Study on Agglomeration of Ultrafine Droplet Particles by Acoustic Air-jet Generators

Abstract

Acoustic agglomeration is a potential technology for fine particle pretreatment, but the high energy consumption restricts its industrial application. In order to develop a reliable sound source with low energy consumption, acoustic air-jet generators with frequencies ranging from 3 kHz to 8 kHz are adopted to study on the agglomeration effect of ultrafine droplet particles. The influences of frequency, flow rate and initial particle concentration on agglomeration efficiency are experimentally investigated. The results show that the acoustic frequency is a crucial factor for the agglomeration efficiency. The agglomeration efficiency of ultrafine droplet particles is higher than 55% at an optimal frequency of 6 kHz. The probability of collision between droplets increases with the increase of the initial mass concentration, which favors aerosol agglomeration. Moreover, it is shown that the sound pressure level increases with the increase of flow rate of compressed air.