Comparison of CFD-DEM and TFM approaches for the simulation of the single- and multiple-spout fluidized bed
Sprache des Vortragstitels:
10th International Conference on Conveying and Handling of Particulate Solids
Sprache des Tagungstitel:
Spout fluidized beds have been employed in various processes, including gasification, chemical looping combustion, and catalytic oxidation. Spout fluidized beds take advantage of both spouted and fluidized beds, enabling them to enhance particle circulation and mixing as well as action in wider operating ranges with less flow rate in comparison with other beds.
In the past decades, two main modelling approaches have been used to analyse spout fluidized beds. On the one hand, the Eulerian-Eulerian approach (e.g. two-fluid model, TFM), where both phases are treated as interpenetrating continua and the particle collisions are considered by the kinetic theory of granular flows (KTGF), is preferably used for larger scales. On the other hand, the Eulerian-Lagrangian approach (e.g. CFD-DEM), where the gas phase is considered as continuous phase and the particles are tracked individually, is commonly used for more detailed descriptions.
In the present study, we compare the predictions of TFM and CFD-DEM with experiments for multiple spout beds. Thereby, we employ OpenFOAM in the case of TFM, where new boundary conditions (Schneiderbauer et al., 2012) and frictional models (Chialvo et al. 2012) have been implemented. In the case of CFD-DEM, the open source framework CFDEMcoupling is used. Computed time averaged velocities show fairly good agreement with PIV and PEPT measurements. Furthermore, bed expansion, time-averaged particle velocity and solids volume fraction profiles are compared in detail. In addition, granular temperature profiles and solids circulation rates were analysed.