The work herein details an optical droplet measurement system based on planar multi-angle Mie scattering. Sizing information consists of a mean droplet diameter and droplet distribution estimates for every individual point within a planar (2D) area of interest. The planar method makes possible the fast acquisition of data within a large field of interest, and uses relatively inexpensive instrumentation.

As presented, the method demonstrated the ability to measure water droplets from a typical simplex spray nozzle, across the range of 5-50 micrometers within +/-10% of known values, and in addition return an estimate of the shape and width of the size distribution at each location within the planar region of interest. Measurements demonstrating the agreement between results from this current method and known PDA data were successfully completed for a 1-gallon-per-hour spray nozzle, and repeatability was demonstrated in 2.5-gallon-per-hour and 4.5-gallon-per-hour nozzles. Additionally the limits of the technique are explored with simulated data. Conclusions from these exercises show that the multi-angle planar Mie scattering method is capable of measuring droplet distribution characteristics and means within a nominal range of 0.3 micrometers up to 150 micrometers.