Simulation of Particle-Laden Pipe Flows with a Homogeneous Stationary Sediment Bed

The characteristics of particle-laden turbulent pipe flows with stationary variable homogeneous bed heights are studied using large eddy simulation coupled to discrete particle simulation, and compared to a reference full pipe flow. Homogeneous stationary sediment beds of various heights are investigated to mimic geometries with the presence of deposited particles that have formed a bed at the bottom of the pipe which are relevant to nuclear waste processing operations. The flat boundary formed by the bed is found to induce different degrees of secondary flows and modifications to the fluid turbulence statistics and particle dynamics. The results obtained are of direct relevance to the behaviour of the two-phase flows encountered during nuclear waste processing, and have implications for particle dispersion, agglomeration, deposition and bed formation, as well as particle re-suspension from beds, in pipe flows transporting such waste.