measure the relationships between pressure value, the sprinkler running time, the working conditions of pressure regulation device. The results showed that when the flow rates decreased, the upstream pressure increased, and the downstream pressure decreased, the range of downstream pressure changed was larger relatively. With the flow rate decreased, the loss coefficient increased. The maximum loss coefficient value of pressure regulation device was 0.582, and the minimum value was 0.265. The study can provide a theoretical basis for the design of complete fluidic sprinkler pressure regulation device.