Regensburg 2022 – wissenschaftliches Programm
DY 11.5: Vortrag
Montag, 5. September 2022, 16:30–16:45, H19
The role of the particle aspect ratio in the discharge of a narrow silo — •Bo Fan2,4, Tivadar Pongó1,2, Dariel Hernández-Delfin1,5, János Török3, Ralf Stannarius6, Raúl Cruz-Hidalgo1, and Tamás Börzsönyi2 — 1Universidad de Navarra, Pamplona, Spain — 2Wigner Research Centre for Physics, Budapest, Hungary — 3Budapest University of Technology and Economics, Budapest, Hungary — 4Wageningen University, Wageningen, The Netherlands — 5Basque Center for Applied Mathematics, Bilbao, Spain — 6Otto von Guericke University, Magdeburg, Germany
The time evolution of silo discharge is investigated for different granular materials made of spherical or elongated grains in laboratory experiments and with discrete element model (DEM) calculations. For spherical grains, we confirm the widely known typical behavior with constant discharge rate (except for initial and final transients). For elongated particles with aspect ratios between 2 < L/d < 6.1, we find a peculiar flow rate increase for larger orifices, especially in the last third of the discharge process. While the flow field is practically homogeneous for spherical grains, it has strong gradients for elongated particles with a fast-flowing region in the middle of the silo surrounded by a stagnant zone. For large enough orifice sizes, the flow rate increase is connected to a gradual change in the character of the flow field, including a shrinkage of the stagnant zone and an increase in both the packing fraction and flow velocity near the silo outlet.