Observation of Aerosol Behavior near Droplet Interface

Abstract

An aerosol particle collection by liquid droplets has been applied in many industries. One example of this is the radioactive aerosol removal system in the safety system of the nuclear reactor. In this study, to clarify the capturing behavior of aerosol particles by liquid droplet, the velocity distribution of aerosol particles around the droplet was measured by the particle image velocimetry (PIV). Moreover, the capturing behavior of the aerosol particles near the droplet interface was observed by using a high-speed and high-resolution video camera. The experimental results showed that aerosol particles flowing near the cross-sectional center of the droplet were captured at the droplet interface after the velocity of the aerosol particles decreases near the droplet. However, aerosol particles that came to positions out of the center did not reach the droplet interface and were not captured at the interface. In addition, there were four behaviors of aerosol particles near the upstream interface of the droplet. The capturing behaviors were categorized into two types, capture at the droplet interface and that inside the droplet. The capture inside the droplet was observed more than the capture at the interface. In the case that particles were not captured, we observed that particles moved along the droplet interface and followed the stream. In the captured case, the diameter of the aerosol particles was larger and the Stokes number was about 1 or more. The result indicated that the main aerosol-particle capturing-mechanism at the upstream side of the droplet was due to inertial collision.