Streaming of a particulate aerosol due to acoustic excitation

Abstract

The acoustic equations pertaining to an aerosol containing small solid particles in suspension are developed. In order to study the acoustic streaming of this medium, that is, the steady unidirectional motion of particles which is superimposed upon the oscillatory acoustic motion, it it necessary to carry the analysis to so-called second order acoustic variables. It is shown that the inclusion of the dynamic and thermal properties of the suspended particles significantly influences the attenuation of sound and the streaming of the medium. Since the well known but presently unexploited process of sonic agglomeration of particulate aerosols depends to a large extent upon the acoustic streaming phenomenon, it is suggested that this work may be useful in further development of this process. A numerical example describing the streaming of an aerosol in a duct under the influence of acoustic excitation is developed in some detail.