Evaluation of drag correlations using particle resolved simulations of spheres and ellipsoids in assembly

Particle-resolved simulations are performed to study the momentum transfer in flow though fixed random assembly of non-spherical particles. Ellipsoidal particles with sphericity (p=0.887) are investigated in a periodic cubic domain to simulate an infinite assembly. The incompressible Navier-Stokes equations are solved using the Immersed Boundary Method (IBM). Pressure and viscous force on each particle are calculated based on the resolved flow field. Flow through an assembly of spherical particles is tested, and predicted drag forces are compared with previous particle resolved simulation results to validate the current framework. The assembly of ellipsoidal particles is simulated for solid fraction between 0.1 and 0.35 using 191 to 669 particles, respectively, at low to moderate Reynolds numbers (10 <= Re <= 200). The simulation results show that the drag force of ellipsoidal particles is 15% to 35% larger than equal volume spherical particles. Widely used drag force correlations are evaluated based on the current simulation results. The comparisons show that for ellipsoidal particles over the range of parameters investigated in the present study, the combination of Tenneti et al.'s correlation with Holzer's single non-spherical particle drag model has the best performance with an average difference of 7.15%. (C) 2017 Elsevier B.V. All rights reserved.