In-depth validation of unresolved CFD-DEM simulations of liquid fluidized beds

In this work, we assess the accuracy of the unresolved CFD-DEM method by confronting simulated and experimental results of a pilot-scale cylindrical liquid-solid fluidized bed. We used two types of particles with significantly different densities (1029 and 3586 kg m-3), allowing for testing a wide range of flow regimes. Comparisons between experimental and simulated particles' dynamics show that the Saffman lift force is essential in predicting the physical dispersion of particles, preventing unphysical plumes. Simulations precisely reproduced the overall force balance in the system. The bed expansion as a function of the inlet velocity results show excellent agreement between simulations and experiments. High agreement between experiments and simulations is observed for the drag models proposed by Di Felice, Rong, and Beetstra but not for Gidaspow. The results validate the use of unresolved CFD-DEM to simulate the liquid-solid fluidized bed.