Particle Dispersion, Agglomeration and Deposition in Fully-Coupled Turbulent Channel Flow using Large Eddy Simulation and Discrete Element Method

The incentive for this research is to gain insight into fundamental aspects of turbulent fluid-particle flows. The project investigates the influence of inter-particle collisions on the particle and fluid phase variables in the context of particle agglomeration, dispersion and deposition for turbulent bounded flows laden with low particle numbers. The mathematical modelling technique used is large eddy simulation (LES), with flow solutions provided by this method coupled to a discrete element method (DEM) to predict particle motion and interaction. The results have been compared with single-phase bounded flows in order to investigate the effect of the particles on turbulence statistics. The four-way coupled simulations are also contrasted with one-way coupled (flow affects the particles only) results in which the inelastic collisions between particles are neglected.
The influence of different particle surface energies, particle size, particle density, particle concentration and flow Reynolds numbers on particle agglomeration is investigated. The turbulent structure of the flow is found to dominate the motion of the particles, although the agglomeration rate is found to be strongly influenced by all of the variables noted above, with most of the particle-particle interactions taking place at locations close to the channel walls, aided by the higher turbulence levels and concentration of particles in these regions.
The research proposed makes an original contribution to the literature in applying advanced predictive techniques which have not been coupled and applied to the problem of cohesive particle-interaction effects in turbulent flows before. It yields a fundamental understanding of how particles interact, and how these interactions result in the formation of agglomerates which affect the dispersion and deposition of particles within the flow. The overall results are relevant, and underpinning, to processes employed in a wide range of applications in the industrial and health sectors.