Experimental and numerical study of fluidization and pressure drop of spherical and non-spherical particles in a model scale fluidized bed

• The DEM–CFD is used to investigate the fluidization of arbitrary shaped particles.
• Pressure drop, particle height and orientation distributions are obtained.
• Based on a PTV-approach, numerical results are validated against experiments.
• Results obtained are in good agreement for most particle shapes.

A laboratory scale fluidized bed was examined experimentally and numerically involving differently sized wooden Geldart-D particle shapes. Simulations were performed with a coupled DEM–CFD approach, which involves a drag force model that realizes for the particle shape and orientation. To validate the drag force model and to learn more about the fluidization behavior of non-spherical particles the pressure drop, particle height and orientation distributions were analyzed. To gain comparable data from the experiments, a PTV-MATLAB script was developed to detect particles and determine their orientations and heights. Experimental and numerical results are in good agreement for most particle types; differences in the pressure drop can be allocated to mismatching particle heights or orientations. Differences in the particle height distribution are a result of particles that stack up in corners or close to the vessel walls. It was found that despite these local deviations the DEM–CFD can accurately reproduce the orientation behavior of elongated particles, which with increasing velocity align themselves with the flow. For elongated particles below a certain elongation ratio this behavior could not be observed, which was confirmed by both experiments and simulations.

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