Numerical simulation of mechanofusion system for dry particle coating process

A numerical simulation of the Mechanofusion device for dry particle coating is carried out using Discrete Element Method (DEM) technique. In dry particle coating, tiny sub-micron guest particles are coated onto larger micron sized host particles by using mechanical forces, which the Mechanofusion device provides. The simulation studies are performed on two scales: system scale to investigate the particle-particle and particle-system interactions, and micro scale to study the degradation of agglomerates prior to the dry particle coating process.; The system-scale simulation is based on a mono-dispersed system (only includes host particles) in two-dimensional configuration. The visualization of the particulate patterns inside the system and the diagnostic analysis derived from the numerical simulations clearly demonstrate the effect of scraper on the system. The calculated forces acting on the inner piece qualitatively agree with the experimental results. Average forces on particles are calculated and categorized into four regions. The effect of particle properties on coating level is examined through a simple deformation analysis.; Another important contribution of the dissertation lies in the dimensional analysis of the Mechanofusion system carried out on the basis of kinetic theory under the assumption of collisional flow, verified qualitatively by simulations. An equation for average force on particles inside the system is derived to establish the correlation between a simulated system and a real system.; Based on the results from system simulation, the fragmentation of an agglomerate during normal interactions with host particle and with wall is examined in detail by the micro-scale simulation. The numerical study is implemented using a DEM code in two-dimensional mode, which enables the simulation of auto-adhesive particles. The study shows that single agglomerate may fracture or even shatter inside the system as a result of interactions with the host particles and system boundaries.; In summary, the work presented in this dissertation, which is one of the first reported work on DEM simulation of dry particle coating system, shows that DEM technique can be used to model important aspects of the Mechanofusion system, such as the overall system performance as well as the agglomerate fragmentation prior to the dry particle coating process.