Modelling of acoustic agglomeration processes using the direct simulation Monte Carlo method

Abstract

The direct simulation Monte Carlo (DSMC) method is applied to simulate acoustic agglomeration in travelling sound waves; orthokinetic and hydrodynamic mechanisms are considered as well as Brownian coagulation. The method is based on the constant-volume Monte Carlo approach combined with a modified full-conditioning algorithm of Gillespie, and is proved accurate by simulating only Brownian coagulation. Using the DSMC method, the validities of the classic Mednikov orthokinetic kernel, the König hydrodynamic kernel and the Song's orthokinetic and hydrodynamic models are examined by simulating acoustic agglomeration with only individual kernels. The predictions obtained by applying simple additive combinations of Song's orthokinetic model with the König equation and Song's hydrodynamic model are validated against experimental data in the literature. It has been found that the individual Song's models and the two combinations yield fairly good agreement with the measurements in some experimental cases, but all have limitations in covering a wide range of experimental conditions. This suggests that the present modelling needs further improvement to correctly describe the coupled contributions of two or more mechanisms.