An ultrasonic fine droplet collector

Abstract

It has been a big challenge to effectively collect coarse and fine droplets from the air by compact and light equipment. In this report, a novel strategy of collecting coarse and fine droplets from the air, which employs an ultrasonic field in the air gap between a flat radiation surface and parallel reflector, is demonstrated. Coarse and fine droplets (PM2.5-10 and PM2.5) can be effectively collected onto the reflector's surface when the air gap thickness is proper. The radiation surface works in a flexural vibration mode at 56.9 kHz, and the collected droplets may form concentric rings and irregular shape on the reflector's surface. Analyses show that both of the acoustic streaming and acoustic radiation force are responsible for the collection.