Computational dynamics modeling of gas–solid flow behaviors in a spouted bed by Coupled Eulerian-Eulerian-Lagrangian method

Abstract

Optimizing gas-particle flow conditions is the key to improve heat and mass transfer capacity of multiphase systems. The Eulerian and Lagrangian approaches represent two standard numerical frameworks for characterizing gas–solid two-phase flows. Comparing and optimizing the similarities and differences between them is of great significance for guiding numerical modeling, revealing and predicting the intrinsic behavior of gas–solid two-phase flow. In this study, a self-developed Coupled Eulerian-Eulerian-Lagrangian (CEEL) method is employed to investigate the flow process of a fluidized bed. The particles are treated as Euler solid phase (ESP) and Lagrangian discrete particles (LDP) respectively to facilitate the comparison of the Eulerian and Lagrangian methods under real-time conditions and the same gas phase conditions. Solid-phase velocity and granular temperature are predicted by the two methods, and the diffusion characteristics of particles are quantified through their trajectory. The results show that there is little difference in the time-averaged axial velocity of the ESP and LDP, which is basically consistent with the experimental results. The instantaneous velocities of ESP and LDP are almost the same except in confined spaces, while the difference in granular temperature between the two is more significant in low concentration regions.