EMMS-based modeling of gas-solid generalized fluidization: Towards a unified phase diagram

Hydrodynamic features of gas-solid generalized fluidization can be well expressed in the form of phase diagrams, which are important for engineering design. Mesoscale structure presents almost universally in generalized fluidization and should be considered in such phase diagrams. However, current phase diagrams were mainly proposed for cocurrent upward flow according to experimental data or empirical correlations with homogeneous assumption. The energy-minimization multiscale (EMMS) model has shown the capability of capturing meso-scale structure in generalized fluidization, so EMMS-based phase diagrams of generalized fluidization were proposed in this article, which describe more reasonable global hydrodynamics over all regimes including the important engineering phenomena of choking and flooding. These characteristics were also found in discrete particle simulation under various conditions. For wider range of application, the typical hydrodynamic parameters of the phase diagrams were correlated to non-dimensional numbers reflecting the effects of material properties and operation conditions. This study thus shows a possible route to develop a unified phase diagram in the future. (C) 2020 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights reserved