The Measurement of Droplet Size Distributions from Rotary Atomizers

Various experimental techniques have been developed to recover droplet size distributions emitted from rotary atomizers. These techniques include both single line-of-sight measurements through the center of the spray cloud and volume weighted averaging from multiple passes through portions of the spray. Because the droplet size distribution of a spray is one of the most important inputs into aerial spray prediction models such as AgDRIFT®, a consistent, widely-accepted standard for rotary atomizers should be developed and implemented with regard to this measurement. No such standard currently exists. The present paper summarizes current measurement techniques and develops a simple computer model to predict droplet movement following emission from a rotary atomizer in a wind tunnel. Qualitative comparisons are made with available data to demonstrate the effects of single line-of-sight measurements and weighted averaging from multiple passes.