| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 237476 | Powder Technology | 2011 | 11 Pages |
The flow multiplicity phenomenon in circulating fluidized bed (CFB) risers, i.e. under the same superficial gas velocity and solids circulation rate, the CFB risers may sometimes exhibit multiple flow structures, was numerically and experimentally investigated in this study. To investigate the flow multiplicity phenomenon, the experiments of gas–solids two-phase flows in a 2-D CFB riser with different flow profiles at the inlet of the CFB riser were conducted. Specially designed gas inlet distributors with add-ons are used to generate different flow profiles at the inlet of the CFB rise. The CFD model using Eulerian–Eulerian approach with k–ε turbulence model for each phase was employed to numerically analyze the flow multiplicity phenomenon. It is experimentally and numerically proved that for gas–solids two-phase flows, the flow profiles in the fully-developed region are dominated by the flow profiles at the inlet. The solids concentration profile is closely coupled with the velocity profile, and the inlet solids concentration and velocity profiles can largely influence the fully-developed solids concentration and velocity profiles.
Graphical abstractIn this study, it is experimentally and numerically proved that for gas–solids two-phase flows, the flow profiles in the fully-developed region are dominated by the flow profiles at the inlet. Fig. A gives different gas distributors used in this study and Fig. B shows the comparison of the experimental and numerical results of the fully-developed lateral profile of axial solids velocity in the CFB riser using different gas distributors.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► For gas–solids two-phase flows, the flow profiles in the fully-developed region are dominated by the flow profiles at the inlet. ► The solids concentration profile is closely coupled with the velocity profile. ► The inlet solids concentration and velocity profiles can largely influence the fully-developed solids concentration and velocity profiles.
