(24h) Situating the High-Density Circulating Fluidized BED with the EMMS MODEL

The dense suspension upflow (DSU) regime is characterized with high suspension densities, high solids flux and no downward flux near the wall. It was defined to explain the different flow behavior in high-density circulating fluidized bed (CFB) from those in fast fluidization and pneumatic conveying. Experimental correlations have been proposed in literature to define the boundary of this regime but we are still far from clear understanding of the underlying mechanisms. In this work, we will apply the energy-minimization multi-scale (EMMS) model to predict the flow regime transitions, in particular, the DSU regime and the choking transition in CFBs. Comparison between model prediction and available experimental data is provided.