A Meso-Scale Flow Model of Gas-Liquid-Solid Fluidized Beds with Acceleration Items

Mechanism modeling is an important method to quantify the flow heterogeneous phenomena of gas-liquid-solid fluidization systems. In this study, a meso-scale flow model with bubble and solid particle acceleration items was developed based on the energy minimum multi-scale theory (EMMS) to predict the global flow parameters of gas-liquid-solid fluidized beds. The consideration of acceleration item makes the model be capable of accurately predicting both the nominal-steady and the unsteady hydrodynamics of the gas-liquid-solid fluidization. Compared with the previously reported EMMS models of gas-liquid-solid fluidization in the literature, the prediction results of this new meso-scale flow model are closer to the experiment data. Furthermore, the predictions indicate that both bubble acceleration and particle acceleration have an influence on the flow behavior of gas-liquid-solid fluidized bed, such as bubble diameter and relative slip velocity, which seriously affect the momentum and mass transfer between phases. In addition, the acceleration behaviors of the unsteady-state give a reasonable explanation for bubble coalescence.