On the Factor Affected for Droplet Size of Water Sprayed Nozzle

Abstract

To use a sprinkler for multiple objects, it is required that the droplet size is gained in a wide range and a validity of the sprinkler nozzle must be studied from the point of a saved energy of a sprayed water. In this report, the effect of the nozzle diameter, the pressure of a water, etc, on the droplet size important in the nozzle design has been investigated. The results were as follows.
(1) The influence of density, coefficient of viscosity, surface tension of the water, the nozzle diameter, the pressure, the nozzle shape and pressure losses in the nozzle on the droplet size were shown with eqs. (19), (20), (21).
(2) Small droplet size was gained with increasing the pressure and making the nozzle diameter small. The effect of the former was larger than the latter by the comparison of its exponent.
(3) Shape factor, β, has been introduced to examine the influence of the nozzle shape difference. When the sprinkler nozzle shape was replaced circle type with triangle shape, in other words, β became large, the droplet size became small. A droplet gained in a triangle type was the same size with double pressures in a circle type. Then, this is useful for the saved energy. Simple nozzle shapes with large, β were demonstrated.
(4) The effects of a internal structure and a manufactured accuracy of the nozzles on the droplet size were determined from the standpoint of pressure losses in the nozzles. When the pressure losses became large, the droplet size became small. It is not easy to estimate the pressure losses because of difficulty of measurement for a velocity in the nozzles. However, this values were assessed easily by using a experimental apparatus in this report, so it is possible for the apparatus to serve for an ability test of a water sprayed nozzle.