Droplet characteristics and behaviors in a high-speed disperser

In order to intensify the gas absorption process, a high-speed disperser with a rotor 219 mm in external diameter was designed to disperse the continuous liquid into droplets. The effects of rotational speed, radial distance, and inlet flow rate on droplet size and velocity were measured by using a high-speed camera in the air-water system. Results showed that the mean droplet diameter decreased with increasing rotational speed and decreasing radial distance or inlet flow rate. On the other hand, the droplet resultant velocity increased with increasing rotational speed or decreasing radial distance, but was hardly affected by the inlet flow rate. The Rosin-Rammler (R-R) distribution and three-parameter volume-based maximum entropy formalism (MEF) appropriately represented the droplet size distribution. Models for droplet motion in the rotor and cavity zones were successfully established to calculate the droplet velocity. The commercial code Fluent was adopted to simulate droplet characteristics and behaviors. The volume of fluid (VOF) model and the Euler-Euler multiphase model were implemented to predict the droplet size and velocity fields for gas and liquid, respectively. A comparison of simulated and experimental results indicated that the VOF model predicted the droplet size reasonably well, and the Euler-Euler multiphase model provided good estimates of the droplet velocity.