Development of Agricultural Sprinkler for Use in Volcanic Ash FallingArea

本文研究了一种适用于火山灰落点地区的新型农业喷头。在这项研究的第一年和第二年，已经制造了几种新型的洒水器。用这些类型的喷头测量了水的体积分布和水滴的程度。结果表明，喷嘴出口宽度或喷头直径等几何结构对喷水的这些特性有很大影响。本文利用yag激光系统、高速摄像机和图像处理系统组成的可视化信息系统，对这些喷头内部的流动进行了可视化。利用这些数字信息，研究了喷头几何形状与最大喷水角度之间的关系。本研究得到的结果如下：(1)横向扁平，长轴为52mm的椭圆型洒水喷头，洒水角最大(2)纵向扁平的椭圆型洒水喷头，洒水角的度数单调。(3)当涡室两侧产生的涡度差变大时，喷水角达到最大值。

This study is on the new type of an agricultural sprinkler for use in the volcanic ash falling area. In the first and second year of this study new several types of sprinkler have been made. The distribution of the watering volume and the degree of droplet of the water have been measured by using these types of sprinklers. As a result, it has been clarified that the geometrical configuration such as the nozzle exit width or the diameter of the sprinkler affect largely on these characteristics of the watering. In this year the flow visualization inside of these sprinklers has been done by using the visualization information system composed of the YAG-laser system, the high speed camera and the image processing system. By using these digital information the relationship between the geometrical configuration of the sprinkler and the maximum angle of the watering has been investigated. The results obtained in this study are as follows ;(1) In the case of the ellipse type sprinkler which is flattened laterally and has the major axis of the 52mm, the watering angle becomes maximum(2) In the case of the ellipse type sprinkler which is flattened longitudinally, the watering angle degrees monotonously.(3) When the difference of the vorticity of the vortices generating in both sides of the vortex chamber becomes large, the watering angle shows the maximum value.