This paper has established an axial meso-scale model based on the Energy-Minimization Multiscale (EMMS) principle for the gas-liquid-solid circulating fluidized bed. Comparisons made with the experimental data show that the established model is able to predict the axial hydrodynamics of the system under study. Model studies demonstrate that the dynamic formation and decomposition of the particle-clusters can illustrate the mechanism of the axial distribution. For the first time, the model predicts the transition points between the expanding fluidization mode, the circulating fluidization mode, and the liquid transporting mode. The maximum value of the solid particles' acceleration in the particle-cluster phase can be an indicator of a change to the length of the transition section. And the particle-clusters gradually form as the bubbles grow. In the pseudo steady state, the solid particles' acceleration in the liquid-solid suspension phase tends to be -9.8 m/s(2), and that of the bubbles tends to be 0 m/s(2). (C) 2019 Elsevier Ltd. All rights reserved.