Videos of liquid-solid fluidisation experiments of calcite pellets and glass beads in water

Abstract

20 videos of liquid-solid fluidisation experiments in a university laboratory. You see a 5.7 cm PVC column where tap water is pumped in an upward direction causing particles to elevate into a fluidised state. Particles are calcite grains obtained from a full-scale drinking water softening reactor or perfectly round monodispersed glass beads. The reason to show these videos is to demonstrate that homogeneous flow regime not always occurs whilst this is often assumed regarding liquid-solid fluidisation systems. The viewer can observe open voids of water between the particles and water which choose a path of least resistance through the particle bed. Besides laminar-turbulent regime also homogeneous-heterogeneous distinction is relevant. These observations brought us to revise the standard drag relations used to predict the bed porosity