A new approach to specify the inlet boundary conditions for computational fluid dynamics (CFD) modeling of hydrodynamic behavior of a circulating fluidized bed (CFB) riser

A new approach to specify the inlet boundary conditions that considering the inlet air jet effect was proposed in this study to simulate gas-solid two-phase flows in circulating fluidized bed (CFB) risers more accurately. A computational fluid dynamics (CFD) model based on Eulerian-Eulerian approach coupled with kinetic theory of granular flow was adopted to simulate the flow using the proposed inlet boundary conditions. Simulation results were compared with experimental data. Good agreement between the numerical results and experimental data was observed under different operating conditions, which indicates the effectiveness and accuracy of the CFD model with the proposed inlet boundary conditions. The results show that the proposed inlet boundary conditions are not only physically more realistic but also result in more-accurate simulation results than commonly used inlet boundary conditions. Both experimental and numerical results illustrate a clear core annulus structure in the CFB riser under all operating conditions.