84
C. Neugebauer et al.
3.5.1 Experimental Validation
Validation was performed with respect to the two-dimensional experimental fluidized
bed, to adopt the setup for the numerical simulation without any assumptions or
simplifications. In fact, the process conditions as well as the experimental setup and
geometrical data were to be adopted for the simulation. Figure 4c shows the CAD
geometry of the used setup for the numerical study. For the simulation the size of the
particles was fixed to 1.8 mm.
The coupled CFD-DEM simulation was performed for 6 s for the over-flow configuration (see Fig. 4c) in order to compare the results regarding the particle transport
between the individual chambers of the two-staged fluidized bed and validate the
simulation by the PTV experiments. The experiments have been evaluated for 5 s of
the recorded high-speed videos, while the simulations have been also evaluated for
5 s after the first second of initialization.
The snapshots in Fig. 8 show that the particle transport behavior in both, the experiment and the simulation is randomly changing from left to right and the opposite
direction. The simulation and the experiment show a good agreement regarding the
flow pattern of the particles within the two compartments and also the transport
behavior of the particles. The quantitative exchange rate in the simulation was determined on the basis of particles crossing from one to the other chamber between two
time steps (0.005 s). Similar to the PTV experiments, the horizontal trajectory of
every particle that crossed the weir defined whether the particle is in the first chamFig. 8 Snapshots of the particle positions obtained from the experiments and the corresponding
simulation at a gas inlet flow of 60 kg/h for the validation setup [42]
C. Neugebauer et al.
3.5.1 Experimental Validation
Validation was performed with respect to the two-dimensional experimental fluidized
bed, to adopt the setup for the numerical simulation without any assumptions or
simplifications. In fact, the process conditions as well as the experimental setup and
geometrical data were to be adopted for the simulation. Figure 4c shows the CAD
geometry of the used setup for the numerical study. For the simulation the size of the
particles was fixed to 1.8 mm.
The coupled CFD-DEM simulation was performed for 6 s for the over-flow configuration (see Fig. 4c) in order to compare the results regarding the particle transport
between the individual chambers of the two-staged fluidized bed and validate the
simulation by the PTV experiments. The experiments have been evaluated for 5 s of
the recorded high-speed videos, while the simulations have been also evaluated for
5 s after the first second of initialization.
The snapshots in Fig. 8 show that the particle transport behavior in both, the experiment and the simulation is randomly changing from left to right and the opposite
direction. The simulation and the experiment show a good agreement regarding the
flow pattern of the particles within the two compartments and also the transport
behavior of the particles. The quantitative exchange rate in the simulation was determined on the basis of particles crossing from one to the other chamber between two
time steps (0.005 s). Similar to the PTV experiments, the horizontal trajectory of
every particle that crossed the weir defined whether the particle is in the first chamFig. 8 Snapshots of the particle positions obtained from the experiments and the corresponding
simulation at a gas inlet flow of 60 kg/h for the validation setup [42]