Temperature and Velocity of the Gas–Vapor Mixture in the Trace of Several Evaporating Water Droplets

Abstract

The optical techniques (particle image velocimetry (PIV), laser-induced phosphorescence (LIP), planar laser-induced fluorescence (PLIF)) are used to study unsteady and inhomogeneous temperature and velocity fields of a gas–vapor mixture forming in the immediate vicinity of rapidly evaporating water droplets. Experiments involve various arrangements of several (two, three, and five) water droplets in a heated air flow. We establish the dependencies of the temperature and velocity of a gas–vapor mixture in the trace of each droplet on the heating time, velocity and temperature of the air flow, initial dimensions, and droplet arrangement scheme. Distinctive features of the synergistic effect of a droplet group on their temperature and aerodynamic traces are identified. Longitudinal and transversal dimensions of the aerodynamic and thermal traces of evaporating droplets are established. The length of the temperature trace of one droplet equals 10–12 of its radii, and the width of the temperature and aerodynamic trace of a droplet is no larger than its diameter.