Particle dispersion in turbulent sedimentary duct flows

A simplified geometric model of a circular tube with a sedimentary layer is proposed and named as sedimentary duct. Based on h = 1/4d (h is the thickness of sedimentary layer and d is the pipe diameter), the flow field (Re = 40000) and particle distribution (5, 10, 50 mu m and St = 0.6, 2.5, 63) in the sedimentary duct are simulated using Large Eddy Simulation (LES) coupled with Lagrange Particle Tracking (LPT) method. As a result, four streamwise eddies are found in the sedimentary duct as distributed in pairs near the corner. The eddy center near ceiling is found to be farther from the corner than that from the floor. Small particles (5 mu m, St = 0.6) tend to move with the secondary flow as their upward movements distribute in both sides. Their centripetal movement is near the floor and preferential distribution near the top. For large particles (50 mu m, St = 63), it is the drag force that dominates their motion while for medium particles (10 mu m, St = 2.5) lift force may have significant influence on their motion. This study is the first work to investigate the characteristics of particle behavior in turbulent sedimentary duct flows. (C) 2021 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.

Automated summary

This study investigates the characteristics of particle behavior in turbulent sedimentary duct flows, revealing that particles of different sizes are influenced by different factors in the flow field, providing important insights for further research.