Contact Mechanisms in Ultrasound-Agitated Particulate Systems

Abstract

Proper modelling of the particle-particle contact and adhesion mechanisms of particulate systems is essential for the simulation of particle processes, e.g. for the development of plant components and adjustment of process conditions during production, handling and conditioning of finest solid powders. The subject of the project is the derivation of the dynamic particle-particle interactions with time-dependent, vibration-induced particle contacts in acoustic, ultrasound-excited particulate systems. The mechanism-based representation of the particle-particle-interactions in (ultra-)sound-excited (i.e. vibration-induced on the gas side) dispersed systems and the modelling and simulation of processes with dispersed phases is performed. The particulate contact and binding mechanisms and their dynamic behavior are derived for different primary particles and aggregate structures at defined process conditions. In addition to applying suitable acoustic parameters (frequency, intensity, …), in particular the ambient conditions (air humidity) need to be specifically adjusted in order to describe the contact behavior and conditions parametrically. Experimental investigations on acoustically-excited particle systems have been carried out in comparison to direct numerical simulations of the fluid and particle behavior in agitated flow fields and are evaluated quantitatively.