Experimental and Simulation Studies of Jamming for Model Two/Three-Dimensional Particles Under Flow

The jamming of particles under flow is of critical importance in many natural and industrial settings, such as the jamming of ice in rivers, or of solid hydrate particles in oil and gas pipelines. Such phenomena can depend on many properties, such as particle/boundary friction, concentration of particles upstream of a restriction, particle size, the restriction opening, and flow velocity. To gain insight into the role of these factors in controlling jamming, both experiments and computer simulations on two-dimensional model systems have been studied to characterize the flow of particles in a channel with a restriction. Using the simulation software PFC2DŽ, we studied the effect of restriction geometry, flow velocity and friction on the jamming process of particles. Results from the simulations were compared to experimental measurements on polyethylene discs floating over water flowing in an open channel. Jamming was observed to proceed first by a build-up of particles at the restriction, followed by particles flowing through the restriction. Maximum likelihood and Pearson's test analyses showed the experimental data to be consistent with the probability of jamming being constant and independent for successive particles that pass through a restriction. The probability of jamming in both experiments and simulations was found to be dependent on the channel opening, particle size, and particle friction coefficient, but only weakly dependent on the flow velocity. The functional dependence on the probability of jamming on the channel opening was found to be consistent with that seen in gravity driven flows.