Laboratory measurements of evaporation rate of droplets at low relative wind speed

Abstract

This article summarizes further experimental data collected regarding the evaporation rate of isolated water droplets and strengthens previously published results regarding droplet evaporation at low relative wind speeds. The results suggest that as the Reynolds number (based on the relative velocity between the droplet and ambient air) decreases toward zero, the droplet evaporation rate falls to one-half its value. Because released spray droplets quickly attain near-background velocities, this result implies that evaporation continues for longer times than historically thought but at a lower rate. Additional measurements on traditional fluids (WHO, deionized, distilled, and tap water) provide a consistent benchmark with which to compare evaporation rates.