Shubhankar Jape

Major: Physics
Mentor: Dr. Ricardo Decca

Characterization of nebulized water droplets

The goal of this UROP was to characterize and analyze nebulized DI water droplets of a nebulizer to learn about the size distribution and the evaporation rates of those droplets. The analysis was necessary as the nebulizer was to be used for a project which involved the nebulization of quantum dots into a chamber and optically trapping them. A Wellue portable mesh nebulizer was used to nebulize the droplets as the manufacturer claimed the particle size was less than 5μm. The nebulized droplets were sprayed onto a slide and then observed under a CMOS camera with 50x magnification. Enough samples were collected until an approximate normal distribution was observed. The observed size of the droplets was with a mean of 3.3μm with a variance of 0.7μm. The observed size of the particles was indeed less than 5μm as claimed by the manufacturer. Magnus’ formula was used to calculate the dew point and Maxwell’s method was used to calculate the evaporation time for the droplets at 40% humidity and 25oC. The evaporation time for the 3.3μm droplets was calculated to be 43 milliseconds which was lower than what was needed for the experiment. The next steps for this project would be to obtain droplets using atomizers that would have a bigger size to obtain a higher evaporation time that would be suitable for the experiment.