An open-source coupled Computational Fluid Dynamics (CFD) – Discrete Element Method (DEM), CFDEM, is employed to study flow through a fixed particle bed. The simulation is repeated for a range of computational cell sizes, and the solution trend is analyzed. A grid-refinement study procedure, standard for publication of CFD simulation results, is applied to the CFDEM simulations. The results are analyzed, with emphasis on the frequency of convergence and a comparison of the expected numerical error and extrapolated-solution error, termed the ‘offset’ method.
Methods of analysis for numerical modeling parameters, as well as uniform reporting procedures, have not been established for granular-flow simulations. This has led to modeling errors and incorrect results that have hampered fluidization research. The present work shows that the standard grid-refinement study is applicable to granular-fluid flows, and produces results that are useful for common modeling choices such as drag correlation and determination of optimal computational cell size. Additional analysis procedures developed in this study, and based on the grid-refinement results, are shown to give good estimates of the resulting solution error.
