Experimental Analysis of Suspension Flows Over and Through Various Porous Media Models

Porous media and suspension flows have been the subject of multiple scientific investigations, independently. The previous literature involving porous media has for the most part examined the nature of pure Newtonian fluids as they flow over and thorough various porous media models. Suspension flow experiments are typically conducted within geometries exhibiting solid, impermeable boundaries. Because of this disparity there is little information discussing the nature of a suspension flow moving over a porous media. This study used optical experimental techniques to investigate the velocity and particle solid volume fraction distributions of a dilute suspension containing non-Brownian, non-colloidal, rigid, spherical particles as it flows through a channel partially obstructed with a porous media along the bottom boundary. Different parameters of this configuration are altered to examine how they each affect the overall flow structure as well as parameters at the interfacial region between the porous media and the free flow region. The first study focused on the suspension particle solid volume fraction (1%, 3%, and 5%) while keeping the porous media constant. Particle image velocimetry (PIV) was used to extract velocity information from the flow. The velocity profiles showed that there was some impact on the local velocity within the porous media due to an interaction of the porous media and the suspension particles. The second study examined the characteristics of the porous media while keeping the particle solid volume fraction at 3% to isolate how the flow is affected due to these properties. Specifically, the porous media thickness and permeability were altered. This data showed that both parameters shifted the location of the maximum velocity within the free flow region, which also changes the properties at the interface. A different experimental technique was developed using optical tracking flow velocimetry (OTFV) to visualize the flow particle solid volume fraction. This data showed the distribution of the suspension particles and how their distribution and velocity were changed with an increase in particle solid volume fraction. The final group of experiments utilized a ~183cm-long flow channel to examine very dilute suspensions and how their particles are distributed over the porous media along two different flow planes.