Droplet size control in the filter expansion aerosol generator

A new capability for droplet generation through the filter expansion aerosol generator (FEAG) process has been found. The mean sizes and size distributions of droplets generated by the FEAG process have been estimated from the resulting powders. The mean sizes of the droplets could be controlled from 1.7 to 25 μm. Surface tension and the viscosity of spray solutions controlled by adding polyethylene glycol (PEG) affected the mean sizes of the droplets. The mean sizes of droplets generated at a pressure of 160 Torr changed from 4.3 to 12.1 μm when the concentrations of PEG were changed from 1.6 × 10^-4 to 1.6 × 10^-3 M. The addition of PEG into the spray solution improved the size distribution of the droplets. The mean sizes of droplets generated from the spray solution with a concentration of 4.8 × 10^-4 M PEG changed from 1.7 to 25 μm when the reactor pressures were changed from 60 to 400 Torr. The droplets generated at pressures between 160 and 360 Torr had a narrow size distribution.