Accurate Determination Of Volume And Evaporation Rate Of Micron-Size Liquid Particle

We developed a noncontact method to measure the liquid droplet size of about 10 mu m diameter within accuracy of 0.1 mu m. A droplet ejected by an inkjet nozzle is induced into the glass windshield and falls due to the gravity against the viscosity of the atmosphere. The droplet is illuminated by a laser passing along the center of the glass windshield and the droplet diameter is determined from the falling velocity by the video analysis with the knowledge about the density of the droplet, and the viscosity of the atmosphere. The real time measurement of the droplet size through the rapid evaporation process thus becomes possible. The evaporation rate from the pure water droplet determined by the present method was found be more than 200 times larger than that from the surface with macroscopic spatial scale. (c) 2010 American Institute of Physics. [doi:10.1063/1.3483250]