折射式喷头喷灌强度及能量空间变化规律研究

Spatial Variation of Application Rate and Droplet Kinetic Energy for Fixed Spray Plate Sprinkler

采用自计雨量筒、视频雨滴谱仪（2DVD）测得不同工作压力下Nelson D3000型蓝色喷盘、喷嘴直径4.76 mm喷头的喷洒水量、喷灌水滴落地速度及粒径等指标,研究了不同压力下该喷头的水量、能量分布及其扩散规律,建立了不同工况下水量峰值、能量峰值与工作压力及喷灌高度的回归关系式。结果表明：增大喷头工作压力、升高喷头安装高度均有利于水量及能量的扩散;喷头的安装高度过低会导致较高的水量峰值和能量峰值,易产生地表径流,0.5 m高度水量峰值变化范围为166.4-196.4 mm/h,能量峰值变化范围为0.607-0.821 W/m^2。喷头水量峰值和能量峰值的计算式可为确定喷灌系统工作压力和喷头安装高度提供参考依据,避免因水量峰值和能量峰值过大而产生地表径流。

Data logging rain gauges and two-dimensional video disdrometer（ 2DVD） were applied to measure its water application rate,droplet diameter and velocity in radial direction of Nelson D3000 blue spray plate sprinkler with 4. 76 mm nozzle. The equations of peak application,peak kinetic energy rate about working pressure and mounting height were regressed based on the diffusion of water application and kinetic energy under different working conditions. The result indicates that the diffusion of water application rate and droplet kinetic energy are facilitated by increasing the working pressure and mounting height. This is due to that the jet flow speed is higher when the operating pressure increased,and with the air turbulence enhanced,it is easy to smash. The water drops to pieces. At the same time,the duration of landing increased when the mounting height is high. That seems to have the same effect. The low nozzle height which presents high peak application and kinetic energy rate leads to the generation of runoff. The peak water application and droplet kinetic energy rate varied from 166. 4 mm / h to196. 4 mm / h,and 0. 607 W / m^2 to 0. 821 W / m^2,respectively. The equation of peak rate can be helpful to design the working pressure and mounting height in sprinkler systems to prevent high peak application rate and kinetic energy rate which leading to occurrence of runoff.