Abstract
Various simulations have been conducted to understand the macroscopic behavior of particles in the solid-gas flow in rotating drums in the past. In these studies, the no-slip wall boundary condition and fixed restitution coefficient between particles were usually adopted. The paper presents a numerical study of the gas-solid flow in a rotating drum to understand the effect of the specularity coefficient and restitution coefficient on the hydrodynamic behavior of particles in the segregation process. The volume fraction, granular pressure, granular temperature and their relationships are examined in detail. The boundary conditions of the no-slip and specularity coefficient of 1 are compared. In the simulations, two different sizes of particles with the same density are considered and the Eulerian–Eulerian multiphase model and the kinetic theory of granular flow (KTGF) are used. The results reveal that the hydrodynamical behavior of the particles in the rotating drum is affected by the boundary condition and restitution coefficient. In particular, the increase of specularity coefficient can increase the active region depth, angle repose, granular pressure for both small and large particles and granular temperature for large particles. With increasing restitution coefficient, the angle of repose decreases and granular pressure and temperature increase at the same volume fraction for both small and large particles.
Highlights
Understanding the dynamical behaviour of particles in rotating drums has attracted numerous research efforts over the past few decades due to their extensive applications in process industries [1,2,3]
Specularity coefficient was defined by Johnson and Jackson [10] for the wall boundary condition, i.e., the relative velocity between particles and wall, which is known as slip velocity
Many researchers have conducted simulations to investigate the hydrodynamics of particles in rotating drums, especially by using computational fluid dynamics (CFD) [2,14,15,16]
Summary
Understanding the dynamical behaviour of particles in rotating drums has attracted numerous research efforts over the past few decades due to their extensive applications in process industries [1,2,3]. Many researchers have conducted simulations to investigate the hydrodynamics of particles in rotating drums, especially by using computational fluid dynamics (CFD) [2,14,15,16] In these studies, the noslip wall boundary condition was normally adopted. Very little investigation has been conducted to understand the difference in particle behaviour between the no-slip and specularity coefficient boundary conditions for a binary particle segregation in rotating drums. Taghizadeh [19] conducted numerical simulation by using the CFD to explore the effect of restitution coefficient on granular temperature by considering single sized particles This does not give a clear picture on how the restitution coefficient can impact the granular temperature in the segregation process where the sizes of the particles are different. The effects of the restitution coefficient on the granular pressure and granular temperature are investigated
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
