Numerical investigation of binary particle mixing in gas-solid fluidized bed with a bubble-based drag EMMS model

Heterogeneous flow structure of bubbling deeply affects gas–solid momentum transfer in a binary gas–solid fluidized bed. This work presented a binary particle bubble-based Energy Minimum Multi-scale (EMMS) model, and an assumption that bubble-emulation drag force acting on solid 1 and solid 2 depending on each solid volume ratio in the emulation phase was applied to simplify the force balance of the binary particle-phase. The bubble-based EMMS drag was incorporated in the Eulerian multi-fluid model to predict the mixing behaviors of two binary particle systems. The simulation results agree well with the experimental observations in terms of binary solid mixing, bed expansion, and bubble diameter. Compared with the prediction results by the Gidaspow drag model, the jetsam solid fraction and bubble size predicted by the present drag model is in more agreement with the measured results, which indicate the EMMS drag model is an alternative choice for modeling binary gas–solid bubbling system.