Characteristics of a Spinning-disk Liquid Sprayer

Abstract

In this paper is described an attempt to increase the output of a spinning-disk sprayer without sacrificing the homogeneous drop-size characteristics found by previous investigators. A disk sprayer inches in diameter was designed, and the characteristics were determined by feeding various quantities of water centrally on to the disk, and noting the resulting drop sizes and their distribution over a range of disk speeds from 600 to 2,000 r.p.m. The critical flow rate for the production of uniform-size drops is in the range 6–22 cu. cm. per sec., and the size of drops produced is inversely proportional to the speed of the disk. The product of drop diameter and peripheral velocity of the disk is approximately constant and varies with the smoothness of the surface of the disk rather than with the rate of liquid flow. Above the critical flow rate the homogeneity of the drops disappears and a wider range of sizes is observed. The distribution and sizes of the drops are independent of the rate of liquid feed over a range of from 22 to 110 cu. cm. per sec, the size of the majority of drops being dependent on the peripheral speed of the disk. Above that range the liquid comes off the disk in a sheet, in which little or no break-up of the liquid takes place. It is concluded that spinning disks of large diameter will produce drops of uniform size even at relatively low rotational speeds.