Development of drag correlation for suspensions of ellipsoidal particles

Abstract

To model drag the current state-of-the-art is to use isolated non-spherical particle drag correlations modified by a solid fraction correlation that is based on experimental or simulation results of spherical particle suspensions. It is shown that this practice can lead to substantial inaccuracies when the particle geometry deviates significantly from a spherical geometry. In this paper particle resolved simulations (PRS) are conducted for ellipsoids of aspect ratio 5 (AR5) and 10 (AR10) in random suspensions with no preferential orientation. Simulations are performed for a Reynolds number Re = 10 to 200, and solid fraction φ = 0.1 to 0.3 and 0.1 to 0.2 for AR5 and AR10 suspensions, respectively. Combined with PRS data from past studies for spherical particle suspensions and ellipsoids with AR2.5, a drag correlation is developed for the mean drag force in suspension as a function of Re, φ , aspect ratio, and inclination angle θ.