A 3D flow visualization in evaporation of water from a meniscus at low pressures

Evaporation of a liquid from a meniscus has been observed to generate vortical motion and instabilities both on the interface and in the bulk liquid. The aim of this work is to develop and demonstrate an automated scanning particle image velocimetry (PIV) system to visualize and quantify the time-resolved threedimensional evaporation-driven velocity field inside the bulk liquid. The evaporating liquid is deionized water which forms a meniscus in a rectangular cross section (10mm x 4mm) quartz cuvette. In preliminary experiments, the three-dimensional velocity and vorticity fields revealed the existence of a large doughnut shape convection pattern in the bulk liquid and also a very small vortex rotating in the opposite direction close to the liquid–vapor interface. Such a detailed 3D observation of the flow field can lead to new understanding of the mechanisms of energy transport to the interface during evaporation of liquids, which has been the subject of intense study for many years.