Online

Storm, Randall

Mechanical Engineering

2023

M.S.

Colloidal particle transport in porous media is observed in several natural and engineered systems and has relevant applications such as enhanced oil recovery operations, targeted drug delivery treatment, and groundwater filtration processes within soil. This thesis presents a pore-scale numerical study of particle transport through a porous bed of fixed spheres arranged in a body-centered cubic (BCC) structure. The fluid flow field through the porous bed was calculated using a combined immersed boundary-lattice Boltzmann method. Individual particle trajectories were determined using the soft-sphere discrete-element method. The effects of particle size, fluid flow rate, and adhesion strength were investigated to illustrate the primary mechanisms influencing particle migration. The BCC pore structure created paths where the fluid flowed preferentially, resembling sinusoidal corrugated channels. The fluid straining field through these channels caused inertial drift of the particles towards the channel centers via a phenomenon related to oscillatory clustering. A measure was introduced to quantify particle drift into these channels over time and was shown to compare well with theoretical models for oscillatory clustering with non-adhesive particles. In the absence of adhesive forces, larger particles and higher flow rates resulted in greater particle clustering. Long-term collisions and particle capture by fixed-bed particles were observed to limit the drift measure. Computations performed with adhesive particles showed a significant reduction in the tendency for oscillatory clustering to occur due to suspended particles being more likely to remain attached to fixed bed particles along with longer collision durations.