A four-quadrant flow regime map for two-phase liquid-solids and gas-solids fluidization systems

Previous flow regime mapping work in both gas-solids (GS) and liquid-solids (LS) fluidization systems were carefully reviewed. A set of complete four-quadrant flow regime maps that unifies all the operating modes in both the GS and LS fluidization systems was proposed. The flow directions of the fluid and particle velocities were used as the abscissa and ordinate of the proposed four-quadrant regime map. All the fluidization systems then can be divided into four groups: cocurrent upward (Quadrant I) and downward (Quadrant III), countercurrent fluid-down and solids-up (Quadrant II) and fluid-up and solids-down (Quadrant IV) in the regime map. The relative density between the particle and fluid was also selected as a parameter to differentiate operations of GS downer and LS inverse fluidized bed in Quadrant III. The transitions to and the limits of the flow regimes were discussed in detail. Some new flow regimes such as the GS circulating turbulent fluidization and the LS conventional circulating fluidization regimes were also outlined in the proposed regime map. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

Previous research on flow regime mapping in gas-solids and liquid-solids fluidization systems were reviewed. A comprehensive four-quadrant flow regime map was proposed to unify all operating modes in the systems. Different flow directions of fluid and particle velocities were used as coordinates in the map to divide the systems into four groups and discuss transitions and limits of flow regimes. New flow regimes such as GS circulating turbulent fluidization and LS conventional circulating fluidization were also outlined in the map.