Interaction times of homogeneous and heterogeneous droplets in gases

Abstract

In this research, we present the results of experiments measuring the interaction times of colliding liquid droplets in different modes (bounce, coalescence, separation, and disruption). The experiments involve water and typical water-based slurries, emulsions, and solutions. The main experimental parameters are close to those of high potential gas-vapor-droplet technologies (heat and mass transfer power plants, thermal and flame water treatment systems, and fuel technologies): droplet size 0.1-5 mm, velocities 0.1-10 m/s, liquid temperature 20-80 ?C, impact angle 0-90?, and relative volume and mass fractions of liquid and solid additives in water 0-10%. We explore how a set of parameters and effects influence the characteristics of the processes under study. The most important of these parameters are relative droplet velocity, impact angle, impact parameter, and temperature. Using dimensionless linear and angular interaction parameters as well as the Weber, Reynolds, and Ohnesorge numbers, we produce interaction mode maps to consider the correlation of the main forces: inertia, surface tension, and viscosity. We determine the interaction times, number, size, and total surface area of the newly formed post-collision droplets and obtain approximations for the experimentally determined functions.