The Eulerian-Eulerian framework was used in the numerical simulation of liquid hydrodynamics and particle motion in liquid-fluidized beds. The kinetic theory of granular flow, which accounts for the viscous drag influ...The Eulerian-Eulerian framework was used in the numerical simulation of liquid hydrodynamics and particle motion in liquid-fluidized beds. The kinetic theory of granular flow, which accounts for the viscous drag influence on the interstitial liquid phase, was used in combination with two-fluid models to simulate unsteady liquid-solid two-phase flows. We focus on local unsteady features predicted by the numerical models. The solid fraction power spectrum was analyzed. A typical flow pattern, such as core annular flow and particle back-mixing near the wall region of liquid-solid fluidized beds is obtained from this calculation. Effects of the restitution coefficient of particle-particle collisions on the distribution of granular pressure and temperature are discussed. Good agreement was achieved between the simulated results and experimental findings.展开更多
We present experimental investigations and numerical simulations of a pseudo-2D riser. Experiments were performed for various airflow rates, particle types/diameters, and particle size distributions. Pres- sure distri...We present experimental investigations and numerical simulations of a pseudo-2D riser. Experiments were performed for various airflow rates, particle types/diameters, and particle size distributions. Pres- sure distributions along the wall of the riser were measured, Additional measurements from a smaller pseudo-2D riser （Kallio et al., 2009; Shah et al., 2012） were used to analyze horizontal solids volume fraction profiles. The experimental data were compared with simulation results carried out using an Euler-Euler approach, A mesh sensitivity study was conducted for numerical simulations and effects associated with simplifying real 3D geometry to a 2D model were examined. In addition, the effect of using an algebraic equation to represent the granular temperature versus a full partial differential equation also was examined for numerical simulations. Results showed small but significant near-wall sensitivity of the flow variables to mesh size. Substantial differences in mean pressure, solids distribution, and solid velocities were obtained, when 2D and 3D simulation results were compared. Finally, applying the simplified granular temperature equation for turbulent fluidization and for dilute-phase transport can lead to incorrect predictions in models,展开更多
文摘The Eulerian-Eulerian framework was used in the numerical simulation of liquid hydrodynamics and particle motion in liquid-fluidized beds. The kinetic theory of granular flow, which accounts for the viscous drag influence on the interstitial liquid phase, was used in combination with two-fluid models to simulate unsteady liquid-solid two-phase flows. We focus on local unsteady features predicted by the numerical models. The solid fraction power spectrum was analyzed. A typical flow pattern, such as core annular flow and particle back-mixing near the wall region of liquid-solid fluidized beds is obtained from this calculation. Effects of the restitution coefficient of particle-particle collisions on the distribution of granular pressure and temperature are discussed. Good agreement was achieved between the simulated results and experimental findings.
文摘We present experimental investigations and numerical simulations of a pseudo-2D riser. Experiments were performed for various airflow rates, particle types/diameters, and particle size distributions. Pres- sure distributions along the wall of the riser were measured, Additional measurements from a smaller pseudo-2D riser （Kallio et al., 2009; Shah et al., 2012） were used to analyze horizontal solids volume fraction profiles. The experimental data were compared with simulation results carried out using an Euler-Euler approach, A mesh sensitivity study was conducted for numerical simulations and effects associated with simplifying real 3D geometry to a 2D model were examined. In addition, the effect of using an algebraic equation to represent the granular temperature versus a full partial differential equation also was examined for numerical simulations. Results showed small but significant near-wall sensitivity of the flow variables to mesh size. Substantial differences in mean pressure, solids distribution, and solid velocities were obtained, when 2D and 3D simulation results were compared. Finally, applying the simplified granular temperature equation for turbulent fluidization and for dilute-phase transport can lead to incorrect predictions in models,
