ABSTRACT
Coagulation of aerosols, which is used to describe the growth process of aerosol particles in contact with each other, causes a continuous change in the size distribution of agglomerates, keeping the total particle volume constant. For aerosol particles of submicron diameter, Brownian coagulation by Brownian motion of particles is essential for the characterization of the behavior of aerosols. In an acoustic field, particles coagulate mainly by the following three mechanisms: orthokinetic coagulation due to relative oscillating motion, coagulation due to hydrodynamic attractive force between particles, and turbulent coagulation due to acoustically induced turbulence in a highly intensive acoustic field. The basic theory for the Brownian coagulation of hydrophobic spherical colloids was constructed by Smoluchowski, solving the diffusion equation of colliding particles in the medium. The basic theory for the rapid coagulation rate in a turbulent flow was constructed by P. G. Saffman and J. S. Turner. Particles in flow fields collide with each other because of their velocity difference.
