Conference Dates

May 22-27, 2016


The mixing of fuel particles is a key issue on the performance of fluidized bed reactors. In this work, the motion of a non-reactive fuel particle in a 2D bubbling fluidized bed at ambient conditions is simulated employing a hybrid-model. The hybrid-model, implemented in the code MFIX, simulates the dense and gas phases using a Two-Fluid Model (TFM) while the fuel particles are modeled using a Discrete Element Method (DEM). The importance of the present hybrid-model is that the interaction of the continuum phases with the fuel particles behavior is fully coupled.

In a previous study, Hernández-Jiménez et al. (1) compared the fuel particles motion obtained from the simulation with experimental results measured in a cold 2D fluidized bed by Soria-Verdugo et al. (2, 3). The simulation results related to the location of the fuel particle in the bed were similar to the experimental data (Figure-1). Nevertheless, some discrepancies were found in important parameters such as the circulation time of the fuel particles. These discrepancies were associated to the overprediction of the simulated solids velocity.

In the present work, in order to improve the accuracy of the simulated fuel particle motion in a bubbling fluidized bed, a friction term accounting for the effect of the walls of the bed on the continuum solid phase is introduced in the hybrid-model, as proposed by Hernández-Jiménez et al. (4). According to the results, prediction of the fuel circulation time is clearly improved when the friction term is included in the simulation (Figure-2).


  1. Hernández-Jiménez F. , Garcia-Gutierrez L.M., Soria-Verdugo A., Acosta-Iborra A. 2015. Fully coupled TFM-DEM simulations to study the motion of fuel particles in a fluidized bed, Chem. Eng. Sci.,134, 29, 57-66.
  2. Soria-Verdugo, A., Garcia-Gutierrez, L.M., Sánchez-Delgado, S., Ruiz-Rivas,U., 2011a. Circulation of an object immersed in a bubbling fluidized bed. Chem. Eng. Sci. 66, 78–87.
  3. Soria-Verdugo, A., Garcia-Gutierrez, L.M., García-Hernando, N., Ruiz-Rivas, U., 2011b. Buoyancy effects on objects moving in a bubbling fluidized bed. Chem. Eng. Sci.66, 2833–2841.
  4. Hernández-Jiménez, F., Cano-Pleite, E., Sánchez-Prieto, J., Garcia-Gutierrez, L.M., Acosta-Iborra, A. Development of an empirical wall-friction model for 2D simulations of pseudo-2D fluidized beds. Submitted for publication.

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